Primary

Migraine

Cluster

Tension

Secondary

Subarachnoid hemorrhage

Intracerebral hemorrhage

Subdural/epidural hematoma

Unruptured arteriovenous malformation

Cerebral venous thrombosis

Ischemic stroke/transient ischemic attack

Cervicocephalic arterial dissection

Arterial hypertension

Meningitis

Cerebral tumor/abscess

Pseudotumor cerebri

Postconcussive headache

Acute glaucoma

Trigeminal neuralgia

Sinusitis

Dental abscess

Giant cell arthritis

Bell palsy

First headache

Nausea/vomiting

Opthalmologic findings

Sudden onset

Severe intensity

Different/persistent headache

Nocturnal worsening and/or awakening from sleep due to pain

Age >50 years

Visual changes

Neck stiffness

Fever and chills

Seizure

Hypertensive urgency/emergency

Weight loss

Dysconjugate gaze

Unequal pupils

Eye globe hard to palpation

Conjunctival injection/lens clouding

Visual field deficits

Preretinal/retinal hemorrhage

Papilledema

Clouding of consciousness

Altered mental status

Head/neck

Recent head trauma

Onset with straining/change in position

Evidence of head/neck trauma (e.g., “raccoon eyes”)

Onset with Valsalva maneuver

History of bleeding disorder

Hypercoagulable state Cancer

Temporal tenderness

Lymphadenopathy

HIV/AIDS

Neurologic

Mental status changes

Focal neurologic signs

Change in gait

Presence of meningeal signs

Evidence of bleeding diathesis

Elevated blood pressure