Polyneuropathy Explained

Polyneuropathy
Symptoms:	Ataxia
Causes:	Hereditary (Charcot–Marie–Tooth disease), and acquired (alcohol use disorder)
Diagnosis:	Nerve conduction study, urinalysis
Treatment:	Occupational therapy, weight decrease (management)

Polyneuropathy 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.^[1] 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.^{[2] [3] [4]}

Classification

Polyneuropathies may be classified in different ways, such as by cause, by presentation,^[1] or by classes of polyneuropathy, in terms of which part of the nerve cell is affected mainly: the axon, the myelin sheath, or the cell body.^{[5] [6]}

• Distal axonopathy, is the result of interrupted function of the peripheral nerves.^[7] It is the most common response of neurons to metabolic or toxic disturbances, and may be caused by metabolic diseases such as diabetes, kidney failure, connective tissue disease, deficiency syndromes such as malnutrition and alcoholism, or the effects of toxins or drugs such as chemotherapy. They may be divided according to the type of axon affected (large-fiber, small-fiber, or both), the most distal portions of axons are usually the first to degenerate, and axonal atrophy advances slowly toward the nerve's cell body. However, if the cause is removed, then regeneration is possible, although the prognosis depends on the duration and severity of the original stimulus. People with distal axonopathies usually present with sensorimotor disturbances such as amyotrophic lateral sclerosis^[8]
• Myelinopathy, is due to a loss of myelin or of the Schwann cells.^[9] This demyelination slows down or completely blocks the conduction of action potentials through the axon of the nerve cell (neurapraxia).^[10] The most common cause is acute inflammatory demyelinating polyneuropathy AIDP, the most common form of Guillain–Barré syndrome^[11] (although other causes include chronic inflammatory demyelinating polyneuropathy)^[12]
• Neuronopathy is the result of issues in the peripheral nervous system (PNS) neurons. They may be caused by motor neurone diseases, sensory neuronopathies, toxins, or autonomic dysfunction. Neurotoxins such as chemotherapy agents may cause neuronopathies.^[13]

Signs and symptoms

Among the signs and symptoms of polyneuropathy, which can be divided (into sensory and hereditary) and are consistent with the following, are:^[1]

• Sensory polyneuropathy – ataxia, numbness, muscle wasting and paraesthesiae.
• Hereditary polyneuropathy – scoliosis and hammer toes

Causes

The causes of polyneuropathy can be divided into hereditary and acquired and are therefore as follows:^[14]

• Inherited – hereditary motor neuropathies, Charcot–Marie–Tooth disease, and hereditary neuropathy with liability to pressure palsy
• Acquired – diabetes mellitus, vascular neuropathy, alcohol use disorder, and vitamin B12 deficiency

Pathophysiology

The pathophysiology of polyneuropathy depends on the type. Chronic inflammatory demyelinating polyneuropathy, for instance, is an autoimmune disease: T cells involvement has been demonstrated, antibodies alone are not capable of demyelination.^[15]

Diagnosis

The diagnosis of polyneuropathy begins with a history (anamnesis) and physical examination to ascertain the pattern of the disease process (such as arms, legs, distal, proximal), if they fluctuate, and what deficits and pain are involved. If pain is a factor, determining where and how long it has been present is important; one also needs to know what disorders are present within the family and what diseases the person may have. Although diseases often are suggested by the physical examination and history alone, tests that may be employed include electrodiagnostic testing, serum protein electrophoresis, nerve conduction studies, urinalysis, serum creatine kinase (CK) and antibody testing; nerve biopsy is done sometimes.^{[1] [16]}

Other tests may be used, especially tests for specific disorders associated with polyneuropathies; quality measures have been developed to diagnose patients with distal symmetrical polyneuropathy (DSP).^[17]

Differential diagnosis

In terms of the differential diagnosis for polyneuropathy, the following must be considered:

Treatment

In the treatment of polyneuropathies one must ascertain and manage the cause, among management activities are: weight decrease, use of a walking aid, and occupational therapist assistance. Additionally, BP control in those with diabetes is helpful, while intravenous immunoglobulin is used for multifocal motor neuropathy.^[1]

