Secondary Headaches - Precipitated by another condition e.g. Trauma or injury to head/neck, Cranial or cervical vascular disorders e.g. intracerebral haemorrhage / giant cell arteritis, Non vascular intracranial disorders e.g. idiopathic intracranial hypertension / brain malignancy, Exposure to substance e.g. alcohol / CO2 / medication over use, Infection e.g. bacterial / viral meningitis, Disorder of homeostasis e.g. hypoxia/hypertension/pregnancy eclampsia, Disorders of the cranium/neck/eyes/ears/teeth/mouth, Psychiatric disorders e.g. psychosis /schizophrenia