Cat Feline Hyperaldosteronism: Adrenal Disease

Hyperaldosteronism is an underdiagnosed cause of hypertension and muscle weakness in older cats treatable with medication or surgery.

Key Facts

Primary hyperaldosteronism (Conn's syndrome) is caused by adrenal adenoma or bilateral hyperplasia in cats
Aldosterone excess causes hypertension, hypokalemia, and episodic muscle weakness
Clinical signs include weakness, cervical ventroflexion from low potassium, and blindness from hypertensive retinopathy
Diagnosis requires plasma aldosterone and renin measurement plus adrenal imaging
Unilateral adrenal tumor is treated with adrenalectomy with good long-term outcomes
Medical management with aldosterone antagonist spironolactone controls bilateral hyperplasia cases
The condition is increasingly recognized as a significant cause of hypertension in older cats

Welfare Considerations

Undiagnosed hyperaldosteronism causes progressive hypertension leading to retinal hemorrhage and sudden blindness - a dramatic welfare harm. Muscle weakness causes inability to hold the head up in severe hypokalemia. These welfare harms are largely reversible with diagnosis and treatment - vision may recover with blood pressure control and weakness resolves with potassium normalization. Routine blood pressure screening in older cats enables earlier diagnosis.

What You Can Do

Measure blood pressure in cats over 10 years annually or when signs of hypertension appear
Investigate adrenal disease in cats with unexplained hypokalemia or muscle weakness
Request plasma aldosterone measurement in hypertensive cats that respond poorly to amlodipine alone
Pursue adrenal imaging in cats with confirmed hyperaldosteronism to identify surgical candidates
Support early ophthalmoscopic examination for hypertensive retinal changes enabling early intervention
Connect with specialist internal medicine practices for management of complex adrenal cases