Hyperaldosteronism
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Hyperaldosteronism is excessive production of the hormone aldosterone, usually from one or both adrenal glands. Aldosterone normally helps regulate sodium, potassium and blood pressure. When too much is produced, the kidneys lose excessive potassium and retain sodium, leading to low blood potassium and often significant hypertension.
The condition is most often recognised in older cats. Low potassium can cause profound muscle weakness. Affected cats may have difficulty walking, become reluctant to jump or develop ventroflexion, where weakness causes the head and neck to droop downwards. Increased thirst and urination may occur. High blood pressure can damage the eyes, kidneys, brain and heart, and sudden blindness from retinal detachment may be the first dramatic sign.
The adrenal cause may be a hormone-producing tumour or nodular enlargement of adrenal tissue. Some cats have changes affecting one adrenal gland, while others have bilateral disease. The distinction matters because a localised adrenal tumour may be surgically treatable.
The combination of hypertension and low potassium is particularly suggestive because it links two major effects of excess aldosterone. Recognising that pattern can shorten the diagnostic process. A cat treated only for blood pressure or only for potassium loss may improve temporarily while the underlying adrenal disorder continues to drive both problems.
Ventroflexion of the neck, a stiff or weak gait, sudden blindness, increased thirst or deterioration in previously stable kidney disease are particularly important clues. Detection is targeted to compatible abnormalities, especially in senior cats. Early recognition is valuable because prolonged severe hypokalaemia and hypertension can cause avoidable muscle, kidney and eye damage. Cats that undergo successful removal of a functional tumour can improve markedly, although recovery depends on kidney function and whether the tumour has invaded surrounding structures.
Screening & Early Detection
Older cats with unexplained hypertension, persistent low potassium or unusual muscle weakness should be evaluated for hyperaldosteronism.
Routine blood chemistry can identify hypokalaemia, while blood pressure measurement reveals hypertension that may otherwise be silent. Eye examination is useful because retinal haemorrhage or detachment can be evidence of target-organ damage from high blood pressure.
When hyperaldosteronism is suspected, the veterinarian measures aldosterone and interprets the result with potassium status and other hormone information. Abdominal ultrasound can identify adrenal enlargement or a mass. CT may be recommended before surgery to define tumour size, blood-vessel involvement and the opposite adrenal gland.
There is no general screening programme for healthy young cats. Cats receiving treatment need repeated potassium and blood-pressure measurements because both can change quickly as therapy begins.
Diagnosis begins with finding persistent low potassium and/or hypertension in a compatible cat. Blood aldosterone concentration and related hormone testing help confirm inappropriate aldosterone production. Ultrasound or advanced imaging is used to examine the adrenal glands and look for invasion or spread when a tumour is suspected. Hyperaldosteronism can mimic other diseases that cause weakness or kidney changes, so diagnosis requires a combination of laboratory and imaging findings.
Treatment & Management
Treatment depends on whether the disease is caused by a surgically removable adrenal tumour or by bilateral adrenal overactivity. A localised unilateral tumour may be treated with adrenalectomy when imaging shows surgery is feasible and the cat is an appropriate anaesthetic candidate. Because adrenal surgery can be complex, referral to an experienced surgical team is often recommended.
Medical management is used for cats that are not surgical candidates or have bilateral disease. Potassium supplementation corrects hypokalaemia, while spironolactone blocks many effects of aldosterone. Additional antihypertensive medication, commonly amlodipine, may be needed to control blood pressure.
Potassium must be corrected carefully and monitored, particularly when severe weakness is present. Kidney function, electrolytes and blood pressure are rechecked regularly so doses can be adjusted. Eye damage from hypertension may not be reversible if retinal injury has been prolonged, making prompt blood-pressure control important.
Medically managed cats can also maintain good quality of life when potassium and blood pressure remain controlled. Long-term monitoring is required whichever approach is used.
Treatment can produce substantial improvement, particularly when potassium deficiency is corrected and blood pressure is controlled promptly.
Breeds or species affected
Abyssinian
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American Bobtail
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American Curl
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American Shorthair
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American Wirehair
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Arabian Mau
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Aegean
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Australian Mist
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Balinese
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Bengal
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Birman
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Bombay
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British Longhair
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British Shorthair
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Burmese
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Burmilla
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Chartreux
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Chausie
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Colorpoint Shorthair
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Cornish Rex
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Cymric
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Devon Rex
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Domestic Longhair
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Domestic Medium Hair
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Domestic Shorthair
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Donskoy
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Egyptian Mau
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European Shorthair
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Exotic Shorthair
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Havana Brown
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Highlander
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Himalayan
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Japanese Bobtail
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Khao Manee
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Korat
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Kurilian Bobtail
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LaPerm
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Lykoi
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Maine Coon
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Manx
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Minuet
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Minskin
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Munchkin
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Nebelung
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Norwegian Forest Cat
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Ocicat
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Oriental Longhair
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Oriental Shorthair
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Persian
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Peterbald
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Pixiebob
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RagaMuffin
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Ragdoll
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Russian Blue
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Savannah
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Scottish Fold
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Scottish Straight
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Selkirk Rex
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Siamese
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Siberian
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Singapura
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Snowshoe
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Somali
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Sphynx
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Thai
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Tonkinese
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Toybob
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Toyger
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Turkish Angora
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Turkish Van
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Bambino
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Cheetoh
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Dwelf
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Elf Cat
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Genetta
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Kinkalow
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Lambkin
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Serengeti
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Skookum
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Ukrainian Levkoy
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