Lockjaw in stiff-person syndrome with autoantibodies against glycine receptors.

A 37-year-old man was admitted to our hospital in 1998 with severe contraction of both masseter muscles, which made him unable to open his mouth. He could only drink using a straw fitting through a tooth gap. Spasms of the facial and masseter muscles had started in 1993 and transiently improved after treatment with benzodiazepines. The patient's history included treatment of back and joint pain in 1990 and several admissions to psychiatry for “conversion neurosis.” At one time, his wife was suspected of poisoning him with an insecticide because of residues of parathion in his serum.