Polyneuropathy (from Greek poly- 'many' neuro- 'nerve' and -pathy 'sickness') is damage or disease affecting peripheral nerves (peripheral neuropathy) in roughly the same areas on both sides of the body, featuring weakness, numbness, and burning pain. It usually begins in the hands and feet and may progress to the arms and legs and sometimes to other parts of the body where it may affect the autonomic nervous system. It may be acute or chronic. A number of different disorders may cause polyneuropathy, including diabetes and some types of Guillain–Barré syndrome.
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👉 Polyneuropathy in the context of Guillain–Barré syndrome
Guillain–Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Typically, both sides of the body are involved, and the initial symptoms are changes in sensation or pain often in the back along with muscle weakness, beginning in the feet and hands, often spreading to the arms and upper body. The symptoms may develop over hours to a few weeks. During the acute phase, the disorder can be life-threatening, with about 15% of people developing respiratory muscle weakness requiring mechanical ventilation. Some are affected by changes in the function of the autonomic nervous system, which can lead to dangerous abnormalities in heart rate and blood pressure.
Although the cause is unknown, the underlying mechanism involves an autoimmune disorder in which the body's immune system mistakenly attacks the peripheral nerves and damages their myelin insulation. Sometimes this immune dysfunction is triggered by an infection or, less commonly, by surgery, and by vaccination. The diagnosis is usually based on the signs and symptoms through the exclusion of alternative causes and supported by tests such as nerve conduction studies and examination of the cerebrospinal fluid. There are several subtypes based on the areas of weakness, results of nerve conduction studies, and the presence of certain antibodies. It is classified as an acute polyneuropathy.
In this Dossier
- ⭐ Core Definition: Polyneuropathy
- 👉 Polyneuropathy in the context of Guillain–Barré syndrome
- Polyneuropathy in the context of Diabetic neuropathy
- Polyneuropathy in the context of Patisiran
- Polyneuropathy in the context of Alcoholic polyneuropathy
- Polyneuropathy in the context of Vitamin E deficiency
Polyneuropathy in the context of Diabetic neuropathy
Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Studies suggests that cutaneous nerve branches, such as the sural nerve, are involved in more than half of patients with diabetes 10 years after the diagnosis and can be detected with high-resolution magnetic resonance imaging. Symptoms depend on the site of nerve damage and can include motor changes such as weakness; sensory symptoms such as numbness, tingling, or pain; or autonomic changes such as urinary symptoms. These changes are thought to result from a microvascular injury involving small blood vessels that supply nerves (vasa nervorum). Relatively common conditions which may be associated with diabetic neuropathy include distal symmetric polyneuropathy; third, fourth, or sixth cranial nerve palsy; mononeuropathy; mononeuropathy multiplex; diabetic amyotrophy; and autonomic neuropathy.
Polyneuropathy in the context of Patisiran
Patisiran, sold under the brand name Onpattro, is a medication used for the treatment of polyneuropathy in people with hereditary transthyretin-mediated amyloidosis, a fatal rare disease that is estimated to affect 50,000 people worldwide.
It is the first small interfering RNA-based drug approved by the U.S. Food and Drug Administration (FDA) and the first drug approved by the FDA to treat this condition. It is a gene silencing drug that interferes with the production of an abnormal form of transthyretin. Patisiran utilizes a novel approach to target and reduce production of the TTR protein in the liver via the RNAi pathway.
Polyneuropathy in the context of Alcoholic polyneuropathy
Alcoholic polyneuropathy is a neurological disorder in which peripheral nerves throughout the body malfunction simultaneously. It is defined by axonal degeneration in neurons of both the sensory and motor systems and initially occurs at the distal ends of the longest axons in the body. This nerve damage causes an individual to experience pain and motor weakness, first in the feet and hands and then progressing centrally. Alcoholic polyneuropathy is caused primarily by chronic alcoholism; however, vitamin deficiencies are also known to contribute to its development. This disease typically occurs in chronic alcoholics who have some sort of nutritional deficiency. Treatment may involve nutritional supplementation, pain management, and abstaining from alcohol.
Polyneuropathy in the context of Vitamin E deficiency
Vitamin E deficiency is a rare condition caused by low levels of vitamin E that may result from malabsorption disorders (such as abetalipoproteinemia, cystic fibrosis, or Crohn's disease), or impaired lipid transport. As a potent antioxidant, vitamin E protects cell membranes from oxidative damage, and its deficiency primarily affects tissues with high fatty acid content, especially the nervous system. Clinically, patients may present with spinocerebellar ataxia, polyneuropathy, muscle weakness, and retinopathy. Diagnosis is confirmed through low serum vitamin E levels, and treatment involves dietary supplementation with vitamin E and (if possible) addressing the underlying cause of malabsorption. The term 'vitamin E' commonly refers to α-tocopherol, and so α-tocopherol deficiency refers to the same syndrome.