Sudden onset of headache and the potential underlying Subarachnoid Haemorrhage(SAH) is not an uncommon presentation to the Emergency Department.

I recently saw a 32 year old male who presented with a sudden onset of severe headache whilst squatting in the gym. He also complained of pre-syncope. What do we need to do for him?

SAH has an incidence of 1:10,000 of the population annually(Stroke1989;20:718-724). Of all the patients presenting with a headache, some 1% will have a SAH, but that incidence increases when the headache is sudden and severe(Lancet 1994;344:590-593).

But how about that group of patients that come in with a sudden onset of headache after weight lifting in the gym, or other physical exertion such as occurs during sexual intercourse? Do we have to take more care or less, or the same in this patient group? It is often said that these headaches are nothing to worry about. BUT BE CAREFUL, as you cannot discern, the sinister from the benign.

Sudden onset of headache, also called  a ‘warning leak’ or ’sentinel headache’, is a red flag as it may indicate a subarachnoid bleed. If that patient re-bleeds, then there is about a 50% chance of mortality. Of the surviving 50%, up to half, will never get back to their normal level of functioning.

So it’s important not to miss this!

What the sentinel headache provides is a window of opportunity to make the diagnosis. At the same time, it identifies a subgroup of patients, with a worst overall outcome, if they have a further aneurysmal bleed(J Neurosurgery 1996;85:995-999).

Usually we order a Non- Contrast CT brain. This is quite sensitive in picking up a subarachnoid Haemorrhage(SAH) when done early ie., a few hours. BUT it’s not 100%. It may be as high as 97-99%(J Neurology Neurosurgery and Psychiatry 1995;58:357-359). The sensitivity decays with time, so that a few days down the track, the CT is almost useless.

If the initial CT is positive for SAH, then call Neurosurgery and off the patient goes. They need further imaging and planning for surgery or radiological coiling.

But what if we don’t find a bleed on CT? We need to be aggressive with our approach and lumbar puncture(LP) that patient. There is some debate about whether the LP should be done early or late. This is related to the development of xanthochromia, which is due to a byproduct or red cell breakdown. This can take up to 8 hours to develop, and is detectable in all patients that have had a bleed at 12 hours and for up to 2 weeks(J Neurology Neurosurgery and Psychiatry 1989;52:826-828).

The methods by which CSF is analysed, are concerning. Some labs use visual detection of xanthochromia, ie., someone holds the tube with cerebrospinal fluid up against a light and comments on whether it looks yellow and thus positive for xanthochromia(I know it sounds crazy, but there it is!). This has a sensitivity, at best of 50%(NEJM 1997;336:28-40). Other labs use spectrophotometry, considered the gold standard. There occassionally are false positives with this method, as the frequency bands for detection are widened, so as not to miss bleeds(Emergency Medicine 2000;12:212-217). This would not be a problem, except that angiography to further plan for surgery, is associated with a 0.1% mortality and 1% morbidity(Stroke 1987;997-1004).

The push now is for early LP and the detection of red blood cells(RBC). In a study I did, several years ago, looking at those patients with SAH and a positive angiogram, a cut-off or 1000 RBC allowed us to rule-out SAH. This was statistically significant. However, this was a retrospective study and needed prospective validation, before we could apply its results. That sort of study is difficult to get ethics approval for.

Why is there this urgency for an early lumbar puncture? Why don’t we wait for 12 hours and then detect xanthochromia? This is because re-bleeds occur in about 25% of cases and with a frequency that is greatest in the first 24 hours(MJA 1989;150:183-188) Ultra-early re-bleeds can occur within a few hours.

What about not doing an LP and just MRI/MRA? One of the issues here is that all aneurysms will be shown if present. Isn’t that good you say? Here’s the catch. Approximately 6% of the population have aneurysms as an incidental finding at autopsy, so we don’t know if the aneurysm found on MRI caused the headache or not. The only real clue, is that these ‘incidental’ aneurysms are usually small ie., less than 6mm and we know that most(not all) aneurysms need to be greater than 1cm or so before they burst. Remember the emphasis on the word ‘most’.

Now let’s get back to the patient. He was well, with GCS of 15 and nil neurology. No past medical history, No medications and nil allergies. He had also never had this headache before, nor was he a migraine sufferer.

The sudden nature of the headache made me nervous. So a CT head was done and was normal. Then a lumbar puncture to look for red cells. How many do you need? Well according to the neurosurgeons(and no-one really knows), if the CSF is discoloured as it comes out, then it’s positive, you don’t need cell counts. If it’s clear, it’s OK. It was a champagne tap. I would still look at the cell count.

So he was discharged.

Exertional headaches have sometimes been called weightlifter’s headache. They were first reported in La Medicine in 1932 by Tinel in the paper, “La Cephalee a l’effort. Syndrome de distension des veines intracranienes”.

We know that exertional headaches are more common in males, by a factor of 4:1 and there is some predisposition, or underlying tendency to migraine. The mechanism is still uncertain. There appear to be two types; firstly a cervical soft tissue strain and secondly a reflex vascular spasm. In reality, no-one is really sure.

They are classified by the International Headache society as being headaches not associated with structural lesions. In most cases, these are benign, with a good outcome. However there is some evidence that these sudden, often described as ‘bursting’ headaches may in fact be associated with underlying intracranial lesions.

In the Medical Clinics of North America in 1961(52:801-808), a study involving 103 patients with exertional headache found that at 3 year followup, 10 had developed intracranial lesions.

In Neurology (1996;46:1520-1524), a small study of 28 patients, with exertional headache demonstrated that 12 had a SAH and one a malignancy.

So next time a weightlifter comes in with a sudden onset of severe headache, whilst doing a squat, you need to work them up as you would anyone with a sudden severe headache. In many cases, you may need to advise the patient that they should cease heavy lifting.

If they disagree, let it be. Remember some of these guys are squatting the weight of my car!

Dr Peter Kas MBBS MArch BArch FACEM

Dizziness and vertigo is a common presentation to the Emergency Department. This month in ‘Medical Talk’, we  describe the Head Thrust test as a means of differentiation between Vestibular Neuritis and Vertebrobasilar Insufficiency. We also look at other causes of vertigo including Benign Paroxysmal Positional Vertigo, Meniere’s Disease, Labyrinthitis, Perilymph Fistula, CNVIII and Cerebellopontine angle tumours, Cerebellar haemorrhage and infarction, Lateral Medullary Infarction, Multiple Sclerosis and Basilar Migraine.