According to Lopate, et al., methylprednisolone is a viable treatment for chronic inflammatory demyelinative polyneuropathy (which can also be treated with intravenous immunoglobulin). The authors also indicate that prednisone has greater adverse effects in such treatment, as opposed to intermittent (high-doses) of the aforementioned medication.^{[1] [18]}

According to Wu, et al., in critical illness polyneuropathy supportive and preventive therapy are important for the affected individual, as well as, avoiding (or limiting) corticosteroids.^[19]

Further reading

• Dimachkie. Mazen M.. Barohn. Richard J.. Chronic Inflammatory Demyelinating Polyneuropathy. Current Treatment Options in Neurology. 7 April 2013. 15. 3. 350–366. 10.1007/s11940-013-0229-6. 3987657. 1092-8480. 23564314.
• Book: Katirji. Bashar. Kaminski. Henry J.. Ruff. Robert L.. Neuromuscular Disorders in Clinical Practice. Springer Science & Business Media. 9781461465676. 26 August 2016. en. 2013-10-11.
• Book: Said. Professor Gérard. Peripheral Neuropathy & Neuropathic Pain: Into The Light. 2014. tfm Publishing Limited. 9781910079027. 17. 3 August 2016. en.

Notes and References

1. Web site: Polyneuropathies. Medical information about polyneuropathy Patient. Patient. en-GB. 2016-07-17. 2016-07-18. https://web.archive.org/web/20160718100414/http://patient.info/doctor/polyneuropathies. live.
2. British Medical Journal. 23 February 2002 . 324 . 7335 . 466–469 . Clinical review: Peripheral neuropathy. Richard A C Hughes. 10.1136/bmj.324.7335.466. 11859051 . 1122393.
3. Journal of the American Medical Association . Janet M. Torpy . Jennifer L. Kincaid . Richard M. Glass . 21 April 2010 . Patient page: Peripheral neuropathy . 303 . 15 . 10.1001/jama.303.15.1556 . 20407067 . 1556. free .
4. Web site: Peripheral neuropathy fact sheet . 19 September 2012 . National Institute of Neurological Disorders and Stroke . 15 January 2013 . 15 December 2016 . https://web.archive.org/web/20161215182814/http://www.ninds.nih.gov/disorders/peripheralneuropathy/detail_peripheralneuropathy.htm . dead .
5. Book: Rakel. David. Rakel. Robert E.. Textbook of Family Medicine. Elsevier Health Sciences. 9780323313087. 1026. 26 August 2016. en. 2015-02-02. 2022-03-19. https://web.archive.org/web/20220319083821/https://books.google.com/books?id=8huMBgAAQBAJ&q=polyneuropathy+can+be+classified+by+neuron%2C+axon%2C+myelin&pg=PA1026. live.
6. Book: McCance. Kathryn L.. Huether. Sue E.. Pathophysiology: The Biologic Basis for Disease in Adults and Children. Elsevier Health Sciences. 9780323316071. 635. 26 August 2016. en. 2014-01-30. 2022-03-19. https://web.archive.org/web/20220319083822/https://books.google.com/books?id=0fskCwAAQBAJ&q=polyneuropathy+classified+as+axon%2C+myelin+or+neuron&pg=PA635. live.
7. Book: Perry. Michael C.. The chemotherapy source book. 2007. Lippincott Williams & Wilkins. Philadelphia, Pa.. 9780781773287. 241. 4th. 26 August 2016. en. 19 March 2022. https://web.archive.org/web/20220319083820/https://books.google.com/books?id=CDADMzS0TKUC&q=Distal+axonopathy&pg=PA241. live.
8. Moloney. Elizabeth B.. de Winter. Fred. Verhaagen. Joost. ALS as a distal axonopathy: molecular mechanisms affecting neuromuscular junction stability in the presymptomatic stages of the disease. Frontiers in Neuroscience. 14 August 2014. 8. 252. 10.3389/fnins.2014.00252. 25177267. 4132373. free .
