Idiopathic Median Neuropathy at the<unk>  Tunnel Most people with<unk>  have median neuropathy of unknown cause. The medical term for this is “idiopathic.” The pathology can be described as idiopathic median neuropathy at the<unk>  tunnel (IMNCT). The association of other factors with<unk>  and IMNCT is a source of notable debate. It’s important to distinguish factors that provoke symptoms, and factors that are associated with seeking care, from factors that make the neuropathy worse. Genetic factors are believed to be the most important determinants of who develops<unk>  due to IMNCT. In other words, your wrist structure seems programmed at birth to develop IMNCT later in life. A genome-wide association study (GWAS) of<unk>  identified 16 genomic loci significantly associated with the disease, including several loci previously known to be associated with human height. Factors that may contribute to symptoms, but have not been experimentally associated with neuropathy include obesity, and Diabetes mellitus . One case-control study noted that individuals classified as obese (BMI > 29) are 2.5 times more likely than slender individuals (BMI It’s not clear whether this association is due to an alteration of pathophysiology, a variation in symptoms, or a variation in care-seeking. Discrete Pathophysiology and<unk>  Hereditary neuropathy with susceptibility to pressure palsies is a genetic condition that appears to increase the probability of developing MNCT. Heterozygous mutations in the gene SH3TC2, associated with Charcot-Marie-Tooth, may confer susceptibility to neuropathy, including<unk> . Association between common benign tumors such as lipomas, ganglion, and vascular malformation should be handled with care. Such tumors are very common and overlap with IMNCT is more likely than pressure on the median nerve. Similarly, the degree to which transthyretin amyloidosis-associated polyneuropathy and<unk>  is under investigation. Prior<unk>  tunnel release is often noted in individuals who later present with transthyretin amyloid-associated cardiomyopathy. There is consideration that bilateral<unk>  could be a reason to consider amyloidosis, timely diagnosis of which could improve heart health. Amyloidosis is rare, even among people with<unk>  (0.55% incidence within 10 years of<unk>  tunnel release. In the absence of other factors associated with a notable probability of amyloidosis, it’s not clear that biopsy at the time of<unk>  tunnel release has a suitable balance between potential harms and potential benefits. Other specific pathophysiologies that can cause median neuropathy via pressure include: * Rheumatoid arthritis and other diseases that cause inflammation of the flexor tendons. * With severe untreated hypothyroidism, generalized myxedema causes deposition of mucopolysaccharides within both the perineurium of the median nerve, as well as the tendons passing through the<unk>  tunnel. Association of<unk>  and IMNCT with lesser degrees of hypothyroidism is questioned. * Pregnancy may bring out symptoms in genetically predisposed individuals. Perhaps the changes in hormones and fluid increase pressure temporarily in the<unk>  tunnel. High progesterone levels and water retention may increase the size of the synovium. * Bleeding and swelling from a fracture or dislocation. This is referred to as acute<unk> . * Acromegaly causes excessive secretion of growth hormones. This causes the soft tissues and bones around the<unk>  tunnel to grow and compress the median nerve. Other considerations * Double-crush<unk>  is a debated hypothesis that compression or irritation of nerve branches contributing to the median nerve in the neck, or anywhere above the wrist, increases sensitivity of the nerve to compression in the wrist. There is little evidence to support this theory and some concern that it may be used to justify more surgery Work related The international debate regarding the relationship between<unk>  and repetitive motion in work is ongoing. The Occupational Safety and Health Administration (OSHA) has adopted rules and regulations regarding cumulative trauma disorders. Occupational risk factors of repetitive tasks, force, posture, and vibration have been cited. The relationship between work and<unk>  is controversial; in many locations, workers diagnosed with<unk>  are entitled to time off and compensation. Some speculate that<unk>  is provoked by repetitive movement and manipulating activities and that the exposure can be cumulative. It has also been stated that symptoms are commonly exacerbated by forceful and repetitive use of the hand and wrists in industrial occupations, but it is unclear as to whether this refers to pain (which may not be due to<unk>  or the more typical numbness symptoms. A review of available scientific data by the National Institute for Occupational Safety and Health (NIOSH) indicated that job tasks that involve highly repetitive manual acts or specific wrist postures were associated with incidents of<unk> , but causation was not established, and the distinction from work-related arm pains that are not<unk>  was not clear. It has been proposed that repetitive use of the arm can affect the biomechanics of the upper limb or cause damage to tissues. It has also been proposed that postural and spinal assessment along with ergonomic assessments should be included in the overall determination of the condition. Addressing these factors has been found to improve comfort in some studies. A 2010 survey by NIOSH showed that 2/3 of the 5 million<unk>  tunnel cases in the US that year were related to work. Women have more work-related<unk>  than men. Speculation that<unk>  is work-related is based on claims such as<unk>  being found mostly in the working adult population, though evidence is lacking for this. For instance, in one recent representative series of a consecutive experience, most patients were older and not working. Based on the claimed increased incidence in the workplace, arm use is implicated, but the weight of evidence suggests that this is an inherent, genetic, slowly but inevitably progressive idiopathic peripheral mononeuropathy. Associated conditions A variety of patient factors can lead to<unk> , including heredity, size of the<unk>  tunnel, associated local and systematic diseases, and certain habits. Non-traumatic causes generally happen over a period of time, and are not triggered by one certain event. Many of these factors are manifestations of physiologic aging.
Carpal tunnel syndrome
Radial tunnel syndrome
Ulnar tunnel syndrome
Calpainopathy
Tarsal tunnel syndrome
Sciatica
Median nerve palsy
Anterior interosseous syndrome