Editing Peripheral neuropathy (section)

==Classification==
Peripheral neuropathy may be classified according to the number and distribution of nerves affected (mononeuropathy, mononeuritis multiplex, or polyneuropathy), the type of [[nerve fiber]] predominantly affected (motor, sensory, autonomic), or the process affecting the nerves; e.g., inflammation ([[neuritis]]), compression ([[nerve compression syndrome|compression neuropathy]]), chemotherapy ([[chemother completion.<ref>{{Cite web|url=https://upoj.org/archive/volume-12-spring-1999/|title=Volume 12, Spring 1999 {{!}} University of Pennsylvania Orthopaedic Journal|language=en-US|access-date=2019-10-28}}</ref>

===Mononeuropathy===
{{See also|Compression neuropathy|Ulnar neuropathy}}
'''Mononeuropathy''' is a type of neuropathy that only affects a single [[nerve]].<ref name="urlDorlands Medical Dictionary:mononeuropathy">{{cite web |url=http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/five/000067367.htm |title=Dorlands Medical Dictionary:mononeuropathy }}</ref> Diagnostically, it is important to distinguish it from polyneuropathy because when a single nerve is affected, it is more likely to be due to localized trauma or infection.{{citation needed|date=July 2022}}

The most common cause of mononeuropathy is physical compression of the nerve, known as [[compression neuropathy]]. [[Carpal tunnel syndrome]] and [[axillary nerve palsy]] are examples. Direct injury to a nerve, interruption of its blood supply resulting in ([[ischemia]]), or [[inflammation]] also may cause mononeuropathy.{{citation needed|date=June 2022}}

===Polyneuropathy===
{{Main|Polyneuropathy}}
"''Polyneuropathy''" is a pattern of nerve damage that is quite different from mononeuropathy, often more serious and affecting more areas of the body. The term "peripheral neuropathy" sometimes is used loosely to refer to polyneuropathy. In cases of polyneuropathy, many nerve cells in various parts of the body are affected, without regard to the [[nerve]] through which they pass; not all nerve cells are affected in any particular case. In [[Polyneuropathy|distal axonopathy]], one common pattern is that the cell bodies of neurons remain intact, but the [[axon]]s are affected in proportion to their length; the longest axons are the most affected. [[Diabetic neuropathy]] is the most common cause of this pattern. In demyelinating polyneuropathies, the [[myelin]] sheath around axons is damaged, which affects axons' ability to conduct electrical impulses. The third and least common pattern directly affects the [[cell bodies]] of neurons. This affects the [[sensory neuron]]s (known as ''[[sensory neuronopathy]]'' or ''dorsal root ganglionopathy'').<ref name="Amato 2020">{{cite journal |last1=Amato |first1=Anthony A. |last2=Ropper |first2=Allan H. |title=Sensory Ganglionopathy |journal=New England Journal of Medicine |date=22 October 2020 |volume=383 |issue=17 |pages=1657–1662 |doi=10.1056/NEJMra2023935|pmid=33085862 }}</ref><ref name="Gwathmey 2016">{{cite journal |last1=Gwathmey |first1=Kelly Graham |title=Sensory neuronopathies |journal=Muscle & Nerve |date=January 2016 |volume=53 |issue=1 |pages=8–19 |doi=10.1002/mus.24943|pmid=26467754 }}</ref>

The effect of this is to cause symptoms in more than one part of the body, often symmetrically on the left and right sides. As for any neuropathy, the chief symptoms include motor symptoms such as weakness or clumsiness of movement; and sensory symptoms such as unusual or unpleasant sensations such as [[Paresthesia|tingling or burning]]; [[Hypoesthesia|reduced ability to feel sensations]] such as texture or temperature, and impaired balance when standing or walking. In many polyneuropathies, these symptoms occur first and most severely in the feet. Autonomic symptoms also may occur, such as dizziness on standing up, [[erectile dysfunction]], and difficulty controlling urination.{{citation needed|date=June 2022}}

Polyneuropathies usually are caused by processes that affect the body as a whole. [[Diabetes]] and [[impaired glucose tolerance]] are the most common causes. Hyperglycemia-induced formation of advanced [[glycation]] end products (AGEs) is related to diabetic neuropathy.<ref name="ReferenceA">{{cite journal | vauthors = Sugimoto K, Yasujima M, Yagihashi S | title = Role of advanced glycation end products in diabetic neuropathy | journal = Current Pharmaceutical Design | volume = 14 | issue = 10 | pages = 953–61 | year = 2008 | pmid = 18473845 | doi = 10.2174/138161208784139774 }}</ref> Other causes relate to the particular type of polyneuropathy, and there are many different causes of each type, including inflammatory diseases such as [[Lyme disease]], vitamin deficiencies, blood disorders, and toxins (including alcohol and certain prescribed drugs).

