Pulmonary Edema and Pleuritis

The signs associated with pulmonary edema include dysp­nea, increased bronchial sounds, crackles, and cough. Thus, it may be difficult to distinguish the condition from a pleuritis or pneumonia of infectious origin.

Anaphylaxis and Fluid Therapy

Acute lung edema may be caused by an anaphylactic reac­tion to, for example, a serum or vaccine product. Emergency treatment measures for such an animal include epineph­rine (1 mL of 1 : 1000 strength or 1 mg/mL per 50 kg), the diuretic furosemide (5 mg/kg), and possibly atropine (100 μg∕kg) (Black 1986). If the edema occurs during the course of IV fluid therapy, the fluids should be temporarily discontinued and furosemide administered.

Cardiac Disease

Pulmonary edema may occur with severe exertion (as when chased by dogs), heart failure (i.e., because of white muscle disease, ionophore coccidiostats, or toxic plants), or a congenital heart defect. Vitamin E and selenium and symptomatic therapy such as diuretics are indicated.

Pulmonary Disease

Edema may occur in pneumonias caused by many of the infectious and parasitic agents already discussed. It is quite pronounced in certain other conditions affecting the lungs.

Toxic Gases and 3-methylindole

Toxic gases, particularly hydrogen sulfide, can cause pulmonary edema, but goats are rarely exposed to high lev­els of gases under normal housing conditions. Ruminal administration of 3-methylindole, a metabolite of L- tryptophan, causes severe pulmonary edema and respira­tory distress and moderate emphysema in goats (Carlson et al. 1972; Dickinson et al. 1976; Huang et al.

Cor Pulmonale

Chronic edema occasionally occurs along with cor pul­monale in severe long-term lung diseases such as pro­gressive pneumonia and adenomatosis (Gay and Richards 1983) or severe lungworm infestation (Buczinski et al. 2010). Goats thus affected also have ascites. Treatment is unrewarding.

Heartwater

In endemic areas (sub-Saharan Africa, Caribbean), infec­tion with the tick-borne rickettsia Ehrlichia (Cowdria) ruminantium (heartwater) may cause hydrothorax and pulmonary edema because of increased capillary permea­bility. In addition to dyspnea, clinical signs may include fever, central nervous system dysfunction, and death (Brown and Skowronek 1990). Edema of other organs such as lymph nodes and brain also occurs (Mebus and Logan 1988). Organisms may be demonstrated in endothe­lial scrapings of the aorta and jugular vein, or in capillaries in histologic sections or smears of the brain, as discussed in Chapter 8.

Pleuritis

Mannheimiosis, pasteurellosis, and mycoplasmosis are the most common causes of pleuritis in goats. Infections result­ing in abscessation, such as caseous lymphadenitis, can also result in pleuritis if an abscess ruptures into the pleu­ral cavity.

Of special note is the condition of sternal abscess or osteomyelitis. Goats that spend much time recumbent, as with arthritis, may develop a chronic draining tract over the sternum. Radiography is important in offering a prog­nosis, because if the infection extends between ribs or through sternebrae into the chest (see Figure 4.8), neither antibiotic nor surgical treatment is likely to be effective. Such animals have enlargement of sternal lymph nodes and, commonly, pleuritis.