Primary hyperaldosteronism in the cat: A series of 13 cases

Abstract

Thirteen cases of feline primary hyperaldosteronism were diagnosed based on clinical signs, serum biochemistry, plasma aldosterone concentration, adrenal imaging and histopathology of adrenal tissue. Two cases presented with blindness caused by systemic hypertension, whilst the remaining 11 cases showed weakness resulting from hypokalaemic polymyopathy. Elevated concentrations of plasma aldosterone and adrenocortical neoplasia were documented in all cases. Seven cases had adrenal adenomas (unilateral in five and bilateral in two) and six had unilateral adrenal carcinomas. Three cases underwent medical treatment only with amlodipine, spironolactone and potassium gluconate; two cases survived for 304 and 984 days until they were euthanased because of chronic renal failure, whilst the third case was euthanased at 50 days following failure of the owner to medicate the cat. Ten cases underwent surgical adrenalectomy following a successful stabilisation period on medical management. Five cases remain alive at the time of writing with follow-up periods of between 240 and 1803 days. Three cases were euthanased during or immediately following surgery because of surgical-induced haemorrhage. One cat was euthanased 14 days after surgery because of generalised sepsis, whilst the remaining cat was euthanased 1045 days after surgery because of anorexia and the development of a cranial abdominal mass. It is recommended that primary hyperaldosteronism should be considered as a differential diagnosis in middle-aged and older cats with hypokalaemic polymyopathy and/or systemic hypertension and should no longer be considered a rare condition.

Treatment of Aldosterone‐Secreting Adrenocortical Tumors in Cats by Unilateral Adrenalectomy: 10 Cases (2002–2012)

“…For cats that underwent surgical adrenalectomy in other studies, survival times were between 240 and 1,803 days 8, 9, 17. Unfortunately, perioperative complications resulted in a high frequency of euthanasia before discharge.…”

“…Medical management alone for PHA has been described in 3 cats17 and normally entails the use of spironolactone treatment, potassium supplementation, and antihypertensive drugs. Correction of hypokalemia was possible in 1 cat, but the others either required increasing doses of spironolactone to maintain normokalemia or normokalemia could not be achieved.…”

“…All 9 of these cats achieved normokalemia and resolution polymyopathy post adrenalectomy (normal, 3.5–4.8 mmol/L) without continued potassium supplementation. Hypertension also was refractory to medical management 17. Reported survival times for cats treated medically range from 50 to 984 days 8, 9, 17.…”

“…This disease was considered rare in humans and companion animals for many decades,2, 3, 4, 5 but recently has been found to be more prevalent with improved screening tests and detection in both humans and cats 6, 7. Since the first reported case of primary hyperaldosteronism in a cat in 1983,8 there have been only a few case reports of feline primary hyperaldosteronism (PHA) 9, 10, 11, 12, 13, 14, 15, 16, 17, 18…”

“…In cats, most cases of PHA are attributed to unilateral adrenal adenomas or carcinomas 19. There are only a few reports of unilateral adrenalectomies in cats, and perioperative complications of hemorrhage and death were reported in 8 of 18 surgical cases,11, 12, 16, 17, 19, 22, 23, 24 with 6 of those reported as fatalities.…”