You are in: eMedicine Specialties > Radiology > PEDIATRICS Sturge-Weber SyndromeArticle Last Updated: Feb 26, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP, Chairman of Medical Imaging, Professor of Radiology, NGHA, King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia Ali Nawaz Khan is a member of the following medical societies: American Institute of Ultrasound in Medicine, Radiological Society of North America, Royal College of Physicians, Royal College of Physicians and Surgeons of the United States, Royal College of Radiologists, and Royal College of Surgeons of England Coauthor(s): Ian Turnbull, MD, Lecturer, Department of Radiology, University of Manchester; Consulting Neuroradiologist, Hope Hospital, Salford, Manchester and North Manchester Hospital; Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute; Riyadh Al-Okaili, MBBS, Interventional/Therapeutic and Diagnostic Neuro-Radiologist, King Abdulaziz Medical City Editors: Charles M Glasier, MD, Professor, Departments of Radiology and Pediatrics, University of Arkansas for Medical Sciences; Chief, Magnetic Resonance Imaging, Vice-Chief, Pediatric Radiology, Arkansas Children's Hospital; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Marta Hernanz-Schulman, MD, FAAP, Professor, Radiology, Radiological Sciences, and Pediatrics, Director, Department of Pediatric Radiology, Radiologist-in-Chief, Director, Department of Diagnostic Imaging, Vanderbilt University Medical Center, Vanderbilt Children's Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; James G Smirniotopoulos, MD, Professor of Radiology, Neurology, and Biomedical Informatics, Chairman, Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences Author and Editor Disclosure Synonyms and related keywords: SWS, Sturge-Weber-Dimitri syndrome, encephalotrigeminal angiomatosis, trigeminal angiomatosis, meningofacial angiomatosis, encephalofacial angiomatosis, Dimitri's hemangiomatosis, Jahnke's syndrome (variant without glaucoma), Kulisher's syndrome, Krabbe's II syndrome, Lawford's syndrome (variant with glaucoma and without increased ocular pressure), meningocutaneous syndrome, neurooculocutaneous syndrome, Parkes Weber's phacomatosis, vascular encephalotrigeminal Weber-Dimitri syndrome INTRODUCTIONSection 2 of 12
  BackgroundSturge-Weber syndrome (SWS) is a congenital disorder caused by the persistence of the transitory primordial sinusoidal plexus stage of vessel development. SWS is usually sporadic and characterized by a vascular malformation, with capillary and/or venous malformation that involve the face, choroid of the eye, and leptomeninges. The facial vascular malformation has a predilection for the distribution of the first division of the trigeminal nerve. In addition to the vascular meningeal malformation, an underlying atrophy of the cerebral hemisphere is often present. The disease process is usually unilateral. Most patients (80%) have Epilepsy, and more than 50% have a mental deficiency.1, 2, 3, 4, 5, 6, 7 PathophysiologyCranial manifestations The pathologic lesions in SWS include vascular malformations of the face (capillary vascular malformation, also known as port-wine stain or nevus flammeus) and venous malformation or angiomas involving the leptomeninges and choroid plexus. These lesions lead to seizures, atrophy, cerebrovascular thrombosis, and dystrophic intracortical calcification. Several variants of cortical calcification have been reported; these include calcification, which is present at birth8; bilateral calcification (15%); and calcification contralateral to the facial nevus. Many cortical veins are either absent or replaced by a few enlarged cortical veins, which drain into the dural venous sinuses. With the absence of cortical veins, venous drainage may occur via enlarged deep medullary veins into the deep venous system. Nonvisualization of dural venous sinuses is common on angiograms in patients with SWS. An increased incidence of a persistent trigeminal artery has also been reported.9, 12 Orbital manifestations Facial capillary vascular malformation (ie, port-wine stain or nevus flammeus) is common in the pediatric population. In their study of 106 patients with port-wine stains, Enjolras and associates concluded that patients with lesions located in the ophthalmic (or cranial nerve VI, trigeminal) cutaneous area are at risk for associated neuro-ocular symptoms.13, 14 FrequencyUnited StatesSWS is a sporadic disease; its exact incidence is not known. InternationalSWS is a sporadic disease; its exact incidence is not known. Mortality/MorbidityReduced intellectual capacity (or developmental delay) and hemiparesis eventually develop in most patients if medical and surgical treatments are unsuccessful. Reduced intellectual capacity occurs in more than 50% of patients. RaceSWS is a sporadic disease; no racial predilection is known. SexSWS is a sporadic disease; no sex predilection is known. AgeSeizures may occur in the first year of life (80% of cases). Clinical DetailsMost patients have a facial capillary vascular malformation lesion (ie, port-wine stain, or nevus flammeus), usually in the distribution of the first and/or second divisions of the trigeminal nerve. A first-division trigeminal distribution is associated with occipital meningeal involvement; a second-division distribution, with parietal meningeal involvement; and a third-division distribution, with frontal meningeal involvement.
