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80-407: The progression from MGUS to multiple myeloma usually involves several steps. In rare cases, it may also be related with a slowly progressive symmetric distal sensorimotor neuropathy . People with monoclonal gammopathy generally do not experience signs or symptoms. Some people may experience a rash or nerve problems, such as numbness or tingling. MGUS is usually detected by chance when the patient has

160-495: A blood-nerve barrier similar to the blood–brain barrier . Molecules are thereby prevented from crossing the blood into the endoneurial fluid. During the development of nerve edema from nerve irritation (or injury), the amount of endoneurial fluid may increase at the site of irritation. This increase in fluid can be visualized using magnetic resonance neurography , and thus MR neurography can identify nerve irritation and/or injury. Nerves are categorized into three groups based on

240-416: A comprehensive metabolic panel screening for diabetes and pre-diabetes, and a serum immunofixation test , which tests for antibodies in the blood. The treatment of peripheral neuropathy varies based on the cause of the condition, and treating the underlying condition can aid in the management of neuropathy. When peripheral neuropathy results from diabetes mellitus or prediabetes , blood sugar management

320-694: A 10–20% response. Three of the seven authors of the review had conflicts of interest declared. In a 2019 Cochrane review of pregabalin the authors conclude that there is some evidence of efficacy in the treatment of pain deriving from post-herpetic neuralgia, diabetic neuropathy, and post-traumatic neuropathic pain only. They also warned that many patients treated will have no benefit. Two of the five authors declared receiving payments from pharmaceutical companies. A 2017 Cochrane systematic review found that oxcarbazepine had little evidence to support its use for treating diabetic neuropathy, radicular pain, and other neuropathies. The authors also call for better studies. In

400-487: A 2015 Cochrane systematic review the authors found a lack of evidence showing any effectiveness of zonisamide for the treatment of pain deriving from any peripheral neuropathy. A 2014 Cochrane review found that studies of levetiracetam showed no indication of its effectiveness at treating pain from any neuropathy. The authors also found that the evidence was possibly biased and that some patients experienced adverse events. A 2013 Cochrane systematic review concluded that there

480-411: A Mauthner cell are so powerful that a single action potential gives rise to a major behavioral response: within milliseconds the fish curves its body into a C-shape , then straightens, thereby propelling itself rapidly forward. Functionally this is a fast escape response, triggered most easily by a strong sound wave or pressure wave impinging on the lateral line organ of the fish. Mauthner cells are not

560-471: A blood test for another condition or as part of standard screening. Pathologically, the lesion in MGUS is in fact very similar to that in multiple myeloma. There is a predominance of clonal plasma cells in the bone marrow with an abnormal immunophenotype ( CD38 + CD56 + CD19 −) mixed in with cells of a normal phenotype (CD38+ CD56− CD19+); in MGUS, on average more than 3% of the clonal plasma cells have

640-583: A command neuron has, however, become controversial, because of studies showing that some neurons that initially appeared to fit the description were really only capable of evoking a response in a limited set of circumstances. In organisms of radial symmetry , nerve nets serve for the nervous system. There is no brain or centralised head region, and instead there are interconnected neurons spread out in nerve nets. These are found in Cnidaria , Ctenophora and Echinodermata . Herophilos (335–280 BC) described

720-421: A debilitating condition which causes bizarre sensory problems to painful sensory problems, no treatment is indicated. The protein electrophoresis test should be repeated annually, and if there is any concern for a rise in the level of monoclonal protein, then prompt referral to a hematologist is required. The hematologist, when first evaluating a case of MGUS, will usually perform a skeletal survey (X-rays of

800-408: A diagnosis of small-fiber peripheral neuropathy. In EMG testing, demyelinating neuropathy characteristically shows a reduction in conduction velocity and prolongation of distal and F-wave latencies, whereas axonal neuropathy shows a reduction in amplitude. Laboratory tests include blood tests for vitamin B 12 levels, a complete blood count , measurement of thyroid stimulating hormone levels,

