Severe Tetanus in an Older Adult Without an Identifiable Portal of Entry: A Case Report.

Tetanus remains a significant health concern, particularly in older adults with waning immunity. The diagnosis is typically clinical, based on characteristic features such as trismus, muscle rigidity, and stimulus-triggered spasms. However, diagnostic challenges arise when tetanus presents without an identifiable acute wound or with an occult portal of entry, as it may be misattributed to more common neurological conditions such as stroke or encephalitis. We report a 65-year-old Chinese male who presented with 15-day cough and sputum, followed by acute trismus and dysphagia. Initial evaluation at a local hospital suggested cerebral infarction, but treatment with neuroprotective agents yielded no improvement. The patient was transferred to a tertiary hospital, where he developed generalized spasms and respiratory distress requiring mechanical ventilation. Extensive neurological investigation revealed only chronic ischemic changes; encephalitis was considered but not confirmed. Subsequent consultation identified characteristic features including trismus, risus sardonicus, opisthotonos, stimulus-triggered spasms, and preserved consciousness during spasms, leading to diagnosis of severe tetanus (Ablett Grade IV, based on severe generalized spasms, respiratory failure requiring mechanical ventilation, and autonomic dysfunction requiring vasopressor support). No acute wound was identified on full-body examination; only remote facial burns and scarring from > 20 years prior was noted. The patient received human tetanus immunoglobulin, intensive sedation and analgesia, mechanical ventilation, and supportive care. After 28 ICU days, the patient was successfully weaned from ventilation, achieved complete spasm resolution, and was transferred to a general ward for rehabilitation. This case demonstrates that severe generalized tetanus should remain in the differential diagnosis of older adults presenting with acute trismus, dysphagia, muscle rigidity, or stimulus-triggered spasms, even when recent trauma is not recalled and no active wound is visible. Clinicians should obtain a thorough exposure history, perform repeated full-body examinations, and initiate timely antitoxin administration and ICU-based supportive care. The absence of an identifiable portal of entry should not delay diagnosis or treatment.