Here’s some of my favourite articles on Acute Headache which shamelessly promotes my own writing:
1. General Acute Headache Overview: Forbes RB. Acute Headache. Ulster Medical Journal 2014;84:3-9 (Link to free full text)
2. Q: What constitutes a brief neurological examination? A: Forbes Quick Neurological Examination!
3. Should people with suspected meningitis have a CT prior to LP? In short, if your patient is fully conscious, has no focal signs (see Quick Neuro Exam), and is not HIV positive then a CT Scan is not required according to the study of Hasbun et al in NEJM 2001
4. A person with Thunderclap Headache will usually describe a headache that goes from its start to maximum in about 2 seconds. Dr Emma Devenney has published a systematic review of known causes of sudden and severe headache based upon 2345 published cases. Note that the most common causes include ‘uncertain’ and non-specific headache. In population based studies the most serious cause remains aneurysmal subarachnoid haemorrhage which is still reliably excluded by early CT Brain and normal CSF.
5. The Reversible Cerebral Vasoconstriction Syndrome is an emerging cause of Thunderclap Headache. Vasoconstriction is difficult to detect. In these cases thunderclap headache is often recurrent and can be provoked by exertion or emotion. Focal symptoms suggest that the vasoconstriction may be causing a degree of cerebral ischaemia, but fortunately lasting serious deficits are rare. Here is an open access systematic review of 214 published cases of reversible cerebral vasoconstriction syndrome. Note that haemorrhage – often cortically based subarachnoid haemorrhage is a known complication of vasoconstriction.
6. How accurate is CT in detecting subarachnoid haemorrhage? This question has recently been answered by Perry et in the BMJ in 2011 and the answer is… VERY ACCURATE. Note that they qualify use of CT Scanning with interpretation by a qualified radiologist – interpreting CT Scans is a complex skill.
7. The indications for an LP in acute headache include: CT negative thunderclap headache, suspected meningitis, suspected Intracranial Hypertension (CT Scan normal before LP please!). Carcinomatous meningitis is another potential cause but this usually presents with a progressive neurological deficit due to involvement of cranial nerves and peripheral nerve roots, and not just headache. An up to date overview of Diagnostic Lumbar Puncture has recently been published by Dr Carolynne Doherty in the UMJ.
8. If CT and LP are normal, when should I do an MRI in acute headache? The reasons for an MRI study in acute headache are:
a) Acute arterial dissection (carotid or vertebral artery) – these usually cause a sudden, severe, unilateral headache with ptosis from Horners syndrome often present in Carotid Dissection. Clinical features of vertebral artery dissection have been reviewed systematically;
b) Spontaneous Intracranial Hypotension – there is a postural headache – usually a dull bilateral heavy/pressure pain that is almost completely relieved by lying horizontal and accompanied by muffled hearing or other non-specific auditory symptoms.
c) Suspected Cerebral Venous Sinus Thrombosis – this is usually a new onset persistent headache often, but not always, with focal neurological deficits. It can be missed on plain CT Brain, but the clue from a LP is an elevated opening pressure and an increased CSF protein concentration.
Patients with any of these 3 causes will usually be experiencing a persistent pain, or their history will not be typical of Thunderclap Headache.
9. New Onset Persistent Headaches. The key diagnoses to search for and rule out are:
a) Carbon Monoxide Poisoning
b) Temporal Arteritis (ESR and age >50)
c) Cervicogenic Headache – the flexion-rotation test is a useful clinical sign that detects musculoskeletal abnormality of the upper cervical spine. Remember that the upper 3 segments of the cervical spine will radiate pain to the head without there being obvious neck pain present. C1 level usually radiates to the orbital area, C2 can also radiate to the back, side, top or front of the head. C3 usually will only reach to the occiput. This condition is under recognised.
d) Intracranial Hypotension – described above
e) Intracranial Hypertension – usually overweight younger females with persistent pressure type headaches associated with a pulsing noise in the head that is in time with their pulse. Weight management is the best known treatment, but surgical procedures (VP shunting) may be required to prevent severe visual failure.
f) Isolated Sphenoid Sinusitis – remember isolated sphenoid sinusitis will lack classic sinus features of nasal congestion and nasal discharge – you may just get a persistent daily headache lasting for months which will often prevent sleep.