Neurofibromatosis and eye damage

Neurofibromatosis is divided into two autosomal dominant forms, characterized by a different clinical course:

1. neurofibromatosis type I (NF1) - Recklinghausen's syndrome (Recklinghausen);
2. neurofibromatosis II type - bilateral acoustic neurofibromatosis.

Additional forms of neurofibromatosis, including segmental neurofibromatosis, cutaneous mixed type III neurofibromatosis, type IV neurofibromatosis and type VII neurofibromatosis with late onset are described. It is not clear whether all the presented forms are separate, separate diseases.

[1], [2], [3]

Prevalence of type I neurofibromatosis

It was found that the prevalence of neurofibromatosis corresponds to 1: 3000-1: 5000, so this disease is one of the most frequently occurring autosomal dominant disorders. Penetration is almost complete, as a result of a high level of spontaneous mutations in 50% of patients with neurofibromatosis determine new mutations. The affected gene is located on the proximal long arm of chromosome 17 (17qll.2).

Symptoms of type I neurofibromatosis

• Pigment spots on the body color of coffee with milk. However, these changes are not a pathognomonic sign of neurofibromatosis and can occur in healthy people.
• Small spots are located mainly in the folds of the skin - in the armpits, in the groin and under the breast in women.

Peripheral neurofibromas

Virtually all patients with Type I neurofibromatosis at the age of 16 develop peripheral neurofibromas of the skin and, in more rare cases, neurofibromas of the subcutaneous tissue palpable along the peripheral nerves.

Plexiform neurofibromas

Specific neoplasms of soft consistency. Pathognomonic symptom for type I neurofibromatosis. Typical signs are hypertrophy of surrounding tissues, local proliferation of tissue and hypertrichosis in the affected area. When the process is localized in the orbit, a significant reduction in vision due to direct compression of the optic nerve or amblyopia due to ptosis and / or strabismus induced by the tumor is possible.

Decreased learning ability

Although mental retardation in Type I neurofibromatosis is rare, there may be a slight decrease in visual perception.

Ophthalmic manifestations

An ophthalmologist's examination of a patient with suspected neurofibromatosis is important not only to confirm the diagnosis, but also to identify complications from the visual organ and, if possible, the early appointment of treatment. Pathological changes in the organ of vision can be localized in the orbit and include:

1. glioma of the optic nerve;
2. shelling meningioma of the optic nerve;
3. the neurofibroma of the orbit;
4. defects in the bones of the orbit.

Exophthalmos can be associated with a change in the position of the eyeball, subsequently stitched and amblyopia. Tumors of the orbit often cause changes in the optic nerve, which are manifested by a stagnant nipple, atrophy and, more rarely, hypoplasia of the optic nerve. Additional changes include:

1. opticciliary shunts (especially in meningioma of the optic nerve);
2. folding of the choroid;
3. amaurosis, determined by the direction of the eye.

Neurological examinations are shown for the differentiation of various causes of exophthalmos in Type I neurofibromatosis.

Eyelids

1. Most often, the eyelids are affected by plexiform neurofibroma with a characteristic S-shaped deformation of the edge of the upper eyelid. Strabismus and / or ptosis, resulting from these changes, can lead to amblyopia.
2. Congenital ptosis occurs even in the absence of a tumor of the orbit.

Iris

Nodules Lisha (melanocytic hamartomy iris) pathognomonic for type I neurofibromatosis. With type II neurofibromatosis, they are rare. With age, their prevalence in Type I neurofibromatosis increases. In early childhood, Lisa's nodules are not observed often, but by the age of 20 they are found in almost 100% of patients.

The optic nerve

The involvement of the optic nerve in the pathological process is manifested by gliomas of the optic nerve (astrogliomas). 70% of all gliomas of the optic nerve are found in patients with type I neurofibromatosis. The true frequency of their prevalence in neurofibromatosis type I is difficult to determine due to the absence of symptoms and therefore subclinical flow. Approximately 15% of patients with type I neurofibromatosis and normal visual acuity are diagnosed with gliomas of the optic nerve. These tumors are divided into two categories.

Forward (gliomy orbits)

These gliomas are exophthalmos, loss of vision and, occasionally, a change in the position of the eyeball. Involvement in the optic nerve process is expressed in its atrophy, dysplasia, direct tumor lesion and stagnant nipple. Sometimes on the side of the tumor are formed opticiliary vascular shunts. As a result of these changes, strabismus often occurs.