880-412: A lesion in the central nervous system as a cause, a diagnosis may be made on the basis of symptoms, laboratory and additional testing, clinical history, and a detailed examination. During physical examination , specifically a neurological examination , those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, although those with a pathology (problem) of

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960-533: A placebo. For tramadol, Cochrane found that there was only modest information about the benefits of its usage for neuropathic pain. Studies were small, had potential risks of bias and apparent benefits increased with risk of bias. Overall the evidence was of low or very low quality and the authors state that it "does not provide a reliable indication of the likely effect". For oxycodone the authors found very low-quality evidence showing its usefulness in treating diabetic neuropathy and postherpetic neuralgia only. One of

1040-520: A prevalence of MGUS of approximately 5.9% in African men over the age of 50. In 2009, prospective data demonstrated that all or almost all cases of multiple myeloma are preceded by MGUS. In addition to multiple myeloma, MGUS may also progress to Waldenström's macroglobulinemia or primary amyloidosis . aggressive: Sézary disease Neuropathy Peripheral neuropathy , often shortened to neuropathy , refers to damage or disease affecting

1120-410: A sweat test and a tilt table test. Diagnosis of small fiber involvement in peripheral neuropathy may also involve a skin biopsy in which a 3 mm-thick section of skin is removed from the calf by a punch biopsy , and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the skin. Reduced density of the small nerves in the epidermis supports

1200-612: A whole (not clinic patients) in Olmsted County, Minnesota . They found that the prevalence of MGUS was 3.2% in people above 50, with a slight male predominance (4.0% vs. 2.7%). Prevalence increased with age: of people over 70 up to 5.3% had MGUS, while in the over-85 age group the prevalence was 7.5%. In the majority of cases (63.5%), the paraprotein level was <1 g/dL, while only a very small group had levels over 2 g/dL. A study of monoclonal protein levels conducted in Ghana showed

1280-460: 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 distal axonopathy , one common pattern

1360-411: Is a special type of identified neuron, defined as a neuron that is capable of driving a specific behavior all by itself. Such neurons appear most commonly in the fast escape systems of various species—the squid giant axon and squid giant synapse , used for pioneering experiments in neurophysiology because of their enormous size, both participate in the fast escape circuit of the squid. The concept of

1440-414: Is also often the case that the aforementioned medications are prescribed for neuropathic pain conditions for which they had not been explicitly tested on or for which controlled research is severely lacking; or even for which evidence suggests that these medications are not effective. The NHS for example explicitly states that amitriptyline and gabapentin can be used for treating the pain of sciatica. This

1520-524: Is called identified if it has properties that distinguish it from every other neuron in the same animal—properties such as location, neurotransmitter, gene expression pattern, and connectivity—and if every individual organism belonging to the same species has exactly one neuron with the same set of properties. In vertebrate nervous systems, very few neurons are "identified" in this sense. Researchers believe humans have none—but in simpler nervous systems, some or all neurons may be thus unique. In vertebrates,

1600-494: Is caused by, or associated with, several medical conditions: 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 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

1680-481: Is completed by the person affected by polyneuropathy. The total score and individual item scores can be followed over time, with item scoring used by the patient and care provider to estimate the clinical status of some of the more common life domains and symptoms impacted by polyneuropathy. The causes are grouped broadly as follows: Peripheral neuropathy may first be considered when an individual reports symptoms of numbness, tingling, and pain in feet. After ruling out

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1760-415: Is despite both the lack of high-quality evidence that demonstrates the efficacy of these medications for that symptom, and also the prominence of generally moderate to high-quality evidence that reveals that antiepileptics in specific, including gabapentin, demonstrate no efficacy in treating it. In general, according to Cochrane's systematic reviews, antidepressants have shown to either be ineffective for

