A case of mononeuropathy multiplex associated with idiopathic thrombocytopenic purpura

We report a case of mononeuropathy multiplex with idiopathic thrombocytopenic purpura (ITP). A 78-year-old man developed patches of purpura on his left forearm. His platelet count was 11,000 / μl and platelet-associated IgG was elevated. He was diagnosed as having ITP. At the beginning of the following month, he noticed dysesthesia and weakness of his left finger and left lower limb, as well as dysesthesia of his bilateral lower thighs. Neurological examination revealed weakness in the area of the left ulnar nerve and of the left anterior tibial muscle. Dysesthesia presented in the area of the left ulnar nerve and bilateral superficial peroneal nerves. Nerve conduction studies revealed asymmetric axonal sensorimotor neuropathy (mononeuropathy multiplex). A cerebrospinal fluid specimen showed a normal cell count and normal protein level. Serum anti-ganglioside antibody was negative. The platelet count gradually increased after the introduction of corticosteroid therapy. His neurological deficits and electrophysiological findings also improved. Immune-mediated neuropathy was suggested as the cause of his mononeuropathy multiplex with ITP.