Songbirds and softbills

• Feather picking—rarely self-mutilation; usually by other birds, especially zebra finches. May indicate iron storage disease in toucans

• Lice (canaries)

• Dermatomycosis (Trichophyton spp. and Microsporum spp.)

Scaling and crusting

• Dermatomycosis (Trichophyton spp.

• Hyperkeratosis (canaries)

Nodules and nonhealing wounds

• Feather cysts (especially canaries)

• Intracutaneous keratinizing epithelioma has been described in the mynah bird (Rodriguez et al 2006).

• Papillomavirus—wartlike growths of the skin on the feet and legs of European finches

• Abscessation—typically due to Staphylococci and Streptococci

• Bumblefoot—typically chronic infection and abscessation of the feet, especially the plantar surfaces

• Head and beak lesions in toucans are often the result of intraspecific aggression.

• Constriction of the extremities, especially the toes of canaries and small finches, often due to entanglement with thin foreign bodies such as human hairs

Changes in pigmentation

• Erysipelothrix (see “Skin Disorders in Psittacines")

• Altered feather coloring

• Nutritional

• Hepatic disease

Ectoparasites

• Flies: Hippoboscids (flat flies/louse flies) occasionally encountered, especially with aviary birds. Can transmit hemoparasites such as Haemoproteus and Leukocytozoon, as well as transfer mites and lice, between individuals

• Lice: Can reach significant numbers on debilitated birds; particularly induce baldness in canaries secondary to irritation

• Ticks: Occasionally on new imports. Sudden death associated with tick attachment to head. Suggested etiologies include hypersensitivity reactions, toxin injection, or a tickborne infection. Can also transmit other diseases such as hemoprotozoa, Borrelia spp., and louping ill

• Red mite Dermanyssus avium and other species

• Northern fowl mite Ornithonyssus sylviarum

• Feather mites: Found between the barbs on the ventral surfaces of feathers; often niche specific

• Quill mites such as Syringophilus, Dermoglyphus, and Picobia spp.; found inside quills. Harpirhynchus mites may induce hyperkeratotic epidermal cysts.

• Skin mites

• Knemidocoptid mites; common one encountered is Knemidocoptes pilae

(scaly face/scaly leg)

Dermatitis

• Commensal bacterial numbers on the skin of birds are considered to be lower than those found on mammals.

• Bacterial

• Staphylococci

• Streptococci

• Fungal

• Candida

Burns

Neoplasia

• Neoplastic-like lesions described in masked bullfinch (Pyrrhula erythaca) due to pox virus (Dorrestein et al 1993).

Noncutaneous findings on clinical examination

• Respiratory distress, PCV (tracheitis in canaries)

• Influenza virus A

Bacterial

• Pasteurella multocida

• Staphylococci

• Streptococci

• Salmonellosis

• Klebsiella pneumoniae

• Yersinia pseudotuberculosis (especially toucans and mynahs)

• Aeromonas spp. and Pseudomonas spp.

• Mycobacteriosis

Fungal

• Aspergillosis (especially mynahs)

• Enterococcus faecalis

• Candida

• Mucormycosis

Protozoal

• Toxoplasmosis

• Trichomonas

• Sarcocystis

Parasitic

• Blood-sucking mites (anemia)

• Sternostoma tracheacolum (air sac mites—especially Australian finches)

• Cytodites nudus mites (also in respiratory tract); rare

• Syngamus trachea (especially mynahs and starlings

Nutritional

• Hypovitaminosis A (see Nutritional Disorders)

Neoplasia

• Coelomic neoplasia (e.g., hepatic)

Other noninfectious problems

• Egg coelomitis

• Anemia (see Cardiovascular and Hematologic Disorders)

• Ruptured air sac

Findings on clinical examination

• Dyspnea

• Tachypnea

• Head swinging and neck stretching. Forward-leaning and extended neck strongly suggest tracheal obstruction.

• Coughing is occasionally encountered, but it is uncommon.

• Tail pumping

• Increased recovery time/exercise intolerance

• Increased inspiratory sounds often associated with upper respiratory tract disease

• Increased expiratory sounds often associated with lower respiratory tract disease

• Abdomen may be distended (fluid, neoplasia, hemorrhage).

• Subcutaneous air-filled swelling; may vary in size (ruptured air sac)

• Scabs and pox lesions on eyelids; commissure of mouth and skin; diphtheritic lesions (avian pox)

• CNS signs, iridocyclitis and other ocular signs (toxoplasmosis)

• Loss of voice; abnormal squeaking or wheezing sounds (sternostomosis, aspergillosis)

• Other, nonrespiratory signs

• Regurgitation (trichomoniasis)

• Debilitation and death.

Investigations

1. Transillumination of trachea (air sac mites)

2. Routine hematology and biochemistry

a. Anemia (blood sucking mites, anemia of chronic illness)

3. Serology for Chlamydophila and aspergillosis

4. Radiography

5. Endoscopy

a. Culture of aseptically collected samples

6. Nasal discharge

a. Tracheal wash

b. Cytology of above samples

7. Fecal samples

a. Modified Ziehl-Neelsen staining or PCR for mycobacteriosis

8. Chlamydophila PCR (collect bulk fecal samples over 5 days to identify intermittent excreters)

9. Biopsy

10. Postmortem

a. Pneumonia

b. Hepatomegaly with miliary abscessation; splenomegaly (Yersinia pseudotuberculosis, salmonellosis)

Management

1. Improve hygiene. Aeromonad and pseudomonad air sac infections have been associated with infected sprays or misters.

2. General supportive care

3. Milk thistle (Silybum marianum) is hepatoprotectant. Dose at 4 to 15 mg/kg PO b.i.d. or t.i.d.

TreatmentZspecific therapy

• Avian pox: Supportive care. Avoid access to blood-sucking insects (carriers). May also be spread by contact with infected blood, rarely in contaminated food and drinking water. Vaccination

• Enterococcus faecalis: Appropriate antibiosis. Infected birds may not recover completely.

• Yersiniosis: Appropriate antibiotics. Source of infection is often fecal contamination from wild birds and rodents.

• Salmonellosis: Treatment as for Yersinia; zoonotic potential

• Mycobacteriosis: Significant potential zoonosis, so treatment rarely undertaken

• Aspergillosis (see Lower Respiratory Tract Disorders in Chapter 8)

• Sarcocystis

• Treat with trimethoprim-sulfadiazine (30 mg/kg PO s.i.d.) plus pyrimethamine 0.5 to 1.0 mg/kg PO b.i.d. for 30 days. May need to supplement with folic acid

• The Virginia opossum is the primary host; cockroaches can act as paratenic hosts.

• Syngamus spp.: Indirect life cycle using earthworms, slugs, and snails. Treat with fenbendazole at 50 mg/kg PO as a single dose.

• Sternostoma tracheacolum (air sac mites)

• Ivermectin 0.1% in propylene glycol applied as 1 drop to skin over pectoral musculature or lateral to thoracic inlet

• Ruptured air sac: Puncture air sac aseptically to deflate. Address any underlying issues. Will often heal spontaneously, but risk of recurrence is high

Cardiovascular and hematologic disorders

Viral

• Avian polyomavirus (AVP) (finches)

Bacterial

• Endocarditis

Fungal

• Endocarditis

Protozoal

• Plasmodium spp.

• Haemoproteus spp.

• Leukocytozoon spp.

• Trypanosoma spp.

Parasitic

• Schistosoma spp.

• Blood-sucking mites

Neoplasia

Other noninfectious problems

• Congestive heart failure

• Atherosclerosis

• Endocardiosis

Findings on clinical examination

• Pale mucous membranes (anemia—if severe, may present similar to respiratory disease)

• Exercise intolerance

• Weight loss

• Vague signs of ill health

Investigations

1. Auscultation

a. Abnormal heart sounds

b. Abnormal cardiac rhythms

2. Routine hematology and biochemistry

a. Demonstration of parasites on stained smear

b. Anemia (Plasmodium, blood-sucking mites)

3. Radiography

a. Hepatomegaly

4. Endoscopy

5. Ultrasonography and Doppler ultrasound

6. Electrocardiogram

7. Postmortem

a. Myocarditis along with liver abnormalities (AVP)

b. Splenomegaly (Plasmodium)

c. Lung congestion (Plasmodium)

Management

1. Reduce stress.

2. Remove high perches.

3. Supply oxygen.

TreatmentZspecific therapy

• Plasmodium, Haemoproteus

• Chloroquine at 250 mg/120 mL fresh drinking water, daily for 14 days

• Pyrimethamine 0.5 mg/kg. PO b.i.d or in feed at 100 mg/kg of food. May need to supplement with folic acid.

• Control of vectors: mosquitoes (Plasmodium); hippoboscid flies, biting midges, or tabanids (Haemoproteus)

• Leukocytozoon

• May be asymptomatic but can be fatal with acute hepatitis, renal tubular necrosis, and myocardial hemorrhage

• Chronic cases may present with wasting and vomiting.

• Pyrimethamine 0.5 mg/kg PO b.i.d. or in feed at 100 mg/kg of food may be effective. May need to supplement with folic acid

• Avoid exposure to vectors such as blackflies (Simulium spp.) or Culicoides/hippoboscids.

• Trypanosoma spp.

