Severe headache is a common symptom of acute glaucoma. It comes from a sudden increase in the intra-ocular pressure caused by the closure of channels that drain fluid from the eyeball. This headache can be similar to a migraine with nausea and light sensitivity. Acute glaucoma is rarely misdiagnosed as a migraine because typically, there is no history of migraines and the eye often gets red, painful with profuse tearing. Cluster headache is sometimes more similar to acute angle closure glaucoma because it also can cause redness of the eye and tearing.
This post was prompted by patient I just saw. This 52-year-old woman has had right-sided migraines for 10 years and about a year ago was found to have mildly elevated intra-ocular pressure (IOP). She has been under my care for almost a year and after receiving three Botox treatments needed only magnesium infusions every 3 weeks. She was still having 2-3 migraines each month, but they were relieved by sumatriptan with naproxen (Treximet). On a recent visit to her ophthalmologist her IOP was higher than usual and she underwent a laser procedure to improve fluid drainage. She reported that it felt as if a balloon was punctured and pressure came out of her eye. The procedure was first done on her right eye where the pressure was higher. Although it’s been only a couple of weeks since the procedure, she feels much improved, without any migraines and without constant mild pressure in her eye, which she was barely aware of until it was gone. Chances are that she will remain susceptible to migraines as they preceded her glaucoma by many years, but she is very likely to have fewer and milder migraines. She may also need to continue intravenous infusions of magnesium because she has a documented severe magnesium deficiency (her RBC magnesium level was 3.7 with the normal range of 4.2 to 6.8), which did not respond to oral magnesium supplements.
The main point of her story is that migraines of long duration can be made worse by a new trigger, such as slow increase in the eye pressure. It is a general rule we teach our neurology residents – if headaches worsen for no obvious reason, search for possible new causes. Another patient who confirmed this rule was a woman who did very well for several years with Botox injections, but then one treatment provided much less relief. Despite the fact that she had no new symptoms or neurological findings, I obtained an MRI scan. Unfortunately, it showed metastatic brain cancer, which originated from undiagnosed breast cancer. Such cases of worsening headaches without other new symptoms of a serious underlying problem are very rare, but require constant vigilance because the temptation is to attribute worsening of migraines to stress, hormones, weather, and other triggers. On the other hand, this needs to be balanced against getting an MRI scan after each unusually severe attack or an increase in headache frequency.