9. Book: Hankey. Graeme J.. Wardlaw. Joanna M.. Joanna Wardlaw. Clinical neurology. 2008. Manson. London. 9781840765182. 580. 26 August 2016. en. 19 March 2022. https://web.archive.org/web/20220319083823/https://books.google.com/books?id=Q8q7E6EJr7IC&q=myelinopathy+is+disorder+affecting+the+myelin+of+peripheral+nerve&pg=PA580. live.
10. Book: Goodman. Catherine C.. Fuller. Kenda S.. Pathology: Implications for the Physical Therapist. Elsevier Health Sciences. 9780323266468. 1597. 26 August 2016. en. 2013-08-07. 2022-03-19. https://web.archive.org/web/20220319083824/https://books.google.com/books?id=PVBPAQAAQBAJ&q=Myelinopathy%2C%2Caction+potentials+through+the+axon+of+the+nerve+cell&pg=PA1597. live.
11. Web site: Orphanet: Acute inflammatory demyelinating polyradiculoneuropathy. RESERVED. INSERM US14 – ALL RIGHTS. www.orpha.net. 2016-08-26. 2016-08-27. https://web.archive.org/web/20160827090138/http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=98916. live.
12. Web site: Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Information Page: National Institute of Neurological Disorders and Stroke (NINDS). www.ninds.nih.gov. 2016-07-30. 2016-07-27. https://web.archive.org/web/20160727233351/http://www.ninds.nih.gov/disorders/cidp/cidp.htm. dead.
13. Barohn. Richard J.. Amato. Anthony A.. Pattern-Recognition Approach to Neuropathy and Neuronopathy. Neurologic Clinics. May 2013. 31. 2. 343–361. 10.1016/j.ncl.2013.02.001. 3922643. 0733-8619. 23642713.
14. Book: MD. Dr Sara J. Cuccurullo. Physical Medicine and Rehabilitation Board Review, Third Edition. Demos Medical Publishing. 9781617052019. 434. 26 August 2016. en. 2014-11-25. 2022-03-19. https://web.archive.org/web/20220319083819/https://books.google.com/books?id=NCzRBQAAQBAJ&q=polyneuropathy+ethiology&pg=PA433. live.
15. Mahdi-Rogers. Mohamed. Rajabally. Yusuf A. Overview of the pathogenesis and treatment of chronic inflammatory demyelinating polyneuropathy with intravenous immunoglobulins. Biologics: Targets and Therapy. 1 January 2010. 4. 45–49. 10.2147/btt.s4881. 2846143. 1177-5475. 20376173 . free .
16. Burns. Ted M.. Mauermann. Michelle L.. The Evaluation of Polyneuropathies. Neurology. 15 February 2011. 76. 7 Supplement 2. S6–S13. 10.1212/WNL.0b013e31820c3622. 21321354. en. 0028-3878. 5766173.
17. England. John D.. Franklin. Gary. Gjorvad. Gina. Swain-Eng. Rebecca. Brannagan. Thomas H.. David. William S.. Dubinsky. Richard M.. Smith. Benn E.. Quality improvement in neurology. Neurology. 13 May 2014. 82. 19. 1745–1748. 10.1212/WNL.0000000000000397. 4032209. 0028-3878. 24696504.
18. Lopate. Glenn. Pestronk. Alan. Al-Lozi. Muhammad. Treatment of Chronic Inflammatory Demyelinating Polyneuropathy With High-Dose Intermittent Intravenous Methylprednisolone. Archives of Neurology. 1 February 2005. 62. 2. 249–54. 10.1001/archneur.62.2.249. 0003-9942. 15710853. free.
19. Zhou. Chunkui. Wu. Limin. Ni. Fengming. Ji. Wei. Wu. Jiang. Zhang. Hongliang. Critical illness polyneuropathy and myopathy: a systematic review. Neural Regeneration Research. 1 January 2014. 9. 1. 101–110. 10.4103/1673-5374.125337. 4146320. 1673-5374. 25206749 . free .