Does a headache result from tiredness or a hangover, or does it stem from a brain haemorrhage or cerebral tumour? Is it a migraine or tension headache, caused by pressure on the spinal nerves in the neck? Or could it be sinusitis, temporal arteritis or from a less frequent cause such as extreme cold or sex? The reasons for a headache are legion and mostly benign.

The biggest fear is that a headache, especially if it is daily, could be the first sign of a cerebral tumour. Cerebral tumours are relatively uncommon, but headaches plague nearly all of us. Classically the headache of a tumour is the result of intracranial pressure being increased because the skull is overcrowded. The headache is usually a dull one, felt across the forehead, and is associated with nausea and dizziness. It is traditionally worse in the mornings after lying in bed all night, but is more severe after coughing, blowing the nose or lifting heavy weights.

As time wears on, the headache lasts longer into the day. The tell-tale mark of a cerebral tumour is usually other neurological signs such as a cranial nerve weakness, often problems with vision, an unexplained facial weakness or differences in skin sensitivity or muscle power in the limbs. In many cases an epileptic seizure or symptoms of a stroke after a bleed into malignant tissue are the first warning of a tumour.

Every alarm bell should ring if a patient develops a sudden disabling headache that comes on not within hours but within minutes. Patients usually say that a brain haemorrhage is the worst headache they have had in their life. It is often associated with signs of meningeal irritation such as neck stiffness and dislike of light. There may be loss of consciousness, nausea or vomiting, and if consciousness is not lost, irritability with social withdrawal follows.

Another important type of headache is temporal arteritis which results from inflammation of the arteries leading to the eyes and scalp in elderly people. The onset may be sudden, vision blurred and the scalp unusually sensitive so that combing or brushing the hair is painful. Immediate prescription of steroids can save sight.