Mycobacterial neuritis in a cat

A 2-year-old spayed female domestic shorthair cat was referred for evaluation of rapidly progressive lameness of the right hind limb, which was paralyzed. Histologic examination of biopsy specimens revealed pyogranulomatous inflammation affecting the sciatic, common peroneal, and tibial nerves, and slender, beaded, acid-fast bacilli within macrophages, nerve fibers, and degenerate axons. A diagnosis of mycobacterial neuritis was made and the cat was treated with clofazimine and enrofloxacin for extended periods. Treatment was partially effective; the goal of returning normal function to the limb was not achieved, but disease progression was halted and the cat remained a viable pet.