A. Pain Structures Irritated
Brain Tumor Pseudotumor cerebri Subdural Hemorrhage Post-concussionB. Inflammation
Meningitis - Infection, Hemorrhage Giant Cell Arteritis Sinusitis, MastoiditisC. Vascular Dilatation
Migraine Cluster Drugs (vasodilators) Fever Arteriovenous Malformation Hypoglycemia Carbon Monoxide poisoning Psychogenic Acute Glaucoma Hypertension Trigeminal Neuralgia