1840-436: Is further subdivided into the sympathetic and the parasympathetic nervous systems. The sympathetic nervous system is activated in cases of emergencies to mobilize energy, while the parasympathetic nervous system is activated when organisms are in a relaxed state. The enteric nervous system functions to control the gastrointestinal system. Both autonomic and enteric nervous systems function involuntarily. Nerves that exit from

1920-492: 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. 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. " Polyneuropathy "

2000-426: Is key to treatment. In prediabetes in particular, strict blood sugar control can significantly alter the course of neuropathy. In peripheral neuropathy that stems from immune-mediated diseases, the underlying condition is treated with intravenous immunoglobulin or steroids. When peripheral neuropathy results from vitamin deficiencies or other disorders, those are treated as well. A range of medications that act on

2080-667: Is revealed in many of the Cochrane systematic reviews listed below, studies of these medications for the treatment of neuropathic pain are often methodologically flawed and the evidence is potentially subject to major bias. In general, the evidence does not support the usage of antiepileptic and antidepressant medications for the treatment of neuropathic pain. Better-designed clinical trials and further review from non-biased third parties are necessary to gauge just how useful for patients these medications truly are. Reviews of these systematic reviews are also necessary to assess their failings. It

2160-466: Is simultaneous or sequential involvement of individual noncontiguous nerve trunks , 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. Therefore, attention to

2240-419: Is tested with a 128-Hz tuning fork , and decreased sensation of light touch when touched by a nylon monofilament. Diagnostic tests include electromyography (EMG) and nerve conduction studies (NCSs), which assess large myelinated nerve fibers. Testing for small-fiber peripheral neuropathies often relates to the autonomic nervous system function of small thinly- and unmyelinated fibers. These tests include

2320-408: Is that the cell bodies of neurons remain intact, but the axons 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 the ability of the axons to conduct electrical impulses. The third and least common pattern affects

2400-432: Is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain , including the brainstem , and spinal cord . The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons , that connect

2480-414: Is unknown. Nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons ) in the peripheral nervous system . Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in

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2560-434: Is wrapped in a layer of connective tissue called the perineurium . Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium . Nerve cells (often called neurons) are further classified as sensory , motor , or mixed nerves . In the central nervous system , the analogous structures are known as nerve tracts . Each nerve is covered on the outside by a dense sheath of connective tissue ,

2640-662: The cell bodies of neurons directly. This affects the sensory neurons (known as sensory neuronopathy or dorsal root ganglionopathy ). 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 tingling or burning ; 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

2720-490: The epineurium . Beneath this is a layer of fat cells, the perineurium , which forms a complete sleeve around a bundle of axons. Perineurial septae extend into the nerve and subdivide it into several bundles of fibres. Surrounding each such fibre is the endoneurium . This forms an unbroken tube from the surface of the spinal cord to the level where the axon synapses with its muscle fibres, or ends in sensory receptors . The endoneurium consists of an inner sleeve of material called

2800-399: The fluoroquinolone class of antibiotics (such as ciprofloxacin , levofloxacin , moxifloxacin )), traumatic injury , ischemia , radiation therapy , excessive alcohol consumption, immune system disease , celiac disease , non-celiac gluten sensitivity , or viral infection. It can also be genetic (present from birth) or idiopathic (no known cause). In conventional medical usage ,

2880-428: The glycocalyx and an outer, delicate, meshwork of collagen fibres. Nerves are bundled and often travel along with blood vessels , since the neurons of a nerve have fairly high energy requirements. Within the endoneurium, the individual nerve fibres are surrounded by a low-protein liquid called endoneurial fluid . This acts in a similar way to the cerebrospinal fluid in the central nervous system and constitutes

2960-711: The nerves . Damage to nerves may impair sensation, movement, gland function, and/or organ function depending on which nerve fibers are affected. Neuropathies affecting motor , sensory , or autonomic nerve fibers result in different symptoms. More than one type of fiber may be affected simultaneously. Peripheral neuropathy may be acute (with sudden onset, rapid progress) or chronic (symptoms begin subtly and progress slowly), and may be reversible or permanent. Common causes include systemic diseases (such as diabetes or leprosy ), hyperglycemia-induced glycation , vitamin deficiency , medication (e.g., chemotherapy , or commonly prescribed antibiotics including metronidazole and

