What Is Sturge-Weber Syndrome?
Sturge-Weber syndrome or encephalotrigeminal angiomatosis is the third most common neurocutaneous syndrome after neurofibromatosis and tuberous sclerosis. This syndrome exhibits neurological brain anomalies and cutaneous, ocular, and severe oral manifestations. Of all, the most evident clinical presentation is the nevus flames or port-wine stain along the course of the first and second branches of the trigeminal nerve (V cranial nerve).
How Common Is Sturge-Weber Syndrome?
Around one in every 20,000 to 50,000 live births are affected by this disease; however, the incidence rate is still not clearly known. SWS affects males and females equally, and there is no race predilection.
What Are the Characteristic Features of Sturge-Weber Syndrome?
Infantile spasms are characteristic features of approximately 90 % of affected patients in the first year of life. They can be followed by developing atonic, tonic, or myoclonic seizures in early infancy. Increasing hemiparesis may frequently accompany these seizures that are not only progressive but also may prove refractory to conventionally prescribed medications. Facial nevus or port-wine stains are a distinguishing feature in most cases seen, which are present along the ophthalmic or maxillary segment of the trigeminal nerve, i.e., along the course of the forehead and cheeks.
What Are the Facial and Ocular Manifestations of Sturge-Weber Syndrome?
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Infants or children with this prominent facial port-wine stain are prone to a 10 % to 35 % risk of having some forms of brain affliction alongside the involvement of upper and lower eyelids. However, it is essential to know that not all patients with port-wine stains possibly suffer from Sturge-Weber syndrome.
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The risk of glaucoma also is increased by up to 50 %. When glaucoma is present, it is nearly almost always ipsilateral to the area of port-wine stains on the face.
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Patients with Sturge-Weber syndrome may alternatively present with cerebral symptoms without any facial findings.
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Ocular involvement in infancy presents with increased vascularity, enlargement of the conjunctiva, strabismus, and prone risk of eye tearing.
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In severe cases, other symptoms are usually forms of either intellectual disability or disturbances in gait or gazing.
What Is the Classification and Pathogenesis of Sturge-Weber Syndrome?
Some authors or researchers usually classify the SWS into three types based on the classic form of the disease.
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Type I: Appears within the cerebral, leptomeningeal angiomas, and glaucoma
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Type II: It exhibits facial angiomas and glaucoma without any intracranial lesions or disorders.
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Type III: This type is characteristic of isolated leptomeningeal angiomas and absence of glaucoma, rarer than type 1 and type 2 forms.
There are multiple neurologic manifestations of SWS, namely:
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Atonic, tonic, or myoclonic seizures are the most common features of SWS.
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Research theories suggest that somatic mosaic mutations in the GNAQ gene are located on the long arm of chromosome 9 and can be responsible for the trigger of the classic form of the disease.
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The presence of facial and pial angiomas in this disease suggests the possibility of persisting sinusoidal vascular channels and hints at the causative hypothesis that the brain's superficial venous drainage may never fully develop. This may lead to the capillaries and small venous channels becoming dilated.
What Are the Oral Manifestations of Sturge-Weber Syndrome?
As documented, oral manifestations are mainly present in approximately 38 % of the cases.
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They are characterized by hemangiomatous lesions involving the lip, oral mucosa, gingiva, tongue, or palatal regions. These oral manifestations are unilateral in most cases.
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Some patients report ipsilateral gingival hyperplasia or enlargement, characterized by increased vascularity accompanied by gingival hemorrhages.
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The accumulation of food and the presence of bacterial plaque further may aggravate inflammation worsening gingival hyperplasia. In addition, gingival enlargement impairs oral hygiene maintenance in these patients. Still, the accumulation of plaque and calculus is chronic and may be a source of frequent oral discomfort and bleeding.
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Macroglossia and the maxillary bone hypertrophy can be severely found in these patients altering occlusion and causing facial asymmetry. In addition, accessory drug therapies recommended, like Dilantin therapy for the convulsive crisis, may exacerbate the gingival tissues further.
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The oral manifestations observed radiographically through intraoral imaging usually reveal a horizontal and vertical bone re-absorption with loss of the hard lamina in patients suffering from SWS.
What Surgical Management Strategies Should a Dental Surgeon Follow in Sturge-Weber Syndrome?
The intraligamentary technique is preferred for local anesthesia, and extraction should be done without causing excessive bleeding, rupturing the hemangiomas, and withdrawing the planned gingivectomies.
Since it can bring about difficulties in maintaining airways, it is recommended to bypass deep sedation techniques that may demand airway manipulation. For this procedure, Propofol is used to cause sedation. This is because it is carried out as an outpatient procedure. Also, Propofol has a rapid onset and aids in fast recovery. In terms of local anesthesia, 2 % lidocaine containing epinephrine at a ratio of 1:80,000 is preferred and is usually administered in the periodontal ligament.
The dentist performs a gingivectomy to relieve these angiomatous gingival enlargements. However, it should still be surgically operated on with caution taking adequate hemostatic measures as oral tissues can bleed profusely, which can bring about post-surgical or intraoperative complications. Gingivectomy may prove difficult, and hemostasis control may be clinically challenging to the oral surgeon. Hence dental operations should include preoperative preparation, monitoring, and equipment for prompt intubation (if there is a rupture of the hemangiomas).
Elevation of blood pressure should be suppressed by the oral surgeon under sedation to prevent the rupture of hemangiomas and intraoperative bleeding. Periodontal ligament injection as a local anesthetic helps prevent bleeding from the injection site. Laser techniques have good hemostatic properties and can be an ideal alternative to oral surgical treatment.
How Is Sturge-Weber Syndrome Diagnosed?
MRI (magnetic resonance imaging) of the brain with contrast imaging is the gold standard diagnostic criterion for detecting SWS. The most common locations are the occipital and posterior parietal or temporal lobes. The neurologist can crosscheck the extent or stage of the disease in these MRI findings.
In the early phase, the observation is of a short hyperperfusion with accelerated myelin maturation. Leptomeningeal enhancement can be seen as serpiginous enhancement along the sulci. Restricted diffusion can be observed if there is a relationship to any acute ischemic event in the patient.
Ophthalmologic changes may be observed through the retinal examination. Therefore, ocular ultrasonography can prove an essential method for diagnosis, especially for locating choroid hemangiomas.
How Is Sturge-Weber Syndrome Managed?
The primary aim is to minimize seizure activity by anticonvulsive medications mainly. Surgery is an option for a patient with poor medical management despite anticoagulant medications and cases that continue to have refractory seizures. The surgical procedures for Sturge-Weber syndrome are hemispherectomy or focal resection of the seizure focus.
The high frequency of oral manifestations of SWS demands the dental surgeon to have a thorough understanding of the clinical aspects and understand the management modalities and post-operative bleeding control in these patients. An interdisciplinary approach between the physician, neurologist, maxillofacial surgeon or dentist, and professional counseling benefits the patient and the family to overcome these general complications in SWS and improve long-term prognosis.
Conclusion:
To conclude, Sturge-Weber syndrome is a chronic neurocutaneous condition that needs multidisciplinary management of facial, oral, and ocular manifestations apart from neurologic classic disease forms. Periodic systemic and oral examinations are mandatory to prevent any cranial and oral complications in these patients.
