Table 1

Causes of headaches presenting in the emergency department

CNS, central nervous system; ENT, ear, nose, and throat; LP, lumbar puncture; SUNCT, short lasting unilateral neuralgiform headache with conjunctival injection and tearing; TIA, transient ischaemic attack
Primary headache syndromes
  •     Migraine

  •     Cluster headache and related syndromes (including paroxysmal hemicranias, SUNCT)

  •     Thunderclap headache

  •     Hypnic headaches

  •     Benign exertional/sex headache

  •     Cough headache

  •     Exploding head syndrome (note this is a sensation, not headache)

Secondary headache syndromes
  •     Traumatic

        –simple closed head injury
        –complex with subdural/extradural/subarachnoid/intracerebral haemorrhage
    Vascular disease
        –subarachnoid haemorrhage (aneurysmal, perimesencephalic, other vascular anomalies)
        –unruptured aneurysms
        –acute cerebral ischaemia (TIA or stroke)
        –non-traumatic subdural/extradural/intracerebral haemorrhage
        –dissection of carotid/vertebrobasilar arteries
        –cerebral venous thrombosis
        –vasculitis (including giant cell arteritis)
  •     CNS infection

        –meningo-encephalitis (bacterial, viral, fungal)
        –cerebral abscess
  •     Non-vascular intracranial disease

    –intermittent hydrocephalus (e.g. colloid cyst)
        –idiopathic intracranial hypertension
        –intracranial hypotension (spontaneous or post LP)
        –intracranial tumour
        –pituitary apoplexy
        –Arnold Chiari malformations
        –optic neuritis
  •     Metabolic or toxic disturbances

        –thyroid disease
        –drug induced
        –withdrawal syndromes
  • Hypertensive encephalopathy

  • Cervical spine disease

  • Dental, ENT or ophthalmic disease (e.g. sinusitis, acute glaucoma)

  • Secondary to general medical conditions (e.g. ischaemic heart disease, infection other than cranial, epilepsy)