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Median Neuropathy

Median neuropathy is a term describing the injury to the median nerve along its path from the brachial plexus to the distal forearm. The nerve is most susceptible to injury within the carpal tunnel. The term carpal tunnel syndrome is used to describe median nerve injury at that site, but median neuropathy can occur through numerous other mechanisms, which is why a thorough diagnostic workup is necessary.


Presentation

The clinical presentation of median neuropathy depends on the location where the median nerve is injured. In the vast majority of cases, however, the carpal tunnel is the site where the injury occurs, and the term "carpal tunnel syndrome" is used as a distinct clinical entity to describe the pathophysiological and clinical changes [1]. Several risk factors have been established, such as diabetes mellitus (a significantly higher incidence rate is observed compared to the general population), genetic predisposition, female gender, and profound occupational wrist efforts [1] [2]. Most important symptoms are a pain of the hand (the thumb and the first two and a half fingers are innervated by the median nerve) and the wrist that often wakes patients at night, and is accompanied by paresthesias. Additionally, sensory loss in the abovementioned fingers on the palmar side of the hand and weakness or wasting of the thenar muscles (opponens pollicis, flexor pollicis brevis and abductor pollicis brevis) are signs of severe median nerve injury [1] [2] [3]. The dominant hand is more frequently affected, but a bilateral presentation may be observed as well. [3] [4]. Apart from the carpal tunnel, the antecubital fossa is also an important site where median neuropathy can originate from, with most common causes being the injury during intravenous injection or cannulation, and trauma [4].

Pain
  • It may be a difficult diagnosis to make, as it often presents with arm pain that is diffuse and can present as radiating pain to the elbow or even pain radiating down further into the wrist or hand.[drlox.com]
  • The most common symptom is mild to moderate aching pain in the proximal forearm, sometimes described as tiredness and heaviness. Use of the arm may cause a mild or dull aching pain to become deep or sharp.[clinicalgate.com]
  • For more information on Pain Management Topics and keywords Go to PainExam.com David Rosenblum, MD specializes in Pain Management and is the Director of Pain Management at Maimonides Medical Center and AABP Pain Managment For evaluation and treatment[painexam.libsyn.com]
  • Spontaneous anterior interosseous nerve (AIN) palsy develops following the resolution of nerve pain, which may be considered as distal neuralgic amyotrophy. NA is assumed to have a complex etiology, but an autoimmune mechanism is likely involved.[ncbi.nlm.nih.gov]
  • The patients with ACTS initially had normal sensation and subsequently developed objective sensory loss (2-point discrimination greater than 15 mm) in the median nerve distribution associated with severe wrist pain.[ncbi.nlm.nih.gov]
Thenar Muscle Atrophy
  • Impairment of sensation in the distribution of the median nerve and thenar muscle atrophy may occur.[fpnotebook.com]
  • Physical examination showed bilateral thenar muscle atrophy and muscle weakness of the abductor pollicis brevis, which was more prominent in the left hand. Tendon reflexes were normal and symmetric.[thenerve.net]
Wrist Pain
  • The patients with ACTS initially had normal sensation and subsequently developed objective sensory loss (2-point discrimination greater than 15 mm) in the median nerve distribution associated with severe wrist pain.[ncbi.nlm.nih.gov]
  • There may be volar (anterior) hand and wrist pain, as well as referral into the proximal forearm, elbow, arm or shoulder.[practicalpainmanagement.com]
Peripheral Neuropathy
  • Routinely performed tests would have missed median neuropathy at wrist with concomitant peripheral neuropathy in 59 (37.3%) hands.[ncbi.nlm.nih.gov]
  • Focal peripheral neuropathy of the median nerve is mainly caused by a traumatic event or pressure, but it may also be produced by systemic illnesses. Among the latter, leprosy is a rare cause.[ncbi.nlm.nih.gov]
  • (HealthDay)—The prevalence of diabetic peripheral neuropathy (DPN) is 25.7 percent among youth with type 2 diabetes, and is significantly higher than that seen among youth with type 1 diabetes, according to a study published ...[medicalxpress.com]
  • Several differential diagnosis have to be considered: compression syndrome as well as iatrogenic damage of the median nerve due to the preliminary procedure or even concomitant disease can generate symptoms of peripheral neuropathy.[pesquisa.bvsalud.org]
Numbness of the Hand
  • Additionally, NCSs may be normal, but the needle EMG examination may demonstrate abnormalities that identify a more proximal nerve lesion that produces symptoms such as numbness in the hand and that may mimic CTS.”[aetna.com]

Workup

The diagnosis of a median neuropathy can be made successfully if all steps during workup are conducted properly, including a detailed patient history, a careful physical examination, and laboratory or imaging studies in the diagnosis is unclear. Firstly, information regarding the onset and severity of symptoms, as well as their location and duration, is of essential importance to the physician. The physical examination must include two tests - flexion of the wrist to 90 degrees for 1 minute, which could result in paresthesia (known as the Phalen's sign) and percussion of the nerve at the carpal tunnel (the onset of paresthesia indicates a positive Tinel's sign) [2] [3]. If these measures do not provide enough clinical evidence, additional investigations include electromyography, nerve conduction studies, magnetic resonance imaging (MRI) and high-resolution ultrasonography (HRUS), a useful adjunctive method for the diagnosis of median neuropathy, being inexpensive, non-invasive and readily available [2] [5]. Because diabetes mellitus is an important risk factor for carpal tunnel syndrome, blood glucose levels should be evaluated in all patients who present with signs and symptoms suggestive of this condition [1] [2].

