Feline urethral plugs. Etiology and pathophysiology.

Feline urethral plugs commonly are composed of large quantities of matrix mixed with minerals (especially struvite). However, some urethral plugs are composed primarily of matrix, some consist of sloughed tissue, blood, and/or inflammatory reactants, and a few are composed primarily of aggregates of crystalline minerals. The formation of matrix-crystalline urethral plugs may be analogous to the preparation of fruit jello.