Sturge-Weber Syndrome (SWS), often referred to as encephalotrigeminal angiomatosis, is a rare, non-hereditary neurocutaneous syndrome present from birth. This condition involves both the nervous system and the skin, and it is characterized by the abnormal growth of blood vessels in specific tissues. The disorder is congenital, meaning it develops before birth, yet it arises spontaneously and is not passed down through the family.
The Primary Manifestations
The presentation of Sturge-Weber Syndrome (SWS) is defined by three distinct features affecting the skin, the brain, and the eyes. The most visible sign is the port-wine birthmark, or Nevus Flammeus, which appears as a flat, reddish-purple discoloration on the skin of the face. This birthmark is caused by an overabundance of capillaries near the skin’s surface and typically follows the path of the trigeminal nerve’s ophthalmic division, covering the forehead and upper eyelid.
The presence of this birthmark, particularly when it includes the eyelid, frequently signals abnormal blood vessel growth inside the head. This neurological component involves a leptomeningeal angioma, a malformation of blood vessels on the surface of the brain (pia mater and arachnoid membranes). This abnormal vascular network impairs blood flow and oxygen supply to the underlying brain tissue, leading to neurological issues.
The most frequent neurological complication is the onset of seizures (epilepsy), which affects a large majority of individuals with brain involvement. These seizures often begin in infancy and can become challenging to manage. Seizures sometimes lead to progressive weakness on the side of the body opposite the birthmark, known as hemiparesis. The persistent disruption of normal brain function also contributes to the risk of developmental delays and intellectual disabilities, which vary in severity.
Ocular involvement represents the third major component of SWS, with the potential development of glaucoma being a serious concern. Glaucoma is characterized by increased pressure inside the eye, which damages the optic nerve and can lead to permanent vision loss. Up to 70% of people with SWS involving the eyelid will develop glaucoma, often presenting early in life.
Vascular malformations in the eye can also include a choroidal hemangioma, a collection of blood vessels located beneath the retina. This lesion can push the retina out of its normal position, potentially causing a retinal detachment and compromising vision. Early and regular ophthalmological examinations are a necessary part of managing the condition from infancy onward.
Understanding the Underlying Cause
The biological origin of Sturge-Weber Syndrome lies in a change to the genetic code that occurs very early in development. SWS is caused by a somatic mutation in the GNAQ gene. This gene provides instructions for making a protein involved in signaling pathways that regulate cell growth and blood vessel formation.
The term “somatic mutation” means the change in the GNAQ gene is acquired randomly after conception and is present only in certain cells of the body, specifically those that give rise to the blood vessels in the affected tissues. Since the mutation is not present in the reproductive cells, it confirms the non-hereditary nature of SWS. This mutation is an “activating” change, causing the GNAQ protein to be overactive.
This overactivity drives the abnormal proliferation and dilation of blood vessels, resulting in the formation of the characteristic angiomas in the skin, brain, and eyes. The timing of this random mutation determines the varying extent and severity of the disorder. The resulting vascular malformations, particularly the leptomeningeal angioma, interfere with normal blood circulation and drainage in the brain, leading to progressive damage.
Identifying Sturge Weber Syndrome
Diagnosis of Sturge-Weber Syndrome begins with clinical observation of the distinctive port-wine birthmark at birth. The location and size of the Nevus Flammeus are important indicators, especially when it involves the area supplied by the first branch of the trigeminal nerve. Diagnosis is confirmed by specialized imaging and testing to determine the extent of brain and eye involvement.
Magnetic Resonance Imaging (MRI) is the preferred imaging method for evaluating the brain. An MRI with contrast visualizes the leptomeningeal angioma, which appears as enhancement on the brain’s surface due to the abnormal blood vessels. Over time, the MRI may also reveal characteristic findings such as brain atrophy (shrinkage of the affected hemisphere) and calcifications in the cerebral cortex, sometimes described as a “tram-track” sign on CT scans.
Specialized ophthalmological examinations are necessary because early glaucoma can rapidly cause irreversible damage. These exams must be conducted even in infancy, sometimes requiring sedation to accurately measure the intraocular pressure (IOP) and inspect the internal structures of the eye. Regular monitoring of the IOP is essential.
The presence and characteristics of seizure activity are evaluated using an Electroencephalogram (EEG). This test measures the electrical activity of the brain, helping medical teams confirm the presence of epilepsy and localize the affected areas. The combination of clinical presentation, MRI visualization of the leptomeningeal angioma, and assessment of eye pressure confirms the diagnosis and establishes a baseline for long-term management.
Treatment and Long-Term Management
The management of Sturge-Weber Syndrome is a lifelong process that requires a multidisciplinary approach focused on controlling symptoms and preserving function. Treatment strategies are tailored to the specific manifestations present in each individual. Early intervention is paramount for achieving the best possible outcomes.
Seizure Control
Seizure control is a primary priority, as frequent seizures contribute significantly to brain injury and developmental regression. Anti-epileptic medications (AEDs) are the primary treatment for managing epilepsy. For individuals whose seizures do not respond to medication, a neurosurgical procedure, such as a hemispherectomy, may be considered to remove the affected portion of the brain.
Treating the vascular malformation in the brain may also involve the use of low-dose aspirin. Aspirin is often prescribed to reduce the risk of stroke-like episodes and help maintain blood flow through the compromised vessels. This preventative approach minimizes secondary damage to the brain tissue caused by impaired circulation and chronic inflammation.
Ocular Management
For ocular complications, glaucoma treatment typically begins with medicated eye drops designed to reduce the pressure inside the eye. If the drops are insufficient, laser therapy or surgical procedures, such as goniotomy or trabeculectomy, may be necessary to create new drainage pathways. Aggressive management of glaucoma is necessary to prevent damage to the optic nerve and preserve vision.
Skin Treatment
Management of the port-wine stain focuses on minimizing its appearance and preventing skin changes. Pulsed dye laser therapy is the standard treatment for the birthmark, using light energy to selectively target and destroy the abnormal, dilated capillaries. Multiple treatment sessions are needed, and the goal is lightening rather than complete removal. Early and consistent laser treatment can improve cosmetic appearance and prevent the skin from thickening.
Developmental Support
Individuals experiencing developmental delays require comprehensive developmental support and rehabilitation services. A coordinated team of specialists, including neurologists, ophthalmologists, dermatologists, and developmental pediatricians, provides continuous care. This includes physical therapy to address muscle weakness, occupational therapy to improve fine motor skills, and speech therapy to aid communication development.