Oral Vesicles, Erosions, Ulcers, or Growths
Bradford P. Smith
Oral lesions are found with many conditions (Boxes 7.20 and 7.21). In general, they result in some degree of dysphagia or reluctance to eat because of pain. The lesions include vesicles, erosions, ulcers, crusts, or growths in or on the lips, tongue, gums, palate, or pharynx.
Oral lesions are often associated with champing and increased amounts of saliva being observed on the lips or running from the mouth. When the volume of saliva is increased, the condition is called ptyalism and the animal may be observed swallowing repeatedly. Pseudoptyalism refers to a normal volume of saliva that, because it is not swallowed, is visible to the observer and may be confused with dysphagia (see previous section).The approach to determining the cause of oral lesions is based on first determining whether the cause is likely to be an infectious disease (Table 7.1). Essentially all these infectious diseases are associated with a fever, although it is short lived and moderate in the case of bovine papular stomatitis (BPS) and actinobacillosis. Papular stomatitis rarely causes illness and is usually an incidental finding in calves with a different clinical problem, although BPS can cause severe lesions and illness. Most of the infectious diseases are associated with additional lesions or symptoms. They can be conveniently grouped into those causing diarrhea and those not usually associated with diarrhea. Of those not associated with diarrhea in North America, BPS, actinobacillosis, and vesicular stomatitis
| ■ BOX 7.21 | |
| Conditions Accompanied by Oral Vesicles, Erosion | s, Ulcers, or Growths in Ruminants |
| Common Causes | Necrotic stomatitis |
| Bluetongue (O) | Epidermolysis bullosa |
| Contagious ecthyma (Orf virus) (O, C) | Familial acantholysis (B) |
| Bovine viral diarrhea/mucosal disease (B) | Oral neoplasia |
| Bovine papular stomatitis (B) | Epitheliogenesis imperfecta |
| Traumatic or irritant stomatitis | Hereditary zinc deficiency (baldy calf) (B) |
| Bristle grass (Setaria Iutescens or Setaria glauca) ulcers | Electrical injury |
| Other plant awn stomatitis | Bovine herpes 2 mammillitis (B) |
| Oral foreign body | Elaeophorosis (O) |
| Actinobacillosis (woody tongue) | Chlorinated naphthalene toxicity (B) |
| Vesicular stomatitis | Thallium toxicity (O) Giant hogweed (Heracleum mantegazzianum) toxicity |
| Less Common Causes | Lead toxicity |
| Actinomycosis (lumpy jaw) | Mycotoxicoses |
| Cheek abscess | Ibaraki disease (exotic) (B) |
| Periodontal gingivitis | Lumpy skin disease (exotic) (B) |
| Oak or acorn toxicity | Sweating sickness (exotic) (B) |
| Malignant catarrhal fever (B) | Sheep and goat pox (exotic) (O, C) |
| Irritant or caustic chemicals | Peste des petits ruminants (exotic) (O, C) |
| Uncommon Causes | |
| Caprine herpesvirus (C) Blister beetle (cantharidin toxicity) | |
B, Bovine; C, caprine; O, ovine.