Rear (glioma of chiasma)

Symptoms of these gliomas include hydrocephalus, endocrine pathology and decreased vision in combination with nystagmus. Nystagmus can be vertical, rotatory or asymmetric (it occasionally mimics spasms of nu-tans). Often there is a dissociated vertical nystagmus.

Conjunctiva

Neurofibroma of the conjunctiva are rarely observed and are usually located in the limbal zone.

Cornea

With Type I neurofibromatosis, there is a thickening of the corneal nerves, but this symptom is not pathognomonic. Much more often this disorder occurs in the syndrome of multiple endocrine neoplasia.

Uveal tract

Pigmentary hamartomas of the choroid are found in 35% of patients. Diffuse neurofibromas cause a thickening of the entire uveal tract, leading to glaucoma.

Retina

With type I neurofibromatosis, the retina is rarely involved in the pathological process. There are isolated reports on the occurrence of astrocytic hamart retina and its pigment epithelium.

Research

1. Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain and orbit can detect the pathology of bones, meningiomas and gliomas of the optic nerve.
2. Spotted evoked potentials (VEP) assist in assessing the state of the chiasma, as well as in monitoring the dynamics of chiasmal gliomas.

Symptoms of type II neurofibromatosis

• Stains on the body color of coffee with milk, occur in approximately 60% of patients.
• Neurofibromas of the skin are observed in about 30% of cases. Plexiform fibroids are rare.

Manifestations from the central nervous system

A distinctive feature of neurofibromatosis are bilateral neurinomas of the auditory nerve. The remaining cranial nerves may also be involved in the process as the tumor grows, especially the V, VI and VII pairs. Widespread gliomas, meningiomas and schwannomas.

Manifestations from the organ of vision

• Nodules Lisha, if found, it is rare.
• Rear subcapsular cataract occurs frequently, but has little effect on visual acuity.
• Combined hamartomes of pigment epithelium and retina.
• Epiretinal membranes with a slight decrease in vision.

In most cases, eye manifestations of type II neurofibromatosis are not required. The need for treatment arises when there is a bilateral meningioma VIII pair of cranial nerves, especially if the tumor is small in size.

Type I neurofibromatosis

Neurofibromatosis type II (bilateral acoustic)

This form of the disease is less common than Type I neurofibromatosis. The gene responsible for the development of the disorder is localized near the center of the long arm of chromosome 22 (22qll.l-ql3.1).

Diagnostic criteria of type I neurofibromatosis

To determine the diagnosis of type I neurofibromatosis, the following characteristics were determined by the criteria. It is necessary to have at least two of them in order to establish a diagnosis.

1. Five or more pigment spots of coffee color with milk, more than 5 mm in diameter, in a prepubescent child and six or more pigmented spots of coffee color with milk more than 15 mm in diameter in a patient at post-pubertal age.
2. Two or more neurofibromas of any type or one plexiform neurofibroma.
3. Axillary or inguinal specks.
4. Glioma of the optic nerve.
5. Two or more Lisch's nodules (Lisch).
6. Characteristic defects of bones (pseudarthrosis of the tibia or dysplasia of the wing of the sphenoid bone).
7. Closest relatives suffering from type I neurofibromatosis.

[4],

Treatment of type I neurofibromatosis

The management of patients with type I neurofibromatosis has remained controversial to this day. Treatment, as a rule, complex. An integral component in the overall complex of prescriptions is genetic consultation of all family members of the patient. Treatment of complications of neurofibromatosis from the side of the organ of vision is complex and includes:

Plexiform neuron

Chemotherapy and radiation therapy are ineffective. Surgical removal is technically difficult and has a high level of complications. If an amblyopia is suspected, occlusion is recommended.

Gliomas of the optic nerve and chiasma

Treatment issues to this day remain relevant. Conservative treatment is indicated for tumors of small size and preserved visual functions. In elderly patients, radiation therapy is sometimes recommended (in younger children, radiotherapy can be complicated by a mental retardation). Surgical intervention is advisable on the blind eye with pronounced exophthalmos. Surgical removal of the gliomas of the chiasm is technically impossible. In some cases, only the accompanying cysts are removed. Chemotherapy is becoming increasingly popular in the treatment of chiasmatic gliomas when combined with dysfunction of the hypothalamus. Some patients with gliomas of chiasma with increased intracranial pressure show shunting. It is desirable to conduct an endocrinological examination of all patients with gliomas of chiasma.

Glaucoma

Usually requires surgical intervention, while it has an unfavorable prognosis.