• Treatment usually not required. Avoid exposure to vectors such as hippoboscid flies, red mites, blackflies (Simulium spp.), and mosquitoes.

• Schistosoma spp.

• Praziquantel at 10 mg/kg PO once only. Repeat after 1 month if necessary.

• Congestive heart failure: Attempt treatment as for other species:

• Furosemide at 0.5 to 2.0 mg/kg IM or SC b.i.d. or 5 mg/100 mL drinking water, fresh daily

• Digoxin 0.02 mg/kg PO s.i.d.

• Aminophylline 4.0 mg/kg PO or IM b.i.d.

Neurological disorders

Viral

• Paramyxovirus

• Adenolike virus infection (canaries)

Bacterial

• Mycobacteriosis

Fungal

• Mucormycosis

Protozoal

• Atoxoplasmosis (Isospora serini) in young canaries 2 to 9 months old

Neoplasia

Other noninfectious problems

• Middle ear disease

• Heavy metal poisoning, especially from zinc in galvanized caging, baths, or drinking receptacles

• Hemochromatosis

• Convulsions similar to epileptic seizures (mynahs)

Findings on clinical examination

• CNS signs such as torticollis and opisthotonos

• Rhythmic nystagmus-like rotations of the head (middle ear disease)

• Collapse

• Depression

• Anorexia

• Weight loss

• Green diarrhea (paramyxovirus)

• Dark spot visible in “abdominal” body wall (hepatomegaly due to a toxoplasmosis)

• Sudden death (paramyxovirus)

Investigations

1. Routine hematology and biochemistry

2. Radiography

3. Postmortem examination

4. Gram stain contents of any lesions

5. Modified Ziehl-Neelsen staining or PCR for mycobacteriosis

6. Histopathology

Management

• Keep in quiet, darkened environment. Fluids may be given per cloaca if there is a risk of aspiration.

TreatmentZspecific therapy

• Zinc/lead poisoning

• Sodium calcium edetate at 20 to 50 mg/kg IM b.i.d. given daily for 7 days, stopped for 7 days, then repeated. This continues until blood levels fall to normal.

• Viral infections

• Supportive treatment only. Give warmth, covering antibiotics, and fluids if necessary.

• Mynahs infected with Newcastle disease excrete virus for 12 to 119 days post infection (Panigrahy & Senne 1991).

• Mycobacteriosis

• Potential zoonosis. Consider euthanasia.

• Two suggested treatment regimens (Rupiper et al 2000) are:

- Ethambutol (200 mg), isoniazid (200 mg), and rifampin (300 mg) all crushed together and mixed with 10 mL of a simple syrup. This is administered by mouth s.i.d. according to Table 9-2.

Fig 10-1. Internal anatomy of a lizard (lateral). (Coelomic fat pads removed for clarity)

bite, however (note: this does not mean that they do not bite) and, in preference, will attempt to fend you off by whipping with their tail.

Restraint involves grasping the animal from behind across the shoulders and across the pelvis, the handler holding the reptile away from the body. If a large lizard, such as an iguana, is especially aggressive, then placing a damp towel over its head is often sufficient to disori­entate it and allow you to gain a hold (N. Highfield, personal communication).

Many lizards, such as Chinese water dragons and young iguanas, can be temporarily immo­bilized by applying digital pressure to both eyes simultaneously. This technique, plus gentle handling, will allow many feisty lizards to be weighed and examined in a controlled fashion,

Lizards

Fig 10-2. Sexing lizards.

before gentle stimulation (such as rerighting the reptile) returns it to a normal state of aware­ness. This may be a manifestation of the oculocardiac reflex.

In those lizards with hypocalcemia/metabolic bone disease, the bones may be so fragile that fractures of the long bones, especially the femurs, can occur if excessive force is applied. A lizard that is presented as flaccid with little or no muscle tone is likely to be hypocalcemic. Other causes can include septicemia or poisoning, but these are much less likely. In such cases, IV calcium is strongly recommended as soon as possible.

When beginning an examination, examine the head first. Most lizards can be induced to open their mouths even if it is in an attempt to bite you. With iguanas, firm traction on the dewlap will often induce them to open up.

Some lizards will shed their tails naturally if stressed or poorly handled (autotomy). These include iguanids, lacertids, geckos, and some skinks. In these species, the tail will regrow but usually has a different shape and/or markings. Note: The crested gecko (Rhacodactylus ciliatus) is an exception—unlike the other geckos in the Rhacodactylus genus, the tails do not regrow once shed.

Microchipping

• Left quadriceps muscle, or subcutaneously in this area (all species)

• In very small species, subcutaneously on the left side of the body

• Skin closure is achieved either by suture or with tissue glue.

Sexing

Many lizards are sexually dimorphic as adults and can be readily distinguished, typically by the presence of pronounced pores cranial to the cloaca (precloacal pores) or medial thigh (femoral pores), combined with the presence of hemipenile bulges caudal to the cloaca (Fig. 10-2). Male veiled chameleons have a caudal spur on each hind foot, present from birth.

Nursing care

Provide the appropriate environment, including provision of:

1. Optimal temperature (e.g., basking lights, heat mats to allow thermoregulation). Use of max-min thermometers will assist in monitoring temperature ranges incumbent reptiles are exposed to

2. Full-spectrum lighting (provision of UVA and UVB)

3. Humidity

4. Ventilation

5. Easily cleaned accommodation; use paper substrate and disposable/sterilizable hides and other vivarium furniture (Fig. 10-3).

6. Keep individually to minimize intraspecies stress and competition for resources.

Fig 10-3. A clinical vivarium setup for lizards and Chelonia.

Fluid therapy

Reptiles lack the loop of Henle and are, therefore, unable to produce hyperosmotic urine. Uric acid is excreted instead of ammonia; this is sparingly soluble and can be excreted at high concentration with minimal water loss as a sludge or paste.

The assessment of dehydration in reptiles can be difficult visually. Typically, signs of dehy­dration are sunken eyes, extensive skin folding, and tenting.

Selection of fluids for reptiles

1. Isotonic fluids for blood loss, surgery, and diarrhea

2. Hypotonic in cases of prolonged anorexia

3. Hypertonic: There is little indication except in exceptionally large reptiles.

4. Blood transfusions can be undertaken using blood from a lizard of the same species or closely related (same genus). Blood can be given IO or IV.

5. Oxyglobin

6. Overhydrating reptiles with compromised renal function can lead to vascular overload, heart failure, and death.

Fluid replacement

1. Plasma volume in reptiles is around 6.0 mL/100 g.

2. Fluid replacement rates are suggested as:

a. 0.5 to 1.0 mL/100 g/hour, averaging around 1.5 to 3.0 mL/100 g/day

b. Administer up to 0.5% to 2% body weight maximum of an isotonic replacement fluid, such as Hartmann’s solution (i.e., 5 to 20 mL/kg), reducing this once the hydration status becomes normal.

3. Daily bathing in shallow, warm water is often beneficial; it encourages many lizards to drink as well as defecate and urinate.

Fluids administration

1. Stomach tubing is relatively straightforward in smaller lizards.

2. Esophagostomy tubes can be used in some cases.

3. All parenteral fluids should be warmed to around 26° C.

4. The easiest vein to access is the ventral tail vein. If attempting to use this vein in male lizards, always allow a gap caudal to the cloaca for the hemipenes.

5. Alternatively, a surgical cutdown onto the cephalic vein will allow catheterization.

6. For IO fluids the tibial cavity (via the tibial crest) is suggested.

7. Intracoelomic fluids should be used with caution:

a. There is a large ventral midline abdominal vein that is likely to be pierced if one attempts to give fluids via the linea alba. Place the needle into a paramedian position—this should also avoid the dorsally positioned lungs.

b. There is no separation of the coelom into an abdomen and thorax, so excessive fluid build-up can compress the lungs.

Nutritional support

Liquidized normal diet or proprietary support diets can be used, given either by stomach tube or by esophagostomy tube.

Analgesia

Anesthesia

All reptiles should be at their optimum temperature. Gaseous anesthetics can be of limited use as induction agents due to intracardiac shunting, tolerance of hypoxia, and physiologic diving reflexes (depending on the species). Chameleons respond relatively quickly, whereas semiaquatic species may take some time.

Standard anesthetic protocol

1. Pre-medication

a. Atropine sulfate at 0.01 to 0.04 mg/kg IM or IC given 10 to 15 minutes prior to induction may help prevent intracardiac shunting.

Several anesthetic protocols have been documented. The author has found the following the most useful:

2. Induction

a. Propofol at 10 mg/kg IV delivered into ventral coccygeal (tail) vein (for alternative dose rates, see Chapters 11 and 12)

3. Intubate and maintain with isoflurane.

4. Most reptiles cease to breathe during anesthesia; therefore, adopt intermittent positive-pressure ventilation (IPPV) every 30 seconds, because high PO2 inhibits ventilation.

5. In larger lizards such as iguanas and water dragons a jugular pulse can be seen sometimes; otherwise the use of pulse oximeters, ultrasound, and/or ECG is required for monitoring.

