Case 2 When is a headache abrupt?

Hannah was 36 when she presented to an Out of Hours general practitioner, Dr Walmesley, situated in an emergency department (ED). She had a headache. She was a known migraine sufferer but had not suffered from migraine for a couple of years and felt that this was the worst attack she had suffered for many years and that her routine analgaesia was inadequate. She stated that four years earlier she had been referred to a specialist with episodes of vertigo associated with headache and the diagnosis had been migraine. Her current headache had come on 6 hours earlier. It was initially in the neck and back of the head and had progressively worsened over 10–15 minutes to being very severe. She had vomited once. On examination she was afebrile with no neck stiffness and no abnormalities other than mild photophobia on retinal examination. Dr Walmesley diagnosed migraine and prescribed strong opiates and an anti-emetic.

What would you have done?

Two days later the woman consulted her own general practitioner Dr Palmer. She told the doctor that she had been to hospital two days earlier and that the hospital had diagnosed migraine but that the painkillers were only relieving the headache for a couple of hours. She had a minor degree of neck ache and stiffness. There was no abnormality on examination and Dr Palmer suggested the use of a tryptan.

What would you do now? What is your differential diagnosis?

Ten days later Hannah was found dead in bed. A post-mortem revealed a large recent subarachnoid haemorrhage (SAH) originating from a 25 mm basilar artery Berry aneurysm. Hannah’s family sued the general practitioners for negligently making a diagnosis of migraine. It was argued that a competent general practitioner would have admitted her for urgent investigation, that an MRI would have demonstrated the Berry aneurysm and that it would have been treated with an endovascular coil.

Do you think their claim will succeed?

Expert opinion

The suspicion and referral of patients suspected of having a SAH or ‘warning bleeds’ present a very significant problem for general practitioners and ED staff. Few general practitioners would fail to suspect a SAH in a patient with the typical presentation of an abrupt onset of a very severe occipital headache (thunderclap headache).

However, case studies indicate that abrupt onset of a headache may not occur in up to 50% of cases (Linn et al., 1994). The time from onset to peak severity maybe several minutes (Linn et al., 1998). This may explain why case studies of SAH find initial rates of misdiagnosis of between 23% and 51%.3 The patients who are misdiagnosed tend to be less unwell, usually with no transient loss of consciousness and have no neurological signs. The commonest incorrect diagnosis is migraine (21% of misdiagnoses).

Even if an explosive headache is the only presenting symptom only 10% will have SAH (Edlow & Caplan, 2000). Nevertheless, it is obviously worth referring and investigating 10 patients (or even 100) to detect one SAH at an early stage. The more difficult question is whether to refer all patients with the ‘worst headache ever’ even if it comes on over several minutes. One US study found that 20 out of 107 patients presenting to an ED department with the ‘worst ever’ headache had SAH (Morgenstern et al., 1998). However, one community study found that 9.1% of the population reported at least one ‘almost unbearable’ headache in the previous year (Newland et al., 1978). Potentially, the whole population of headache sufferers will have their ‘worst ever headache’ at some stage. While the presence of neck stiffness makes the diagnosis more likely one unpublished study from Durham found neck stiffness was absent in 64% of cases of SAH. Nuchal rigidity may take 3 to 12 hours to develop, and maybe absent in small bleeds.

Duration of headache can be helpful in excluding SAH. It is generally accepted that the headache from a SAH usually lasts days and certainly does not last less than an hour (Davenport, 2002).

The conclusion of the studies is that clinical suspicion of a SAH needs to be set at a low level because up to half the cases may not present with a typical thunderclap headache. Nevertheless, close questioning about the onset of a headache is critical to the assessment of any new headache and details about onset should be recorded. Brief duration headaches that resolve are not due to SAH but general practitioners should have a low threshold for urgently referring sudden onset headaches or ‘first and worst’ headaches even if the onset is over a few minutes and there are no neurological signs such as nuchal rigidity.

Dr Walmesley should have recognized that SAH was a significant possibility (the chance of SAH was probably about 1 in 10) and admitted Hannah urgently to hospital for a CT head scan and a lumbar puncture. The second general practitioner Dr Palmer should have retaken the crucial history about the onset of the symptoms and realized that a SAH may have been missed and again admitted her urgently. Dr Palmer should not have been reassured by the earlier negative assessment ‘in hospital’.

Legal comment

The duty of a GP is to act in accordance with a responsible body of medical opinion skilled in that particular field. The expert in this case believes that both Dr Walmesley and Dr Palmer have failed to do so. He says they should both have recognized the possibility of SAH and arranged for further investigations.

However, a lawyer acting for either of those two doctors may wish to explore whether there is another responsible body of medical opinion which takes a different view. Maybe it could be argued for Dr Walmesley that the lack of neurological symptoms and the history of a gradual progression of the headache made it reasonable for him to diagnose migraine at the first consultation? (No doubt it will be more difficult for an expert to argue this for Dr Palmer who saw Hannah two days later when she had a persistent headache and some neck ache and stiffness.)

The lawyers for the doctors will also want to explore the consequences of the failure to refer Hannah for investigation. Was it more likely than not that Hannah could have been saved if referred for a CT scan? If so, then Hannah’s family will have a valid claim for bereavement damages of £11 800. The administrators of her estate could sue for the pain and suffering she endured before her death, due to the GP’s negligence. If Hannah has children, they will have a potentially substantial claim as her dependents for the loss of care and support from their mother during their childhood. The family will also be entitled to compensation representing her financial contribution to the household.

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