White Matter Lesions
Top 5 Causes for White Matter Lesions
Two types of matter are present in the brain; grey and white matter. Lesions can occur on either type, but are more prevalent on white matter. The occurrence of these lesions is generally attributed to specific conditions, but diagnosing these conditions can be challenging.
Physiology of the brain
The brain and the spinal cord compose the body’s central nervous system; controlling the responses of the entire body and providing our emotional capabilities. The brain is divided into 3 separate components; the cerebrum, the cerebellum and the brainstem. The largest section of the brain is the cerebrum, which is where both grey and white matter is found.
- Grey matter, which is the home for areas that control muscle control and sensory perceptions (sight, hearing, memory, speech and emotions, for example), are cell bodies made up of nuclei.
- White matter is composed of nerve fiber tissue that is involved with the transmission of sensory information from the entire body to the cerebral cortex, as well as controlling the body’s temperature, blood pressure and heart rate. These fibers are encased within fatty protein called myelin, which creates the white coloration. Myelin insulates and protects the nerve fibers.
In other words, any type of sensation travels through the nervous system through the spinal cord to the brainstem to the white matter before arriving at the cerebral cortex for processing.
Lesions occurring on white matter
Certain diseases and conditions cause lesions or tissue damage to the white matter of the brain. Damage to the fatty encasement exposes nerve fibers, causing abnormal behavior of the nerves. The most frequent reasons for the lesions are: age, multiple sclerosis, Alzheimer’s disease, Lyme disease and Epstein Barr infections.
- Age is considered to the be the foremost cause of periventricular white matter, or the white matter that is located immediately to the side of the two lateral ventricles of the brain. It is assumed that it occurs merely due to usage; basic wear and tear of the brain.
- Multiple sclerosis is an autoimmune disease affecting both the brain and the central nervous system. White matter lesions attributed to the disease can occur at any location of the brain and may vary in severity from individual to individual. The disease is caused by the destruction of the myelin sheath, exposing the nerve fibers and thereby slowing or stopping nerve impulses.
- Recent studies have shown that lesions on the white matter of the brain of individuals who are in their mid-40’s may be indicative of early risk for Alzheimer’s disease. A cognitive test was given, and only those who fared less well on the test were then given an MRI; revealing tiny lesions on the brain. The lesions found were akin to those found in deceased Alzheimer’s patients during autopsies.
- Lyme disease is a bacterial infection that is transmitted through the bite of a tick. It is a complex disease that is often misdiagnosed as MS, ALS, fibromyalgia and other neurological conditions due to the similarities of symptoms. Lesions of the brain’s white matter detected through an MRI also attribute to the confusion.
- A virus that is the root cause for a number of diseases, Epstein Barr (EBV) is estimated to have affected approximately 95% of all adults at some time in their life. It may have presented as a flu like condition or as serious as infectious mononucleosis. Once in the system, Epstein Barr virus never leaves.
White matter lesions on the brain are found during an MRI, usually as a result of symptoms indicating one of these conditions. Because each of the conditions closely mimic the others, it is imperative that doctors specializing in diagnosing the conditions be consulted for the most accurate diagnosis and successful treatment.