Sturge–Weber syndrome
Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare type of phakomatosis, a congenital disorder that affects the central nervous system, skin, and eyes. It is often associated with port-wine stains of the face. Clinical manifestations include glaucoma, choroidal lesions, seizures, intellectual disability, and benign tumors of the blood vessels of the leptomeninges.
Sturge–Weber originates from embryonic development, resulting from errors in mesodermal and ectodermal development. Unlike other phakomatoses, Sturge–Weber occurs sporadically. It is caused by a mosaic, somatic activating mutation occurring in the GNAQ gene.
Diagnosis is usually done through imaging; findings may include tram track calcifications in the cerebral cortex on a CT scan, angiomatosis of the pia mater, and hemicerebral atrophy. Managing Sturge–Weber focuses on treating the symptoms as they appear. Around 1 in 50,000 newborns are affected by the disease. It was originally described in 1879 by William Allen Sturge.
Signs and symptoms
Sturge–Weber syndrome is usually manifested at birth by a port-wine stain on the forehead and upper eyelid of one side of the face, or the whole face. The birthmark can vary in color from light pink to deep purple and is caused by an overabundance of capillaries around the ophthalmic branch of the trigeminal nerve, just under the surface of the face. There is also malformation of blood vessels in the pia mater overlying the brain on the same side of the head as the birthmark. This causes calcification of tissue and loss of nerve cells in the cerebral cortex.Neurological signs include seizures that begin in infancy and may worsen with age. Convulsions usually happen on the side of the body opposite the birthmark, and vary in severity. There may also be muscle weakness on the side of the body opposite the birthmark.
Some children will have developmental delays and cognitive delays; about 50% will have glaucoma, which can be present at birth or develop later. Glaucoma can be expressed as leukocoria, which should suggest further evaluation for retinoblastoma. Increased pressure within the eye can cause the eyeball to enlarge and bulge out of its socket.
Sturge–Weber syndrome rarely affects other body organs.
| Presentation | |
| Seizures | 75–90% |
| Vascular headache | 40–60% |
| Developmental delay | 50–70% |
| Glaucoma | 30–70% |
| Hemianopsia | 40–45% |
| Hemiparesis | 25–60% |
Cause
The blood vessel formations associated with SWS start in the fetal stage. Around the sixth week of development, a network of nerves develops around the area that will become a baby's head. Normally, this network goes away in the ninth week of development. In babies with SWS due to mutation of gene GNAQ, this network of nerves doesn't go away. This reduces the amount of oxygen and blood flowing to the brain, which can affect brain tissue development.Diagnosis
CT and MRI are most often used to identify intracranial abnormalities. When a child is born with a facial cutaneous vascular malformation covering a portion of the upper or the lower eyelids, imaging should be performed to screen for intracranial leptomeningeal angiomatosis. The haemangioma present on the surface of the brain is in the vast majority of cases on the same side as the birth mark and gradually results in calcification of the underlying brain and atrophy of the affected region.Classification
Sturge–Weber syndrome can be classified into three different types. Type 1 includes facial and leptomeningeal angiomas as well as the possibility of glaucoma or choroidal lesions. Normally, only one side of the brain is affected. This type is the most common. Type 2 involvement includes a facial angioma with a possibility of glaucoma developing. There is no evidence of brain involvement. Symptoms can show at any time beyond the initial diagnosis of the facial angioma. The symptoms can include glaucoma, cerebral blood flow abnormalities and headaches. More research is needed on this type of Sturge–Weber syndrome. Type 3 has leptomeningeal angioma involvement exclusively. The facial angioma is absent and glaucoma rarely occurs. This type is only diagnosed via brain scan.Treatment
Treatment for Sturge–Weber syndrome is symptomatic. Laser treatment may be used to lighten or remove the birthmark. Anticonvulsant medications may be used to control seizures. Doctors recommend early monitoring for glaucoma, and surgery may be performed on more serious cases. When one side of the brain is affected and anticonvulsants prove ineffective, the standard treatment is neurosurgery to remove or disconnect the affected part of the brain. Physical therapy should be considered for infants and children with muscle weakness. Educational therapy is often prescribed for those with intellectual disability or developmental delays, but there is no complete treatment for the delays.Brain surgery involving removing the portion of the brain that is affected by the disorder can be successful in controlling the seizures so that the patient has only a few seizures that are much less intense than pre-surgery. Surgeons may also opt to "switch-off" the affected side of the brain.
Latanoprost, a prostaglandin, may significantly reduce IOP in patients with glaucoma associated with Sturge–Weber syndrome. Latanoprost is commercially formulated as an aqueous solution in a concentration of 0.005% preserved with 0.02% benzalkonium chloride. The recommended dosage of latanoprost is one drop daily in the evening, which permits better diurnal IOP control than does morning instillation. Its effect is independent of ethnicity, gender or age, and it has few to no side effects. Contraindications include a history of cystic macular edema, epiretinal membrane formation, vitreous loss during cataract surgery, history of macular edema associated with branch retinal vein occlusion, history of anterior uveitis, and diabetes mellitus. It is also wise to advise patients that unilateral treatment can result in heterochromia or hypertrichosis that may become cosmetically objectionable.
| Complication | Treatment | Treatment |
| Glaucoma | Beta blocker drops | Adrenergic drops |
| Partial epilepsy | Carbamazepine | Valproate, topiramate |
| Headache | Ibuprofen | Sumatriptan |
| Stroke-like episodes | Aspirin | - |
| Neurobehavior | Methylphenidate | Clonidine |