Oxalate Nephrosis and Renal Sclerosis After Renal Transplantation in a Cat

A 10-year-old castrated domestic shorthair cat received two renal allografts, 14 days apart, for the treatment of chronic renal failure. Oxalate nephrosis developed in both allografts, and they became nonfunctional. During the transplantation period, the cat was not exposed to exogenous sources of oxalate, and there was no evidence of primary type 2 hyperoxaluria before surgery. Urologic surgery, in particular renal transplantation, has been identified as a factor that can precipitate renal failure in human patients with decompensated renal function and hyperoxaluria. If hyperoxaluria was present before surgery in this cat, it was most likely caused by increased absorption or decreased metabolism of dietary oxalate.     

Chronic vomiting associated with a gastric carcinoid in a cat.

A geriatric domestic shorthair cat was presented for evaluation of chronic vomiting. Chronic renal failure was diagnosed on the basis of physical examination findings and results of a serum biochemical profile and urinalysis. Endoscopically obtained gastric biopsies were suggestive of a carcinoid tumor. Subsequently, an exploratory celiotomy with partial gastrectomy was performed. Histopathological and electron microscopic analysis of surgical biopsy specimens confirmed the diagnosis of a gastric carcinoid, which has not been previously reported in the cat. Following complete excision, the cat remained clinically stable and free of signs of gastrointestinal disease for 4 months before requiring treatment for progressive renal failure.     

Distal renal tubular acidosis and hepatic lipidosis in a cat

Clinical and laboratory evidence of hepatic failure was found in a chronically anorectic cat. Simultaneous blood and urine pH determinations established a diagnosis of distal renal tubular acidosis. The cat did not respond to treatment. Necropsy revealed distal tubular nephrosis and hepatic lipidosis. The finding of distal renal tubular acidosis in a cat with hepatic lipidosis emphasizes the importance of complete evaluation of acid-base disorders in patients.     

Retrieval of ureteral calculus using a new method of endoscopic assistance in a cat

A 9-year-old female spayed domestic short-haired cat presented with ureteral obstruction due to a ureteral calculus 4 cm distal to the renal pelvis. Preoperative creatinine was 844 mmol/L. A novel approach to this condition was utilised whereby a flexible endoscope was passed through a hole made in the renal capsule into the renal pelvis and ureter. The calculus was visualised, and the endoscope was removed. A 1.4 mm flexible grasping forceps was introduced into the proximal ureter through the same hole in the renal capsule and the calculus was removed. The creatinine dropped to 282 micromol/L within 2 weeks of surgery. The cat died of apparently unrelated causes several months after surgery.     

Renal cystadenoma in a domestic shorthair

An 11-year-old domestic shorthair was examined after an enlarged left kidney was palpated by the referring veterinarian. No abnormalities were noted on complete blood count, serum biochemical profile and total thyroxine concentration, and the urine specific gravity was 1.039. An abdominal ultrasound identified the presence of a large cystic structure on the caudal pole of the left kidney. No abnormalities of the right kidney were seen. A left ureteronephrectomy was performed, and the cat recovered uneventfully from the procedure and was discharged from the hospital 5 days after surgery. The cat remains clinically normal 16 months postoperatively. Histopathology of the removed kidney demonstrated the presence of a renal cystadenoma. This report describes the successful surgical treatment of a renal cystadenoma. Renal cystadenoma should be considered as a differential diagnosis when renomegaly is noted. To the author's knowledge, a renal cystadenoma has not been previously reported in a cat.     

Renal adenoma in a cat

Renal adenoma, a benign tumor of epithelial origin, was diagnosed in a 10-year-old cat. Clinical signs included decreased appetite and weight loss. Nephrectomy resulted in clinical improvement. Seven months after surgery, the cat died, and pulmonary papillary adenocarcinoma was discovered. The pulmonary neoplasm differed markedly from the renal neoplasm.     

Primary aldosteronism (Conn's syndrome) in a cat; a case report and review of comparative aspects

An aged cat was presented with a history of chronic relapsing weakness and depression. Profound hypokalaemia was detected in association with increased serum aldosterone levels and marginally subnormal plasma renin activity. A diagnosis of primary aldosteronism (Conn's syndrome) was made and the cat was successfully treated for 2 ½ months with spironolactone. When renal failure developed, the cat was destroyed and at autopsy a large adrenal cortical adenocarcinoma was found.     

Hypertensive retinopathy in a cat

A 12-year-old cat presented for sudden blindness was diagnosed with hypertensive retinopathy on the basis of ophthalmologic and ultrasonic examination. Renal failure due to a large intranephric cyst obstructing the right ureter and renal artery was the suggested cause of the systemic hypertension. The cat died 8 hours after unilateral nephrectomy.     

