Acute sphenoiditis involving the second branch of the trigeminal nerve.
Learning point for clinicians

Acute sphenoiditis may affect the second branch of the trigeminal nerve because of anatomical reasons and should be included in differential diagnoses in patients with headache accompanied by facial numbness.

A 67-year-old man visited our hospital with complaints of headache, vomiting and numbness on the right side of the face. He noted preceding transient upper respiratory tract symptoms 7 days before his visit. The headache that occurred 2 days before his visit was the most severe he had ever experienced and worsened. On the day before his visit, it was accompanied by vomiting and numbness on the right side of the face. Physical examination showed a temperature of 36.6°C, blood pressure of 167/83 mmHg, pulse rate of 72 beats per minute, and oxygen saturation as measured using pulse oximetry (SpO2) of …