Medicine:Multifocal motor neuropathy
| Multifocal motor neuropathy | |
|---|---|
| Other names | Multifocal motor neuropathy with conduction block |
| Specialty | Neurology |
Multifocal motor neuropathy (MMN) is a progressively worsening condition where muscles in the extremities gradually weaken. The disorder, a pure motor neuropathy syndrome, is sometimes mistaken for amyotrophic lateral sclerosis (ALS) because of the similarity in the clinical picture, especially if muscle fasciculations are present. MMN is thought to be autoimmune. It was first described in the mid-1980s.[1]
Unlike ALS, which affects both upper and lower motor neuron pathways, MMN involves only the lower motor neuron pathway, specifically, the peripheral nerves emanating from the lower motor neurons. Definitive diagnosis is often difficult, and many MMN patients labor for months or years under an ALS diagnosis before finally getting a determination of MMN.
MMN usually involves very little pain; however, muscle cramps, spasms and twitches can cause pain for some people. MMN is not fatal, and does not diminish life expectancy. Many patients, once undergoing treatment, only experience mild symptoms over prolonged periods, though the condition remains slowly progressive. MMN can however, lead to significant disability, with loss of function in hands affecting ability to work and perform everyday tasks, and "foot drop" leading to inability to stand and walk; some patients end up using aids like canes, splints and walkers.
Symptoms
Wrist drop and foot drop (leading to trips and falls) are common symptoms. Other effects can include gradual loss of finger extension, leading to a clawlike appearance. Cold & hot temperatures exacerbate MMN symptoms to such an extent, unlike other neuropathies, that this temperature response is being investigated as a diagnostic tool.[2]
Cause
Diagnosis
Treatment
Multifocal motor neuropathy is normally treated by receiving intravenous immunoglobulin (IVIG), which can in many cases be highly effective, or immunosuppressive therapy with cyclophosphamide or rituximab. Steroid treatment (prednisone) and plasmapheresis are no longer considered to be useful treatments(not usually some pt highly recommended);[3] prednisone can exacerbate symptoms. IVIg is the primary treatment, with about 80% of patients responding, usually requiring regular infusions at intervals of 1 week to several months. Other treatments are considered in case of lack of response to IVIg, or sometimes because of the high cost of immunoglobulin. Subcutaneous immunoglobulin is under study as a less invasive, more-convenient alternative to IV delivery.[4]
Ongoing specialist community support, information, advice, and guidance is available from a range of Charities, Non-Government Organisations (NGOs), and Patient Advisory Groups around the world. In the United Kingdom this is provided by Inflammatory Neuropathies UK,[5] in the USA it is provided by GBS/CIDP Foundation International,[6] and in The European Union by a range of organisations under the umbrella of EPODIN (European Patient Organization for Disimmune & Inflammatory Neuropathies)[7]
References
- ↑ Roth, G; Rohr J; Magistris MR; Ochsner F (1986). "Motor neuropathy with proximal multifocal persistent conduction block, fasciculations and myokymia. Evolution to tetraplegia.". Eur Neurol 25 (6): 416–423. doi:10.1159/000116045. PMID 3024989.
- ↑ "Cold paresis in multifocal motor neuropathy". J Neurol 258 (2): 212–217. February 2011. doi:10.1007/s00415-010-5712-3. PMID 20803025.
- ↑ Chaudhry, V (2004). "Multifocal motor neuropathy: response to human immune globulin.". Annals of Neurology 33 (3): 237–42. doi:10.1002/ana.410330303. PMID 8498806.
- ↑ "Subcutaneous versus intravenous immunoglobulin in multifocal motor neuropathy: a randomized, single-blinded cross-over trial". Eur. J. Neurol. 16 (5): 631–8. 2009. doi:10.1111/j.1468-1331.2009.02568.x. PMID 19236457.
- ↑ "Inflammatory Neuropathies UK" (in en-GB). https://inflammatoryneuropathies.uk.
- ↑ "Home" (in en-US). https://www.gbs-cidp.org/.
- ↑ "Epodin" (in en-US). https://www.epodin.org/.
External links
| Classification | |
|---|---|
| External resources |
- Overview of MMN at National Institute of Neurological Disorders and Stroke
- Information on MMN from UK Charity GAIN (Guillain–Barré and Associated Inflammatory Neuropathies)
- Information on MMN from NGO GBS/CIDP Foundation International
- Information on MMN from NGO EPODIN (European Patient Organization for Disimmune & Inflammatory Neuropathies)
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