6. For optimum anesthesia, it can be of benefit to infiltrate the surgical site with local anesthetic.

Parenteral anesthesia

1. Ketamine at 5.0 mg/kg IM plus medetomidine 100 to 150 gg/kg IM

2. Reverse with atipamezole at 5 times medetomidine dose (can take 25 to 90 minutes to take effect).

Recovery

1. Continue with IPPV until spontaneous respiration is resumed.

2. If using oxygen alone, switch to manual ventilation with air if possible.

3. Lizards are tolerant of anoxia; therefore, continue with IPPV even if there is no obvious response.

4. Doxapram at 5 to 10 mg/kg IV, IO, or onto lingual mucosa may be beneficial.

Skin disorders

The epidermis of both lizards and snakes consists of two layers:

1. The stratum corneum, which consists of:

a. Oberhautchen layer

b. β-keratin layer

c. α-keratin layer

d. Thickened plates of stratum corneum form the scales. This layer also contains a complex mixture of neutral and polar lipids designed to reduce water loss across the skin.

2. Stratum germinativum

The dermis is mainly connective tissue; it may contain bony plates termed osteoderms.

Most lizards shed their skin piecemeal and uncoordinated—cellular proliferation and keratinization are continuous; however, geckos normally shed their skin simultaneously over the whole of the body surface. Many lizards, such as leopard geckos (Eublepharis macularis), will eat their shed skin.

Differential diagnoses of skin disorders

Shedding difficulties (dysecdysis)

• Humidity too low

• Other environmental problems (e.g., incorrect photoperiod, temperature, nutrition)

• Lack of cage furniture to allow initiation of shedding

• Ectoparasites (e.g., Hirstiella spp.; snake mites, or Ophionyssus natracis)

• Scarring or other underlying dermal disease

• Hypovitaminosis A

• Hypothyroidism and possibly other endocrinopathies

• Secondary bacterial and fungal infections common

Pruritus

• Ectoparasites

Scaling and crusting

• Dysecdysis (see above)

• Bacterial dermatitis (Aeromonas spp., Pseudomonas spp., Serratia spp.)

• Dermatophilosis

• Burns

• Hypovitaminosis A

Erosions and ulceration

• Behavioral interactions with transparent barriers (ITB). Rostral nares and intermandibular joint often affected.

• Lesions from hungry, uneaten crickets and other invertebrate prey

• Bites from conspecifics, especially during mating—these are typically over the shoulders and back of the neck.

Nodules and nonhealing wounds

• Abscess

• Filarial nematodes (see also Systemic Disorders), especially chameleons and day geckos

• Granulomas (mycobacterial—see also Systemic Disorders; fungal—e.g., Chrysosporium anamorph of Nannizziopsis vriesii, or CANV, Trichophyton spp., Aspergillus spp., Geotrichium candidum, Cryptococcus neoformans)

• Poxvirus

• Viral papillomas (green lizard Lacerta viridis and occasionally other lacertids); often very dark to black, and proliferative

• Trichomonas spp. (subcutaneous abscesses in leopard gecko)

• Sebaceous cysts (green iguana)

• Pseudoaneurysm, especially on the head (bearded dragon)

• Calcinosis cutis and calcinosis circumscripta

• Endolymphatic glands in certain geckos, such as day geckos (Phelsuma spp.)

Changes in pigmentation

• Scarring

• Yellowing of skin patches in bearded dragons (Pogona spp.); common following skin disease (e.g., burns, dysecdysis, infections) but also linked to yellow fungus disease

• Yellow fungus disease of bearded dragons

• Dermatomycosis: Trichophyton, CANV

Ectoparasites

• Arthropods

• Ticks (Aponomma exornatum, A. varanensis, A. fuscolineatus, see Kenny et al 2004)

• Lizard mites (Hirstiella trombidiiformis, Geckobiella spp., Pterygosoma spp.)

• Snake mite (Ophionyssus natracis—Walter and Shaw 2002)

Burns

Neoplasia

• Fibrosarcoma

• Squamous cell carcinoma

• Liposarcoma

• Chromatophoroma (malignant)

Findings on clinical examination

• Distinct single or multiple swellings palpable in the skin

• Dysecdysis: Patches of dull, thickened skin may indicate areas where several layers of skin have built up over successive dysecdysis episodes. Rings of unshed skin may form bands around the tips of extremities such as toes and tail tips. These may constrict as they dry, acting as tourniquets and compromising blood flow to the extremities. Lizards that have had previous problems may lack one or more digits.

• Thickened or hyperkeratotic skin. History of high-protein diet (e.g., rodents with no vegetable or vitamin supplementation fed long term to known omnivorous lizards, such as monitors), tegus (hypovitaminosis A)

• Damage to rostral nares and intermandibular joint, linked to repetitive trauma against transparent barriers such as glass doors and sides. Particularly common in water dragons (Physignathus spp.), which consistently attempt to leap through the barrier (ITB)

• Anemia (heavy ectoparasitic infestations)

• Pseudoaneurysm—large fluctuant swelling on neck

• Burns

• Bilateral swellings on the neck of certain gecko species such as day geckos (Phelsuma spp.). These are normal calcium storage sites and can be quite pronounced in healthy breeding females.

Investigations

1. Radiography

2. Routine hematology and biochemistry

3. Thyroid levels (Table 10-3)

4. Culture and sensitivity

5. Cytology

a. Fine needle aspirate

b. Aspiration—whole blood (pseudoaneurysm)

6. Endoscopy

7. Biopsy/necropsy

a. Circulating microfilaria (Oros et al 2002)

8. Ultrasonography

TreatmentZspecific therapy

• Dysecdysis

• Moisten the affected areas to loosen the retained skin from the underlying epidermis.

• Retained spectacular scales in geckos are best removed using a damp cotton bud.

• Injection of vitamin A at 1000 to 5000 IU/kg IM will often trigger a further shed, allowing a closer management of the sloughing procedure such that both the old shed and the new are removed.

• Supplementation with thyroxine will often help with lizards showing dysecdysis. Serum thyroid levels may be useful, but normal ranges for comparison may not be available for your target species.

• Abscess

• Requires surgical removal if possible

• ITB

• Treat lesions topically or systemically as required. May require removal of devitalized bone with associated teeth.

• Alter environment—attempt to remove to a larger, more naturalistic environment without transparent boundaries (Scott and Warwick 2002).

• Poxvirus: No treatment

• Viral papillomas

• Usually self-limiting; may require surgical resection if present at a sensitive site (e.g., mouth, where they may interfere with normal feeding)

• Fungal dermatitis, granulomas, yellow fungus disease

• Ketoconazole at 10 to 30 mg/kg PO s.i.d.

• Topical ketoconazole cream

• Itraconazole 5 mg/kg PO every other day

• Topical chlorhexidine solution

• Topical iodine solution

- Note: CANV can act as a primary reptile pathogen.

• Filarial nematodes

• Surgical resection where feasible

• Ivermectin at 200 μg∕kg SC. Repeat after 4 weeks if necessary, (care with Solomon Island skinks, Corucia zebrata)

• Ticks

• Individual removal of ticks

• Ivermectin at 200 μg∕kg SC. Repeat after 4 weeks if necessary (care with Solomon Island skinks, Corucia zebrata)

- Note: Ticks are vectors for Babesia/Hepatozoon and Ehrlichia-like organisms.

• Snake and lizard mites

• Snake mites are parthenogenetic, so numbers can rapidly build up in vivaria; treatment must include thorough cleaning of all affected vivaria. What cannot be sterilized with a mild bleach solution (5 mL/gallon) must be disposed of.

• Replace usual substrate with paper (changed daily)

• Repeated washing with warm water will physically remove any mites.

• Application of topical fipronil spray once weekly for at least 4 weeks. This is best first applied to a cloth and rubbed over the entire surface of the lizard. Fipronil spray can also be used to treat the environment.

• Injection of ivermectin at 200 μg^g SC (note: toxic to indigo snakes and chelonia) every 2 weeks will kill those that feed on the lizard.

• Commercial imidacloprid (100 g/L) plus moxidectin (25 g/L) (Advocate Dog (UK), Advantage Multi (USA), Bayer) applied at double (32 mg/kg imidacloprid + 8.0 mg/ kg moxidectin) to 10-fold dosages (160 mg/kg imidacloprid + 40 mg/kg moxidectin) according to thickness of skin (care with lacertids, especially the six-striped grass lizard Takydromus sexlineatus) (Mehlhorn et al 2005a)

• Cultures of predatory mites (Hypoaspis miles) are commercially available for use in vivaria.

• Pseudoaneurysm

• Surgical repair

• Hypothyroidism

• Supplement with levothyroxine at 0.02 mg/kg PO every other day.

• Calcinosis circumscripta and calcinosis cutis

• Consider surgical resection if viable.

• May be linked with renal disease

• Neoplasia

• Surgical resection

• Chemotherapy in reptiles is in its infancy. Accessible cutaneous tumors can be treated by injecting cisplatin directly into the tissue mass on a weekly basis as a debulking exercise.

• Radiation has been used to treat an acute lymphoblastic leukemia in a sungazer lizard (Cordylus giganteus), while surgical laser has been used in the treatment of a dermal melanoma in a green iguana.

• Chromatophoromas carry a poor prognosis with early metastasis.

