Sturge–Weber syndrome (SWS) is a nonfamilial neurocutaneous disorder with a potentially progressive course. The syndrome consists of a nevus flammeus (port-wine stain) involving part of the face, in most of the patients all or part of the area supplied by the trigeminal nerve (V₁ distribution most commonly). In all patients a venous angioma of the leptomeninges and less often, a choroidal angioma, and ipsilateral glaucoma is present. The facial and leptomeningeal angioma are usually ipsilateral, but both can be bilateral. Pial angiomatosis more frequently occurs in the occipital region, but it can be localized anywhere and can involve an entire hemisphere or even be bilateral. The extent of lesions that affect the facial skin, eyes, and central nervous system vary between patients, and in some cases only a single-organ system may be affected.¹ Cases of SWS exist without the facial port-wine stain.

Associated common neurological symptoms include seizures, hemiparesis or hemiplegia, visual field deficits, headaches, stroke-like events (SLEs), and learning disabilities. The degree of disability associated with SWS varies significantly between patients and some may remain seizure free with no neurological deficits while others may present with severe intractable epilepsy, profound neurological deficits, and developmental delay.² Migraines can also be very problematic in these children as well.³

Seizures are usually the presenting neurologic symptom. Roughly 70% of patients with epilepsy have their first seizure within the first year of life. In about 20%, the onset of seizures is between the ages of 1 and 3 years but may vary from birth to 23 years of age.^4,5 Early seizures are triggered by fever in about one-third of patients, and are often long lasting, usually consisting of unilateral status epilepticus. Seizures are focal in most of the cases with frequent secondary generalization.^6,7,8 Status epilepticus, occurring as prolonged clonic seizures, is reported in 50% of cases, and less commonly, infantile spasms, and myoclonic seizures.^6,9 Bilateral leptomeningeal involvement is correlated with an earlier seizure onset and a poorer developmental prognosis.¹⁰

In one series of 77 patients with SWS, 39% evidenced a clustering pattern of severe seizures separated by prolonged periods (months to years) of seizure freedom.¹¹ The clusters can be problematic and require benzodiazepines or hospitalization to treat status epilepticus. The prolonged recovery period is similarly problematic in regards to making decisions about when to proceed with epilepsy surgery.¹¹

Hemiplegias of SWS often appear after an episode of serial seizures or unilateral status epilepticus that generally occurs during the first year of life.⁶ Therefore, they are acquired hemiplegias that closely resemble those observed in the hemiconvulsion–hemiplegia–epilepsy (HHE) syndrome. Temporary hemiplegia or hemiparesis that is not preceded by epileptic seizures is also observed. Some have referred to these manifestations as “SLEs” or “stroke-like events.” Their timing with respect to seizures can be difficult, and therefore may represent a subtle postictal phenomenon. However, they are often treated with aspirin to theoretically reduce frequency.¹² One recent retrospective study found that the median number of seizures was also reduced from 3 to 1 episode per month (p = 0.002) with aspirin use.¹³

Approximately 60% of SWS patients present with psychomotor retardation of variable degree, and profound mental retardation is present in 32.5%.^4,14,15 Early onset of seizures and severity of the epilepsy represent the most important contributing factors. Anticonvulsant medications may also play a role, especially with multidrug regimens that are typical in children with SWS.

Ocular manifestations include glaucoma in 28%–70% of cases.^16,17,18 Glaucoma may be present at birth but can develop at any age, even in adults. Glaucoma is bilateral in almost half of bilateral facial angioma patients. Contralateral glaucoma is relatively rare in patients with SWS. This appears anecdotally to be more common when the port-wine stain involves the upper eyelid.

The presence of a port-wine stain at birth may lead to a suspicion of SWS, although in most cases neurological deficits are absent (Fig. 33–1).

Neuroimaging is the investigation of choice when SWS is suspected. Head computerized tomography (CT) scan will often demonstrate the double contour “train-track,” intracranial calcifications. It can also demonstrate localized or hemispheric atrophy. In the neonatal period, CT scan can also detect an increase in the cerebral density of the affected hemisphere. Gadolinium-enhanced magnetic resonance imaging (MRI) is the best modality for demonstrating the presence of a leptomeningeal angiomatosis. Both CT and MRI may initially be normal and subsequently reveal abnormalities after 1 year of age. Therefore, there may be some value to waiting on neuroimaging in an asymptomatic infant with a port-wine stain.

Determining whether the pial angioma is strictly unilateral and its extent is crucial when discussing epilepsy surgery indications. In most Gadolinium-enhanced studies, MRI demonstrates the angioma, but should be performed at least 3 weeks after an episode of status epilepticus to avoid intracortical leakage due to blood–brain barrier alterations which do not correlate well with the extent of the angioma.¹⁹ Both short echo and long repetition time and/or echo-time studies should be performed. In addition, gradient-echo sequences are helpful for demonstrating the presence of microcalcifications.²⁰ One report suggests that postcontrast FLAIR imaging and time-of-flight MR venography may be more sensitive for detecting the leptomeningeal angioma,^21,22 and magnetic resonance spectroscopy and susceptibility-weighted imaging may detect abnormalities not be seen on standard MRI with contrast.^23,24 In addition, most children with SWS have an enlarged ipsilateral choroid plexus, which may assist in diagnosis.

Video-electroencephalography (V/EEG) is often obtained after the child with SWS develops seizures but is generally of limited diagnostic value. The interictal EEG shows nonspecific focal or unilateral depression of the background activity over the area of the leptomeningeal angiomatosis. Polymorphic delta slowing is the next most common EEG abnormality, and, when unilateral, correctly lateralizes the angiomatosis.^6,25 Focal epileptiform abnormalities are uncommon in infants, even in those with frequent seizures. Bilateral epileptiform abnormalities occur early in cases with bilateral lesions, but usually do not appear until after 3 years of age in cases with unilateral lesions.^26,27 Quantitative EEG has emerged as a method of determining asymmetry in children with SWS, but remains investigational.²⁸

The diagnosis of SWS is clinically evident in a child presenting with seizures. However, in some cases, the pial angiomatosis occurs without a facial angioma, and, in others, the pial angioma may be bilateral, while the facial nevus is unilateral.^2,29

Neuropsychological evaluation is indicated early in the course of the disorder. It serves as a reference for future decisions, particularly in cases with potentially surgically treatable epilepsy. Neuro-ophthalmological screening should complete the diagnostic workup. Children with SWS should be regularly followed in a pediatric neurology department with extensive experience in epilepsy care and epilepsy surgery.