Headaches are common – loss of eyesight is not. However devastating loss of vision can follow a regular headache.
The British Medical Journal recently published a paper, Raised intracranial pressure in those presenting with headache (BMJ 2018:363: k3252), as a warning to clinicians to be alert to this possibility. The paper was written by neurologists, who see the results, and a GP, who might miss the symptoms.
There is variability in the symptoms but typically the patient may complain of new onset constant or near constant headaches. Most experience steadily worsening headaches over weeks but development can be much quicker. Sometimes it is a pulsating headache - which can be made worse by bending over, coughing or straining or physical activity.
It may be just a chronic migraine or a tension headache but a new headache or substantial change in symptoms could be caused by intra-cranial pressure (ICP) and needs investigation. Blurring of vision or double vision is a common symptom. There may be transient loss of vision or ‘greying out’ of vision which could be related to postural changes and tends to be short lived. The incidence of symptoms increases as the pressure increases.
The ability to distinguish print (visual acuity) will most likely remain normal but visual fields will be affected with blind spots developing. As the pressure rises this progresses to constriction of the peripheral visual field until the central field is extinguished.
Other symptoms which may otherwise be part of normal life can be neck and back pain, problems with moving or talking, decreased consciousness, and sometimes fitting. Occasionally there is a rhythmic whooshing sound (pulsatile tinnitus) which can be heard in either ear and follows the heartbeat.
If a number of these symptoms are present then the correct procedure is to measure blood pressure (to exclude malignant hypertension), to perform a full neurological examination but most importantly to visualise the optic discs (fundoscopy).
If swelling (papilloedema) is seen, then the patient must be referred for an MRI or CT scan that day. Neuroimaging will exclude a tumour being the cause of these symptoms and the patient can then undergo a lumbar puncture to reduce the intra-cranial pressure.
Subsequent treatment will depend on the suspected cause but the risk of permanent visual loss will have been reduced because pressure will no longer be affecting the optic nerves.
Tim Wright, a senior associate in Penningtons Manches’ clinical negligence team, comments: “We are aware of a number of cases where the appropriate steps have not been taken by medical professionals and permanent visual loss has occurred. A particular area of difficulty seems to be interpretation of the fundoscopy which requires an experienced eye although improvement may occur as smart phone based ophthalmoscopes become more widely used.”