Complications | Neurofibromatosis type 2

Complications

Since the tumors occur along nerve tracts, depending on the location and function of the affected nerve, they can lead to weakening or even complete loss of function. Even benign tumors always carry a risk of malignant degeneration.

  • Deafness
  • Loss or weakness of visionand
  • Paralysis

Diagnosis

Clouding of the lens in childhood is atypical, so this usually first and very early symptom should always be considered as a neurofibromatosis type 2. Those affected become conspicuous by increasing loss of vision and sensitivity to glare. The progressive hearing loss usually begins years before diagnosis.

As with NF1, there are also clinical diagnostic criteria. The detection of bilateral tumors of the auditory and vestibular nerve using imaging techniques is considered a clinical diagnostic criterion. If a patient has first-degree relatives with a confirmed diagnosis of neurofibromatosis type 2 and early lens opacities or neurinomas, neurofibromas, meningiomas or gliomas occur, this is considered a further clinical diagnostic criterion.

Laboratory analytical procedures for the detection of the mutated gene are possible, but at the same time both expensive and complex. are the means of choice, especially to determine the severity or progression (progression) of the disease.

  • Imaging procedures (X-ray, CT, MRT)
  • Hearing test (audiometry) and
  • Functional testing of nerves (e.g. Acoustically Evoked Potentials AEPs)

Age

Type 2 neurofibromatosis typically manifests itself between the ages of 18 and 24 years.

Lens clouding

However, so-called “subcapsular posterior cataracts”, which frequently occur even in childhood, can be trend-setting. This is a special form of lens clouding comparable to cataracts in old age.

Tumors of the nervous system

Neurofibromatosis type 2 is a tumor disease that affects the nervous system. Typically, these patients have meningiomas, i.e. tumors of the meninges and neurinomas. Neurinomas, also called Schwannomas, are benign tumors that originate from Schwann cells.The task of Schwann cells is to envelop and protect nerve fibers, to isolate them along their long extensions and thus enable their function.

The proliferation of Schwann cells leads to a functional limitation or a functional failure of the affected nerves. In 80% of those affected, these Schwannomas develop on both sides along the 8th cranial nerve. Since this vestibulocochlear nerve is responsible for hearing and balance, symptoms such as progressive hearing loss to deafness, gait disorders and balance problems and the resulting tinnitus and dizziness occur. In about 6% of patients, only one side is affected. Other cranial nerves and peripheral nerves may also be affected.