Polyneuritis: Definition, Types, Symptoms, Causes and Treatment

It is a condition that involves lower motor and sensory neurons characterized by inflammation that affects multiple nerves.

It is an inflammatory condition that causes damage to the peripheral nerves. The condition of polyneuritis affects the peripheral nervous system that forms the complex network that connects the brain and spinal cord with internal organs, muscles, and skin.

The peripheral nervous system contains all the nerves located outside the central nervous system .

Nerves in the peripheral nervous system are made up of axons or bundles of axons ranging in size from small nerves to large nerves.

The nervous system is divided into two parts: the sensory nervous system which is responsible for transmitting sensory and motor information to the central nervous system and the autonomic nervous system which is responsible for controlling involuntary bodily functions.

Both parts of the peripheral nervous system are vital to normal body function, so damage to any or all parts of the peripheral nervous system can have a drastic effect on normal body function.

Types of polyneuritis

Polyneuritis is divided into two main groups:

  1. Axonopathy – Usually occurs from poisoning with toxic substances.
  2. Demyelinating neuropathy: In this case, the myelin sheath of the nerve endings of the organs is affected.
  3. Alcoholic polyneuritis: usually affects the distal parts of the nerve endings of the kidneys. As a result, the muscles lose strength, there is paralysis and a sensitivity disorder.


The signs and symptoms of polyneuritis depend on the nerve that is affected. The onset of symptoms is usually in the longest nerve that reaches the toes.

The sensory nerve is responsible for receiving different sensations, such as heat and cold. When this nerve is affected or damaged, it can lead to symptoms of paresthesia , burning pain, numbness, and loss of sense of position and vibration.

Loss of sensitivity can expose an affected individual to a risk of burns due to the alteration in the detection temperature.

Numbness and tingling in the feet or hand appear gradually and can spread to the legs and arms. Touch sensitivity is extreme even with the slightest touch.

The motor nerve controls muscle movement and damage to this part of the peripheral nervous system can lead to symptoms such as:

  • Lack of coordination.
  • Muscle paralysis or weakness.
  • Loss of bladder or bowel control.
  • Dry and pale skin due to decreased sweating.
  • Diarrhea or constipation .

The autonomic nerve is responsible for controlling involuntary bodily functions.

Polyneuritis that affects this nerve produces symptoms such as:

  • Cold extremities.
  • Heat intolerance
  • Abnormally low blood pressure
  • Dizziness or lightheadedness
  • Erectile dysfunction .
  • Digestive problems.
  • Dry and flaky skin.

Muscle wasting also manifests itself in polyneuritis and is characterized by thin and weak muscles.

The wasting of muscle tissue leads to its detachment of the motor nerve, resulting in symptoms of decreased movement and loss of muscle strength.

Causes of polyneuritis

Polyneuritis does not have a single cause and the etiology is quite difficult to determine.

Numerous factors can be involved in the onset of polyneuritis and these can include the following:

  • Autoimmune disease such as Guillain-Barre syndrome is among those implicated in the incidence of polyneuritis. It is a rare disorder in which the immune system attacks the peripheral nerve and damages the myelin sheaths that surround the nerves.
  • Metabolic and endocrine disorders such as diabetes, uremia , acromegaly , gout, and amyloidosis, and thyroid dysfunction are also implicated in the development of polyneuritis.
  • Chemical exposures are also considered to cause polyneuritis, and such exposures include poisons, carbon monoxide, carbon disulfide, carbon tetrachloride, arsenic, lead, mercury, and thallium.
  • Infectious diseases include direct infection of the peripheral nerve, such as leprosy and shingles. Associated or secondary acute or chronic infections, such as measles, chickenpox, scarlet fever, and influenza, are also considered in the etiology of polyneuritis.
  • Nutritional disorder, such as vitamin B12 deficiency, is also among the causes of polyneuritis. Beriberi, pellagra, chronic alcoholism, and chronic gastrointestinal diseases are among the nutritional disorders implicated in polyneuritis.
  • Medications can also cause polyneuritis often as a side effect of certain drugs. Medications intended to treat cancer are among the medications that can cause polyneuritis apart from other drugs such as sulfonamides , phenytoin , isoniazid, cytarabine , ethambutol, and others.
  • Trauma to the nerve, such as sports injuries, falls, and vehicle accidents, can cause nerve damage that can lead to polyneuritis.


The initial treatment of polyneuritis involves a neurological evaluation to determine the nerves involved in the onset of the disorder.

The treatment method depends on the underlying condition that results in polyneuritis.


Medications of various types can be used to alleviate the pain symptom in the disorder and other medications may include the following:

  • Antiseizure medications.
  • Analgesics.
  • Capsaicin
  • Immunosuppressive drugs.
  • Antidepressant drugs.
  • Transcutaneous electrical nerve stimulation.

It is used to relieve symptoms by applying a mild electrical current.

A supportive device, such as walking aids and foot or hand braces, may be required for patients with severe leg or arm weakness to help the patient move.

A splint can also be administered to facilitate weak wrist extension.

Polyneuritis usually resolves or improves on its own when proper treatment of the underlying condition is applied.