Sturge-Weber Syndrome

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Original Editors - Marti Bradbury & Kayla Stull from Bellarmine University's Pathophysiology of Complex Patient Problems project.

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Definition/Description

Sturge-Weber Syndrome (SWS) is a sporadic neurocutaneous disorder that affects the meninges (most often the pia mater and acrachnoid mater) of the brain and the skin of the face.  Involvement is normally unilateral, but may be bilateral.  The disease is caused by embryonic blood vessels that fail to regress at the appropriate time of development.  This leaves residual blood vessels that result in the formation of angiomas on the face, in the meninges, and in the ipsilateral eye.  The angiomas of the face are referred to as port wine stains and are most often present in the opthalmic and maxillary divisions of the trigeminal nerve.  

Those affected by the disorder may have involvement of both the CNS and the skin of the face or they present with only one area of involvment.  The Roach Scale is used to classify the disorder into three types, based on the areas that are affected by the residual blood vessels.

1. Type I: Angiomas are present in both the skin of the face and meninges, ipsilateral eye is also typically affected
2. Type II: Angioma only present on the face, ipsilateral eye may be affected
3. Type III: Angioma only present in the meninges, ipsilateral eye is usally not affected  

Hypertrophy of the tissue directly beneath the angioma is typically present.  This may lead to assymetries in facial features in addition to the port wine stain.  Hypertrophy may also also lead to calcification within CNS resulting in neurological symptoms that include seizures, focal deficits, headaches, and developmental delays.

The neurological symptoms of SWS are progessive in nature.  This is most commonly attributed to the "vascular steal phenomenon" in which the residual blood vessels steal blood from the rest of the cortex resulting in hypoxic injury to CNS tissue and increased calcification around the angioma.  This leads to increased risk for seizures and neurological deficits.

Prevalence

The incidence of SWS is estimated to be 1 per 50,000.  Race has not been reported to have an influence on the prevalence of the disorder.  Both sexes have been documented to be affected equally.

Characteristics/Clinical Presentation

As it was stated before, SWS primarly affects three areas - the skin of the face, the meninges of the brain, and the eye.  Each of these areas can be affected in a number of different ways.  The possible manifestions of the disease are described below.

Manifestions of the Face:

• Port Wine Stains most often present in the distribution of the trigeminal nerve.  Typically the opthalmic and maxiallary are most affected, while the mandibular portion is affected less often.  Port wine stains associated with SWS are often progressive.  They begin as a light pink color at birth and then become to a dark red or purple color as the disease progresses.  Port wine stains are not always isolated to the face and may be present on other areas of the body.  The presence of a port wine stain alone does not indicate SWS.  It is necessary to differeniate between SWS and other cutaneous disorders that may present similar skin pigmentation abnormalities.

Manifestations of the CNS:

• Seziures can be attributed to ischemia of the cortex and irritation of the brain secondary to calfication.  Most seizures begin within the first 24 months of life and indicate a higher risk for developmental delay than those who do not have seizures.  Earlier onset may be seen in those with bilateral involvement.  Seizures are normally partial and focal due to the focal nature of the angioma associated with SWS.  Seziures can often be at least partially controlled with medication.  In rare cases, status epilepticus may be present.  These are expecially dangerous in idividuals with SWS because the vascular system is already compromised.
• Hemiparesis may occur is CNS damage is present in an area of the brain responsible for motor control.  The specific location of the damage will determine that areas of the body that are affected and to what extent.  Hemiparesis is often accompanied by a migraine headache indicating a vascular problem.
  
• Developmental delay may occur as result of decreased blood supply to the cortex. The severity of developmental delay is based upon the amount of neurological damage.  Earlier onset of seizures generaly indicates a greater risk for developmental delay.  Learning disorders may also present.  Attention deficit hyperactivity disorder is often noticed in children with SWS.
• Headaches tend to develop because of vascular disease.  Headaches are typically described migraine-like and can be debilitating.  Onset of headaches varies based on the progression of the disease.  Onset at <10 years of age is a common finding in children with SWS.