Most types of polyneuropathy progress fairly slowly, over months or years, but rapidly progressive polyneuropathy also occurs. It is important to recognize that at one time it was thought that many of the cases of [[small fiber peripheral neuropathy]] with typical symptoms of tingling, pain, and loss of sensation in the feet and hands were due to [[glucose intolerance]] before a diagnosis of diabetes or pre-diabetes. However, in August 2015, the Mayo Clinic published a scientific study in the Journal of the Neurological Sciences showing "no significant increase in...symptoms...in the prediabetes group", and stated that "A search for alternate neuropathy causes is needed in patients with prediabetes."<ref name="pmid26049659">{{cite journal | vauthors = Kassardjian CD, Dyck PJ, Davies JL, Carter RE, Dyck PJ | title = Does prediabetes cause small fiber sensory polyneuropathy? Does it matter? | journal = Journal of the Neurological Sciences | volume = 355 | issue = 1–2 | pages = 196–8 | date = August 2015 | pmid = 26049659 | pmc = 4621009 | doi = 10.1016/j.jns.2015.05.026 }}</ref>

The treatment of polyneuropathies is aimed firstly at eliminating or controlling the cause, secondly at maintaining muscle strength and physical function, and thirdly at controlling symptoms such as [[neuropathic pain]].{{citation needed|date=June 2022}}

===Mononeuritis multiplex===
'''Mononeuritis multiplex''', occasionally termed '''polyneuritis multiplex''', is simultaneous or sequential involvement of individual noncontiguous [[Spinal nerve|nerve trunk]]s,<ref>{{MedlinePlusEncyclopedia|000782|Multiple mononeuropathy}}</ref> either partially or completely, evolving over days to years and typically presenting with acute or subacute loss of sensory and motor function of individual [[nerves]]. The pattern of involvement is asymmetric.  However, as the disease progresses, deficit(s) becomes more confluent and symmetrical, making it difficult to differentiate from polyneuropathy.<ref>{{cite web|last1=Ball|first1=Derick A. |title=Peripheral Neuropathy|url=http://www.neuravite.com/peripheral-neuropathy|publisher=NeuraVite|access-date=24 March 2016}}</ref> Therefore, attention to the pattern of early symptoms is important.

Mononeuritis multiplex is sometimes associated with a deep, aching pain that worsens at night and frequently in the lower back, hip, or leg. In people with [[diabetes mellitus]], mononeuritis multiplex typically is encountered as acute, unilateral, and severe thigh pain followed by anterior muscle weakness and loss of knee reflex.{{medical citation needed|date=March 2016}}

[[Electrodiagnostic medicine]] studies will show multifocal sensory motor [[axon]]al neuropathy.{{citation needed|date=July 2022}}

