Clinical signs of hyperadrenocorticism (HAC), an uncommon endocrinopathy in cats, can include polyuria, polydipsia, and polyphagia, although these signs are usually attributed to concurrent diabetes mellitus that occurs in 80% of affected cats. Dermatologic signs (eg, thin, easily bruised skin) may also be seen.

This report of systemic hypertension and blindness secondary to pituitary-dependent HAC in the cat documented a 7-year-old neutered Burmese cat presented for acute blindness caused by bilateral retinal detachment. Systolic arterial blood pressure was found to be elevated at 300 mm Hg. The cat’s hypertension was controlled with amlodipine besylate; however, the cat again presented later for polyuria, polydipsia, weight loss, and thinning skin with poor hair regrowth. Dexamethasone suppression test, endogenous ACTH concentration, ACTH stimulation test, and ultrasonography of the adrenal glands were consistent with pituitary-dependent HAC. Trilostane treatment was initiated but discontinued because of anorexia. Bilateral adrenalectomy was performed and adrenocortical hyperplasia was confirmed on histopathology. Although concurrent chronic kidney disease at presentation could not be ruled out as a cause of hypertension, blood pressure remained normal after adrenalectomy and discontinuation of amlodipine. Four years after presentation, the cat suffered a hypoglycemic seizure and was euthanized; pituitary adenoma was identified on postmortem examination.

Commentary
This interesting feline case report documented hypertension and retinal detachment that resolved with bilateral adrenalectomy. The clinical signs noted were typical for HAC in cats (thin skin, diabetes), and testing supported the diagnosis of pituitary-dependent HAC. What should not have been completely excluded was the contribution of hyperaldosteronism to the high blood pressure, as bilateral hyperplasia of the adrenal glands can be seen with this as well; however, hypokalemia is usually present and tends to be severe and difficult to treat. In dogs, hypertension is common with Cushing’s disease, but serious adverse effects (hypertensive retinopathy) have not been documented. The take-home point is that adrenal gland form and function may be worth investigating in cats with clinically significant hypertension.—Anthony P. Carr, DrMedVet, DACVIM (Small Animal)

Source
Severe systemic hypertension in a cat with pituitary-dependent hyperadrenocorticism. Brown AL, Beatty JA, Lindsay SA, Barrs VR. J SMALL ANIM PRACT 53:132-135, 2012.