Recently, one of my colleagues was conducting a routine health check on a cat when she felt a large mass in its abdomen. The cat was otherwise well, still quite young and healthy, but clearly something was not quite right. The cat was booked in for an ultrasound and hydronephrosis of the left kidney was diagnosed.

This is where the flow of urine away from the kidney has been blocked and, with nowhere for it to go, urine builds up in the kidney. This causes swelling and, eventually, permanent damage.

Ultimately, the kidney resembles a large cyst with very little internal structure remaining and this was what my colleague was able to feel. Hydronephrosis is from the Greek words of hydro (water) and nephros (kidney).

An increased risk of rupturing

Although the large swollen kidney didn’t seem to be bothering the cat, we know in humans they can be painful. Hydronephrosis can also predispose to kidney infections and the kidney would be at an increased risk of rupturing. We were also worried for the healthy right kidney. Having the diseased organ examined would enable us to tell whether the underlying cause might eventually damage the healthy kidney.

Our feline patient was booked in for surgery and the diseased kidney and ureter were carefully removed (nephroureterectomy). All went well and our patient made a quick recovery. Our suspicion in this cat was that the condition was congenital, so the other kidney should remain unaffected. Our patient should go on to live a full and healthy life, even with only one kidney.

Kidney disease is very common in older cats. Common symptoms can be an increased thirst, urination, weight loss, nausea and loss of appetite. In cats it can lead to high blood pressure, which in turn can cause blindness and other neurological signs. Kidney disease can be detected with blood tests, and blood pressure can be easily monitored and treated as well. A routine health check is a great opportunity to get your cat checked over and discuss any health concerns you have with your vet.