Diseases involving the feline ureters, bladder and urethra will be discussed during this lecture and illustrated with case studies.
Ureteral Disease
Diseases of the ureters are uncommon in the cat and usually diagnosed at an advanced stage of the disease as most disease processes will only affect one ureter. Most ureteral diseases will cause some degree of obstruction of urine flow through the affected ureter. Ureteral obstruction will result in secondary renal changes in the kidney(s) associated with the affected ureter(s). The cat may exhibit signs of abdominal discomfort caused by the distension of the renal capsule secondary to obstruction of urine flow. Irreversible renal damage occurs rapidly, but recovery of some function is possible after relief of the obstruction. In unilateral ureteral obstruction (most common) only one kidney is affected and as long as the other kidney functions normally, no clinical signs may be noticed at all. The contralateral kidney will compensate for the reduction in glomerular filtration in the affected kidney.
Ureteral obstruction can be caused by uroliths, ureteral strictures secondary to inflammation, iatrogenic ligation, trauma or neoplasia.
A high index of suspicion is important to diagnose this disease at an early stage.
Bladder Disease
The most common bladder disease in the cat is cystitis and in the majority cases the disease is 'idiopathic'. It is now recognised that there is a central role for the neuroendocrine system in some cases.
Other diseases affecting the bladder include developmental abnormalities, urolithiasis, neoplasia or problems secondary to trauma.
The clinical signs associated with bladder disease include pollakiuria, dysuria, periuria and haematuria. Cats often express bladder discomfort by licking the ventrocaudal abdomen. On physical examination the bladder may be small and thickened (cystitis) or large and distended if there is obstruction of urine flow. In cases of neoplasia the bladder wall is thickened.
Urethral Disease
The most common urethral problem in the cat is obstructive urethral disease, most commonly caused by urethral 'plugs'. This is an emergency situation, which needs to be dealt within 24 hours to prevent life-threatening complications.
Other urethral problems include developmental abnormalities, urolithiasis, urethral strictures, neoplasia or traumatic injury.
The clinical signs associated with urethral disease include pollakiuria, dysuria, periuria, haematuria and, in case of complete obstruction, anuria. In a case of urethral obstruction, which is more common in the male cat because of the smaller diameter of the urethra, the cat will become lethargic, inappetent, severely uraemic, hyperkalaemic, bradycardic and moribund. Relief of obstruction is necessary as well as dealing with the metabolic consequences of the obstruction.