Painful Peripheral Swellings
Close inspection of the skin and extremities of patients can reveal evidence of peripheral vascular or lymphatic system disease. These diseases can be manifested by diffuse swelling; localized swelling (papules, nodules, macules, or wheals); or subcutaneous edema of the extremities.
Frequently there is necrosis, ulceration of the skin, and exudation as the disease progresses. Animals may be lame, have heat in the involved area, or exhibit a painful response to palpation of the area (Boxes 6.14 and 6.15), which helps to differentiate these conditions from nonpainful peripheral edema. Swellings in the neck may cause dyspnea or abnormal carriage of the head. In light of the zoonotic potential of certain infectious agents (e.g., glanders, sporotrichosis), donning of appropriate personal protective equipment should be considered.Approach to Diagnosis of Painful
Peripheral Swellings
1. Take history. Establish whether there is a history of a wound or trauma to the area or previous drainage; inquire about previous infections, particularly those referable to the respiratory system, in this animal or others; determine vaccination, deworming, and drug administration history.
Causes of Painful Peripheral Swellings in Ruminants
Common Causes
Thrombophlebitis Abscess
Clostridial myositis Malignant edema Blackleg
Muscle disruption/trauma/hematoma
Carpal hygroma Fescue foot
Ergotism
Cellulitis (injection site or wound) Fracture
Insect bite
Frostbite
Uncommon Causes
Disseminated hemangiosarcoma
Heartwater disease (Ehrlichia ruminantium, exotic) Snakebite
Septic tenosynovitis Bursitis
2. Perform a physical examination. Determine vital signs. Note whether the animal is febrile; examine extremities for wounds, dilated lymphatic channels, ulcers, focal swellings, and edema; determine the temperature and sensitivity of the swollen area; examine mucous membranes for color and presence of hemorrhages; perform a rectal examination and palpate aortic quadrifurcation in horses for vessel size, firmness, pain, fremitus, and strength of pulse; evaluate these vessels before and after exercise, if indicated; test saphenous refill by holding off the saphenous vein distally over the hock, stripping the vein proximally, and releasing the pressure over the vein at the level of the hock.
3.
Obtain blood for the following:a. CBC (includes examination of red blood cells, neutrophils, and eosinophils for inclusion bodies or morula and determination of platelet count)
b. Fibrinogen concentration
c. SAA concentration
d. Total protein concentration
e. Coombs or direct immunofluorescence test
f. Appropriate tests for equine ehrlichiosis (immunofluorescence assay), piroplasmosis (complement fixation), or viral arteritis (serum neutralization), if indicated
4. Take radiographs of swollen extremities, if appropriate.
5. Perform an ultrasound examination of the swelling, if appropriate. Perform transrectal ultrasound examination of terminal aorta and iliac arteries of horse if palpation or physical examination findings suggest thrombus.
6. Obtain Gram stain and bacterial and fungal culture of ulcerated area or exudate.
7. Perform a biopsy of granulomas and submit for histopathology and culture and sensitivity testing, if appropriate.
8. Analyze and culture fluid obtained from dilated lymphatic channels or localized edematous areas.
9. Analyze urine to look for hemoglobinuria or hematuria.
10. Test feces for fecal occult blood.