Treatment

  • Corrective osteotomy without carpal tunnel release is a sufficient treatment for neuropathy in malunited distal radius fractures.[ncbi.nlm.nih.gov]
  • These measures improved with treatment of acromegaly in symptomatic patients; asymptomatic patients experienced no change or worsening.[ncbi.nlm.nih.gov]
  • Closed reduction and percutaneous pin fixation may be the optimal treatment for these patients.[ncbi.nlm.nih.gov]
  • Treatment of carpal tunnel syndrome [PDF] 12 September 2008 - Publisher: American Academy of Orthopaedic Surgeons Clinical guideline on the treatment of carpal tunnel syndrome.[evidence.nhs.uk]

Prognosis

  • In selected cases, nerve conduction studies at the onset of symptoms may provide insights into localization, mechanism, and prognosis. References Dhuner K: Nerve injuries following operations: A survey of cases occurring during a 6 year period.[anesthesiology.pubs.asahq.org]
  • […] mobilisation interventions for CTS. [ 13 ] There is only poor-quality evidence from very limited data to suggest that therapeutic ultrasound may be more effective than placebo for either short- or long-term symptom improvement in people with CTS. [ 14 ] Prognosis[patient.info]
  • The frequency of surgical failure in CTS patients was 3%, whereas it was reported to be more than 50% in patients with BMN.[ 14 , 22 , 23 ] Ultrasonographic examination of patients before carpal tunnel surgery may also be used to predict prognosis.[archivesofrheumatology.org]
  • They also note that bilateral carpel tunnel syndrome subsequent to cervical spine Double Crush is associated with a worse prognosis for clinical recovery.[chiro-trust.org]

Etiology

  • Contrary to earlier studies, this report demonstrates that GH-induced CTS is not an age-related phenomenon and alerts physicians to include GH abuse as a possible etiology of median neuropathy in athletes.[ncbi.nlm.nih.gov]
  • NA is assumed to have a complex etiology, but an autoimmune mechanism is likely involved. However, precise assessment of the lesion is challenging. We examined five consecutive patients with suspected spontaneous AIN palsy using ultrasonography.[ncbi.nlm.nih.gov]
  • Etiological and pathological findings favored the conception of this disorder as some type of localized rheumatic disease. Immobilization of the wrist by a splint and administration of hydrocortisone relieved the symptoms in many cases.[jamanetwork.com]
  • Conclusion A diagnostically challenging case of median neuropathy in the forearm is presented in which high-resolution ultrasound was valuable in establishing an anatomic etiology and directing appropriate management.[jbppni.biomedcentral.com]
  • […] slowing at the wrist w/o symptoms not CTS-common in polyneuropathy, not uncommon for patients with polyneuropathy to have slowing at entrapment sites w/o symptoms--diagnosis is median neuropathy at wrist superimposed on polyneuropathy w/o ED most common etiology[quizlet.com]

Epidemiology

  • Level of Evidence : Level III, prognostic study Keywords Perilunate dislocations Perilunate fracture-dislocations Epidemiology Median neuropathy Carpal tunnel release This is a preview of subscription content, log in to check access.[link.springer.com]
  • Higher values were blue-collar workers and lower-grade services, sales, and clerical white-collar workers. [13] Epidemiology Mortality/Morbidity CTS is associated with high costs to the Health Care system and society.[emedicine.medscape.com]
  • Adequate grip and elbow strength must be achieved before returning to pre-operative activity. [19] Epidemiology [ edit ] The number of discharges related to median nerve injuries decreased from 3,402 in 1993 to 2,737 in 2006.[en.wikipedia.org]
Sex distribution
Age distribution

Pathophysiology

  • Assessment of nerve conduction across the common entrapment sites could provide new insights into the pathophysiology of diabetic neuropathy related to metabolic factors.[ncbi.nlm.nih.gov]
  • The pathophysiology of this type of lesion is mainly mechanical: a repeated and prolonged compression may develop either directly by the contracting muscle itself or by fixation against more rigid osteoligamentous tissues; the movements performed by our[jnnp.bmj.com]
  • Pathophysiology The median nerve is formed by C5-C7 fibers from the lateral cord and C8-T1 fibers from the medial cord of the brachial plexus.[emedicine.medscape.com]
  • The pathophysiology is not completely understood but can be considered compression of the median nerve traveling through the carpal tunnel.[ocneurosurgery.com]

Prevention

  • All members of the Industrial Injuries and Prevention Committee of the American Society for Surgery of the Hand provided electrodiagnostic reports from their office practices indicating an electrodiagnosis of CTS or median neuropathy at the wrist.[ncbi.nlm.nih.gov]
  • A patient must receive treatment for hypothyroidism to prevent further bilateral median nerve neuropathy.[livestrong.com]
  • A focused neurophysiological approach is mandatory to reach the proper diagnosis and start specific treatment early enough to prevent possible irreversible hand function disabilities.[semanticscholar.org]
  • Preventive measures and diligent health care are required for this category of worker. Full text Full text is available as a scanned copy of the original print version.[ncbi.nlm.nih.gov]

References

Article

  1. Horinouchi S, Deguchi T, Arimura K, et al. Median neuropathy at the wrist as an early manifestation of diabetic neuropathy. J Diabetes Investig. 2014;5(6):709-713.
  2. Bland JDP. Carpal tunnel syndrome. BMJ. 2007;335(7615):343-346.
  3. Thatte MR, Mansukhani KA. Compressive neuropathy in the upper limb. Indian J Plast Surg. 2011;44(2):283-297.
  4. Melli G, Chaudhry V, Dorman T, Cornblath DR. Perioperative bilateral median neuropathy. Anesthesiology. 2002;97(6):1632-1634.
  5. Ginn SD, Cartwright MS, Chloros GD, et al. Ultrasound in the diagnosis of a median neuropathy in the forearm: case report. J Brachial Plex Peripher Nerve Inj. 2007;2:23.

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Last updated: 2018-06-22 07:08