White matter lesions and stroke

The little white spots seen on brain MRI scans have long been thought to be benign. A nagging concern has always persisted since their meaning has remained unclear. A recent study by researchers at several medical centers across the US established that even very small brain lesions seen on MRI scans are associated with an increased risk of stroke and death.

This is a very credible study since it involved 1,900 people, who were followed for 15 years. Previous studies of these white matter lesions (WML), which are also called white matter hyperintensities (WMH) involved fewer people and lasted shorter periods of time (these are my previous 4 posts on this topic).

Migraine sufferers, especially those who have migraines with aura are more likely to have WMLs. One Chinese study showed that female migraine sufferers who were frequently taking (“overusing”) NSAIDs, such as aspirin and ibuprofen actually had fewer WMLs than women who did not overuse these medications. Even though most neurologists and headache specialists believe that NSAIDs worsen headaches and cause medication overuse headaches, this is not supported by rigorous scientific evidence (the same applies to triptan family of drugs, such as sumatriptan). Another interesting and worrying finding is that the brain lesions were often very small, less than 3 mm in diameter, which are often dismissed both by radiologists who may not report them and neurologists, even if they personally review the MRI images.

The risk of stroke and dying from a stroke in people with small lesions was three times greater compared with people with no lesions. People with both very small and larger lesions had seven to eight times higher risk of these poor outcomes.

This discovery may help warn people about the increased risk of stroke and death as early as middle age, long before they show any signs of underlying blood vessel disease. The most important question is what can be done to prevent future strokes.

An older discovery pointing to a potential way to prevent strokes is that people who have migraines with aura are more likely to have a mutation of the MTHFR gene, which leads to an elevated level of homocysteine. High levels of this amino acid is thought to damage the lining of blood vessels. This abnormality can be easily corrected with vitamin B12, folic acid and other B vitamins.

More than 800,000 strokes occur each year in the United States, according to the National Institute of Neurological Disorders and Strokes. Strokes are a leading cause of death in the country and cause more serious long-term disabilities than any other disease. Routine MRI scans should not be performed, even in migraine sufferers, but if an MRI is done and it shows these WMLs, it is important to warn the patient to take preventive measures.

There are several known ways to prevent or reduce the risk of strokes. These include controlling weight, hypertension, cholesterol, diabetes, reducing excessive alcohol intake, stopping smoking, and engaging in regular aerobic exercise.