Misplaced Pages

#378621

40-479: 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

80-412: A "lesion" at some point along the nerve. For example, if the nerve is blocked in the forearm, an electrical impulse can easily get from the wrist to the hand if the stimulus is placed at the wrist. However, the signal will be blocked from reaching the hand if the stimulus is applied at the elbow. In MMN, sensory conduction along the same path should be normal. The EMG portion of the test looks for signals in

120-454: 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. MMN is thought to be caused by alterations in the immune system, such that certain proteins (antibodies) that would normally protect one from viruses and bacteria begin to attack constituents of peripheral nerves. Antibodies may be directed against "GM-1",

160-427: A clear liquid called blood plasma , is initially taken out of the body through a needle or previously implanted catheter . Plasma is then removed from the blood by a cell separator. Three procedures are commonly used to separate the plasma from the blood cells, with each method having its own advantages and disadvantages: After plasma separation, the blood cells are returned to the person undergoing treatment, while

200-475: A ganglioside found at the Nodes of Ranvier . These antibodies have been detected in at least one-third of MMN patients. More recent studies also suggest that newer tests for antibodies directed against GM-1, as well as a number of related gangliosides, are positive in over 80% of MMN patients. There are increasing reasons to believe these antibodies are the cause of MMN. The diagnosis of MMN depends on demonstrating that

240-696: A larger quantity of plasma when compared to the conventional method of whole blood donation. The results of the study were presented at the 4th International Congress of Blood Transfusion in Lisbon (1951), and were published in 1952 in the British Medical Journal and Medicina Clínica in Spain. At the Lisbon congress, Grifols-Lucas met Edwin Cohn . While Grifols-Lucas was presenting a safe technique for obtaining large quantities of plasma from healthy donors, Cohn presented

280-461: A liter of plasma at a time and can donate with only a few days between donations, unlike the 56-day deferral for blood donation. The amount allowed in a donation varies vastly from country to country, but generally does not exceed two donations, each as much as a liter (one-third of the total plasma volume), per seven-day period. If a significant amount of red blood cells cannot be returned, the donor may not donate for 56 days, just as if they had donated

320-403: A mixture of these. Other uses are the removal of blood proteins where these are overly abundant and cause hyperviscosity syndrome . There is weak evidence that therapeutic plasma exchange (TPE) might be of benefit in severe cases of COVID-19 . Though plasmapheresis is helpful in certain medical conditions, like any other therapy, there are potential risks and complications. Insertion of

360-518: A muscle), and an extensor plantar response known as the Babinski sign . Plasmapheresis Plasmapheresis (from the Greek πλάσμα, plasma , something molded, and ἀφαίρεσις aphairesis , taking away) is the removal, treatment, and return or exchange of blood plasma or components thereof from and to the blood circulation . It is thus an extracorporeal therapy , a medical procedure performed outside

400-621: A patient has a purely motor disorder affecting individual nerves, that there are no upper motor neuron (UMN) signs, that there are no sensory deficits, and that there is evidence of conduction block. These criteria are designed to differentiate the disorder from ALS (purely motor but with UMN signs), the Lewis-Sumner Syndrome variant of Chronic inflammatory demyelinating polyneuropathy (CIDP) (similar to MMN but usually with significant sensory loss), and " vasculitis " (a type of multiple mononeuropathy syndrome caused by inflammatory damage to

440-543: A plasma fractionator, a device that separated out the proteins contained in plasma. These two major contributions marked the birth of a new industry: plasma fractionation to obtain plasma products. In 1955, further data were presented at the 5th Congress of the European Hematology Society, in Freiburg, Germany, based on the ongoing performance of plasmapheresis over a five-year period. In 1956 Grifols-Lucas presented

SECTION 10

#1732844246379

480-445: A rather large intravenous catheter can lead to bleeding, lung puncture (depending on the site of catheter insertion), and, if the catheter is left in too long, it can get infected. Aside from placing the catheter, the procedure itself has complications. When patient blood is outside of the body passing through the plasmapheresis machine, the blood has a tendency to clot. To reduce this tendency, in one common protocol, sodium citrate

520-439: A unit of blood. Depending on the collection system and the operation, the removed plasma may be replaced by saline . The body typically replaces the collected volume within 24 hours, and donors typically donate up to twice a week, though this varies by country. The collected plasma is promptly frozen at lower than -20 °C (-4 °F) and is typically shipped to a processing facility for fractionation. This process separates

560-412: Is characterized by weakness, muscle atrophy, cramping, and often profuse fasciculations (muscle twitching). The symptoms are progressive over long periods, often in a stepwise fashion, but unlike ALS are often treatable. Sensory nerves are usually unaffected. Wrist drop and foot drop (leading to trips and falls) are common symptoms. Other effects can include gradual loss of finger extension, leading to

600-460: Is collected solely for further manufacturing is called Source Plasma. Plasma donors undergo a screening process to ensure both the donor's safety and the safety of the collected product. Factors monitored include blood pressure , pulse , temperature, total protein, protein electrophoresis , health history screening similar to that for whole blood, as well as an annual physical exam with a licensed physician or an approved physician substitute under

640-462: Is infused while the blood is running through the circuit. Citrate binds to calcium in the blood, calcium being essential for blood to clot. Citrate is very effective in preventing blood from clotting; however, its use can lead to life-threateningly low calcium levels. This can be detected using the Chvostek's sign or Trousseau's sign . To prevent this complication, calcium is infused intravenously while

680-608: 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); 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

720-498: 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. Usually beginning in one or both hands, MMN

