FUUTD

From Felipedia

Feline upper urinary tract disease (FUUTD) describes any disease process which affects the upper urinary system (kidneys and ureters), and thus distinguishes it from the lower urinary tract (Feline lower urinary tract disease (FLUTD)).

Causes of feline upper urinary tract disease include:

• chronic renal disease, including interstitial nephritis and chronic pyelonephritis.
• renal lymphosarcoma, renal carcinoma
• acute pyelonephritis (immune-mediated, bacterial, viral, fungal)
• ureteral calculi
• ureteral neoplasia
• Leptospirosis

Ureteral calculi are being recognized with increased frequency in cats and are a cause of chronic renal disease and acute renal failure. Clinical signs in these cats will be absent, or vague, with inappetence, vomiting, lethargy and weight loss observed in some cases. Abdominal pain is an inconsistent finding. Most cats, whether they have unilateral or bilateral calculi, are azotemic. Cats with unilateral calculi can be azotemic due to prerenal azotemia, or because they have pre-existing renal disease and the unilateral ureteral obstruction resulted in damage to the already limited number of remaining nephrons, decompensation and an acute rise in azotemia result. Only a small number of cats (8%) have been found to have a concurrent urinary tract infection. Only about a third of cases studied have been found to have crystalluria in the urine sediment[1].

Diagnosis

Both survey abdominal radiographs and abdominal ultrasound will help to diagnose ureteral calculi in cats, and the methods are complementary, with the sensitivity of detecting a case being highest when both are done (90%). The increasingly common practice of omitting abdominal radiography and performing only abdominal ultrasound may delay a diagnosis of ureteral calculi[2].

Treatment

If ureteral calculi are non-obstructing, they can be monitored for size changes and movement with serial radiographs. Calculi may continue to move very slowly, over months to years. Medical management consisting of intravenous fluid therapy, diuretics, pain management therapy and drug therapy that causes smooth muscle relaxation, such as amitriptyline, can be considered, although these drugs have not been proven to be effective. Emergency nephrostomy tube placement (surgically or with ultrasound-guidance) and hemodialysis may be indicated in some cases. As most feline ureteral calculi are calcium oxalate, medical dissolution with special diets is not a treatment option[3].

Surgery is indicated when there is obstruction that is resulting in decreased renal function and destruction of nephrons, when the renal lesions are suspected to be reversible, or when there is unresolved infection. Most cats have pre-existing renal dysfunction, thus after therapy for ureteral calculi they will likely still have chronic renal failure. Post-operative complications have been reported to be high (31%), with urine leakage into the abdomen and persistent ureteral obstruction being most common. A 20% peri-operative mortality rate has been reported[4].

Prognosis

Taking into account the high peri-operative mortality rate, survival of ureteral calculi cats has been observed to be similar with or without surgery (short-term survival [6 months] 72%, and long-term survival [24 months] 66%).