Acute Angle Closure Glaucoma (AACG): an important differential diagnosis for acute severe headache.

Acute headache is a common presenting symptom in the acute medical unit. We present a case of Acute Angle Closure Glaucoma (AACG) presenting with acute severe headache. It highlights the importance of remembering this ophthalmologic emergency and reminds us of its clinical presentation. The rapid assessment and diagnosis of AACG allowed prompt treatment and likely prevented the patient from losing her vision.