3040-401: 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: Types of neuritis include: Those with diseases or dysfunctions of their nerves may present with problems in any of

3120-532: The CNS to all remaining body parts. Nerves that transmit signals from the CNS are called motor or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory or afferent . Spinal nerves serve both functions and are called mixed nerves. The PNS is divided into three separate subsystems, the somatic , autonomic , and enteric nervous systems. Somatic nerves mediate voluntary movement. The autonomic nervous system

3200-518: The actual site of damage, a phenomenon called referred pain . Referred pain can happen when the damage causes altered signalling to other areas. Neurologists usually diagnose disorders of nerves by a physical examination , including the testing of reflexes , walking and other directed movements, muscle weakness , proprioception , and the sense of touch . This initial exam can be followed with tests such as nerve conduction study , electromyography (EMG), and computed tomography (CT). A neuron

3280-402: The affected glands and organs, but common symptoms are poor bladder control, abnormal blood pressure or heart rate, and reduced ability to sweat normally. 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

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3360-412: 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. The signs and symptoms of autonomic neuropathy include the following: Neuritis is a general term for inflammation of a nerve or the general inflammation of

3440-456: The benefit of antidepressant medications for several types of chronic non-cancer pains (including neuropathic pain) in children and adolescents and the authors found the evidence inconclusive. A 2017 Cochrane systematic review found that daily dosages between 1800–3600 mg of gabapentin could provide good pain relief for pain associated with diabetic neuropathy only. This relief occurred for roughly 30–40% of treated patients, while placebo had

3520-428: The best known identified neurons are the gigantic Mauthner cells of fish. Every fish has two Mauthner cells, located in the bottom part of the brainstem, one on the left side and one on the right. Each Mauthner cell has an axon that crosses over, innervating (stimulating) neurons at the same brain level and then travelling down through the spinal cord, making numerous connections as it goes. The synapses generated by

3600-538: The blood vessels surrounding the nerve all cause nerve damage , which can vary in severity. Multiple sclerosis is a disease associated with extensive nerve damage. It occurs when the macrophages of an individual's own immune system damage the myelin sheaths that insulate the axon of the nerve. A pinched nerve occurs when pressure is placed on a nerve, usually from swelling due to an injury, or pregnancy and can result in pain , weakness, numbness or paralysis, an example being CTS. Symptoms can be felt in areas far from

3680-763: The body are affected it is called " mononeuritis multiplex ", "multifocal mononeuropathy", or "multiple mononeuropathy". Neuropathy may cause painful cramps , fasciculations (fine muscle twitching), muscle loss, bone degeneration, and changes in the skin, hair, and nails. Additionally, motor neuropathy may cause impaired balance and coordination or, most commonly, muscle weakness; sensory neuropathy may cause numbness to touch and vibration, reduced position sense causing poorer coordination and balance, reduced sensitivity to temperature change and pain, spontaneous tingling or burning pain, or allodynia (pain from normally nonpainful stimuli, such as light touch); and autonomic neuropathy may produce diverse symptoms, depending on

3760-435: The case of sensory nerves , from the periphery back to the central nervous system . Each axon, within the nerve, is an extension of an individual neuron , along with other supportive cells such as some Schwann cells that coat the axons in myelin . Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium . The axons are bundled together into groups called fascicles , and each fascicle

