Polyarteritis nodosa as a cause of sudden deafness. A human temporal bone study.

Pathological changes in the temporal bone are described in a case of polyarteritis nodosa in a 48 year old man in whom the onset of sudden unilateral deafness and vertigo occurred seven months prior to death as one of the early manifestations of the disease. The patient had received only a seven week course of prednisolone and, earlier, a two week course of anti-inflammatory agents. Autopsy revealed involvement of the arteries supplying the kidneys, testes, and pancreas. Changes within the temporal bone were seen bilaterally and there was thickening of the mucosa of the middle ear. Inner ear involvement was mainly limited to the cochlea, the deaf ear showing more pronounced changes. These changes included loss of the organ of Corti in the hook portion of the basal coil, absence of the tectorial membrane, and atrophy of the stria vascularis. The scala tympani was obliterated by fibrosis and new bone formation. The scala media showed hydrops, and a marked decrease in the spiral ganglion cells and nerve fibers supplying this portion of the cochlea was evident. Focal changes were seen throughout the remainder of the cochlea. The vestibular structures showed no detectable pathologic changes. Small vessel arteritis was found in the dural and subacuate vessels in both temporal bones.