■ TABLE 7.1
Infectious Diseases Associated With Oral Lesions in Cattle, Sheep, Goats, and Horses
| Disease | Natural Species | Oral Lesions | Other Lesions |
| Vesicular stomatitis (VS) | Cattle Horse Sheep (rare) | Vesicles for short time, then large ulcers; tongue usually severely involved | Teats and feet may be involved |
| Bluetongue | Sheep Goat (rare) Cattle (rare) | Large oral ulcers; dental pad and tongue most affected; generalized vasculitis | Coronitis, muscle degeneration, lameness, pulmonary edema, edema of face and ears |
| Contagious ecthyma (CE; Orf) | Sheep Goat | Proliferative scabby lesion on lips to fleshy growth on gums | Occasionally on teats of nursing dams |
| Bovine papular stomatitis* | Cattle | Round, dark red, raised papules on muzzle and on hard palate | Occasionally in esophagus |
| Foot-and-mouth (exotic) | Cattle Sheep Goat | Vesicles for short time, then large ulcers | Teats and coronary bands often involved |
| Bovine viral diarrhea/ mucosal disease (BVD/MD) | Cattle | Ulcers in mouth, particularly on hard palate; erosive stomatitis | May have skin lesions; a few have corneal edema or enlarged lymph nodes; pneumonia and lesions in esophagus and gastrointestinal tract common; severe diarrhea |
| Malignant catarrhal fever | Cattle | Erosive stomatitis with ulcers; | Purulent nasal discharge, corneal edema, |
| (MCF) | (Bison) | generalized vasculitis | enlarged lymph nodes, ± cracking skin, ± central nervous system signs; severe diarrhea; high fever |
| Rinderpest (exotic)f | Cattle | Erosive stomatitis | Blepharospasm, severe intestinal involvement, and diarrhea |
| Peste des petits ruminants (PPR) | Sheep Goat | Erosive stomatitis | Severe diarrhea, purulent ocular and nasal discharge |
| Alimentary form of infectious bovine rhinotracheitis (IBR) in calves | Cattle | Gray pinpoint pustules on soft palate and occasionally in nares; minimal oral lesions | Rhinotracheitis, conjunctivitis, pneumonia |
(VS) are most common in cattle; VS in horses; bluetongue in sheep; and contagious ecthyma (CE) in sheep and goats.
CE can be readily differentiated from bluetongue because it involves primarily lips and gums and is proliferative, whereas bluetongue involves the tongue and dental pad most severely, is erosive, and is associated with other signs of generalized vasculitis. Laboratory diagnosis in acute cases of VS is done by working with state and federal veterinarians. Because VS is highly contagious and similar in clinical appearance to foot-and-mouth disease, quarantine and proper diagnosis are essential. CE can be diagnosed serologically, by fluorescent antibody on the impression smear or biopsy of a lesion, and by isolation. Bluetongue is diagnosed by ELISA, serology (AGID), PCR, and virus isolation. Asymptomatic seroconversion to bluetongue is common where Culicoides vectors are active. Congenital defects can result from bluetongue infection of the fetus in sheep, goats, and cattle.The two most common North American infectious diseases associated with oral lesions and diarrhea in cattle are bovine viral diarrhea/mucosal disease (BVD/MD) and malignant catarrhal fever (MCF). MCF can usually be differentiated because it most commonly occurs sporadically in single animals and has signs of generalized vasculitis such as bilateral corneal opacity, mucopurulent nasal discharge, enlarged lymph nodes, and high fever. Dysentery is common in MCF, and some animals exhibit CNS signs or have thickened and cracking skin. See Chapter 32 for more on diagnosis of MCF. Laboratory diagnosis in acute cases of BVD (see the Bovine Viral Diarrhea section in Chapter 32) involves fluorescent antibody testing of slides made from ear notch biopsies, lesion swabs, buffy coat, or tissue. Virus isolation from swabs, serum, or blood or a rise in serum titer from acute to convalescent samples is also diagnostic. Asymptomatic seroconversion is also common, and infection of the fetus may result in congenital anomalies including cerebellar hypoplasia in cattle.
In animals without fever and other signs of systemic involvement, irritants and caustic chemicals should be considered as possible causes of oral lesions.
Horses and young calves are susceptible to severe ulceration when consuming hay contaminated with yellow bristle grass, which is armed with barbed bristles.40 Horses sometimes develop gingivitis or oral ulcers associated with dry plant awns called foxtails, which become embedded into the gums around teeth. Foals and ponies are most susceptible to phenylbutazone toxicity, which can produce oral ulceration. In cattle the surfaces of masses produced by actinobacillosis and actinomycosis sometimes ulcerate. Many cattle without significant disease have one or more small ulcers of traumatic origin from plant awns on the hard palate and in the cleft (sulcus lingualis) where the base and shaft of the tongue meet.Dental Abnormalities
Chronic fluorosis is a cause of a variety of dental abnormalities in young animals with developing teeth (Boxes 7.22 and 7.23). Although cattle are most frequently involved, all large animals are susceptible. The teeth may appear mottled, striated, chalky, or hypoplastic or may have defective calcification. In severe cases teeth may be yellow, brown, or black and have multiple caries. Animals of any age may also develop bone lesions associated with chronic fluorosis.