It is caused by, or associated with, several medical conditions:
{{columns-list|colwidth=30em|
* [[Diabetes mellitus]]
* [[Vasculitis|Vasculitides]]: [[polyarteritis nodosa]],<ref>{{cite journal | vauthors = Criado PR, Marques GF, Morita TC, de Carvalho JF | title = Epidemiological, clinical and laboratory profiles of cutaneous polyarteritis nodosa patients: Report of 22 cases and literature review | journal = Autoimmunity Reviews | volume = 15 | issue = 6 | pages = 558–63 | date = June 2016 | pmid = 26876385 | doi = 10.1016/j.autrev.2016.02.010 }}</ref><ref name="pmid25153486">{{cite journal | vauthors = Samson M, Puéchal X, Devilliers H, Ribi C, Cohen P, Bienvenu B, Terrier B, Pagnoux C, Mouthon L, Guillevin L | title = Mononeuritis multiplex predicts the need for immunosuppressive or immunomodulatory drugs for EGPA, PAN and MPA patients without poor-prognosis factors | journal = Autoimmunity Reviews | volume = 13 | issue = 9 | pages = 945–53 | date = September 2014 | pmid = 25153486 | doi = 10.1016/j.autrev.2014.08.002 }}</ref> [[granulomatosis with polyangiitis]]<ref name="pmid25153486"/> and [[eosinophilic granulomatosis with polyangiitis]].<ref name="pmid25153486"/> This results in [[vasculitic neuropathy]].
* Immune-mediated diseases, such as [[rheumatoid arthritis]],<ref name="pmid2835572">{{cite journal | vauthors = Hellmann DB, Laing TJ, Petri M, Whiting-O'Keefe Q, Parry GJ | title = Mononeuritis multiplex: the yield of evaluations for occult rheumatic diseases | journal = Medicine | volume = 67 | issue = 3 | pages = 145–53 | date = May 1988 | pmid = 2835572 | doi = 10.1097/00005792-198805000-00001 | s2cid = 24059700 | doi-access = free }}</ref> [[systemic lupus erythematosus]] (SLE)
* Infections:  [[leprosy]], [[lyme disease]], [[parvovirus B19]],<ref>{{cite journal | vauthors = Lenglet T, Haroche J, Schnuriger A, Maisonobe T, Viala K, Michel Y, Chelbi F, Grabli D, Seror P, Garbarg-Chenon A, Amoura Z, Bouche P | title = Mononeuropathy multiplex associated with acute parvovirus B19 infection: characteristics, treatment and outcome | journal = Journal of Neurology | volume = 258 | issue = 7 | pages = 1321–6 | date = July 2011 | pmid = 21287183 | doi = 10.1007/s00415-011-5931-2 | s2cid = 8145505 }}</ref> [[HIV]]<ref>{{cite journal | vauthors = Kaku M, Simpson DM | title = HIV neuropathy | journal = Current Opinion in HIV and AIDS | volume = 9 | issue = 6 | pages = 521–6 | date = November 2014 | pmid = 25275705 | doi = 10.1097/COH.0000000000000103 | s2cid = 3023845 | doi-access = free }}</ref>
* [[Sarcoidosis]]<ref>{{cite journal | vauthors = Vargas DL, Stern BJ | title = Neurosarcoidosis: diagnosis and management | journal = Seminars in Respiratory and Critical Care Medicine | volume = 31 | issue = 4 | pages = 419–27 | date = August 2010 | pmid = 20665392 | doi = 10.1055/s-0030-1262210 | s2cid = 260321346 }}</ref>
* [[Cryoglobulinemia]]<ref>{{cite journal | vauthors = Cacoub P, Comarmond C, Domont F, Savey L, Saadoun D | title = Cryoglobulinemia Vasculitis | journal = The American Journal of Medicine | volume = 128 | issue = 9 | pages = 950–5 | date = September 2015 | pmid = 25837517 | doi = 10.1016/j.amjmed.2015.02.017 | s2cid = 12560858 | url = https://hal.sorbonne-universite.fr/hal-01142000/file/Cacoub_Cryoglobulinemia.pdf | url-access =  | url-status =  | archive-url =  | archive-date =  }}</ref>
* Reactions to exposure to chemical agents, including [[trichloroethylene]] and [[dapsone]]{{medical citation needed|date=March 2016}}
* Rarely, following the sting of certain [[jellyfish]], such as the [[sea nettle]]{{medical citation needed|date=March 2016}}
}}

===Autonomic neuropathy===
'''Autonomic neuropathy''' is a form of polyneuropathy that affects the non-voluntary, non-sensory [[nervous system]] (i.e., the [[autonomic nervous system]]), affecting mostly the internal organs such as the [[urinary bladder|bladder]] muscles, the [[cardiovascular system]], the [[digestive tract]], and the [[genital]] organs. These nerves are not under a person's conscious control and function automatically. Autonomic nerve fibers form large collections in the thorax, abdomen, and pelvis outside the [[spinal cord]]. They have connections with the spinal cord and ultimately the brain, however. Most commonly autonomic neuropathy is seen in persons with long-standing [[diabetes mellitus]] type 1 and 2. In most—but not all—cases, autonomic neuropathy occurs alongside other forms of neuropathy, such as sensory neuropathy.{{citation needed|date=June 2022}}

Autonomic neuropathy is one cause of malfunction of the autonomic nervous system, but not the only one; some conditions affecting the brain or spinal cord also may cause [[autonomic dysfunction]], such as [[multiple system atrophy]], and therefore, may cause similar symptoms to autonomic neuropathy.{{citation needed|date=June 2022}}