Manifestations of the Eye:

• Glaucoma normally develops in the ipsilateral eye only when the eyelid is affected by the port wine stain (opthalmic portion of the trigeminal nerve).  Occasionally, bilateral glaucoma my occur in cases of bilateral vascular abnormalities.  Glaucoma tends to development either in the first year of life or between the ages of 5-9.
• Blindness may result if glaucoma is left untreated.  Blindness is attributed to increased intra-ocular pressure associated with glaucoma. The elevated intra-ocular pressure leads to damage of the optic nerve. Visual deficits may present as feild cuts or total blindness.
• Buphthalmos or enlargement of the eye may occur secondary to the hypertrohy is often present beneath areas of port wine stain.

Associated Co-morbidities

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Medications

Medications used to treat Sturge-Weber Syndrome will vary greatly depending the presentation of symptoms in those with the disorder. Medical Intervention can include any of the following:

• Anticonvulsants work to discontinue electrical siezure activity quickly and reduce the likelihood of siezure reoccurance. Examples of these medications include Carbamazepine (Tegretol), Phenytoin (Dilantin), Valproic acid (Depakote, Depakene, Depacon), Gabapentin (Neurontin), Lamotrigine (Lamictal), as well as many others.
• Beta Blockers are used to help decrease intraoccular pressure by reducing the amount of aqueous humor produced in the eye. Aqueous humor is a plasma-like substance largely composed of protiens which help support and nourish occular tissue. Aqueous humor also assists in maintaining appropriate intraoccular pressure but in those with Sterge-Weber Syndrome this substance is overproduced. Levobunolol 0.25% or 0.5% (Betagan) is a beta blocker commonly used in Sterge-Weber Disease.
• Carbonic Anhydrase Inhibitors lower intraoccular pressure in much the same way that beta blockers do, by reducing production of aqueous humor. These drugs include Dorzolamide 2% (Trusopt) and Brinzolamide 1% (Azopt).
• Prostaglandin Analogues also work to lower intraoccular pressure, though instead of decreasing aqueous production directly they, instead, increase the outflow of the fluid away from the eye through the proper pathway. This pathway is known as the uveoscleral pathway and is located inferior to the eye. Latanoprost 0.005% (Xalatan) is a prostaglandin analogue used for this purpose.
• Topical Corticosteroids are used to treat occular. Prednisolone acetate 1% inhibits the edema, fibrin deposition,capillary dilation and phagocytic migration during the acute inflammatory response.  Dexamethasone ophthalmic (Maxidex, Ozurdex) and Triamcinolone (Triesence) work by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability.
• Antineoplastic Agents work by inhibiting DNA synthesis in order to decrease or stop cell growth and proliferation. Two examples of antineoplastic agents are Fluorouracil (Efudex) and Mitomycin. 

Diagnostic Tests/Lab Tests/Lab Values/Imaging ¹⁶

The diagnosis of Sturge-Weber Syndrome is most commonly made by the observation of a facial port wine stain in combination with abnormal blood vessels on the suface of the brain and/or glaucoma. Diagnosis is typically made at birth. The following lab tests and imaging techniques can be used to diagnose SWS.

Lab Tests:

• Cerebrospinal Fluid Analysis may show elevated protein levels.  It is thought that protein may be elevated because of microhemorrhage that may occur within the brain. 

Imaging:

• Radiographs of the skull may show "tram-track" calcification. These calcifications are located between the arachnoid and the pia mater.  The follow the pattern of the gyri in a curvilinear and parallel pattern.  The calcifications are predominately seen in the parietal and occipital lobes.  In more severe cases, the frontal lobe may also be involved and the calcifications may be seen bilaterally.¹⁷  Califications are not present initially and will not be seen on early radiographs.  For this reason, plain radiographs are no longer used to diagnose the disease but rather to determine the severity and prgression of the disease.

• Angiography will illustrate the abnormal vasculature associated with SWS.  Most abnormalities are seen within the venous system.
• CT Scan will show early calcification in infants.  Other abnormal findings on CT scans may also include brain atrophy scondary to a lack of normal blood flow, choroid plexus enlargement due to the inability to aquately transport CSF, and a breakdown of the blood-brain barrier during seizures.
• MRI will allow for early diagnosis of SWS because the images will show the formation of the angioma and early venous abnormalities.  MRI may also show increased myelination in the area of the angioma, an enlarged choroid plexus, atrophy of cortical tissue (predominately white matter), and anbormalties in the corticospinal tracts when hemiparesis is present.
• Single-photon Emission Commuted Tomography (SPECT) measures cerebral blood flow and will demonstrate lack of adequate blood flow in the area of the angioma.  Underperfusion of the cortex is one of the earliest signs of SWS.  It is typically present before calicification develops or the onset of seizures.  SPECT will also illustrate areas of ischemia within the cortex during seizures.
• Positron Emission Tomography (PET) will identify metabolic abnormalities within the ffected hemisphere.

