Causes of Headache

No other signs or symptoms:
1) Tension headache
2) Cluster headache
3) Migraine (one-sided headache)
4) Post-traumatic
5) Drugs (nitrates, calcium channel antagonists)
6) Carbon monoxide poisoning
Associated with decreased level of consciousness:
1) Meningitis (inflammation of membrane surrounding the spinal cord)
2) Stroke
3) Cerebral abscess (pus in brain)
4) Tumour
5) Intracranial haemorrhage (rupture of blood vessels in brain)
Associated with papilloedema (swelling of the eyeballs):
1) Tumour
2) Intracranial hypertension (increased blood pressure)
3) Infection