Porphyria is a rare congenital condition of cattle transmitted by a simple autosomal-recessive gene. The teeth often appear pink because of the presence of porphyrins and fluoresce pink, purple, or red when exposed to ultraviolet light. Affected calves often develop photosensitization and anemia. This condition must be differentiated from superficial staining caused by ingestion of black walnut hulls or other compounds with staining properties. Cattle fed sweet potato cannery waste develop dental erosions and tooth discoloration.
Excessive or uneven wear or loss of teeth is often seen in horses and ruminants as they age. Tooth wear, particularly of incisors, is more rapid in animals on sandy range. Periodontal disease can cause premature loss of teeth (broken mouth) and tends to be most common in sheep in some geographic areas; the cause of this is unknown.41
The most common dental disease in horses has been described as periodontal disease.42 In horses fractured teeth or teeth with a small tract into the root through an open infundibulum often result in tooth root abscesses.
This dental decay is a result of hypoplasia of the cementum of the enamel lakes and occurs most frequently in the second and third lower cheek teeth and third and fourth upper cheek teeth.43 These can cause sinusitis and foul-smelling unilateral nasal discharge if upper cheek teeth are involved or draining tracts to the exterior skin surface if lower cheek teeth are involved.Most of the other causes of dental abnormalities listed here are bone abnormalities that cause secondary loss of teeth. See dental sections of Chapter 32 for more details.
Icterus (Jaundice)
Icterus and jaundice are synonymous terms referring to the expression of a yellow coloration in the sclera and mucous membranes resulting from increased amounts of bilirubin in tissues and increased serum bilirubin levels (Boxes 7.24 and
■ BOX 7.23
■ BOX 7.22
Causes of Dental Cavities, Abnormalities of Tooth Color, and Loose Teeth in Horses
Causes of Dental Cavities, Abnormalities of Tooth Color, and Loose Teeth in Ruminants
Chronic fluoride toxicity
Bovine erythropoietic porphyria Fractured teeth
Osteogenesis imperfecta in Holstein Friesians Osteomalacia, osteodystrophy
Actinomycosis
Skeletal neoplasia of mandible or maxilla Lymphosarcoma (goat and sheep)
Periodontal disease
Broken mouth (old worn teeth)
Tooth root abscess with osteomyelitis
Ingestion of black walnut hulls or other dental stain Ingestion of sweet potato cannery waste (B)
B, Bovine.
■ BOX 7.24
■ BOX 7.25
Causes of Icterus in Horses
Liver
Common Causes
Pyrrolizidine alkaloid toxicity Serum-associated hepatitis Acute hepatitis
Chronic active hepatitis Cholangitis or cholangiohepatitis
Bile stones, other biliary obstruction Fasting hyperbilirubinemia
Less Common Causes
Aflatoxicosis with liver failure
Tyzzer disease (foals) Hepatic lipidosis Hepatic abscess
Uncommon Causes
Infectious necrotic hepatitis (black disease) Hemangioma, hemangiosarcoma, angiosarcoma Cardiac neoplasm
Viral arteritis
Gastric or duodenal ulcers
Severe ascarid infection
Lymphosarcoma
Hemolytic Anemia
Common Causes
Immune-mediated hemolytic anemia
Equine granulocytic ehrlichiosis (Anaplasma phagocytophilum, formerly Ehrlichia equi)
Neonatal isoerythrolysis
Less Common Causes
Piroplasmosis (babesiosis) Equine infectious anemia Snake bite
Blood transfusion
Erythrocytosis
Uncommon Causes
Equine viral arteritis Leptospirosis
Hemochromatosis
Bee or wasp sting Sulfur toxicity
Trichloroethylene-extracted feed
Iron toxicity
Phosphorus toxicity Herbicide toxicity
Phenothiazine toxicity
White snakeroot poisoning (tremetol)
Onion poisoning
Red maple (Acer rubrum) Pentachlorophenol toxicity
Oak toxicity
Mycotoxicosis
Surra, Trypanosoma evansi (exotic) Mal de caderas, Trypanosoma equinum (exotic) Murrina de caderas, Trypanosoma hippicum (exotic)
7.25).