Respiratory tract disorders

Viral

• Ophidian paramyxovirus (OPMV)

Bacterial

• Mycobacterial (see also Systemic Disorders)

• Bacterial pneumonia (especially water dragons)

Fungal

• Mycotic pneumonia

• Mycotic pleuritis

Parasitic

• Lungworms (Entomelas spp.; verminous pneumonia)

• Pentastomids (e.g., Raillietiella, especially monitor lizards—Varanus spp.)

Neoplasia

• Metastases

Other noninfectious problems

• Sneezing in iguanas—normal removal of salts from nasal salt glands

• Firefly (Photonis spp.) intoxication (see also Systemic Disorders and Cardiovascular and Hematologic Disorders)

• Aspiration pneumonia (following oral administration of food or fluids; regurgitation after stomach tubing)

• Glottal foreign bodies

• Cardiovascular disease (see Cardiovascular and Hematologic Disorders)

• Epistaxis (metastatic mineralization of nasal vasculature, trauma, infection, liver disease)

• Anemia (various causes)

Findings on clinical examination

• Dyspnea

• Tachypnea

• Open-mouthed breathing and respiratory distress

• Oral and/or nasal discharge

• Unusual respiratory noises

• Altered color of respiratory membranes (cyanosis, pallor)

• Neck extension

• Epistaxis

• Anorexia

• Depression

• Muscle wastage

• Sudden death

Investigations

1. Microscopy

a. Sputum examination (either from mouth, pulmonary lavage, or endoscopic collection)

b. Staining for cytology

c. Gram stain

d. Lungworm eggs and larvae

e. Pentastomid eggs

2. Fecal examination

a. Pentastomid eggs

b. Entomelas eggs (swallowed from trachea)

3. Radiography

a. Pneumonia—areas of increased opacity in the lung fields

4. Routine hematology and biochemistry

5. Serology for OPMV

6. Culture and sensitivity

7. Endoscopy

a. Adult pentastomes present in lung

8. Biopsy/necropsy

9. Proliferative interstitial pneumonia (OPMV)

10. Ultrasonography

Management

• If very cyanosed, provide oxygen; otherwise normal supportive care (see Nursing Care)

TreatmentZspecific therapy

• OPMV

• No direct treatment

• Supportive treatment only

• Often asymptomatic—frequently diagnosed and monitored serologically

• Lungworm

• Fenbendazole at 50 to 100 mg/kg PO. Repeat every 2 weeks if necessary. Note: Fenbendazole is metabolized to oxfendazole by the liver.

• Oxfendazole at 68 mg/kg PO. Repeat every 2 weeks if necessary.

• Ivermectin at 0.2 mg IM, SC repeated every 2 weeks for 3 treatments (care with Solomon Island skinks, Corucia zebrata)

• Lungworms have a direct life cycle; infective larvae can penetrate the skin or infect via contaminated food and water.

• Pentastomids

• Ivermectin at 0.2 mg IM repeated every 2 weeks for 3 treatments (care with Solomon Island skinks, Corucia zebrata)

• Foreign body

• Attempt surgical removal. Likely to need tracheotomy

• Epistaxis

• Investigate possible causes.

• Anemia

• Investigate causes (e.g., hemorrhage, high ectoparasite load, gastrointestinal disease, renal disease).

Gastrointestinal tract disorders

Disorders of the oral cavity

In crested geckos, calcium is stored in bilaterally symmetrical endolymphatic glands dorsally at the back of the pharynx. In breeding females on a good calcium intake these can appear as quite pronounced whitish to grayish swellings and should not be mistaken for pathological lesions.

• Periodontal disease

• Especially affects acrodont lizards (agamids—including bearded dragons, water dragons, and chameleons)

• May be related to feeding soft insects, such as crickets, waxworms

• Discoloration, loss of tissue and teeth, osteomyelitis

• Radiography to assess underlying osteomyelitis

• Culture of lesions

• Appropriate antibiosis

• Ultrasonic and instrument scaling

• Regular cleaning with oral cleansing product as control measure

• Metabolic bone disease

• Softening or pathological fractures of the mandibles

• The weakened bone is unable to support orthopedic techniques; in some cases supporting the jaw closed with strong adhesive plaster (taking care to leave the nares open) accompanied by placement of an esophagostomy tube may allow healing to occur.

• Ossifying fibroma

• Usually unilateral; typically affects mandibles

• Occasionally seen in iguanas

• Surgical debulking and/or cryosurgery

• Usually self-limiting

• Other neoplasia (Fig. 10-4)

Fig 10-4. Oral mass in a pink-tongued skink.

• Fungal mandibular periodontal osteomyelitis

• Attempt systemic antimycotics such as:

- Ketoconazole at 10 to 30 mg/kg PO s.i.d.

- Topical ketoconazole cream

- Itraconazole 5 mg/kg PO every other day

• Stomatitis

• Uncommon. Often linked with respiratory or gastrointestinal diseases (see Gastrointestinal Tract Disorders). See Chapter 11 for further advice on treatment of stomatitis.

- Mycotic (Emmonsia spp.)

- Herpesvirus (Wellehan et al 2003c)

- Infection of the temporal glands on chameleons

• Swellings dorsolateral to the angle of the jaw: Require debridement under general anesthesia (GA) and appropriate antibiosis

• Pharyngeal edema

• Renal disease

• Cardiovascular disease

• Icterus (see Hepatic Disorders and Cardiovascular and Hematologic Disorders). Adult bearded dragons naturally have very yellow mucous membranes.

• Cyanosis (see Respiratory Tract Disorders)

• Disorders of the tongue

• In many lizards including the green iguana the rostral tip of the tongue bears a symmetrical darker patch that may be mistaken for an ulcer or inflammatory condition.

• Chameleons and monitor lizards have long tongues that are vital for food location and prehension.

• Lingual sheath may become infected and adhesions may result. Debride under GA and instigate appropriate antibiosis.

• Hypocalcemia/metabolic bone disease in chameleons may present as partial or complete paralysis of the tongue.

• In some old chameleons there is a failure of the tongue-protruding mechanism. These must be hand-fed.

Differential diagnoses for gastrointestinal disorders

Viral

• Reovirus (Drury et al 2002)

• Adenovirus (fat-tailed gecko Hemitheconyx caudicinctus—Wellehan et al 2003b)

Bacterial

• Salmonella spp.

• Escherichia coli

• Other bacteria

Fungal

• Mycotic enteritis (especially chameleons)

• Yeast infections (in some cases may be linked with long-term antibiosis)

Protozoal

• Cryptosporidium spp.

• Flagellates (e.g., Trichomonas)

• Giardia

• Isospora (especially I. amphiboluri in bearded dragons)

• Eimeria spp.

• Cilates (e.g., Nyctotherus, green iguana, and Clevelandellida spp.)

Parasitic

• Hookworms: Oswalsocruzia spp.

• Spirurids (stomach worms), such as Abbreviata spp., Physaloptera spp. (in ant-eating lizards, such as the horned lizard Phrynosoma)

• Pinworms

• Oxyurids (e.g., Pharyngodon spp).

• Capillaria

• Strongyloides

• Trematodes, especially molluscivores (e.g., pink-tongued skinks)

Nutritional

• Metabolic bone disease

• Intestinal tympany secondary to excessive fermentable carbohydrate intake in folivorous lizards

Neoplasia

• Colonic adenocarcinoma (Patterson-Kane and Redrobe 2005)

Other noninfectious problems

• Foreign body/impaction (especially large/inappropriate pieces of substrate)

• Cloacal prolapse

Findings on clinical examination

• Progressive weight loss (tail shrinkage in leopard geckos and related fat-tailed geckos)

• Inappetence

• Very wet or fluidy feces (flagellates, Strongyloides)

• Lack of feces

• Hemorrhagic and/or mucusy feces (hookworms)

• Chronic wasting, mortalities, high parasitism levels (possible reovirus—see Drury et al 2002)

• Gastrointestinal stasis and bloating may occur as part of metabolic bone disease, often accompanied by more typical signs (see Nutritional Disorders).

• Vomition (uncommon)

• Cloacal prolapse

• Cloacitis

• Cloacoliths

• Intestinal foreign body

• Intussusception

• Extraintestinal mass (e.g., renal neoplasm)

• Dystocia

• Hypocalcemia/metabolic bone disease

• Parasitism

Investigations

1. Fecal examination

a. Wet prep

i. Worm eggs (Fig. 10-5)

(1) Ascarid eggs

(2) Capillaria (vase-shaped eggs with two poles)

(3) Hookworm eggs (thin-walled, oval eggs)

(4) Oxyurid eggs; note that rodent pinworm eggs may be seen in lizards fed on infested prey rodents

(5) Spiruroid eggs (medium walled; contain larvae)

(6) Strongyloides (larvae in fresh fecal samples; eggs are thin-walled and similar to Entomelas)

(7) Flagellates (seen as motile protozoa)

(8) Pentastomid eggs (see Respiratory Tract Disorders)

(9) Trematode eggs

(10) Protozoal cysts (Table 10-4)

b. Gram stain

Fig 10-5. Common gastrointestinal parasites of lizards (not drawn to scale).

