In January of 1999, Daisee, a very affectionate five-month-old domestic shorthaired cat was diagnosed with an unusual and potentially life-threatening condition. Large fluid filled structures called pseudocysts had formed around each kidney and were rapidly expanding. The pressure within each pseudocyst was increasing and causing damage to her kidneys. Daisee was becoming anemic and her kidney function tests were abnormal. The blood level of urea and creatinine, waste products normally removed by the kidneys, was starting to rise. Her urine concentration was below normal a further indication of her compromised kidney function.
When Daisee first presented to our hospital in early January, her symptoms were very vague but her owner knew something was wrong. Daisee had been quieter than usual and had not eaten well for a few days. She had diarrhea for a few days as well. Dr. Barbara Wohlfahrt examined Daisee and submitted preliminary blood work to further evaluate Daisee’s condition. Daisee’s lab tests were normal but this initial screen would serve as a valuable baseline for comparison as her condition progressed. Daisee was sent home with medication to help control the diarrhea.
Over the next two weeks Dr. Wohlfhart had several phone consultations with Daisee’s owner. Daisee seemed better at times. The diarrhea had stopped and she was eating and more playful, but she was still not as active as a kitten her age should be. Dr. Wohlfahrt recommended another exam and Daisee returned to the hospital. Follow up examination and laboratory tests revealed the progression of her illness. Most remarkably she now had palpable fluid masses within her abdomen and these structures were expanding. As mentioned earlier her kidney function tests were abnormal and she was becoming anemic. Abdominal radiographs revealed two greatly enlarged kidney silhouettes. The list of possible causes for this apparent kidney enlargement included diseases such as Feline Lymphosarcoma, Hydronephrosis, Polycystic Kidney Disease, and an unusual condition called Paranephric Pseudocyst. Feline Lymphosarcoma is a cancer condition that occurs in young as well as older cats. Hydronephrosis is a life threatening condition caused by obstructive urinary tract disease that results in the kidney itself becoming distended by fluid. Polycystic Kidney Disease results when multiple fluid filled cysts form within the kidneys. Paranephric Pseudocyst is a rare condition that results in a fluid filled space developing around, rather than within, the kidneys. Each diagnosis carries with it a very different prognosis. Narrowing the list of possibilities was very important.
The radiographs below show two perspectives of the large fluid filled structures within Daisy’s abdomen. While the radiographs were very helpful the next challenge was to further narrow the lists of possibilities.
Daisee’s abdominal ultrasound provided the needed information. We were encouraged to find that within these large fluid-filled cysts, Daisee had reasonably normal sized kidneys. Based on ultrasound, the most likely diagnosis was Paranephric Pseudocyst.
There was a good possibility that Daisee could be helped. The next hurdle was surgery to remove the cysts surrounding her kidneys. Daisee was taken to surgery where Dr. Lemieux removed the cystic structures while carefully preserving the kidneys. A circulating warm water blanket and IV fluids helped maintain her body temperature and blood pressure during the procedure. Careful monitoring of her heart rate, pulse pressure, and blood oxygen saturation helped minimize the anesthetic risks associated with this procedure.
The procedure is repeated on the right kidney and both pseudocysts are removed. This photo shows the right kidney after the pseudocyst has been removed. The dark area on the kidney was biopsied and found to be organized fibrin.
Daisee was very stable throughout the surgery. Her smooth recovery was enhanced with the use of pain relief medication.
he tissue removed at the time of surgery was submitted to Tufts University for histopathology. The diagnosis of Paranephric Pseudocyst was confirmed.
Daisee went home two days after surgery. She returned ten days later for suture removal and was doing great. Her long-term prognosis is very good.
The cause of the development of Paranephric Pseudocyst remains a mystery today.
The condition has been well described in the veterinary literature but the cause is unknown.
One of the great dangers with this condition is irreversible kidney damage that may be caused by prolonged increased pressure within the pseudocyst.