A case of renal oxalosis in a 3-month-old cat raised under controlled conditions

The kidneys of a 3-month-old female cat were examined. The cat which had been raised under controlled conditions with no history of any poisoning showed progressive weight loss with increases in blood BUN and creatinine concentrations. At necropsy, both kidneys were firm in consistency with formation of focal scars. Histopathologically, widespread deposition of crystals was observed in the renal tubules (in both dilated lumina and degenerative epithelia) accompanying mild interstitial fibrosis with lymphocyte infiltration. The crystals were colorless or basophilic on the hematoxilin and eosin-stained section and could be visualized with polarized light as doubly fractile crystals. The crystals were identified as calcium oxalate crystals by histochemical examinations using von Kossa stain and alizarin red S stain under different conditions and by ultrastructural examination. Judging from the above-mentioned findings, the present renal lesion detected in an infant cat was diagnosed as renal oxalosis which was suspected to be hereditary in nature.     

Cholecalciferol rodenticide intoxication in a cat.

A 4-month-old 2.5-kg sexually intact female domestic shorthair cat was referred to the teaching hospital because of suspected cholecalciferol intoxication after ingestion of a cholecalciferol-containing rodenticide. At referral, the cat was hypercalcemic, hyperkalemic, and acidotic. Despite management of hypercalcemia and preservation of renal function with physiologic saline solution, furosemide, dopamine, and calcitonin, the cat died, apparently as a result of extensive pulmonary mineralization.     

Proximal ureteral ectopia causing hydronephrosis in a kitten

A 2-month-old, female cat was presented for abdomen dilation. The patient was undernourished, and severe left hydronephrosis was diagnosed after clinical, ultrasonographical and radiographical examination. Although pyelography was performed in order to visualise the ureteral course, surgery was necessary to reach a final aetiological diagnosis and treatment. At gross examination, the left ureter crossed the renal capsula at the level of the caudal renal pole, and the subcapsular ureteral segment was markedly dilated. Distal to the renal capsula, the left ureter was very thin when compared to the right. The parenchyma of the left kidney, as suggested by ultrasonographical evaluation, was extremely reduced in thickness. An ureteronephrectomy was performed. Histopathological evaluation revealed glomerular sclerosis and diffuse parenchymal fibrosis. Severe hydronephrosis derived from an altered renal pelvic anatomy and abnormal ureteral course determining functional stenosis. Diagnosis of congenital anomaly before development of complications such as hydronephrosis could have allowed a surgical renal capsulectomy and obstruction relief. To the author's knowledge, this is the first report of severe hydronephrosis associated to altered renal pelvic anatomy and proximal ureteral ectopia in cat.     

Renal pelvic rupture,intrapelvic haematoma and retroperitoneal haemorrhage associated with obstructive ureterolithiasis in a cat

A neutered female cat presented with a 9-day history of hyporexia and depression. The referring veterinarian had identified moderate non-regenerative anaemia, haematuria and suspected unilateral obstructive ureterolithiasis. Subsequent ultrasonography revealed moderate distension of the left renal pelvis with echogenic material, ureteral distension and ureterolithiasis. A partial ureteral obstruction was suspected. After 4 days of medical management, there was further distension of the renal pelvis with well-delineated echogenic material and an accumulation of perinephric fluid. A left nephroureterectomy was performed. Renal pelvic rupture with intrapelvic haematoma and retroperitoneal haemorrhage was confirmed by histopathology. Eighteen months following surgery, the cat remained clinically well with normal renal values.     

Unilateral improvement in glomerular filtration rate after permanent drainage of a perinephric pseudocyst in a cat

A 12-year-old, 6 kg, castrated male Siamese-cross cat was referred for investigation of an abdominal mass. The cat was found to have a left perinephric pseudocyst (PNP), accompanied by azotemia, with a small right kidney detected on ultrasound. Glomerular filtration rate (GFR) was determined by renal scintigraphy and was found to be low, with the left kidney contributing 64% of the total GFR. Percutaneous ultrasound-guided drainage of the PNP did not improve the GFR, and fluid reaccumulated within a short period of time. Laparoscopic fenestration of the cyst capsule was performed to allow for permanent drainage. The PNP did not recur, renal values progressively improved, and 8 months after the capsulotomy the GFR of the left kidney had increased by 50%, while renal function remained static on the right side.     

