Causes of Headache, Acute meningeal irritation, Rising intracranial pressure, infectious diseases, Giant-cell arteritis, Migraine, Tension headache, Analgesia-induced headache

Headache

The brain parenchyma is insensitive to pain. Headaches result from distension, traction, or inflammation of the cerebral blood vessels and dura mater. Pain is referred from the anterior and middle cranial fossae to the forehead and eye via the trigeminal nerve, and from the posterior fossa and upper cervical spine to the occiput and neck via the upper three cervical nerves. Both infratentorial and supratentorial masses can lead to frontal headaches by causing hydrocephalus.

Causes of a headache

• Acute meningeal irritation: due to subarachnoid haemorrhage or meningitis caused by bacteria, viruses, fungi, or metastases.
• Rising intracranial pressure
• Infectious diseases: cause a headache during the acute phase. Locally important infections need to be determined (e.g. malaria; meningitis including TB; trypanosomiasis; typhoid, arboviral and typhus fevers; fungal infections).
• Giant-cell arteritis: may rapidly result in blindness. Occurs in elderly people. There may be a tender engorged occipital or temple artery; ESR is markedly raised. Temporal artery biopsy may confirm the diagnosis, but do not delay giving steroids while awaiting biopsy.
• Migraine: headaches which occur at intervals (not daily) and are associated with N&V, anorexia, photophobia, phonophobia, and in 20% of cases visual, mood, sensory, or motor disturbances. Most individuals have their first attack while young. Identify and avoid precipitating factors; give analgesia (paracetamol, NSAIDs, or codeine) together with metoclopramide 10 mg (not in children). Ergotamine is useful in 50% of patients. Chemoprophylaxis may work for regular migraines.
• Tension headache: most common cause of headache. It is normally a benign symptom due to an identifiable cause (e.g. overwork, family stress, lack of sleep, emotional crisis). It is often a daily occurrence unlike migraine headache, getting worse as the day goes on. Visual disturbances, vomiting, and photophobia do not occur. Management involves thorough examination and reassurance of its benign course, analgesia (usually paracetamol 1g qds), and rest. Ask about drugs, caffeine, and alcohol. Amitriptyline starting at 10 mg at night, increasing by 10 mg each week until side-effects occur, is also often of benefit. Tension headaches may be part of a depressive illness. Check for other signs or symptoms such as mood change, loss of appetite, weight or libido, or a disturbed sleep pattern.
• Analgesia-induced headache: follows long-term and inappropriate use of analgesia for headaches. History reveals increasing and frequent use of often multiple forms of analgesia. Management involves reassurance followed by stopping all forms of analgesia. The headache initially gets worse before improving.
• Others: Trauma, Cluster headaches, Hypertension, Drugs, Indometacin-sensitive headaches

Pain may be referred to the forehead and temple from the orbits, paranasal sinuses, teeth, skull or spine pathology, and venous sinuses.

So what do I look for when a patient has a headache?

The major responsibility of a physician faced with a patient with a headache is to exclude a treatable, structural or dynamic cause. Specifically exclude either a space occupying lesion or meningitis. I look for Localizing signs Neurological Signs, Papilloedema, Neck stiffness, Rash.