Preferred ExaminationExaminations for SWS include the following: plain skull radiography, CT, MRI, angiography, and nuclear medicine studies.16, 17, 18, 19, 20, 21, 22, 23, 24, 25 CT is more sensitive then plain skull radiography and MRI in the detection subcortical calcifications. However MRI with contrast is probably the best imaging test. It is superior to CT in the demonstration of abnormal myelination, and it is more sensitive in the demonstration of leptomeningeal enhancement, particularly in the presence of dense cortical calcification on CT scans. In addition, orbital associated malformations are well depicted on contrast-enhanced orbital MRI. Limitations of TechniquesCalcification may not be detectable in individuals younger than 2 years. Other causes of gyriform intracranial calcification cannot always be differentiated from those found in SWS.
DIFFERENTIALSSection 3 of 12
Other Problems to Be ConsideredKlippel-Trenaunay syndrome Other causes of gyriform intracranial calcification are rare but may include cerebral infarction, meningitis and encephalitis, skull irradiation, meningioangiomatosis, celiac disease, and leukemia after the intrathecal administration of methotrexate. RADIOGRAPHSection 4 of 12
FindingsPlain skull radiographs may show ipsilateral skull-table and orbital thickening, elevation of the sphenoid wing and petrous ridge, and enlarged ipsilateral paranasal sinuses and mastoid air cells due to underlying ipsilateral cerebral atrophy. Plain radiographs of the skull in older children and adults may reveal asymmetry, with a smaller hemicranium on the ipsilateral side. Rarely, ipsilateral enlargement of the hemicranium occurs secondary to the vascular malformation. The most striking feature is the presence of tramline gyriform patterns of intracranial calcification in the subcortical region, primarily in the parietal and occipital regions.
Degree of ConfidenceSkull radiographs usually do not demonstrate calcifications until patients are older than 2 years. The increased sensitivity of CT allows earlier demonstration of calcifications. False Positives/NegativesOther causes of gyriform intracranial calcification can lead to a false-positive diagnosis. The detection of calcifications in patients younger than 2 years is unusual with plain radiography. CT SCANSection 5 of 12
FindingsCT scans show the tramline gyriform calcification of apposing gyri that underlies the contrast-enhancing leptomeningeal vascular malformation. Cortical enhancement may be difficult to appreciate on CT when cortical calcification is dense. The subjacent white matter may be hypoattenuating on CT scans. The ipsilateral choroid plexus may be enlarged. Enlarged transcortical (medullary) veins are frequently associated with an enlarged choroid glomus. Other features on CT scans include ipsilateral cortical atrophy, enlargement of the ipsilateral ventricle, and loss of volume of the ipsilateral cranial cavity. Occasionally, the hemicranium is enlarged on the ipsilateral side, with associated enlargement of the cerebrospinal fluid (CSF) space.
