Feline matrix‐crystalline urethral plugs: A unifying hypothesis of causes

Abstract

ABSTRACTThe hypothesis is advanced that various combinations of aetiologically different events may lead to three different, but common, clinical manifestations of feline lower urinary tract disease. One manifestation, characterised by nonobstructive haematuria, dysuria, pollakiuria, and increased production of proteinaceous and cellular inflammatory reactions occurs as a consequence of urinary tract infections with viruses and occasionally other infectious agents. A second manifestation is that of classical urolithiasis, which occurs in response to oversaturation of urine with different types of calculogenic substances. Naturally occurring feline uroliths containing magnesium ammonium phosphate, calcium oxalate, ammonium urate, calcium phosphate, cystine and xanthine have been observed. A third manifestation, resulting from the concomitant occurrence of urinary tract infections and various types of urine crystals, is characterised by formation of matrix‐crystalline plugs that may obstruct the urethra, especially of male cats. Preliminary data suggest that urethral plug matrix contains Tamm‐Horsfall mucoprotein, similar to that observed involved in the formation of renal tubular casts.