Page 1053 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

1028 CHAPTER 9

VetBooks.ir Aetiology/pathophysiology Differential diagnosis
The main differentials include other causes of pete-
EPH usually develops 2–4 weeks after infection with
S. equi, S. zooepidemicus, equine herpesvirus-1 (EHV-1)
EIA and anaplasmosis.
or equine influenza virus. Other infectious agents are chial haemorrhage and vasculitis including EVA,
less commonly implicated.
Hypersensitivity to infectious antigens is sus- Diagnosis
pected as the cause of this phenomenon. As a result, EPH can be suspected based on a clinical history of
a vasculitis develops, and this leads to most of the recent S. equi infection or vaccination, or infection
clinical and laboratory abnormalities. with other respiratory pathogens and appropriate
clinical signs. Histological evidence and identifica-
Clinical presentation tion of globulin deposition along vessel walls via
Clinical signs can be variable and include head, ventral immunofluorescence testing in a skin or mucous
body and limb oedema, petechiation, ecchymosis, fever membrane biopsy is confirmatory. CBC abnormali-
and anorexia (Fig. 9.31). Heart rate is often elevated ties may include neutrophilia, mild anaemia and
consistent with the severity of disease. Rapid weight hyperfibrinogenaemia. Thrombocytopenia is not
loss may occur, presumably because of an advanced often present. Testing should also be directed at
catabolic state in severe cases. Respiratory stridor and identifying the inciting cause.
dysphagia may occur with pharyngeal oedema and
inflammation. Oedema may be severe, with oozing of Management
serum and sloughing of skin. Inflammation of the GI Early and aggressive therapy is required to
mucosa, while less common, can cause abdominal pain treat EPH. Corticosteroids (dexamethasone
and ileus. Renal failure may develop. 0.05–0.2 mg/kg i/m or i/v q24 h or prednisolone
0.5–1.0 mg/kg p/o q12–24 h) are almost always
used. Dexamethasone may be more effective than
9.31 prednisolone early in the disease. Corticosteroids
should be tapered gradually and treatment for
14–21 days is often provided. Antimicrobials
(sodium penicillin, 20,000 IU/kg i/v q6 h; pro-
caine penicillin, 20,000 IU/kg i/m q12 h; ceftiofur
sodium, 2.2 mg/kg i/v/or i/m q12 h; or trime-
thoprim/sulpha, 24–30 mg/kg p/o or i/v q12 h) are
indicated to help prevent bacteraemia and sepsis
and to eliminate any remaining inciting bacterial
antigenic stimulus. With severe vasculitis and tis-
sue sloughing, adequate gram-negative coverage
should be provided by using ceftiofur or combin-
ing penicillin with an aminoglycoside (gentamicin,
6.6 mg/kg i/v q24 h) provided hydration, perfusion
and renal function are adequate. Intravenous fluid
therapy may be required in severe cases. Provision
of soft feed may be required in dysphagic animals.
Rarely, tracheostomy will be required. Frequent
walking, cold water hosing and application of sup-
port wraps are useful for controlling limb oedema.
Fluids, analgesics and NSAIDs are required to
Fig. 9.31 Severe limb oedema in a horse with correct dehydration, reduce pain and decrease
purpura haemorrhagica. inflammation, respectively.