Surgical significance of prolonged fixed and dilated pupils in a case of non-traumatic, spontaneously regressing, acute subdural haemorrhage.

Bilaterally fixed and dilated pupils (BFDP) in traumatic acute subdural haematoma (ASDH) patients represent an ominous sign that portends irreversible brainstem injury and death. Whether patients with spontaneous ASDH and BFDP follow similar outcomes is unknown. We present a mid-60s man, found unconscious, with a Glasgow Coma Scale (GCS) of 4 following 8 days of headaches. Emergency CT imaging demonstrated a large right ASDH and the patient exhibited BFDP for >3 hours despite sedation and mannitol. Neurological improvement and spontaneously reduced SDH thickness were observed 10 hours postadmission, and he was later transferred for craniotomy and ASDH evacuation. His long-term outcomes were good: achieving independence in his activities of daily living and a GCS of 15. To the best of our knowledge, this is the first reported patient with a spontaneous, regressing ASDH and prolonged BFDP who clinically improved. This case raises important questions regarding factors used to determine prognosis and surgical viability for ASDH.