Degree of ConfidenceCT is more sensitive than skull radiography and MRI in the detection subcortical calcifications, and detection is sometimes possible in patients younger than 2 years. False Positives/NegativesOther causes of gyriform intracranial calcification could lead to a false-positive diagnosis. MRISection 6 of 12
FindingsMRI reveals a pial, enhancing, angiomatous malformation, often in the occipital or posterior temporoparietal region ipsilateral to the facial angioma. MRI demonstrates atrophy of the cerebral hemisphere subjacent to the leptomeningeal angioma, with small gyri and enlarged adjacent sulci. Subtle atrophy is frequently more obvious on MRIs than on CT scans. On T2-weighted images, the angioma appears as a hyperintense leptomeningeal thickening. In patients with choroidal angiomas, high-resolution, T1-weighted, fat-suppressed, enhanced images show choroidal enhancement. Gadolinium enhancement improves visualization of the angiomatous malformation. Calcification in the underlying cortex is not as evident as on CT scans, but it does not mask enhancement of the underlying angiomatous malformation, which can be a problem with CT. As in contrast-enhanced CT, the glomus of the choroid plexus may be enlarged, and enlarged draining transcortical veins may be present in the involved cerebral hemisphere. The overlying superficial cortical veins are reduced in size and number, with a prominent deep collateral venous system. Abnormally low signal intensity from the involved cortex may result from dystrophic calcification or from abnormal iron deposition in the cortex. Abnormal myelination has been described in association with SWS; myelination may be delayed or deficient in some patients and accelerated in others. Quantitative brain MR spectroscopy (MRS) and diffusion tensor imaging (DTI) have been used in the characterization of SWS. Differences have been recorded between the abnormal cerebral cortex and the normal contralateral normal cerebral cortex. A choline increase and N-acetylaspartate decrease are observed in a pathologic cortex, while an unaffected cerebral cortex shows no change in the DTI parameters. These changes in the pathologic cortical gray matter in SWS patients probably reflect neuronal loss or dysfunction and demyelination as a result of recurrent seizures.26 Physiologic alterations in SWS can be assessed by using MR perfusion imaging (PWI) and proton spectroscopic imaging (MRSI). PWI changes in SWS indicate cerebral hypoperfusion predominantly due to impaired venous drainage, with only the most severely affected regions showing arterial perfusion deficiency. The severity of cerebral hypoperfusion correlates well with neuronal loss/dysfunction, which is reflected in the severity of neurologic symptoms and disability. The highest correlation is found with the degree of hemiparesis. These parameters may be useful in quantifying disease severity.27 Blood-oxygen-level-dependent (BOLD) MR venography has been shown to identify leptomeningeal internal veins in a 4-month-old with SWS when other MR sequences failed to show any abnormality. Follow-up MRI after the first seizure at the age of 12 months demonstrated strong leptomeningeal enhancement, while BOLD venography revealed abnormal medullary and subependymal veins, as well as deep venous structures. At the time of the second MR scan signs of cerebral atrophy and calcifications were apparent on CT. The report shows that BOLD venography may allow early diagnosis of venous anomalies in SWS.28 Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. Degree of ConfidenceAlthough MRI is not as good as CT in depicting calcification, it is superior to CT in the demonstration of abnormal myelination. MRI is much more sensitive in the demonstration of leptomeningeal enhancement, particularly in the presence of dense cortical calcification on CT scans. Choroidal lesions are well depicted on high-resolution contrast-enhanced orbital MRIs. False Positives/NegativesSWS must be differentiated from other neurocutaneous disorders, although correlation of the intracranial findings with the clinical characteristics is usually diagnostic. Statistically, most patients with facial capillary malformations (port-wine stains) do not have SWS. In addition, some patients with classic intracranial findings of SWS have no facial abnormalities. NUCLEAR MEDICINESection 7 of 12