2. Radiography

a. Contrast studies with 25 mL/kg of 25% barium sulfate in the green iguana (Iguana iguana) (Table 10-5)

b. Recommended timing for serial radiographs in iguanas is 0, 1, 2, 3, 4, 5, and 6 hours postgavage, then every 12 hours until barium is present within the distal descending small colon. Note: The total gut transit time for carnivorous lizards will be significantly shorter than for a herbivorous lizard such as the green iguana.

c. Herbivorous lizards (e.g., green iguana) have a large sacculated colon adapted as a fermentative vat, which may normally appear as a large, gas-filled viscus on radiography.

Fig 10-6. Radiograph of a bearded dragon following ingestion of large pieces of gravel.

d. Enteritis: Gas-filled intestine especially obvious in carnivorous (i.e., simple gut) lizards.

e. Radiodense foreign bodies (e.g., stones, gravel, and sand impactions; Fig. 10-6)

f. Radiolucent foreign bodies (e.g., bark chippings) may require contrast studies to identify.

2. Routine hematology and biochemistry

3. Culture and sensitivity

4. Endoscopy

5. Biopsy/necropsy

a. Cryptosporidium—especially the large intestine/colon

6. Ultrasonography

Management

• Good nursing care including fluid therapy (see Nursing Care)

TreatmentZspecific therapy

• Adenovirus

• No treatment. Supportive therapy only

• Reovirus

• No treatment. Supportive therapy only

• Salmonellosis

• Probably best considered as a normal constituent of lizard cloacal/gut microflora

• Rarely pathogenic to lizards

• Excretion likely to increase during times of stress (e.g., movement, illness)

• Treatment usually not appropriate, as unlikely to be effective long term and may encourage resistance

• Recommendations for prevention of salmonellosis from captive reptiles issued by the Centers for Disease Control and Prevention include:

- Pregnant women, children on iguanas weighing between 356 g and 496 g.

4. Coelomic tap and cytology

a. Avoid midline as likely to puncture ventral vena cava.

5. Culture and sensitivity

6. Endoscopy

7. Biopsy/necropsy

a. Pale-colored liver (hepatic lipidosis)

b. Hepatomegaly (Fig. 10-7)

8. Ultrasonography

a. Hepatomegaly

b. Ascites

Management

• Milk thistle (Silybum marianum) is a hepatoprotectant. Dose at 4 to 15 mg/kg PO b.i.d. or t.i.d.

• For ascites try furosemide at 2 to 5 mg/kg PO, SC, IM s.i.d. if ascitic.

• Lactulose 0.05 mL/100 g PO s.i.d.

TreatmentZspecific therapy

• Adenovirus

• Supportive therapy only

Fig 10-7. Hepatomegaly in a green iguana (postmortem).

• Herpesvirus

• Attempt treatment with acyclovir at 80 mg/kg PO s.i.d. Very guarded prognosis

• Mycobacteriosis

• Potential zoonosis. Consider euthanasia.

• No successful treatment for mycobacteriosis in reptiles reported

• Hepatic lipidosis

• Fluid therapy and nutritional support

• Covering antibiotics

• Lactulose 0.05 mL/100 g PO s.i.d.

• Esophagostomy tube may be appropriate in some cases.

• Neoplasia: Treatment unlikely

• Amyloidosis

• No treatment. Address possible initiating factors (e.g., chronic inflammatory conditions).

Pancreatic disorders

Diabetes mellitus (see Endocrine Disorders)

Cardiovascular and hematologic disorders

Viral

• Iguana herpesvirus

• Chameleon erythrocyte virus (iridovirus)

Bacterial

• Vegetative endocarditis (e.g., Salmonella, Streptococcus)

Fungal

Protozoal

• Haemogregarina spp.

• Haemoproteus spp.

• Plasmodium spp.

• Shellackia spp.

• Sauroplasma spp.

Parasitic

• Filarial nematodes (especially chameleons)

Nutritional

• Calcification of major vessels, including the aorta

Neoplasia

• Lymphoproliferative disorders (e.g., lymphoid and monocyte leukemia—see Systemic

Disorders)

Other noninfectious problems

• Endocardiosis

• Myocardiosis

• Cardiomyopathy

• Myocardial infarction

• Metastatic calcification, especially of aorta

• Visceral gout (uric acid in pericardial sac—see Renal Disorders)

• Firefly (Photonis spp.) intoxication, especially in bearded dragons (see also Systemic

Disorders and Respiratory Tract Disorders)

• Autoimmune hemolytic anemia (Boyer 2002)

Findings on clinical examination

• Lethargy

• Anorexia

• Edema, especially in back of pharynx

• Pale mucous membranes

• Exophthalmia (see also Ophthalmic Disorders)

• History of exposure to fireflies, linked with clinical signs of gaping, head shaking, blackened coloration, breathing difficulties, and death

• Swollen pharynx, hepatomegaly, depression, anorexia

• Murmurs may be heard in cases with marked heart disease (e.g., endocarditis). In most reptiles nothing will be heard.

• Necrosis of the extremities secondary to septicemic thrombi (often resulting from vegetative endocarditis—see Systemic Disorders; Fig. 10-8)

Investigations

1. Auscultation

a. For many lizard species no heartbeat is audible with standard stethoscopes, except in cases of severe cardiac disease such as endocarditis. However, larger lizards such as bearded dragons can often be auscultated.

Fig 10-8. Necrosis of the digits in a Parson's chameleon secondary to septicemic thrombi.

b. Frequency (HBF) per minute in reptiles can be estimated at:

HBF = 33.4 (Weight_kg^-0∙²⁵) assuming the reptile is at its correct body temperature

2. Radiography

a. In many lizards the heart lies in the thoracic girdle and is, therefore, obscured somewhat radiographically.

b. Mineralization of the aorta and intrapulmonary airways (metastatic calcification)

3. Ultrasonography and Doppler blood-flow detectors

4. Electrocardiogram

a. ECG values recorded from lacertid lizard (Gallotia bravoana—Table 10-6)

b. In this study higher temperatures increased the P segment and decreased the ST duration, RR duration, and cardiac axis.

5. Routine hematology and biochemistry

6. Cytology: May find filarial worms on blood smear

a. Iguana blood: Clear spherical intracytoplasmic lesions (iguana herpesvirus)

b. Chameleon blood: Intracytoplasmic inclusions (iridovirus)

7. Autoagglutination, Rouleaux formation, anisocytosis (autoimmune hemolytic anemia)

8. Culture and sensitivity

a. Blood culture

9. Endoscopy

10. Biopsy/necropsy

TreatmentZspecific therapy

• Iguana herpesvirus

• Acyclovir 80 mg/kg s.i.d. for 6 weeks

• Often associated with severe hepatic fibrosis and interstitial nephritis

• Chameleon erythrocyte virus: No treatment

• Filarial nematodes—see Skin Disorders

• Firefly (Photonis spp.) intoxication

• Fireflies contain cardiac glycoside-like cardenolides that suppress heart rate.

• Supportive treatment, including gavage with activated charcoal

• Hemoparasites

• Loading dose of chloroquine phosphate (5 mg/kg PO) and primaquine phosphate (0.5 mg/kg PO)

• Continue with chloroquine at 2.5 mg/kg PO once weekly and primaquine at 0.5 mg/kg PO once weekly for 12 to 16 weeks

• Shelackia spp.: Rarely pathogenic—may indicate immunosuppression consistent with concurrent disease or poor environmental conditions

• Leukemia

• Treatment potentially difficult and untried

• Radiation therapy was used by Martin et al (2003). Single low-dose whole-body radiation treatment of 1 gray. A reduction in WBC count was noted after 1 month and was normal, with normal differential by 3 months.

• Autoimmune hemolytic anemia

• Prednisolone at 0.5 mg/kg PO s.i.d. for 2 weeks and then every other day until packed cell volume (PCV) stable

• Cimetidine 4 mg/kg PO s.i.d. if evidence of gastric hemorrhage

• Covering antibiosis

• Blood transfusion

• Cardiomyopathies and other cardiac disorders

• Furosemide at 2 to 5 mg IM, IV, or PO s.i.d. or b.i.d.

• Pimobendan at 0.2 mg/kg PO s.i.d.

• Metastatic calcification

• See Musculoskeletal Disorders.

Brumation is a naturally occurring period of reduced activity that in the wild is associated with adverse environmental conditions such as low temperatures, aridness, or inadequate food supplies. It can be incorrectly referred to as hibernation.

Brumation is commonly seen in bearded dragons but may be seen in other species from high-latitude areas or climates that experience adverse seasons such as leopard geckos. Normal brumation behavior involves the lizard going off its food, basking less, and hiding away more. This change in behavior can be quite rapid and alarming if not expecting it. If unsure, check these pointers:

1. Weigh the lizard every 3 to 4 days. Brumating reptiles lose little or no weight during brumation, typically no more than around 1% to 2% per month.

2. Assess the lizards. A sick lizard will show fairly rapid signs of loss of condition, closed eyes, and loss of muscle tone and may gape, whereas a brumating reptile will appear otherwise normal and healthy with bright eyes and an alert appearance when disturbed.

3. Has this happened before? With older reptiles there may be a history of its happening around the same time the previous year.

If you are confident that your bearded dragon is brumating, then reduce the ambient temperature by a few degrees and alter the day-length settings to around 8 to 10 hours and monitor. Do not offer food during brumation unless the lizard appears hungry. Typically brumation will last for around 6 to 8 weeks, although it can extend up to 5 months.

