8.1.8 Headache attributed to exogenous acute pressor agent

Identification: Female patient, 32 years old, with no prior history of primary headaches.

History of Present Illness: Reports sudden onset of intense, diffuse headache with a "pressurizing" quality, occurring 1 hour after using intranasal phenylephrine (a decongestant) for a common cold. The headache worsened with movement and was associated with nausea, without vomiting or visual symptoms. She denied photophobia or phonophobia. The pain persisted for 6 hours, resolving spontaneously after discontinuation of the medication.

Physical/Neurological Examination: Blood pressure: 160/100 mmHg (elevated from her usual ~120/80 mmHg); normal neurological examination, without meningeal signs or focal deficits.

Investigation: Non-contrast brain CT – normal. Laboratory tests (including electrolytes and renal function) – normal.