Case 13 A woman with classical migraine
Rachel consulted Dr Dewan. She was aged 48 and stated that she had suffered from migraines all her life. She had never previously sought medical advice about the matter. In the last month she had had three episodes of severe left sided headache associated with visual disturbance in her left eye. She thought that the lights at work (she worked in a call centre) triggered the attacks because she had twice experienced them when leaving work. She had vomited once.
What would you do now? What bits of information would you want to elicit?
Dr Dewan took Rachel’s blood pressure and checked that her fundi were normal. She suggested a trial of a triptan wafer, which would be absorbed through the buccal mucosa and thus would be absorbed even if Rachel was nauseated.
Ten days later Rachel consulted the Out of Hours service with a severe left-sided unilateral headache, vomiting and visual disturbance. She was given an injection of an intramuscular opiate and prochlor-perazine.
On the following Monday Rachel consulted Dr Dewan again. Her symptoms had all resolved but she was concerned at the frequency of the migraine attacks and the visual disturbances which were new to her. Dr Dewan suggested that she try propanolol to reduce the frequency and severity of the attacks.
Three days later Rachel consulted one of Dr Dewan’s colleagues. He was experiencing another migraine and she stated that the vision in her right eye was blurred. The doctor noted that her right eye was slightly red, measured her blood pressure, noted he could not visualize the fundus, and questioned the diagnosis of cluster headaches. He referred her for a neurological opinion. He also advised that she see an optician to measure the pressure in her eyes.
What would be your differential diagnosis and how would you discriminate between them?
The following day Rachel attended the surgery again as an emergency. She had been vomiting overnight, had a red right eye, reduced visual acuity and had perception of light only in that eye. The doctor referred her immediately to hospital and she was diagnosed with acute angle closure glaucoma. The ophthalmology SHO noted a history of recurrent episodes of uniocular blurring of vision, visual haloes and that these had occurred twice when she left work (she worked nights at a call centre). She was treated but was left with perception of light only in her right eye.
Rachel made a claim against the practice alleging that if Dr Dewan had taken a careful history it would have been clear that her new visual symptoms were uniocular rather than homonymous.
Do you think her claim will succeed?
Expert comment
General practitioners have relatively little training in, or experience of, significant eye disease. Training in ophthalmology usually comprises a couple of weeks as a medical student and an occasional day course in ophthalmology once qualified.
Despite this, it is relatively common for general practitioners to be consulted about visual symptoms and ‘the red eye’.
The most important aspects of assessing visual disturbances is to establish whether the visual disturbance is in both eyes and extends over the visual field (placing the disturbance behind the optic chiasm and most likely in the occipital cortex) or in one eye (placing the disturbance most likely in the eye itself). If the disturbance is in one eye it is important to check whether there is any pain, whether the eye is red or not, measure a visual acuity and look at the fundus.
If the visual disturbance is transient and homonymous (affecting the visual field rather than one eye) then the diagnosis is very likely to be a migrainous aura. Typically the patient will describe shimmering, often coloured lights, it may be difficult but not impossible to see through the visual obscuration (sometimes described like a fog) and the negative scotoma may migrate slowly over the visual field and resolve after 10 to 30 minutes.
If, on the other hand, the visual disturbance is in one eye it will be likely that the cause is pathology in that eye. Migraine can be associated with uniocular (retinal) auras but it is very rare. Uniocular flashing lights or scintillating spectra or scotomas are much more likely to be due to retinal tears or detachments. Uniocular flashing lights usually indicate vitreoretinal traction caused by a posterior vitreous detachment.
Uniocular visual blurring with haloes around bright lights (similar to those that occur on a window wet with condensation) is very likely to be due to corneal oedema from a acute angle closure glaucoma. This is particularly the case if there is a unilateral red eye, headache or vomiting.
Ophthalmological conditions do pose a problem for general practitioners because of the lack of expertise and the lack of specialized equipment. However, a few basic rules can ensure that serious conditions are unlikely to be missed:
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