Headache is one of the commonest neurological presentations, and almost all headaches are benign. The skill tested in the Neurology SCE and MRCP, and the one that matters most in practice, is recognising the few that are not.
Red flags in the history
- Thunderclap onset, reaching maximum intensity within about a minute.
- New headache after the age of 50.
- Headache with fever, neck stiffness or a rash.
- Headache that is worse on lying down or wakes the patient, especially with vomiting.
- New headache in someone with cancer, HIV or immunosuppression.
- Headache with focal neurological signs, seizures, confusion or papilloedema.
- New headache in pregnancy or soon after childbirth.
Thunderclap headache
The main concern is subarachnoid haemorrhage. Brain imaging is the first investigation, and lumbar puncture has a role in selected patients when imaging is normal. Other causes include reversible cerebral vasoconstriction syndrome, cervical artery dissection, cerebral venous sinus thrombosis and pituitary apoplexy.
Giant cell arteritis
Giant cell arteritis should be considered in anyone over 50 with a new headache, scalp tenderness, jaw claudication or visual symptoms. Inflammatory markers are usually raised. It matters because of the risk of permanent visual loss, which is why it is treated as an urgent diagnosis.
Idiopathic intracranial hypertension
The typical patient is a young woman with a raised body mass index, headache and papilloedema, sometimes with brief visual obscurations or pulsatile tinnitus. Imaging is used to exclude other causes before the raised pressure is confirmed.
Medication overuse headache
Frequent use of painkillers, including simple analgesics, triptans and opioids, can itself maintain a daily headache. It is common and often overlooked.
How to revise
Most headache questions give you one red flag and expect you to recognise the condition it points to. Practise linking each red flag to its likely diagnosis and to the investigation that would confirm it.