An 86-year-old man with diabetes mellitus presented to our hospital with a 3-day history of difficulty opening his mouth. He reported that he had injured his right index finger while farming 15 days ago, resulting in a 1-cm-diameter red bruise. He had not received any diphtheria, tetanus, and pertussis vaccinations. He was afebrile and alert, presenting no mental status changes. Physical examination revealed a stiff neck, trismus, and spasmodic laughter (Fig. 1). Blood tests showed leukocytosis, high creatinine kinase, and high glucose levels.