3840-775: The central nervous system have been used to symptomatically treat neuropathic pain. Commonly used medications include tricyclic antidepressants (such as nortriptyline , amitriptyline . imapramine , and desipramine , ) serotonin-norepinephrine reuptake inhibitor (SNRI) medications ( duloxetine , venlafaxine , and milnacipran ) and antiepileptic medications ( gabapentin , pregabalin , oxcarbazepine zonisamide levetiracetam , lamotrigine , topiramate , clonazepam , phenytoin , lacosamide , sodium valproate and carbamazepine ). Opioid and opiate medications (such as buprenorphine , morphine , methadone , fentanyl , hydromorphone , tramadol and oxycodone ) are also often used to treat neuropathic pain. As

3920-553: The cranium are called cranial nerves while those exiting from the spinal cord are called spinal nerves . Cancer can spread by invading the spaces around nerves. This is particularly common in head and neck cancer , prostate cancer and colorectal cancer . Nerves can be damaged by physical injury as well as conditions like carpal tunnel syndrome (CTS) and repetitive strain injury . Autoimmune diseases such as Guillain–Barré syndrome , neurodegenerative diseases , polyneuropathy , infection, neuritis , diabetes , or failure of

4000-403: The direction that signals are conducted: Nerves can be categorized into two groups based on where they connect to the central nervous system: Specific terms are used to describe nerves and their actions. A nerve that supplies information to the brain from an area of the body, or controls an action of the body is said to innervate that section of the body or organ. Other terms relate to whether

4080-416: The drug is ineffective for treating neuropathic pain. The authors caution against positive interpretations of the evidence. For sodium valproate the authors of a 2011 Cochrane review found that "three studies no more than hint that sodium valproate may reduce pain in diabetic neuropathy". They discuss how there is a probable overestimate of the effect due to the inherent problems with the data and conclude that

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4160-500: The evidence does not support its usage. In a 2014 systematic review of carbamazepine the authors believe the drug to be of benefit to some people. No trials were considered greater than level III evidence; none were longer than 4 weeks in length or were deemed as having good reporting quality. A 2017 Cochrane systematic review aiming to assess the benefit of antiepileptic medications for several types of chronic non-cancer pains (including neuropathic pain) in children and adolescents found

4240-647: The evidence inconclusive. Two of the ten authors of this study declared receiving payments from pharmaceutical companies. A Cochrane review of buprenorphine, fentanyl, hydromorphone, and morphine, all dated between 2015 and 2017, and all for the treatment of neuropathic pain, found that there was insufficient evidence to comment on their efficacy. Conflicts of interest were declared by the authors in this review. A 2017 Cochrane review of methadone found very low-quality evidence, three studies of limited quality, of its efficacy and safety. They could not formulate any conclusions about its relative efficacy and safety compared to

4320-432: The feet. Autonomic symptoms also may occur, such as dizziness on standing up, erectile dysfunction , and difficulty controlling urination. 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. Other causes relate to

4400-428: The four authors declared receiving payments from pharmaceutical companies. More generally, a large-scale 2013 review found opioids to be more effective for intermediate-term use than short-term use, but couldn't properly assess effectiveness for chronic use because of insufficient data. Most recent guidelines on the pharmacotherapy of neuropathic pain however are in agreement with the results of this review and recommend

4480-518: The functions of the optic nerve in sight and the oculomotor nerve in eye movement. Analysis of the nerves in the cranium enabled him to differentiate between blood vessels and nerves ( Ancient Greek : νεῦρον (neûron) "string, plant fiber, nerve"). Modern research has not confirmed William Cullen 's 1785 hypothesis associating mental states with physical nerves, although popular or lay medicine may still invoke "nerves" in diagnosing or blaming any sort of psychological worry or hesitancy, as in

4560-487: The growth processes finds the regeneration tube, it begins to grow rapidly towards its original destination guided the entire time by the regeneration tube. Nerve regeneration is very slow and can take up to several months to complete. While this process does repair some nerves, there will still be some functional deficit as the repairs are not perfect. A nerve conveys information in the form of electrochemical impulses (as nerve impulses known as action potentials ) carried by

