Canine Cystitis Study Guide

Overview and Clinical Importance

Bacterial cystitis is inflammation of the urinary bladder caused by bacterial infection. It represents one of the most common infectious diseases in dogs, affecting approximately 14% of dogs at some point during their lifetime. Unlike cats, where most lower urinary tract disease is idiopathic and sterile, bacterial infection is the predominant cause of cystitis in dogs. This distinction is critical for the NAVLE, as it influences diagnostic and therapeutic approaches.

Cystitis typically arises from bacteria ascending from the perineum through the urethra to the bladder. Female dogs are at significantly higher risk due to their shorter, wider urethra compared to males. The urinary tract possesses multiple defense mechanisms against infection, including antimicrobial peptides in urine, high urine osmolality, the physical barrier of the urothelium, and normal voiding patterns that flush bacteria. Bacterial cystitis occurs when these host defenses are compromised.

Classification of Bacterial Urinary Tract Disease

Understanding the classification of bacterial urinary tract disease is essential for appropriate diagnosis and management. The 2019 ISCAID guidelines provide standardized definitions that have replaced older terminology such as "simple" and "complicated" UTI.