Peripheral neuropathy is common, distressing, and disabling or fatal. The population prevalence is about 2400 per 100 000 (2.4%), rising with age to 8000 per 100 000 (8%).
In Europe the commonest cause is diabetes mellitus, which can produce painful neuropathy, disabling foot ulcers, and death from autonomic neuropathy. Leprosy is still prevalent in Africa, India, and South East Asia. Patients with peripheral neuropathy may present with altered sensation, pain, weakness, or autonomic symptoms.
The features vary widely and may resemble myelopathy, radiculopathy, muscle disease, or even hyperventilation. Identifying a neuropathy in patients with coexistent problems can be difficult. The symptoms usually begin in the toes and spread proximally. The classic picture of advanced polyneuropathy with distal wasting and weakness, absent tendon reflexes, and glove and stocking sensory loss can be easy to recognize.
The clinical features allow acute symmetrical peripheral neuropathy, chronic symmetrical peripheral neuropathy, and multiple mononeuropathy to be distinguished.
Acute symmetrical peripheral neuropathy is rare and commonest cause is Guillain-Barre syndrome, which can be fatal & can be asymmetrical affecting only one limb.
Common early symptoms are distal paraesthesiae and proximal or distal weakness occurring one to two weeks after a respiratory or gastrointestinal infection. Traditionally, the reflexes are absent, but their retention during the first hours of the illness has led many patients to be dismissed as "hysterical." Small fiber GBS & Axonal GBS will have increased reflexs.
Once a patient loses the ability to walk and develops facial and bulbar weakness the diagnosis is obvious.
The rapid progression of sensory or motor deficit requires emergency investigation. Patients may have to be admitted to hospital due to danger of respiratory failure. Early treatment stops the pathological process before axonal dysfunction becomes irreversible.
Guillain-Barre syndrome is usually due to acute inflammatory demyelinating polyradiculoneuropathy caused by an autoimmune response directed against the Schwann cells or myelin. Some cases are due to acute axonal neuropathy, in which glycolipid in the axolemma is targeted. In both forms, treatment with intravenous immunoglobulin hastens recovery and reduces the long term disability and is more convenient than plasma exchange. A recent trial suggests that combination treatment with steroids is more effective than intravenous immunoglobulin alone.