Paediatrics: Peripheral neuropathies

Peripheral neuropathies

Charcot–Marie–Tooth disease (hereditary motor and sensory neuropathies)

This refers to a group of disorders with mainly autosomal dominant inheritance:

·The hallmark is progressive distal weakness, initially presenting in the lower limbs with peroneal muscle weakness and atrophy.

·Also there is clumsiness and loss of fine motor control.

·Later, these patients develop sensory disturbances with pins and needles in a glove and stocking distribution.

The most common types are:

·Type 1: demonstrates reduced conduction velocities on nerve conduction studies due to demyelination.

·Type 2: near normal nerve conduction and symptoms due to axonal degeneration.

·Type 3: has an onset much earlier and is sometimes called Dejerine– Sottas syndrome. Characterized by very slowed motor nerve conduction velocities.

The diagnosis of these conditions is based on the clinical picture, nerve conduction studies, and genetic analysis of the P0, PMP 22, (AD) and, less commonly, the Connexin 32 gene (X chromosome). There are now other genetic tests available including mitofusin 2 and ganglioside-induced differentiation-associated protein (GDAP).

Treatment is symptomatic with physiotherapy and orthoses in order to encourage joint mobility and maintain range of movement. Particular emphasis is put on the avoidance of contractures in the hands—‘clawing’, as well as peroneal muscle weakness, with foot drop and shortening of the Achilles tendons.

Other neuropathies

Neuropathy may also occur in many systemic disorders, including the following conditions:

·Leucodystrophies.

·Porphyria.

·Diabetes.

·Uraemia.

·Hypothyroidism.

·Vitamin deficiencies (B₁, B₆, B₁₂, and E).

·Autoimmune disorders such as SLE.

Acutely as part of the Guillain–Barré syndrome (G-BS).