Kidney Inflammation Due to Fluid Accumulation in Cats


PetMD Editorial

Published Mar. 18, 2010

Perirenal Pseudocysts in Cats


A perirenal pseudocyst is a condition in which fluid accumulates in a capsule surrounding the kidney, causing the kidney to enlarge. However, it is not technically a cyst because it lacks a true membrane covering. Perirenal pseudocysts primarily affects mature male cats (more than 8 years); if found in young cats, it commonly affects only one kidney.


Symptoms and Types


Although most cats with a perirenal pseudocyst have a nonpainful, enlarged abdomen, some may not display any symptoms (asymptomatic). In severe cases, symptoms of renal failure may manifest.




Although the exact cause of a perirenal pseudocyst is not completely understood, kidney tumors, surgeries involving the kidney, and certain types of injuries are thought to be factors for developing the capsule.




You will need to give a thorough history of your cat’s health, including the onset and nature of the symptoms, to your veterinarian. He or she will then perform a complete physical examination, as well a biochemistry profile, urinalysis, and complete blood count (CBC) -- the results of which are normal unless severe renal insufficiency is present.


Imaging studies, including X-rays and ultrasounds, may identify which kidney is affected. Additionally, a fluid sample from around the affected kidney may be taken for further evaluation.



Perirenal pseudocysts are usually not life-threatening and some cats need no treatment whatsoever. Otherwise, the fluid is surgically drained from the capsule, especially when the cat's abdomen is distended. There are also forms of treatment when severe renal diseases are involved.


Living and Management


Regular follow-up examinations (every two to six months) are required to evaulate the progression of the disease and the effectiveness of the treatment. Watch your cat for untoward symptoms, such as increased thirst (polydipsia), blood in urine (hematuria), and weight loss, and inform your veterinarian of them immediately, as they may be signs of renal failure.

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