The signs and symptoms of autonomic neuropathy include the following:
* [[Urinary bladder]] conditions: [[bladder incontinence]] or [[urine retention]]
* [[Gastrointestinal tract]]: [[dysphagia]], [[abdominal pain]], [[nausea]], [[vomiting]], [[malabsorption]], [[fecal incontinence]], [[gastroparesis]], [[diarrhoea]], [[constipation]]
* [[Cardiovascular system]]: disturbances of heart rate ([[tachycardia]], [[bradycardia]]), [[orthostatic hypotension]], inadequate increase of heart rate on exertion
* [[Respiratory system]]: impairments in the signals associated with regulation of breathing and [[gas exchange]] ([[central sleep apnea]], [[hypopnea]], [[bradypnea]]).<!-- "decreased hypoxia-induced respiratory drive" --><ref>{{cite book | vauthors = Vinik AI, Erbas T | chapter = Diabetic autonomic neuropathy | volume = 117 | pages = 279–94 | year = 2013 | pmid = 24095132 | doi = 10.1016/b978-0-444-53491-0.00022-5 | isbn = 978-0-444-53491-0 | series = Handbook of Clinical Neurology | title = Autonomic Nervous System }}</ref>
* Skin: thermal regulation, dryness through sweat disturbances
* Other areas: [[hypoglycemia]] unawareness, [[genital]] impotence

===Neuritis===
'''Neuritis''' is a general term for inflammation of a [[nerve]]<ref>{{DorlandsDict|six/000071661|neuritis}}</ref> or the general [[inflammation]] of the [[peripheral nervous system]]. Symptoms depend on the nerves involved, but may include [[pain]], [[paresthesia]] (pins-and-needles), [[paresis]] (weakness), [[hypoesthesia]] (numbness), [[anesthesia]], [[paralysis]], wasting, and disappearance of the [[reflexes]].

Causes of neuritis include:
{{columns-list|colwidth=30em|
* [[Physical injury]]
* [[Infection]]
** [[Diphtheria]]
** [[Herpes zoster]] (shingles)
** [[Leprosy]]
** [[Lyme disease]]
* [[Chemical]] injury such as [[chemotherapy]]
* [[Radiation therapy]]
Types of neuritis include:
* [[Brachial plexus injury|Brachial neuritis]]
* [[Cranial nerves|Cranial neuritis]] such as [[Bell's palsy]]
* [[Optic neuritis]]
* [[Vestibular neuritis]]
* [[Wartenberg's migratory sensory neuropathy]]
* Underlying conditions including:
** [[Alcoholism]]
** [[Autoimmune disease]], especially [[multiple sclerosis]] and [[Guillain–Barré syndrome]]
** [[Beriberi]] ([[Thiamine|vitamin B<sub>1</sub>]] deficiency)
** [[Cancer]]
** [[Celiac disease]]<ref>{{cite journal | vauthors = Chin RL, Latov N | title = Peripheral Neuropathy and Celiac Disease | journal = Current Treatment Options in Neurology | volume = 7 | issue = 1 | pages = 43–48 | date = January 2005 | pmid = 15610706 | doi = 10.1007/s11940-005-0005-3 | s2cid = 40765123 }}</ref>
** [[Non-celiac gluten sensitivity]]<ref name=ZisHadjivassiliou2019 />
** [[Diabetes mellitus]] ([[Diabetic neuropathy]])                                        
** [[Hypothyroidism]]
** [[Porphyria]]
** [[Vitamin B12|Vitamin B<sub>12</sub>]] deficiency<ref>{{cite journal |last1=Ghosh |first1=Shampa |last2=Sinha |first2=Jitendra Kumar |last3=Khandelwal |first3=Nitin |last4=Chakravarty |first4=Sumana |last5=Kumar |first5=Arvind |last6=Raghunath |first6=Manchala |title=Increased stress and altered expression of histone modifying enzymes in brain are associated with aberrant behaviour in vitamin B12 deficient female mice |journal=Nutritional Neuroscience |date=1 September 2020 |volume=23 |issue=9 |pages=714–723 |doi=10.1080/1028415X.2018.1548676 |pmid=30474509 |s2cid=53785219 }}</ref>
** [[Vitamin B6|Vitamin B<sub>6</sub>]] excess<ref>{{EMedicine|article|819426|Vitamin Toxicity}}</ref>
}}