Bilirubin especially stains elastic tissues and is thus most visible in the sclera and vulva. Icterus usually indicates decreased excretion of bilirubin with liver or biliary tract diseases or increased production of bilirubin with hemolytic anemia.The accumulation of conjugated bilirubin results in more pronounced jaundice than does a similar amount of unconjugated
Causes of Icterus in Ruminants
Liver
Common Causes
Pyrrolizidine alkaloid toxicity Aflatoxicosis
Fat cow syndrome (fatty liver)
Less Common Causes
Acute hepatitis
Liver flukes
Infectious necrotic hepatitis (black disease) Liver abscess
Cholangiohepatitis
Uncommon Causes
Sarcocystosis Hepatic neoplasia Ruptured gallbladder
Cholelithiasis
Biliary obstruction
Nolina (beargrass) toxicity Lantana, toxicity
Agave, toxicity Wesselsbron disease (exotic) (B, O)
Hemolytic Anemia
Common Causes
Leptospirosis Anaplasmosis
Bacillary hemoglobinuria (Clostridium hemolyticum) Piroplasmosis, babesiosis (exotic)
Less Common Causes
Snake bite
Oak (acorn) toxicity
Immune-mediated hemolytic anemia Transfusion reaction
Postparturient hemolytic anemia Copper toxicity (especially sheep)
Neonatal isoerythrolysis
Yellow lamb disease (Clostridium perfringens, type A) (O)
Uncommon Causes
Anaplasma ovis Eperythrozoonosis Bee or wasp sting Brassica species toxicity Trichloroethylene-extracted feed toxicity Iron toxicity
Onion poisoning Zinc poisoning Phosphorus poisoning Mercury poisoning
Fireweed (Kochia scoparia) poisoning Mycotic lupinosis
Mycotoxicosis Theileriosis (East Coast fever) (exotic)
B, Bovine; O, ovine.
bilirubin, with the result that the most pronounced jaundice is usually seen with hepatic or biliary obstructive disease. Laboratory examination of serum for relative amounts of unconjugated (indirect reacting) and conjugated (direct reacting) bilirubin is essential in determining the cause of the icterus. Generally, mainly unconjugated bilirubin levels are elevated with hemolytic anemia. Anorectic horses may have a plasma unconjugated bilirubin of 5 or 6 mg/dL without any evidence of hemolytic anemia or liver disease. Anorectic ruminants also experience a rise in plasma unconjugated bilirubin, often to a level between 0.5 and 2 mg/dL.
In determining the cause of icterus, laboratory tests including PCV, RBC count, and the liver enzymes SDH and GGT should be determined. In horses, alkaline phosphatase (AP) may also be useful, although it is not liver specific.
When active hepatocellular damage is occurring, SDH, which is liver specific, and aspartate aminotransferase (AST [SGOT]), which is not liver specific, are found in serum in elevated levels. GGT and AP are more indicative of biliary tract disease or proliferation and tend to rise more slowly but also remain elevated for a longer period than SDH, which has a short half-life. Elevated levels of GGT or AP are often associated with chronic liver disease, cholangitis, cholelithiasis, or liver flukes. It is possible to have liver disease without icterus. Production and elimination of bilirubin are often equal in chronic liver disease, but acute liver disease or liver failure is usually associated with icterus. Although liver function tests such as BSP half-time can be run to determine the extent of liver damage, in most cases a liver biopsy must be taken for histopathologic examination to make a specific etiologic diagnosis of the cause of liver disease.
Liver abscesses rarely result in icterus because they rarely damage a sufficient percentage of liver to impair bilirubin clearance. They do cause multifocal hepatic damage and therefore are often associated with increased levels of SDH and AST when in the acute stages of formation.
Hemolytic anemia is characterized by destruction of RBCs either intravascularly or in the reticuloendothelial organs. This increased destruction results in production of bilirubin more rapidly than it can be removed by the liver, resulting in icterus. The specific cause of hemolytic anemia may sometimes be evident, as when autoagglutination is seen (autoimmune hemolytic anemia). Anaplasma bodies are visible in stained RBCs of cattle, or Anaplasmaphagocytophilum (formerly Ehrlichia equi) blue cytoplasmic inclusion bodies are seen in stained neutrophils from horses.
In mature sheep, the most common cause of severe icterus is copper toxicity. In lambs, yellow lamb disease caused by C. perfringens, type A is a leading cause.