Minimal change glomerulopathy in a cat

A 6-year-old domestic shorthair male castrated cat was evaluated for sudden onset of vomiting and anorexia. A diagnosis of hypereosinophilic syndrome (HES) was made, and the cat was treated with imatinib mesylate. The cat had an initial clinical improvement with the normalization of the peripheral eosinophil count. After approximately 8 weeks of treatment, lethargy and anorexia recurred despite the normal eosinophil count and a significant proteinuric nephropathy was identified. Treatment with imatinib was discontinued. Ultrasound guided renal biopsies exhibited histologic, ultrastructural, and immunostaining changes indicative of a minimal change glomerulopathy (MCG) which has not previously been reported in the literature in a cat. The proteinuria and HES initially improved while the cat was treated with more traditional medications; however, both the problems persisted for 30 months that the cat was followed subsequently. Previous studies demonstrating the safety and efficacy of imatinib in cats do not report any glomerular injury or significant adverse drug reactions, and the exact cause of this cat's proteinuric nephropathy is uncertain. Nonetheless, the possibility of an adverse drug reaction causing proteinuria should be considered when initiating treatment with imatinib in a cat.     

Preliminary study of urinary excretion of liver-type fatty acid-binding protein in a cat model of chronic kidney disease

Urinary liver-type fatty acid-binding protein (uL-FABP) is a clinically useful biomarker for monitoring chronic kidney disease (CKD) in humans. However, long-term monitoring of uL-FABP in CKD cats has not been reported. The objective of this preliminary study was to investigate whether the urinary excretion of L-FABP could predict the deterioration of renal function in 2 CKD model cats. Urinary liver-type fatty acid-binding protein (uL-FABP) increased before standard renal biomarkers, including serum creatinine, blood urea nitrogen, and symmetric dimethylarginine, in 1 cat with deteriorating renal function, but remained low and relatively stable in another cat with stable renal function. Our results suggest that uL-FABP is a potential clinical biomarker for predicting the progression of CKD in cats, as it is in humans.     

Adenocarcinoma of the disseminated prostate in a cat

An adenocarcinoma of the disseminated prostate gland with pulmonary, myocardial and renal metastases is described in a 12-year-old, neutered male European cat. Histologically, the tumour was localised in the spongy layer of the prostatic urethra and showed an epithelial alveolar pattern. Considering the anatomic, microscopic and immunohistochemical findings, the tumour was diagnosed as an adenocarcinoma of the disseminated prostate gland. To our knowledge this is the first report of adenocarcinoma of the disseminated prostate gland in a cat.     

Calcinosis involving multiple paws in a cat with chronic renal failure and in a cat with hyperthyroidism

Calcinosis of multiple paws is described in two cats. A metastatic pathogenesis was supported by the laboratory findings of hyperphosphataemia and a calcium x phosphorus solubility product > 7 g/L. Hyperparathyroidism could not be confirmed because a valid feline parathyroid hormone assay was not available at the time. One cat was diagnosed with chronic renal failure and presented initially with an irregular nodular calcification on the chin. Dietary and medical management was unsuccessful and ultimately the animal was euthanased. Hyperthyroidism was diagnosed in another cat by laboratory findings and scintigraphic imaging. In addition, the cat had a hyperphosphataemia in the absence of azotaemia. Intravenous administration of radioactive iodine as (131)I was accompanied by reduction and normalization in serum total thyroxine and phosphorus concentrations and resulted in resolution of calcification in the paws.     

Use of trilostane for the treatment of pituitary-dependent hyperadrenocorticism in a cat

Hyperadrenocorticism occurs much less frequently in cats than in dogs and, at present, is more difficult to manage successfully. This report documents the use of the steroid synthesis inhibitor trilostane for the treatment of hyperadrenocorticism in a domestic shorthaired cat with pituitary-dependent disease. Although trilostane was able to alleviate the severity of the clinical signs and was well tolerated, the cat subsequently died of renal failure secondary to a fungal infection of the urinary tract.     

Primary hypoparathyroidism in a cat

Primary hypoparathyroidism caused by lymphocytic parathyroiditis was diagnosed in a cat. Other causes of hypocalcemia (ethylene glycol toxicosis, phosphate enema administration, pancreatitis, renal insufficiency, and malabsorption) were ruled out on the basis of history, clinicopathologic data, and lack of supportive clinical signs, which in this cat included inappetence and tetanic muscle spasms. The diagnosis was confirmed by histologic examination of a surgically excised thyroparathyroid lobe that comprised lack of recognizable parathyroid tissue and a lymphocytic plasmacytic infiltrate adjacent to the cranial pole. A treatment regimen similar to that for iatrogenic postthyroidectomy hypoparathyroidism was successful in controlling clinical signs of the disease.