Other Tests:

• Electroencephalogram (EEG) is used to measure electrical activity of the brain though the use of surface electrodes placed on the scalp.¹⁸  In the presence SWS, EEG finding typically include less electrical current on the affected side.  The difference in electrical activity between the affected and unaffected side can be useful in determining the severity of disease.  When multiple tests are performed over time, progression of the disease can also be evaluated.¹⁹ 
• Transcranial Doppler Ultrasonagraphy is used to evaluate cortical blood flow.  Decreased blood flow velocity is often found in the middle and posterior cerebral arteries in chilldren with SWS.  This may explain the hypoperfusion associated with the disorder.

Etiology/Causes

Though it is not believed to be hereditary in nature, this is a congenital disease which develops in utero and manifests at birth. Because of the lack of knowledge surrounding its cause, prevention of this syndrome is impossible. ²⁰

Systemic Involvement

Sturge-Weber Syndrome does not typically present with impairments or abnormalities in systems outside of the following five.

Integumentary 

• The signiture sign of Sturge-Weber Syndrome is a port wine stain that presents unilaterally in the face of the majority of patients. This mark is caused by swollen blood vessels that cause the skin to become pinkish-purple color. In most patients, the mark covers the forehead and eyelid but can sometimes extend into the rest of the face, even crossing midline to become bilateral. It is estimated that 96% of Sturge-Weber patients have some kind of port wine stain.²¹ This is a sign that is immediately noticeable at birth and can darken over time. While it is uncommon, the facial port wine stain can also fade over time to the point where it can no longer be seen. It is important to note that while this is a common sign of Sturge-Weber Syndrome, the existance of a port wine stain does not mean an individual will have this syndrome. These markings can exist outside of a Sturge-Weber diagnosis. 
• Swelling of the lips, throat, and gums can become a problem due to the port wine stain. This swelling can cause the patient to experience issues with tooth decay and bleeding of the gums.^21,22

Neurological

• Venous Angiomatosis is almost always present meaning these patients develop angiomas within the venous capillaries of the meninges. The occipital and parietal lobes of the hemisphere ipsilateral to the facial port-wine stain are most commonly involved although it is not impossible for angiomatosis to also occur bilaterally as well as advance to the frontal and temporal lobes as the patient ages and the disease progresses^21,23.   
• Damage to the cerebral cortex due to the angiomas and associated tissue calcification of brain is believed to be linked with seizure activity which is one of the most common neurological features of Sturge-Weber patients. These seizures can be focal or generalized affecting approximately 85% of people living with this diagnosis. Convulsions generally present on the side of the body opposite the facial port wine stain. It is critical that individuals be diagnosed as early as possible in order to treat these seizures with the appropriate medical intervention; if left undiagnosed and untreated these seizures can cause permanent damage to the soft tissues of the brain resulting in further deficits.
• Mental Retardation is common in individuals with Sturge-Weber Syndrome. Mental delay becomes more significant when seizure activity is noted within the first year of life and is likely to continue to advance in severity if seizure treatment is not sought or is resisted.^21,22 

Neuromuscular

• Due to atrophy of the cortical areas in the hemisphere of the brain ipsilateral to the facial port wine stain, these individuals can experience muscle weakness and even hemiparesis contralateral to the facial mark. Hemiparesis most commonly occurs when an individual has a series of seizures or seizures of increased intensity. Muscular weakness can be intermittant but is often progressive with the progression depending on the amount of cortical atrophy present in the brain.²⁴

Occular

• Glaucoma is a problem that can effect these individuals at any point in their lives. It can be present at birth or later in life and is likely to lead to vision changes due to damage of the optic nerve. If severe enough blindness can occur. ²²

Medical Management (current best evidence)

Because the presentation of SWS can vary greatly between children, medical treatment is based upon the symptoms of each child.  The medical treatments available for the various aspects of SWS are addressed below.