Viral

• Adenovirus (inland bearded dragon Pogona vitticeps and Rankin's dragon P. henrylawsonii)

• Iguana herpesvirus (see Cardiovascular and Hematologic Disorders)

• Iridovirus

Bacterial

• Septicemia/bacteremia

• Chlamydophila and Chlamydophila-like organisms

• Mycobacteriosis (see also Respiratory Disorders and Skin Disorders)

• Streptococci (bacteremia)

• Salmonella arizona

• Listeria monocytogenes (Girling and Fraser 2004)

Fungal

Protozoal

• Intranuclear coccidiosis

• Microsporidae (see also Hepatic Disorders), especially bearded dragons

Parasitic

• Filarial nematodes (see also Skin Disorders and Cardiovascular and Hematologic Disorders)

Neoplasia

• Lymphoma and leukemia

• Mesothelioma

• Hemangiosarcoma

Other noninfectious problems

• Cardiac disease (see Cardiovascular and Hematologic Disorders)

• Intracoelomic hemorrhage

• Firefly (Photonis spp.) intoxication (see also Cardiovascular and Hematologic Disorders and Respiratory Tract Disorders)

• Gout (visceral, articular, and renal—see Renal Disorders)

• Amyloidosis

Findings on clinical examination

• Lethargy

• Anorexia (see Anorexia notes in Chapter 11 for a differential list)

• Edema

• Sudden mortalities

• Neurologic signs

• Anorexia, lethargy, and death, especially in bearded dragons (adenovirus). Petechial to ecchymotic hemorrhages may occur.

• Necrosis of the extremities secondary to septicemic thrombi (often resulting from vegetative endocarditis—see Cardiovascular and Hematologic Disorders)

Investigations

1. Radiography

2. Routine hematology and biochemistry

3. Cytology: May find filarial worms on blood smear

4. Culture and sensitivity

a. Blood culture

5. Ziehl-Neelsen staining and polymerase chain reaction (PCR) for mycobacteria

6. Immunohistochemistry and PCR for Chlamydophila and Chlamydia-like organisms (Soldati et al 2004)

7. Endoscopy

8. Biopsy/necropsy

a. Single or multiple granulomas (mycobacteria, fungi, Chlamydophila pneumoniae, Chlamydia-like organisms)

b. Microsporida (gram-positive, acid fast) found in liver, kidneys, lung, gonads, and CNS

c. Adenovirus

d. Neoplasia

9. Ultrasonography

TreatmentZspecific therapy

• Adenovirus

• Symptomatic treatment only

• Exclude parents and siblings from breeding groups to eliminate potential carriers.

• Iridovirus

• Symptomatic treatment only

• Some may actually be invertebrate iridoviruses, originating from infected crickets.

• Bacterial infections

• Appropriate antibiosis

• Supportive therapy

• Symptomatic management of necrotic extremities; may require surgical amputation

• Listeriosis

• Not normally a part of reptile gut flora

• Case described in Girling and Fraser (2004) linked to feeding contaminated mouse pups that had been frozen and defrosted

• Mycobacteriosis

• Potential zoonosis. Consider euthanasia.

• No successful treatment for mycobacteriosis in reptiles reported

• Microsporidae

• No effective treatment

• Albendazole at 10 mg/kg PO s.i.d. may prevent replication.

• Fenbendazole at 10 to 20 mg/kg PO s.i.d.

• Intranuclear coccidiosis

• Potentiated sulfonamides at 30 mg/kg PO s.i.d.

• Filarial nematodes

• Ivermectin at 200 pg/kg SC (care with Solomon Island skinks, Corucia zebrata)

• Surgical resection of associated skin granulomas

• Neoplasia

• Surgical resection if feasible

• Lymphoma and leukemia (see Cardiovascular and Hematologic Disorders)

Swollen/distended body cavity

Infections may cause organopathies that in turn result in a swollen or distended coelom.

Neoplasia

• Hepatic neoplasia

• Renal neoplasia

Other noninfectious problems

• Obesity (enlarged coelomic fat pads)

• Distension of the gastrointestinal tract (e.g., secondary to foreign body obstruction, intussusception, or hypocalcemia—intestinal atony)

• Distension of the bladder (bladder calculi, bladder atony, CNS lesions)

• Hepatomegaly

• Ascites

• Liver disease

• Hypoproteinemia

• Cardiovascular disease

• Septicemia

• Renomegaly

Reproductive causes

• Gravid

• Dystocia (see Reproductive Disorders)

Findings on clinical examination

• Swollen coelom

• Constipation (secondary to external compression of the gut by enlarged fat pads)

• Dyspnea

• Other clinical signs may be present depending on the underlying cause.

Investigations

1. Radiography

a. Distended viscus

b. Bladder calculi

c. Foreign bodies (e.g., sand or stone impactions)

2. Routine hematology and biochemistry

3. Coelomic tap

4. Culture and sensitivity

5. Endoscopy

6. Biopsy/necropsy

7. Ultrasonography

a. Coelomic fluid

b. Distended viscus

Management

• Fluid can be drawn from the coelom to relieve the distension, but this may interfere with the fluid balance of the lizard.

• Furosemide at 2 to 5 mg IM, IV, or PO s.i.d. or b.i.d.

TreatmentZspecific therapy

• See individual headings.

Musculoskeletal disorders

Bacterial

• Septic arthritis

• Osteomyelitis

• Cellulitis

• Myositis

Fungal

Parasitic

• Heavy parasite burden, especially hemoparasites (anemia) or gastrointestinal parasites (protozoa, helminths)

Nutritional

• Metabolic bone disease

• Nutritional secondary hyperparathyroidism from dietary calcium deficiency, dietary calcium/phosphorus imbalance, hypovitaminosis D₃ (lack of exposure to ultraviolet light, lack of dietary vitamin D₃, protein deficiency—see also “Noninfectious Problems”)

• Metastatic calcification of smooth muscle of various organs, including cardiovascular system, pulmonary system, gut, and urogenital system. Typically linked to excess dietary vitamin D₃ intake (e.g., oversupplementation, feeding with dog and cat food). Especially problematic in herbivorous reptiles, such as iguanas (but see "Treatment”)

• Hypovitaminosis E (often combined with selenium deficiency)

Neoplasia

• Fibromas (especially mandibles in green iguana)

• Liposarcoma

• Myeloma

• Osteosarcoma

Other noninfectious problems

• Metabolic bone disease

• Renal secondary hyperparathyroidism

• Also liver and intestinal disease—see also "Nutritional” above

• Autotomy (geckos, iguanids, lacertids, and some skinks)

• Fractures (traumatic), especially long-toed lizards such as green iguanas and water dragons

• Spondylosis/spondylitis

• Hypertrophic osteopathy (also known as hypertrophic pulmonary osteoarthropathy, HPOA)

• Osteopetrosis

• Kyphosis/scoliosis: Genetic; disease of the associated musculature (myopathies); nutritional disorders

• Floppy-tail—a particular form of kyphosis associated with small arboreal lizards, especially day geckos and crested geckos

• Dysecdysis with resultant sloughing of distal extremities, such as toes and tail-tip (see Skin Disorders)

• Avascular necrosis of the distal tail

• Swelling at tail base in males (seminal plugs—see Reproductive Disorders)

• Congenital defects—typically abnormal incubation environment

Findings on clinical examination

• Any limb or spinal swelling, fracture, or paralysis should be considered as a possible sign of a pathological fracture (Fig. 10-9).

• Soft mandibles, foreshortening of the maxillae, swollen midshaft of long bones, kyphosis/scoliosis, weakness, inability to support own body weight (metabolic bone disease)

• Muscle weakness, inability to support body or hunt/locate food (Fig. 10-10)

Fig 10-9. Swollen tarsus with osteolysis arising from a septic arthritis in the bearded dragon above. Note the pathological fracture in the distal femur.

Fig 10-10. A young bearded dragon with extreme muscle weakness secondary to metabolic bone disease.

• Muscle fasciculations and other neurologic signs

• Withering and fracture of distal tail

• Loss of digits

• Scoliosis in crested geckos, often accompanied by kinking of the tail

• In arboreal geckos the tail hangs either to the side or over the back when resting in a head-down position (floppy-tail).

Investigations

1. Husbandry

a. Discuss access to full-spectrum lighting, frequency of lightbulb changing, provision of calcium/provision in suitable form, intraspecies or interspecies interactions that may influence access to basking sites and/or food/calcium sources.

Fig 10-11. Traumatic fracture of the radius in a green iguana.

