White Brain Matter Disease

The white matter portion of the brain consists of nerve fibers, the cells that supplement the nerve fibers, vascular structures and interstitial space. The white matter portion of the brain makes up roughly 60 percent of the total brain volume. White matter exists in the subcortical and central regions of the cerebellar and cerebral hemispheres in the brain.

Types

• The most common white matter brain disease is multiple sclerosis. Other diseases that affect the white matter of the brain include infectious and inflammatory disorders, acquired toxic-metabolic disorders, hypertension-related posterior reversible encephaly syndrome (PRES), central pontine myelinolysis, hereditary metabolic disorders, metabolic disorders and Hurler's disease and Lowe's syndrome.

Significance

• White matter diseases are widely varied in symptoms, involvement and impairment. White matter diseases cause problems with nerve signals, which can lead to problems with cognition, body-wide nerve impairment, pain, headaches, coma and even death. The type and location of impairment corresponds with the location of the lesion and what that nerve is responsible for communicating.

Identification

• White matter brain disease is most visible using magnetic resonance imaging (MRI). Abnormalities of white matter in the brain appear as hyperintensities on T2-weighted MRIs and as hypointensities on T1-weighted MRIs. Each type of white matter brain disease has hallmark characteristics including shape, size and border pattern, overall pattern throughout the white matter, location and reaction to contrast material such as gadolinium. Gadolinium-enhanced MRIs are especially sensitive to identifying active white matter brain disease that creates a break in the blood-brain barrier, such as multiple sclerosis. Hurler's disease and Lowe's syndrome cause cystic changes in the white matter rather than lesions.

Effects

• Most white matter brain diseases cause permanent damage. However, some white matter brain diseases, such as PRES, are usually completely reversible. Most white matter disease damages resolve as the brain repairs itself, although incomplete repairs result in lingering problems, although they are not usually as severe as the original symptoms.

Considerations

• Migraines also cause white matter changes. However, doctors can easily identify whether migraine is the root cause of white matter changes by the patient's reported symptoms.

Prevention/Solution

• Treatment of white matter disease prevents further damage in progressive disease and reverses the damage in PRES. Since chemotherapy and radiation cause white matter brain damage, it is imperative to discuss the risks and benefits with a doctor before beginning these therapies.

Time Frame

• Radiation-induced white matter damage takes a progressive course for two to three years. Chemotherapy-induced white matter changes can be acute or delayed. Acute damage begins during chemotherapy treatments, and chronic begins within weeks to months after treatments. Multiple sclerosis can affect any age group, although it is most common in adults ages 20 to 50.