FindingsAbnormal cerebrovenous drainage is associated with ischemia, hypoxia, and glucose deprivation, which can account for progressive neurologic deterioration in SWS. Single-photon emission CT (SPECT), technetium-99m hexamethylpropyleneamine oxime (HMPAO) scanning, and fluorodeoxyglucose (FDG) PET scans show diminished perfusion and reduced glucose metabolism in the affected cerebral hemisphere.29 Approximately 50% of the patients with SWS have bihemispheric disease when they are examined with functional imaging, which reveals abnormal perfusion and glucose metabolism. Widespread abnormalities of cerebral perfusion and glucose metabolism might explain the high prevalence of developmental delay associated with SWS. Hypoperfusion of the involved cerebral hemisphere usually appears in patients older than 1 year. SPECT depicts cerebral blood flow asymmetry in infants with SWS, which tends to shift with age. The cortex involved in the vascular malformation is hyperperfused during the first year of life, before the first seizures occur. The characteristic hypoperfusion appears after 1 year of age, even in patients without epilepsy.30 Degree of ConfidenceTechnetium-99m HMPAO imaging is a useful addition to the examination when delineation of the full extent of the abnormality is of particular relevance (eg, before surgery). Technetium-99m imaging is more likely to depict areas of hypoperfusion, which represent ischemic regions; these areas may act as epileptogenic foci and may not be detected by using CT or MRI. False Positives/NegativesCerebral perfusion defects and areas of hypometabolism are seen on PET images in epileptogenic foci secondary to multiple underlying abnormalities. ANGIOGRAPHYSection 8 of 12
FindingsAlthough SWS is usually categorized with venous malformations, it is an extensive capillary and venous malformation that affects 1 or sometimes both cerebral hemispheres. Cerebral angiograms show early capillary blush in the areas involved with the pial vascular malformation associated with abnormally large veins in the subependymal and periventricular regions. Enlarged deep medullary veins that drain deep to the subependymal veins are present. The superficial cortical veins in the region of the dystrophic calcification have markedly slow flow as a result of venous thrombosis, but most of the cortical veins are largely absent on the affected side. Rarely, high-flow shunting of arteriovenous malformations are seen. Venous drainage occurs via bizarre, enlarged deep medullary veins into the deep venous system or via a few patent enlarged cortical veins into the dural venous sinus. The deep veins and dural venous sinus are often not visualized in these patients. Whether the absent veins are congenitally aplastic or occluded as a result of thrombosis is not certain. Some authorities advocate antiplatelet therapy in SWS, believing that clinical exacerbations may be the result of progressive venous thrombosis, although this has never been clearly documented with conventional angiography. However, progressive dural venous occlusion has been documented with magnetic resonance venography in an infant with SWS, although no luminal thrombus was evident on spin-echo images. So far, observations in SWS do little to clarify the issue of congenital versus acquired abnormality of the intracranial venous system. Other vascular abnormalities seen with SWS include arterial occlusion (rare), segmental venous ectasia, and absent or luminal irregularities and deformities of the deep veins.
Degree of ConfidenceIn light of an appropriate history, the angiographic appearances of SWS can be fairly characteristic, although the role of angiography in the management of SWS is decreasing. However, in patients with medically unresponsive seizures, resection of brain deep to the angioma is sometimes undertaken. In these patients, the identification of large diploic vessels by using angiography can help avoid a difficult craniotomy. False Positives/NegativesKlippel-Trenaunay-Weber syndrome and Wyburn-Mason syndrome may cause similar angiographic appearances. INTERVENTIONSection 9 of 12
Cerebral lobectomy may be considered in some patients. In cases with severe drug-refractory focal epilepsy caused by SWS, promising results have been achieved with hemispherectomy.31 Devlin and associates described the clinical course and outcomes in 33 children who underwent hemispherectomy and concluded that the optimal timing of surgery with respect to age at presentation and the influence of the underlying pathology are only slowly emerging. At surgery, their patients were aged 0.33-17 years.32 Vining and associates from John-Hopkins hospital reported their experience with 58 children after hemispherectomy. They concluded that early surgery relieves the burden of constant seizures and allows the child to return to a more-normal life.33 Kossoff et al concluded that the patient's age at surgery does not have an adverse effect on either seizure or cognitive outcomes.34 Medical/Legal Pitfalls
See also the Medscape topic Medical Malpractice and Legal Issues. ACKNOWLEDGMENTSSection 10 of 12
The authors and editors would like to thank Ramesh Chandra Raja, MBBCH, for his contributions to this article. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
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