Acute suprarenal occlusion in an American Miniature Horse

A 7-month-old Miniature filly was examined because of a 4-day history of abnormal posture, lethargy and weakness. On initial evaluation, the filly presented with an abnormal stiff gait in her hindlimbs associated with hindlimb ataxia and lumbar kyphosis. She showed hindlimb discomfort by weight shifting from one hindlimb to the other. A complete blood count revealed an acute inflammatory leukogram associated with hyperfibrinogenaemia. The measurement of the serum amyloid A concentration indicated anactive inflammatory process. Biochemistry and urinalysis results revealed a severe azotaemia associated with diluted urine despite clinical dehydration, consistent with acute renal failure. Medical treatment was initiated with fluid therapy and antimicrobials. The pain was managed with morphine sulphate only, to avoid further kidney damage. The filly maintained an abnormal gait during this time, became progressively more ataxic and uncomfortable, and developed colic episodes. Because the horse was unresponsive to pain management, euthanasia was elected by the client. Post-mortem examination revealed an occlusive thrombus within the abdominal aorta, firmly attached to the intima, partially recanalised and extending from the aorta 1 cm along the right renal artery. In the left and right kidneys, severe subacute neutrophilic pyelonephritis, with lymphoplasmacytic interstitial nephritis was noted. In the hindlimb muscles, multifocal myocyte necrosis and evidence of regeneration was present. To the authors' knowledge, this is the first case of acute suprarenal occlusion to be described in a horse.

Automated summary

A 7-month-old Miniature filly presented with abnormal posture, lethargy, and weakness, which ultimately led to euthanasia due to severe renal occlusion and nephritis.