Brain Involvement

Individuals with SWS may experience a variety of neurological abnormalities due to the atypical growth of blood vessels on the surface of the brain (leptomeningeal angiomas).
These abnormalities often result in secondary effects to the affected tissue including lack of oxygen in affected body tissue (hypoxia), inadequate blood supply to affected areas (ischemia), obstruction of affected veins (venous occlusion), the formation of blood clots (thrombosis), and/or tissue death cause by lack of oxygen (infarction).
Calcifications of affected areas of the brain may also occur. A brain calcification is most easily seen with a head computer tomography (CT), but this is not usually an early finding.

Implications

Implications varies based on the extent of the brain involvement:

  • if it’s involved just a very small area on one side of the brain, then the patient has likely 75% chance of epilepsy or seizure development at some point in time, but a much lower chance of significant cognitive issues
  • if much of one side of the brain is involved, then the patient has a much higher change of some learning disabilities, cognitive issues, or attention deficit
  • if it’s involved much of both sides of the brain, then there’s a very high chance, like 95% or more, of epilepsy and seizures to begin at some point in time and of significant cognitive issues

Another predictive factor is the age seizure onset, the earlier the onset, the harder to control the seizures.

Neurological deficits, such as cognitive impairments, can improve once the seizures get fully controlled through medication.

Risk Factors

When there’s an extensive facial involvement by the port wine stain, there’s a higher chance of brain involvement, and if the baby presents a glaucoma other than the birthmark, that chance increases more.

As a general idea:

  • 20% risk if the port wine stain is located on one side and is smaller (like mostly forehead and upper eye)
  • 25% if the port wine stain involves most of one side of the face (like forehead, over the eye, plus down to the chick)
  • 35-50% if the port wine stain involves most of both sides
  • 50% or more if the child has a glaucoma on top of the port wine stain

Rule out brain involvement

When normal development is observed together with no seizures and proper imaging after one year of age comes out completely normal, then the child can be considered cleared. Proper imaging refers to a magnetic resonance imaging (MRI) with contrast. It’s worth to mention that early scans of the brain (meaning before one year of age) may not reveal the presence of brain involvement.

An early electroencephalogram (EEG), which is a very safe exam, can reveal any abnormality in the brain activity. If something is detected by the EEG, then an MRI can cast further light on the condition of the brain.

When a MRI is recommended

If the baby has the port wine stain covering the upper part of the face, from outer edges of the eye, out to the temple region, involving the forehead or the upper eye lid, or the mid forehead, then there’s a greater chance of brain involvement. In these cases, it is recommended a neurologic exam and an EEG, and if they are ok, repeat them at three to five months of age. If everything keeps doing ok, then an MRI with contrast after one year of age.
In some case, a one to two months old baby can receive an MRI without sedation or contrast.