2. Radiography

a. Pathologic (metabolic bone disease, neoplasia) or traumatic fractures (Fig. 10-11)

b. Osteolysis (osteomyelitis, myeloma, osteosarcoma)

c. Fibrous osteodystrophy (metabolic bone disease)

3. Other signs of metabolic bone disease: Loss of bone density and cortical bone thinning

a. Fibromas and other neoplasias

b. Hypertrophic osteopathy

c. Osteopetrosis—excessive thickening of the bones

d. Septic arthritis

e. Gout: Radiolucent uric acid accumulation

4. Routine hematology and biochemistry

a. Blood vitamin D₃ (25-hydroxycholecalciferol) levels: normal plasma levels for Pogonids = 105 nmol/L; for green iguana (Iguana iguana) = 265 nmol/L

b. Total calcium, ionized calcium, phosphate

c. Hyperphosphatemia (renal secondary hyperparathyroidism)

5. Culture and sensitivity

6. Spondylitis, osteomyelitis

7. Cytology (fine-needle aspiration)

8. Endoscopy

9. Biopsy

10. Ultrasonography

TreatmentZspecific therapy

• Autotomy

• For those species that naturally autotomize, then no treatment beyond minimizing blood loss is necessary; suturing will prevent normal tail regeneration. Note: The crested gecko (Rhacodactylus ciliatus) is an exception—unlike the other geckos in the Rhacodactylus genus the tails do not regrow once shed. For other species with traumatic or surgical tail amputation, skin closure is necessary.

• Metabolic bone disease

• Usually due to secondary nutritional hyperparathyroidism linked with either failure to provide sufficient calcium supplementation or exposure to UVB

• Parenteral calcium gluconate or lactate at 1.0 to 2.5 mg/kg daily

• Oral vitamin D₃ at 200 IU/kg every 7 days PO, IM

• Dietary calcium supplementation

• Exposure to full-spectrum lighting as a UVB source

• Calcitonin at 1.5 IU/kg SC s.i.d. if normocalcemic

• Metastatic calcification

• No effective treatment

• Reduce hypercalcemia by

- Calcitonin at 1.5 IU/kg SC s.i.d.

- Fluid therapy at 15 mL/kg Hartmann's solution intracoelomic until normocalcaemic

• Although often linked to excessive vitamin D₃ supplementation, many cases may be due to low levels of calcitrol, commonly secondary to renal disease. This leads to toxic levels of parathormone production with associated abnormal tissue mineralization and further renal damage.

• Osteopetrosis

• Hereditary disorder. Symptomatic treatment

• Hypertrophic osteopathy

• Symptomatic treatment

• Usually terminal

• Heavy parasite burden

• Treat as described under relevant sections.

• Septic arthritis

• Surgical investigation and treatment. May require partial or complete amputation. Consider underlying possibility of vegetative endocarditis (see Cardiovascular and Hematologic Disorders).

• Abscessation and osteomyelitis, myositis

• Appropriate antibiosis

• Consider amputation if damage is extensive.

• Spondylosis: No treatment

• Spondylitis

• Appropriate antibiosis

• Consider NSAIDs (e.g., meloxicam at 0.2 mg/kg once daily or every other day); in the green iguana, see Hernandez-Divers 2006b

• Kyphosis/scoliosis/ floppy-tail

• No specific treatment

• Assess for underlying metabolic bone disease (see above).

• Can occur in crested geckos without obvious metabolic bone disease. May be a muscular dystrophy-like disorder

• Floppy-tail is an acquired disorder seen in certain arboreal lizards and is related to excessive time resting head-down on completely vertical surfaces (e.g., vivarium sides). It is not always associated with metabolic bone disease but is associated with pelvic and sacral abnormalities, which are presumed to be linked to the mechanical stress of the weight of the tail on the tail base musculature and underlying skeleton.

• Hypertrophic pulmonary osteopathy

• Likely linked to multiple organ disorders. Very guarded prognosis

• Neoplasia

• Surgical resection if possible (e.g., amputation of distal extremities)

Neurologic disorders

Viral

• Paramyxovirus

• Adenovirus (rare)

Bacterial

• Septicemia

• CNS granuloma

Fungal

• CNS granuloma

Protozoal

• Microsporidae (see Systemic Disorders), especially bearded dragons

• Acanthamoeba

• Toxoplasma

Parasitic

• Larval migrans

Nutritional

• Biotin deficiency

• Hypovitaminosis E (often combined with selenium deficiency—see Musculoskeletal Disorders)

• Hypocalcemia (see “Metabolic Bone Disease” in Musculoskeletal Disorders)

• Hypoglycemia

Neoplasia

• Schwannoma

Other noninfectious problems

• Hepatic disease (see Hepatic Disorders)

• Toxins

• Iatrogenic (e.g., aminoglycosides, ivermectin, metronidazole)

• Nicotine

• Cedar wood shavings

• Ingestion of toxic plants (e.g., Diffenbachia, azaleas)

Findings on clinical examination

• Twitching of toes, occasionally tail tip, muscle fasciculations (hypocalcemic tetany).

May be pronounced or complete muscle Aaccidity Often accompanied by other signs of metabolic bone disease (see Musculoskeletal Disorders)

• Varied neurologic signs may be seen with paromyxovirus infections in lizards, but infections are often asymptomatic.

• Weakness

• Head tilt (vestibular disease)

• Convulsions

• Death

• History of prolonged intake of raw eggs (biotin deficiency)

Investigations

1. Radiography

2. Routine hematology and biochemistry

a. Blood vitamin D₃ (25-hydroxycholecalciferol) levels; also total calcium, ionized calcium, phosphate

b. Serology for paromyxovirus

3. Culture and sensitivity

4. Endoscopy

5. Biopsy/necropsy

6. Ultrasonography

TreatmentZspecific therapy

1. Acanthamoeba and Toxoplasma

a. Treatment difficult

b. Metronidazole at 100 to 275 mg/kg PO once only

c. Trimethoprim-sulfadiazine at 15 mg/kg PO daily

d. Potential zoonoses

2. Biotin deficiency

a. Described in monitor lizards (Varanus spp.) fed on raw eggs

b. Supplement diet.

c. Treat symptomatically.

3. Hypoglycemia

a. Uncommon

b. Parenteral and oral glucose therapy

4. Larval migrans: Treat as for endoparasites. Poor prognosis

5. Toxins

a. Remove from source of toxin.

b. For ingested toxins, flush out stomach under GA or perform gastrotomy.

c. Provide supportive care.

Ophthalmic disorders

Ophthalmic examination

Diurnal lizards have all cone retinae; nocturnal lizards have both rods and cones. Lizards have one or two fovea and a conus papillaris (analogous to the avian pecten). The lacrimal and harderian glands are well developed.

Most lizards have eyelids, but many geckos possess instead a snakelike spectacle (an excep­tion to this is the commonly kept leopard gecko, Eublepharis macularis). The eyelids may be fused as in chameleons. These lizards also lack a nictitating membrane.

Examination of the posterior segment of the eye is difficult as the iris muscle fibers are striated and partly under voluntary control. Therefore, parasympatholytics (e.g., atropine) and sympathomimetics (e.g., phenylephrine) will not work. Consider examination by:

1. Using low light levels

2. General anesthesia

3. Nonparasympatholytic mydriatics such as vecuronium. These are inappropriate in lizards that possess a spectacle.

Differential diagnoses for ophthalmic disorders

Bacterial

• Pseudomonas

• Aeromonas

Fungal

• Keratitis

• Panophthalmitis

Protozoal

• Trichomonas spp. (subspectacular abscess)

Nutritional

• Hypovitaminosis A (chameleons)

Neoplasia

Other noninfectious problems

• Trauma

• Photokeratitis

• Foreign body

• Retained spectacle

• Occlusion of nasolacrimal duct

• Congenital absence of nasolacrimal duct

• Stenosis due to or following inflammation

• Cardiovascular disease (bilateral exophthalmos)

• Congenital defects

• Microphthalmia—often associated with head abnormalities

• Some Caribbean iguanas have red sclerae; this should not be mistaken for pathology.

Findings on clinical examination

• Conjunctivitis

• Blepharitis

• Blepharospasm (foreign body, ulceration)

• Ocular discharge

• Corneal ulceration

• Deep ulceration followed by perforation and iris collapse

• Hypopyon

• Uveitis

• Keratitis

• Whitish material in eye (hypovitaminosis A, secondary infection)

• Cataracts

• Retinal degeneration

• Exophthalmia

• Distension of the subspectacular space (in species with a spectacle)

Investigations

1. Ophthalmic examination

a. For those species with a spectacle:

i. Space beneath spectacle distended with clear fluid (occlusion of nasolacrimal duct)

ii. Subspectacular abscess: The eye appears opaque and the spectacle may be bulge due to increased pressure in the corneospectacular space. This condition may be unilateral or bilateral.

2. Radiography

3. Routine hematology and biochemistry

4. Culture and sensitivity

5. Endoscopy

6. Biopsy/necropsy

7. Ultrasonography

TreatmentZspecific therapy

• Bacterial keratitis

• Topical ophthalmic antibiotics; may also benefit from systemic antibiotics

• Fungal keratitis

• Topical ophthalmic antimycotics

• Corneal ulceration

• Topical antibiosis and lubrication

• Suturing of eyelids together may be of benefit.

• Excoriation followed by topical tissue glue may be of use.

• Deep ulceration followed by perforation and iris collapse

• Enucleation if ocular penetration and uveitis

• Subspectacular abscess

• Treatment involves surgical incision into the spectacle to allow an assessment for any corneal lesions.

• All debris should be flushed from the corneal surface and, if possible, the nasolacrimal duct cannulated and flushed.

• Topical ophthalmic antibiotic or antimycotic preparations should be used.

• A new spectacle should form at the next skin shed. To prevent desiccation, consider attempting to suture the contact lens in place.

• Photokeratitis

• Treat topically as for keratitis in other species.

