Introduction
Hyperaldosteronemia in cats, sometimes called Conn’s syndrome or primary hyperaldosteronism, is a condition where a cat’s adrenal glands produce too much of the hormone aldosterone. While this disease is relatively uncommon, veterinarians are recognizing it more often as feline diagnostics advance.
Excess aldosterone leads to low potassium (hypokalemia), high blood pressure (hypertension), muscle weakness, and increased thirst and urination. Left untreated, hyperaldosteronemia can cause severe complications, including sudden blindness, kidney damage, and life-threatening crises.
This guide explains the causes, clinical signs, diagnostic steps, treatment options, and prognosis for cats with hyperaldosteronemia.
What Causes Hyperaldosteronemia in Cats?
In most cats, hyperaldosteronemia develops due to:
- Adrenal tumors – often benign (adenomas), though malignant tumors (carcinomas) are possible.
- Adrenal hyperplasia – abnormal enlargement of one or both adrenal glands, causing hormone overproduction.
Both conditions disrupt the body’s ability to regulate sodium, potassium, and blood pressure.
Clinical Signs of Hyperaldosteronemia in Cats
Because aldosterone affects potassium levels and blood pressure, signs can be dramatic or subtle. Common clinical signs include:
- Muscle weakness – especially in the hind limbs; cats may struggle to jump or show ventroflexion of the neck (head drooping).
- Increased thirst and urination (polydipsia and polyuria).
- Vision problems – high blood pressure may cause retinal detachment or bleeding in the eyes, leading to sudden blindness.
- Weight loss and lethargy despite a normal or good appetite.
- Hypertension-related complications – such as seizures, disorientation, or stroke-like events.
Because these signs can overlap with more common conditions like chronic kidney disease (CKD) or diabetes mellitus, hyperaldosteronemia is sometimes overlooked.
How Veterinarians Diagnose Hyperaldosteronemia
Diagnosis requires a stepwise approach:
- Physical examination – noting weakness, poor vision, or hypertension.
- Blood tests – often show:
- Low potassium (hypokalemia)
- High sodium (hypernatremia)
- Elevated kidney values (BUN, creatinine)
- Blood pressure measurement – hypertension is a hallmark feature.
- Hormone testing – aldosterone levels are measured to confirm overproduction.
- Abdominal ultrasound – helps identify adrenal gland enlargement or tumors.
- Advanced imaging (CT or MRI) – sometimes recommended before surgery for better surgical planning.
Treatment Options for Hyperaldosteronemia in Cats
1. Surgical Treatment
- Adrenalectomy (surgical removal of the affected adrenal gland) is the treatment of choice for cats with adrenal tumors.
- Surgery can be curative, especially if the tumor is benign.
- Cats usually require stabilization (correction of potassium and blood pressure) before surgery.
2. Medical Management
If surgery isn’t an option (due to age, concurrent disease, or owner preference), medical treatment can control the condition:
- Potassium supplementation (oral potassium gluconate).
- Antihypertensive medications such as amlodipine.
- Aldosterone antagonists such as spironolactone to block aldosterone’s effects.
- Supportive care tailored to kidney health and blood pressure control.
Prognosis for Cats with Hyperaldosteronemia
- Surgical cases: Cats with successful adrenalectomy may return to normal strength and activity, often regaining vision if retinal damage hasn’t been permanent. Prognosis is excellent if the tumor is benign.
- Medical management: Lifelong treatment can provide good quality of life though regular monitoring is essential. Prognosis is more guarded if cancer is present or if blood pressure/ potassium remain difficult to control.
Early detection makes a huge difference—cats diagnosed before severe complications often live several more healthy years.
Living with a Cat with Hyperaldosteronemia
Cats on medical management will need:
- Regular bloodwork (to monitor potassium and kidney function).
- Blood pressure checks.
- Eye examinations if blindness or vision loss has occurred.
Owners should watch closely for changes in thirst, urination, mobility, and appetite.
FAQs About Hyperaldosteronemia in Cats
Is hyperaldosteronemia common in cats?
It’s considered rare, but veterinary awareness is growing, and cases are being recognized more frequently.
Can blindness from hyperaldosteronemia be reversed?
Sometimes. If retinal detachment is treated quickly, vision may improve, but chronic damage can be permanent.
What age do cats usually get this condition?
Middle-aged to older cats (typically over 10 years old) are most commonly affected.
