Sturge-Weber Syndrome Clinical Presentation

History

The 3 forms of Sturge-Weber syndrome are generally diagnosed on clinical grounds by the association of the typical cutaneous, CNS, and ocular abnormalities.

Children with bisymptomatic or trisymptomatic Sturge-Weber syndrome may initially seem neurologically normal and have no symptoms of glaucoma or other ocular manifestations; thus, in some instances, the diagnosis may not become clear for an extended period of time.

Physical examination

When a typical facial vascular skin lesion is found in a newborn, it should alert the physician to perform a complete ophthalmologic and systemic assessment for the potentially serious associated disorders.

Ocular signs, including a corneal diameter of more than 12 mm during the first year of life, corneal edema, tears in the Descemet membrane (Haab striae), unilateral or bilateral myopic shift, optic nerve cupping greater than 0.3, or any cup asymmetry associated with intraocular pressure above the high teens, may indicate the presence of infantile glaucoma.

Increased conjunctival vascularity can be seen on slit lamp examination or can be viewed by the naked eye as a pinkish discoloration. The abnormal plexus of episcleral vessels may be hidden by the overlying tissue of the Tenon capsule in infancy and only appreciated clinically in later childhood.

Prominent, tortuous conjunctival and episcleral vascular plexuses affect as many as 70% of patients with Sturge-Weber syndrome and often correlate with increased episcleral venous pressure, probably resulting from arteriovenous shunts within the episcleral hemangiomas. The overlying retinal vessels may be affected, demonstrating dilation and tortuosity, as well as peripheral arteriovenous communications.

Iris heterochromia occurs in approximately 10% of patients with Sturge-Weber syndrome. The more deeply pigmented iris usually is ipsilateral to the port-wine stain, signifying an increase in melanocyte number or activity.

The diagnosis of diffuse choroidal hemangioma is based on tumor appearance on indirect binocular ophthalmoscopy.

Ocular involvement may include hemangiomalike, superficial changes (which on histology demonstrate only venous dilation) in the eyelid; glaucoma; conjunctival and episcleral hemangiomas; diffuse choroidal hemangiomas; and heterochromia of the irides. Tortuous retinal vessels with occasional arteriovenous communications may be found.

The facial cutaneous venous lesion is usually the first component of the syndrome to be observed, because it is visible at birth. It may be very pale at first. Although it does not increase in extent, it usually becomes darker with age. The port-wine stain is not a medically threatening condition, but because it is a cosmetic deformity, it may carry a psychological impact.

Several possible mechanisms may be responsible for decrease in visual function in patients with Sturge-Weber syndrome. As soon as Sturge-Weber syndrome is first suspected or documented, a complete ophthalmologic evaluation is essential to rule out glaucoma, since the infant's eye is damaged quickly by increased intraocular pressure. The earlier glaucoma is documented and the more effectively it is controlled, the less likely secondary glaucomatous changes will occur, including buphthalmos, increased corneal diameter, tears in the Descemet membrane, corneal edema, and optic nerve damage resulting in myopia, anisometropia, amblyopia, strabismus, and visual field defects.

Amblyopia is an important cause of poor vision in patients with infantile glaucoma. Amblyopia usually is anisometropic from glaucoma-induced myopia or secondary to unilateral or bilateral pattern deprivation caused by cloudy corneas. Even when glaucomatous optic nerve damage is present, amblyopia may be superimposed on the organic damage. Therefore, a trial of amblyopia therapy is indicated.

Diffuse choroidal hemangioma, characteristically seen in patients with Sturge-Weber syndrome, is present in as many as 40-50% of patients (see the image below). A circumscribed, isolated form occurs in otherwise normal adults. It is almost always unilateral and ipsilateral to the port-wine stain, but bilateral cases associated with bilateral nevus flammeus have been described.

The choroidal hemangiomas are flat, commonly covering over one half of the fundus, involving the posterior pole, and extending into the equatorial zone. Diffuse involvement of the entire uvea may be seen. In some cases, the extent and character of the pathognomonic choroidal vascular lesion results in a striking reddish glow, to which the descriptive term tomato-catsup fundus has been applied. (See the images below.) Some patients have a focal, often paramacular area where the angioma is more thickened and elevated.

The choroidal angiomatosis grows slowly and usually remains asymptomatic in childhood. During adolescence or adulthood, marked thickening of the choroid sometimes becomes evident with secondary changes to overlying ocular structures.

Changes in the overlying retinal pigment epithelium range from mild atrophy to focal proliferation with drusen formation to severe fibrous transformation and focal ossification. The retina over the hemangioma may be attached and well preserved, attached and degenerated, or detached.

Degenerative changes in the overlying retina include focal chorioretinal adhesions, loss of photoreceptors, severe cystoid degeneration of the outer layers, and marked gliosis. Widespread serous detachment, retinal leakage, and edema may occur. In its early stages, the choroidal thickening and elevation of the retina may produce an increasing ipsilateral hyperopia. With progression of secondary changes, visual loss and visual field defects may develop. Subretinal fibrosis in the macular area and cystoid macular edema are associated with the most severe visual loss.

The glaucoma is almost always unilateral and ipsilateral to the port-wine stain, although contralateral or bilateral glaucoma with unilateral cutaneous lesions have been reported. The occurrence of glaucoma has been especially noted when the facial skin changes involve the upper and lower eyelids.

Glaucomatous damage, as well as degenerative changes in the outer retinal layers and vascular abnormalities in the occipital lobe, may cause visual field defects. Careful visual field perimetry is indicated.