Polyneuropathy is a generalized disease of the peripheral nerves with the distal nerves usually most severely affected. There are various causes including toxic, metabolic (chronic liver disease), endocrine (diabetes mellitus, hypoglycemia, hypothyroidism etc.) immune-mediated, carcinomatous, idiopathic and inherited. It most commonly presents as symmetric numbness, paraesthesias and dysaesthesias.
Presentation
The signs and symptoms of polyneuropathy include pain, accompanied by numbness, hypersensitivity and weakness in the affected arms and legs. In the majority of cases, there is development of tingling sensation in the affected area [7].
Sensory neuropathy occurs along with ataxia and hereditary polyneuropathy favors the development of high arches, hammer toes and scoliosis. In conditions when the autonomic nervous system is affected, there is onset of constipation accompanied by orthostatic hypotension and loss of control over bowel movements. Affected individuals also complain of skin turning pale, along with dryness and significant reduction in sweat production.
Workup
A preliminary physical examination along with past medical history is taken initially. This is important for gathering information about the duration, severity and nature of symptoms that are being experienced by the individual. In many cases, physical examination is enough for arriving at a definite diagnosis. In cases when this isn’t enough, additional tests may be required [8].
Specialized nerve tests such as nerve conduction testing and electromyography are employed for further evaluation of the condition. Both these procedures are painful, wherein a needle is pricked into the muscles and electric shocks are given to understand the severity of condition. Quantitative sensory testing is another type of nerve test that is employed for diagnosing polyneuropathy. This test gives information about how well the patient is able to tolerate temperature changes and respond to vibration.
Treatment
Treating the underlying cause and effective management of symptoms forms the basis of treatment. In many instances, it has been observed that with correction of the underlying disease condition (for example diabetes), neuropathy begin to show signs of improvement without any additional treatment [9].
Debilitating pain due to polyneuropathy needs to be controlled first. This is done using the following methods:
- Medications: For mild pain, over the counter pain medications may do the needful. In severe cases, corticosteroids may have to be employed for reducing the pain and associated inflammation. Anti-seizure medications have also shown to have a profound effect on nerve pain.
- Transcutaneous electrical nerve stimulation: This method employs administration of electrical impulses to specific affected areas. It can be given along with other treatment methods for relieving acute and severe forms of pain [10].
- Antidepressants: Antidepressants have also been found to be helpful in relieving the nerve pain. They work by blocking the chemical processes in the brain that get activated in response to pain.
Prognosis
The prognosis of the condition is favorable but depends on the extent of severity of symptoms and its underlying cause. Symptoms improve with initiation of treatment and if underlying etiology is effectively treated or managed. However, if initiation of treatment is delayed then various debilitating complications can set in.
Etiology
Acute polyneuropathy is caused due to infections, exposure to toxins, HIV/AIDS, various drugs, autoimmune reactions and diseases such as cancer. When the cause of polyneuropathy cannot be determined, it is known as idiopathic polyneuropathy. Drug induced polyneuropathy is a result of cancer chemotherapy drugs. Autoimmune reactions can cause the body’s own immune system to mistakenly attack the peripheral nerves giving rise to Guillan-Barre syndrome; also known as acquired polyneuropathy [2].
Chronic form of polyneuropathy occurs as a secondary complication of various conditions and factors such as diabetes mellitus, alcohol consumption, impaired tolerance to glucose and connective tissue diseases characterized by degeneration of the nerves. In rare cases, nutritional deficiencies, kidney or liver failure and Lyme disease can also cause polyneuropathy [3].
Epidemiology
Polyneuropathy is estimated to affect about 80 per 1000 individuals [4]. Many scientific research trials have suggested that peripheral polyneuropathy frequently affects individuals above 55 years of age.
Pathophysiology
Anatomically, the peripheral nerves pass through the spinal cord and reach the skin, muscles, glands and internal organs. In polyneuropathy, malfunctioning of nerves may be noticed simultaneously in several regions of the body. The basic phenomenon that induces polyneuropathy is injury to the peripheral nerves that eventually disrupt the blood supply to the body part, interfering with oxygen and nutrient supply that are required for appropriate nerve functioning, ultimately giving rise to several debilitating symptoms [5].
Polyneuropathy is classified into 3 distinct categories based on the type of nerve cell that is affected. These include distal axonopathy, myelinopathy and neuronopathy. Distal axonopathy primarily occurs due to metabolic derangement of neurons. Myelinopathy develops as a result of loss of myelin sheath. Neuronopathy occurs due to destruction of peripheral nervous system [6].
Prevention
Effective management of conditions that can increase the risk of developing polyneuropathy should be done. Individuals are advised to remain healthy, lead an active lifestyle and adopt healthy dietary practices. It is also necessary to avoid the factors that can lead to nerve damage.
Summary
Polyneuropathy is a disease affecting the peripheral nerves and is therefore, also known as peripheral polyneuropathy. The condition can be both acute or chronic in nature. In the preliminary stages, the condition strikes the feet and hands and then eventually affects the arms and legs. As the disease progresses to the advanced stages, it can also significantly affect the autonomic nervous system. Polyneuropathy affects almost the same areas on both sides of body. In such a type of condition, many body parts are affected at almost the same time [1].
Patient Information
Polyneuropathy occurs due to damage of the peripheral nerves which eventually leads to development of debilitating signs and symptoms. The condition can significantly affect both the sides of body. Various factors such as diabetes, HIV/AIDS, inherited disease, alcoholism, autoimmune diseases, vitamin deficiencies and trauma or injury to nerve can predispose an individual to develop polyneuropathy. Symptoms of polyneuropathy include pain and numbness in the affected limb, along with reduced tolerance to heat and a decreased production of sweat. Affected individuals also lose control over bowel movements and there is development of dizziness and /or lightheadedness. Treatment is geared towards pain management and correction of the underlying cause. Various medications are administered to relieve the debilitating pain and inflammations. In many instances, anti-seizure medications may also have to be employed.
References
- Hughes R. Investigation of peripheral neuropathy. BMJ 2010; 341:c6100.
- Kumar S, Alexander M, Markandeyulu V. Guillain-Barre syndrome presenting in the anti-HIV seroconversion period. Neurol India. Dec 2003;51(4):559.
- Morrison B, Chaudhry V. Medication, toxic, and vitamin-related neuropathies. Continuum (Minneap Minn) 2012; 18:139.
- Bharucha NE, Bharucha AE, Bharucha EP. Prevalence of peripheral neuropathy in the Parsi community of Bombay. Neurology 1991; 41:1315.
- England JD, Gronseth GS, Franklin G, et al. Distal symmetric polyneuropathy: a definition for clinical research: report of the American Academy of Neurology, the American Association of Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation. Neurology 2005; 64:199.
- Hafer-Macko C, Hsieh ST, Li CY, et al. Acute motor axonal neuropathy: an antibody-mediated attack on axolemma. Ann Neurol 1996; 40:635.
- England JD, Asbury AK. Peripheral neuropathy. Lancet 2004; 363:2151.
- England JD, Gronseth GS, Franklin G, et al. Practice Parameter: evaluation of distal symmetric polyneuropathy: role of autonomic testing, nerve biopsy, and skin biopsy (an evidence-based review). Report of the American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Academy of Physical Medicine and Rehabilitation. Neurology 2009; 72:177.
- Effect of intensive diabetes treatment on nerve conduction in the Diabetes Control and Complications Trial. Ann Neurol 1995; 38:869.
- Dubinsky RM, Miyasaki J. Assessment: efficacy of transcutaneous electric nerve stimulation in the treatment of pain in neurologic disorders (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2010; 74:173.