4640-404: The individual neurons that make up the nerve. These impulses are extremely fast, with some myelinated neurons conducting at speeds up to 120 m/s. The impulses travel from one neuron to another by crossing a synapse , where the message is converted from electrical to chemical and then back to electrical. Nerves can be categorized into two groups based on function: The nervous system

4720-613: The monoclonal protein may be the first discovery before a formal diagnosis is made: MGUS occurs in over 3 percent of the White population over the age of 50, and is typically detected as an incidental finding when patients undergo a protein electrophoresis as part of an evaluation for a wide variety of clinical symptoms and disorders (e.g., peripheral neuropathy, vasculitis, hemolytic anemia, skin rashes, hypercalcemia, or elevated erythrocyte sedimentation rate). Although patients with MGUS have sometimes been reported to have peripheral neuropathy ,

4800-441: The most common form, length-dependent peripheral neuropathy, pain and parasthesia appear symmetrically and generally at the terminals of the longest nerves, which are in the lower legs and feet. Sensory symptoms generally develop before motor symptoms such as weakness. Length-dependent peripheral neuropathy symptoms make a slow ascent of the lower limbs, while symptoms may never appear in the upper limbs; if they do, it will be around

4880-401: The nerve affects the same side ("ipsilateral") or opposite side ("contralateral") of the body, to the part of the brain that supplies it. Nerve growth normally ends in adolescence, but can be re-stimulated with a molecular mechanism known as " Notch signaling ". If the axons of a neuron are damaged, as long as the cell body of the neuron is not damaged, the axons can regenerate and remake

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4960-515: The nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies, such as Guillain–Barré syndrome ; or may show focal sensory disturbance or weakness, such as in mononeuropathies. Classically, ankle jerk reflex is absent in peripheral neuropathy. A physical examination will involve testing the deep ankle reflex as well as examining the feet for any ulceration . For large fiber neuropathy, an exam will usually show an abnormally decreased sensation to vibration, which

5040-610: The normal nerve functions. Symptoms vary depending on the types of nerve fiber involved. In terms of sensory function, symptoms commonly include loss of function ("negative") symptoms, including numbness , tremor , impairment of balance, and gait abnormality . Gain of function (positive) symptoms include tingling , pain , itching , crawling, and pins-and-needles . Motor symptoms include loss of function ("negative") symptoms of weakness, tiredness , muscle atrophy , and gait abnormalities ; and gain of function ("positive") symptoms of cramps , and muscle twitch ( fasciculations ). In

5120-408: The normal phenotype, whereas in multiple myeloma, less than 3% of the cells have the normal phenotype. MGUS is a common, age-related medical condition characterized by an accumulation of bone marrow plasma cells derived from a single abnormal clone. Patients may be diagnosed with MGUS if they fulfill the following four criteria: Several other illnesses can present with a monoclonal gammopathy , and

5200-441: The only identified neurons in fish—there are about 20 more types, including pairs of "Mauthner cell analogs" in each spinal segmental nucleus. Although a Mauthner cell is capable of bringing about an escape response all by itself, in the context of ordinary behavior other types of cells usually contribute to shaping the amplitude and direction of the response. Mauthner cells have been described as command neurons . A command neuron

5280-422: 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

5360-479: The pattern of early symptoms is important. Mononeuritis multiplex is sometimes associated with a deep, aching pain that is worse 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. Electrodiagnostic medicine studies will show multifocal sensory motor axonal neuropathy. It

5440-419: The prediabetes group", and stated that "A search for alternate neuropathy causes is needed in patients with prediabetes." 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 . Mononeuritis multiplex , occasionally termed polyneuritis multiplex ,

5520-425: The process affecting the nerves; e.g., inflammation ( neuritis ), compression ( compression neuropathy ), chemotherapy ( chemotherapy-induced peripheral neuropathy ). The affected nerves are found in an EMG (electromyography) / NCS (nerve conduction study) test and the classification is applied upon completion of the exam. Mononeuropathy is a type of neuropathy that only affects a single nerve . Diagnostically, it