Treatment of Port Wine Stain:

Laser treatment is used to reduce port wine stains in children with SWS. Multiple treatments given over period of several months is effective in decreasing the prominence of port wine stains. Most often a Flashlamp-Pulsed Tunable Dye Laser is used to target the abnormal vascular structure beneath the skin. This type of laser has been effective reduing port wine stains in children of all ages and over all areas of the face. Children under the age of 7 and port wine stains over bony prominences typically require fewer treatments than those in older children or over the fleshy part of the cheek. In most cases, affected skin is identical in color and texture to adjacent skin after treatment. A small percentage of individuals may have resulting hyperpigmentation or smal depressed scars over the area of the port wine stain post-treatment.
(Treatment of Children with Port-Wine Stains Using the Flashlamp-Pulsed Tunable Dye Laser
Oon Tian Tan, M.D., Karen Sherwood, M.D., and Barbara A. Gilchrest, M.D. N Engl J Med 1989; 320:416-421)

Treatment of Headaches:

Headaches are typically treated with medication if they interfere with daily activities of the child. Headaches may also occur in accordance with seizures. In this case, it is important to treat the seizure the relieve the headache pain.
(http://www.physio-pedia.com/index.php?title=Sturge-Weber_Syndrome&action=edit&section=9)

Treatment of Epilepsy:

In most cases, antiepileptic drugs are effective in treating seizures. In more severe cases of SWS, children may experience uncontrolled and life threatening seziures despite medication. These children may require surgery to remove the areas of brain tissue responsible for the epilepsy. Surgical options include a complete hemispherectomy or a focal resection - determination of most appropriate surgical option is based upon the amount and location of epileptic tissue. The age of the child at time of surgery does not effect the reduction in seizure activity, however, surgery at an early age may porduce more developmental gains than surgery at a later age.
(Surgical treatment of epilepsy in Sturge–Weber syndrome in children
Marie Bourgeois, M.D.1, Darach William Crimmins, F.R.C.S.I.2, Ricardo Santos De Oliveira, M.D.3, Alexis Arzimanoglou, M.D.4, Matthew Garnett, F.R.C.S.1, Thomas Roujeau, M.D.1, Federico Di Rocco, M.D.1, and Christian Sainte-Rose, M.D.1)

Treatment of Glaucoma:

Eye drops are prescribed to maintain normal pressure in the affected eye(s). If the drops are ineefective, surgery may be necessary. Surgical options include goniotomy (an opening in the trabecular meshwork is created), trabeculectomy (a peice of the trabecular network is removed), tube-shunt (plastic tube is placed is connected to the drainage pouch in the eye and directs fluid out of the eye), trabeculotomy, and trabeculoplasty. A tube shunt is placed after a failed trabeculectomy or if the individual is likely to form or has already formed scar tissue.

Alternative/Holistic Management (current best evidence)

Medicinal Marijuana (cannabis oil) is often prescribed to patients who suffer from neurological issues and to those who battle glaucoma on a regular basis. Marijuana has the potential to present less adverse affects when compared to more mainstream medications, but must be administered judiciously as they can effect heart rate and blood pressure almost immediately upon use.  

Marijuana has been found to have a positive affect on reducing intraoccular pressure within the eye, which is generally increased in patients with glaucoma. As for the treatment of seizures, it is inconclusive if marijuana can be an effective alternative to more traditional anti-seizure medications. Many patients have found relief through the use of marijuana but it remains unclear if this alternative medication has widespread seizure use or can only target specific seizure types such as partial or tonic-clonic.

The use of medicinal marijuana remains a controversial issue and is often only prescribed as a last resort. The exact scientific reason for its effects are not currently known which adds to its controversy.

Differential Diagnosis

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Case Reports/ Case Studies

Sturge-Weber syndrome: a case report

http://vdisk.univille.edu.br/community/depto_odontologia/get/ODONTOLOGIA/RSBO/RSBO_v8_n4_outubro-dezembrobro2011/v8n4a16.pdf

Sturge-Weber syndrome: A case report

http://www.jpad.org.pk/april%20-%20june%20%202006/12sturge-weber%20syndrome.pdf

Resources

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Recent Related Research (from Pubmed)

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References

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