Peripheral neuropathy

Published on 05/05/2015 by admin

Filed under Internal Medicine

Last modified 22/04/2025

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55 Peripheral neuropathy

Instruction

Examine this patient’s legs.

Carry out a neurological examination of this patient’s legs.

Salient features

History

• Progressive and symmetrical numbness in the hands and feet that spreads proximally in a glove and stocking distribution

• Distal weakness, which also ascends

• History of diabetes, alcohol, connective tissue disorder, malignancy.

Diagnosis

This patient has symmetrical, bilateral sensory loss for touch and pain (lesion) caused by diabetes mellitus (aetiology).

Questions

How are polyneuropathies classified?

• Polyneuropathies can be classified as demyelinating or axonal

• Demyelinated: acute inflammatory demyelinating polyradiculoneuropathy (subtype of Guillain-Barré syndrome), diphtheria, chronic inflammatory polyradiculoneuropathy, Charcot-Marie-Tooth disease type 1

• Axonal: acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, multifocal motor neuropathy, associated with HIV, diabetic, medications, toxins.

• They can also be classified according to the diameter of the affected nerve fibre. Larger fibres are heavily myelinated and, therefore, most subject to processes that damage myelin.

• Most polyneuropathies, including the diabetic type, are axonal.

Mention a few causes of thickened nerves

• Amyloidosis

• Charcot–Marie–Tooth disease

• Refsum disease (retinitis pigmentosa, deafness and cerebellar damage)

• Déjérine–Sottas disease (hypertrophic peripheral neuropathy).

What are the causes of motor neuropathy?

• Guillain–Barré syndrome

• Peroneal muscular atrophy

• Lead toxicity

• Dapsone toxicity

• Organophosphorous poisoning.

Mention a few causes of predominantly sensory neuropathy

• Diabetes mellitus

• Deficiency of vitamins B₁₂ and B₁

• Chronic renal failure

What are the types of neuropathy described in diabetes mellitus?

• Symmetrical, mainly sensory, polyneuropathy

• Asymmetrical, mainly motor, polyneuropathy (diabetic amyotrophy)

• Mononeuropathy

• Autonomic neuropathy.

Be aware there are different classifications (Fig. 55.1).

Fig. 55.1 Different clinical presentations of diabetic neuropathies.

What drugs are used for painful peripheral neuropathy of diabetes?

Tricyclic antidepressants, phenytoin, carbamazepine and topical capsaicin.

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