My patient – a 35-year-old nursing sister – had a long history of migraine. But over the last three months her headaches had been increasing in frequency and she was now getting headaches almost every day. She was taking regular cocodamol on five days each week.
I diagnosed migraine with medication overuse headache but she insisted on having an MRI – a colleague of hers at work had had a similar headache and developed a brain tumour. So, against my better judgement, I ordered an MRI.
The MRI showed a small, 4mm aneurysm in the posterior cerebral circulation which was totally unrelated to her headache.
She had an appointment with the neurosurgeon who told her that the natural history of lesions of this size was not known. If he operated she would have an 8% risk of stroke and a 2% risk of death, and he suggested that she was imaged again in a year’s time.
Now my anxious patient had become a nervous wreck!
What I learned
The increasing sensitivity of modern imaging technology has overtaken our ability to understand the abnormalities it reveals. This is particularly relevant in the case of MRI brain scans, where incidental abnormality rates of up to 10% have been reported. Not only do these results have implications for patient anxiety but also for their future insurance applications.
The incidence of primary brain tumours is between six and 10 per 100,000 population per year. Some 72% of brain tumours will present above the age of 50 and 10% of tumours will present with isolated headache. Only 0.09% of all headache presentations in primary care are because of a primary tumour. Brain metastases occur in 20-40% of patients with cancer elsewhere.
How this changed my practice
I now think more carefully about why an investigation is needed when patients present with headache, and provide them with more comprehensive information on the pros and cons of screening. The new NICE headache guidelines1 advise that imaging should not be done for reassurance alone and if imaging is considered it should be for a good clinical reason and following discussion with the patient on the benefits and drawbacks of this investigation.
Dr David Kernick is a headache GPSI in Exeter and RCGP headache champion
The British Association for the Study of Headache (BASH) publish a free newsletter three to four times a year containing education, review and research updates. If you would like to join the mailing list please contact Paul Astwood (email@example.com).
Do you have a story to share? Submit your own ‘a case that changed my practice’ feature – in the format of Dr Kernick’s article – to firstname.lastname@example.org. Advise your GP colleagues on what you learned. There is a £100 honorarium for every article published.