• Remove full-spectrum lighting for several days and adjust lighting.

• Usually associated with incorrect positioning of full-spectrum lights—lights should be above the reptile, not to the side, where horizontal rays of UVB can bypass protective eyebrow ridges and damage the cornea.

• Nasolacrimal duct occlusion

• Treatment is similar to subspectacular abscess.

• Congenital defects

• No treatment

• Consider incubation parameters (temperature, humidity, etc.) as well as genetic factors when considering cause.

Endocrine disorders

Endocrine disorders are poorly investigated in reptiles.

• Hypothyroidism (see Skin Disorders)

• Diabetes mellitus

Findings on clinical examination

• Anorexia

• Polydipsia/polyuria

• Weight loss

• Dysecdysis (see Skin Disorders)

Investigations

1. Radiography

2. Routine hematology and biochemistry

a. Hyperglycemia (differentiate from stress hyperglycemia)

b. Serum insulin

c. Serum glucagon (may be more important in glucose regulation than insulin)

3. Coelomic tap

4. Culture and sensitivity

5. Endoscopy

6. Biopsy/necropsy

7. Ultrasonography

TreatmentZspecific therapy

• Diabetes mellitus

• Symptomatic therapy

• Start on high-fiber, low-protein diet.

• Consider use of insulin.

Renal disorders

Impairment of fluid balance, or renal disease, causes pathological crystallization of uric acid crystals, which presents as visceral or articular gout.

Viral

• Iguana herpesvirus (see Cardiovascular and Hematologic Disorders)

Bacterial

• Bacterial nephritis

Fungal

• Fungal nephritis

Neoplasia

Other noninfectious problems

• Gout (renal, visceral, and articular)

• Bladder calculi

• Renal failure of middle-aged iguanas

• Iatrogenic (nephrotoxic drugs, such as aminoglycosides)

Findings on clinical examination

• Anorexia

• Lethargy

• Weight loss

• Polydipsia/polyuria (see also “Diabetes Mellitus” in Pancreatic Disorders)

• Anuria

• Edema and swellings (Fig. 10-12)

• Hind-limb weakness (see also Neurologic Disorders)

Fig 10-12. Severe gout in the foot of a pink-tongued skink.

• Constipation (swollen kidneys may occlude pelvic canal)

• Pale mucous membranes

• Pharyngeal edema

• Mortalities

• Vague ill health, anorexia in 3- to 8-year-old iguanas (renal failure of middle-aged iguanas)

Investigations

1. Radiography

a. Renomegaly The kidneys of many lizards, especially iguanids, are located in the pelvic cavity. Difficult to see normally, they can extend into the coelomic cavity if enlarged.

2. Routine hematology and biochemistry

a. No good single test

b. Lizards with renal disease may show hyperuricemia, hyperuremia, hyperphosphatemia, hyperkalemia, hyponatremia, and hyperproteinemia or hypoproteinemia, although none of these is a consistent finding.

Renal failure of middle-aged iguanas

1. High serum phosphorus (normal range 1.0 to 3.0 mmol/L; can be up to 5.7 mmol/L in gravid female iguanas) and Ca:PO₄ < 1.

2. Serum urea and creatinine levels usually normal. Uric acid levels only elevated in terminal disease.

3. Creatine kinase and AST often high.

4. May be hypocalcemic or hypercalcemic.

Estimation of renal clearance in the green iguana

1. Fast the reptile for 24 hours (allow normal access to water).

2. Maintain at preferred body temperature.

3. Inject IV iohexol at 75 mg/kg.

4. Collect blood samples (minimum 0.5 mL) at 4 hours, 8 hours, and 24 hours.

5. Centrifuge and submit plasma on ice for analysis.

6. Mean glomerular filtration rate (GFR) for healthy iguanas is 14.8 to 18.3 mL/kg per hour.

(Hernandez-Divers 2006a)

3. Urinalysis

a. Renal casts

b. Inflammatory cells

4. Culture and sensitivity

5. Endoscopy

a. Abnormalities in shape, color, or size of kidneys

6. Biopsy/necropsy

7. Ultrasonography

a. Hyperechoic or hypoechoic, focal or multifocal changes; alteration of size

b. Renomegaly (renal failure of middle-aged iguanas; chronic interstitial fibrosis—may be associated with iguana herpesvirus; renal gout)

Management

• For fluid therapy, see Nursing Care.

TreatmentZspecific therapy

• Renal failure of middle-aged iguanas

• Etiology probably dietary (excessive animal protein) and may include chronic mild dehydration

• Fluid therapy

• Other renal therapeutic drugs could, with caution, be tried.

• Gout

• Fluid therapy

• Allopurinol at 10 mg/kg PO s.i.d. Note: This will only prevent subsequent uric acid deposition.

• Very guarded prognosis

• May be linked to excess dietary protein, renal disease, chronic dehydration, use of nephrotoxic drugs

Reproductive disorders

Nutritional

• Hypocalcemia (with subsequent oviductal inertia)

Neoplasia

Other noninfectious problems

• Hemorrhage from ovarian artery

• Dystocia

• Preovulatory ovarian stasis (POOS)

• Egg stasis (postovulatory)

• Egg yolk peritonitis

• Ovarian necrosis

• Seminal plugs (caseous debris accumulating in the inverted hemipenes)

Findings on clinical examination

• Inappetence, anorexia

• History of reproductive activity (e.g., mating, burrowing in nesting chamber or other areas of vivarium). Some eggs may have been laid. Note: Some healthy females (especially iguanas, water dragons, bearded dragons, veiled chameleons) will spontaneously ovulate without the presence of a male or others of the same species.

• Restlessness

• Obvious swelling of the coelomic cavity (not always obvious)

• Hind-limb weakness

• Signs of metabolic bone disease (see Systemic Disorders)

• Dehydration in neglected cases (especially veiled chameleons)

• Swelling caudal to cloaca in males (seminal plugs)

• Sudden death (hemorrhage from ovarian artery)

Fig 10-13. Dystocia complicated by superovulation in a veiled chameleon.

Investigations

1. Radiography

a. The hemipenes are calcified and therefore visible in some lizard species, especially monitor lizards (Varanidae).

b. Eggs may be reasonably well calcified (many geckos) or poorly calcified (iguanas, water dragons); these latter are visible as circular to oval opacities. Typically these are in the caudal coelom, but because there is no diaphragm, in extreme cases they can occupy much of the coelomic cavity, displacing other organs dorsally. Eggs that are heavily mineralized, excessively large, or irregular in shape are usually abnormal (Fig. 10-13).

c. Ensures there are no obvious obstructions (e.g., pelvic deformities from metabolic bone disease)

d. Fetal skeletons may be visible in advanced gestation in live-bearing lizards, such as Solomon Island skinks (Corucia zebrata).

2. Transillumination

a. Useful in small, lightly pigmented lizards such as leopard geckos

b. Direct a small bright light (e.g., from an otoscope) through the body so as to view the underside of the lizard. The liver is usually readily identified and its relative size assessed. Eggs, bladder size, and fat pads can all be identified and assessed.

3. Routine hematology and biochemistry

a. Blood calcium levels

4. Culture and sensitivity

5. Endoscopy

6. Biopsy/necropsy

a. Hemorrhage in periovarian tissue

7. Ultrasonography

a. Useful for preovulatory ovarian stasis

TreatmentZspecific therapy

• Seminal plugs

• Gentle removal

• May be linked with hypovitaminosis A

• Dystocia

• Provision of correct environment, including appropriate temperature, humidity, and nesting chamber, may induce normal egg-laying. Supplement with calcium (e.g., calcium gluconate at 1 mL/kg PO b.i.d.).

• Medical induction

- Calcium gluconate at 100 mg/kg IM, SC every 6 to 12 hours

- Oxytocin 5 to 20 IU∕kg IM given 1 hour after last calcium

- Repeat over 2 to 3 cycles if lizard is otherwise healthy.

- If some eggs still retained after 48 hours, consider surgery.

- Argipressin at 0.01 to 1.0 μg∕kg IV every 12-24 hr for several treatments (more potent than oxytocin in reptiles)

• Percutaneous ovocentesis (Hall and Lewbart 2006)

• Only useful in small lizards with small numbers of eggs

• Performed under anesthesia with sterile 23G butterfly catheter. Beware of yolk leaking into coelomic cavity, aspiration of the viscera or their contents, both of which will trigger a serositis. Allow lizard to pass collapsed eggs.

• Salpingotomy

• Ovariosalpingectomy: Make a paramedian incision. Avoid incising into the ventral midline due to ventral vena cava (visible with transillumination).

Neonatal disorders

See Neonatal Disorders in Chapter 11.

Behavioral disorders

• Behavioral ITB (see Skin Disorders)

• Aggression in adult male iguanas

Signs

• Heightened aggression; iguanas may attack owner or passersby through the vivarium glass.

• Some male iguanas show heightened aggression at particular times of their female owner's menstrual cycle. Thought to be pheromonal in origin

TreatmentZspecific therapy

• Behavioral management is difficult due to restricted space available to give each iguana its personal space.

• With sexually motivated behavior, temporary improvement may be achieved with regular injections of delmadinone acetate at 1 mg/kg IM. Repeat as necessary.

• If delmadinone is effective, consider castration.

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