5600-497: The proximal skeleton), check the blood for hypercalcemia and deterioration in renal function , check the urine for Bence Jones protein and perform a bone marrow biopsy . If none of these tests are abnormal, a patient with MGUS is followed up once every 6 months to a year with a blood test (serum protein electrophoresis). At the Mayo Clinic, MGUS transformed into multiple myeloma or similar lymphoproliferative disorders at

5680-414: The rate of about 1–2% a year, or 17%, 34%, and 39% at 10, 20, and 25 years, respectively, of follow-up—among surviving patients. However, because they were elderly, most patients with MGUS died of something else and did not go on to develop multiple myeloma. When this was taken into account, only 11.2% developed lymphoproliferative disorders. Kyle et al. studied the prevalence of myeloma in the population as

5760-404: The synaptic connections with neurons with the help of guidepost cells . This is also referred to as neuroregeneration . The nerve begins the process by destroying the nerve distal to the site of injury allowing Schwann cells, basal lamina, and the neurilemma near the injury to begin producing a regeneration tube. Nerve growth factors are produced causing many nerve sprouts to bud. When one of

5840-418: 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. Autonomic neuropathy is one cause of malfunction of

5920-548: The time that leg symptoms reach the knee. When the nerves of the autonomic nervous system are affected, symptoms may include constipation, dry mouth, difficulty urinating, and dizziness when standing . A user-friendly, disease-specific, quality-of-life scale can be used to monitor how someone is doing living with the burden of chronic, sensorimotor polyneuropathy. This scale, called the Chronic, Acquired Polyneuropathy - Patient-reported Index (CAP-PRI), contains only 15 items and

6000-508: The treatment of neuropathic pain or the evidence available is inconclusive. Evidence also tends to be tainted by bias or issues with the methodology. Cochrane systematically reviewed the evidence for the antidepressants nortriptyline, desipramine, venlafaxine, and milnacipran and in all these cases found scant evidence to support their use for the treatment of neuropathic pain. All reviews were done between 2014 and 2015. A 2015 Cochrane systematic review of amitriptyline found that there

6080-494: The use of opioids. A 2017 Cochrane review examining mainly propoxyphene therapy as a treatment for many non-cancer pain syndromes (including neuropathic pain) concluded, "There was no evidence from randomised controlled trials to support or refute the use of opioids to treat chronic non-cancer pain in children and adolescents." A 2016 Cochrane review of paracetamol for the treatment of neuropathic pain concluded that its benefit alone or in combination with codeine or dihydrocodeine

6160-451: The word neuropathy ( neuro- , "nervous system" and -pathy , "disease of") without modifier usually means peripheral neuropathy . Neuropathy affecting just one nerve is called "mononeuropathy", and neuropathy involving nerves in roughly the same areas on both sides of the body is called "symmetrical polyneuropathy" or simply " polyneuropathy ". When two or more (typically just a few, but sometimes many) separate nerves in disparate areas of

6240-653: Was high-quality evidence to suggest that lamotrigine is not effective for treating neuropathic pain, even at high dosages 200–400 mg. A 2013 Cochrane systematic review of topirimate found that the included data had a strong likelihood of major bias; despite this, it found no effectiveness for the drug in treating the pain associated with diabetic neuropathy. It had not been tested for any other type of neuropathy. Cochrane reviews from 2012 of clonazepam and phenytoin uncovered no evidence of sufficient quality to support their use in chronic neuropathic pain." A 2012 Cochrane systematic review of lacosamide found it very likely that

6320-405: Was no evidence supporting the use of amitriptyline that did not possess inherent bias. The authors believe amitriptyline may have an effect in some patients but that the effect is overestimated. A 2014 Cochrane systematic review of imipramine notes that the evidence suggesting benefit were "methodologically flawed and potentially subject to major bias." A 2017 Cochrane systematic review assessed

6400-587: 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

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