760-541: Is used as a therapy in particular diseases . It is an uncommon treatment in the United States, but it is more common in Europe and particularly Japan. An important use of plasmapheresis is in the therapy of autoimmune disorders , where the rapid removal of disease-causing autoantibodies from the circulation is required in addition to other medical therapy. It is important to note that plasma exchange therapy in and of itself

800-448: Is useful to temper the disease process, while simultaneous medical and immunosuppressive therapy is required for long-term management. Plasma exchange offers the quickest short-term answer to removing harmful autoantibodies; however, the production of autoantibodies by the immune system must also be suppressed, usually by the use of medications such as cyclophosphamide , cyclosporine , mycophenolate mofetil , prednisone , rituximab , or

840-611: The U.S. Food and Drug Administration (FDA), the European Union , and by a professional organization, the Plasma Protein Therapeutics Association (or PPTA), which audits and accredits collection facilities. A National Donor Deferral Registry (NDDR) is also maintained by the PPTA for use in keeping donors with prior positive viral antibody test results from donating at any facility. Almost all plasmapheresis in

SECTION 20

#1732844246379

880-660: The USA it is provided by GBS/CIDP Foundation International, and in The European Union by a range of organisations under the umbrella of EPODIN (European Patient Organization for Disimmune & Inflammatory Neuropathies) Upper motor neuron Upper motor neurons ( UMNs ) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons , which in turn directly signal muscles to contract or relax. UMNs represent

920-406: The lower motor neurons . The neurotransmitter glutamate transmits the nerve impulses from upper to lower motor neurons, where it is detected by glutamate receptors . Upper motor neurons travel in several neural pathways through the central nervous system (CNS): Any upper motor neuron lesion , also known as pyramidal insufficiency, occurs in the neural pathway above the anterior horn of

960-552: The major origin point for voluntary somatic movement. Upper motor neurons represent the largest pyramidal cells in the motor regions of the cerebral cortex. The major cell type of the UMNs is the Betz cells residing in layer V of the primary motor cortex , located on the precentral gyrus in the posterior frontal lobe. The cell bodies of Betz cell neurons are the largest in the brain, approaching nearly 0.1 mm in diameter . The axons of

1000-453: The US is performed by automated methods. In some cases, automated plasmapheresis is used to collect plasma products like fresh frozen plasma for direct transfusion purposes, often at the same time as plateletpheresis . These procedures are performed at facilities such as community blood centers . Since returning red cells causes the body to replace plasma more rapidly, a donor can provide up to

1040-421: The application of plasmapheresis in a series of plasma donors. Performed in 1951, this was the most exhaustive study to date of the medium-term effects on the human body, and involved more than 320 plasmapheresis procedures. Grifols-Lucas concluded that it was possible for donors to undergo plasmapheresis on a weekly basis without the quality of their plasma suffering, while the method also made it possible to obtain

1080-433: The blood vessels in nerves that also causes sensory and motor symptoms). A neurologist is usually needed to determine the diagnosis, which is based on the history and physical examination along with the electrodiagnostic study, which includes nerve conduction studies (NCS) and needle electromyography (EMG). The NCS usually demonstrate conduction block. This can be done by showing that the nerve signal cannot conduct past

1120-414: The body. Three general types of plasmapheresis can be distinguished: Plasmapheresis of the autologous and exchange types is used to treat a variety of disorders, including those of the immune system , such as Goodpasture's syndrome , Guillain–Barré syndrome , lupus , myasthenia gravis , and thrombotic thrombocytopenic purpura . During plasmapheresis, blood , which consists of blood cells and

1160-684: The collected plasma into specific components, such as albumin and immunoglobulins , most of which are made into medications for human use. Sometimes the plasma is thawed and transfused as Fresh Frozen Plasma (FFP), much like the plasma from a normal blood donation. Plasmapheresis was originally described by doctors Vadim A. Yurevick and Nicolay Rosenberg of the Imperial Medical and Surgical Academy of Saint Petersburg in 1913. and John Abel and Leonard Rowntree of Johns Hopkins Hospital in 1914. Both studies carried out on animals, are considered precedent to subsequent studies held in humans and offered

1200-469: The collected plasma is used for injectable products. The plasma is also treated in processing multiple times to inactivate any virus that was undetected during the screening process. In a few countries, plasma (like blood) is donated by unpaid volunteers. In others, including the United States, Austria, Germany and some Canadian facilities plasma donors are paid for their donations. Standards for donating plasma are set by national regulatory agencies such as

1240-449: The first description of the technique. The first studies of the effects of plasmapheresis on humans were undertaken during the WWII period, and the results were reported in a study over six plasma donors presented by doctors Co Tui, F.C. Bartter and A.M. Wright in 1944. Aware of the rising demand for plasma for transfusion, Dr. Josep Antoni Grífols-Lucas conducted the first systematic study of

Multifocal motor neuropathy - Misplaced Pages Continue

1280-507: The high cost of immunoglobulin. Subcutaneous immunoglobulin is under study as a less invasive, more-convenient alternative to IV delivery. 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 GAIN (Guillain–Barré and Associated Inflammatory Neuropathies), in

1320-418: The patient is undergoing the plasmapheresis; in addition, calcium supplementation by mouth may also be given. Other complications include: Donating plasma is similar in many ways to whole blood donation , though the end product is used for different purposes. Most plasmapheresis is for fractionation into other products; other blood donations are transfused with relatively minor modifications. Plasma that

1360-431: The plasma, which contains the antibodies , is first treated and then returned to the patient in traditional plasmapheresis. Rarely, other replacement fluids, such as hydroxyethyl starch , may be used in individuals who object to blood transfusion but these are rarely used due to severe side-effects. Medication to keep the blood from clotting (an anticoagulant ) is given to the patient during the procedure. Plasmapheresis

1400-912: The results at the 6th Congress of the International Hematology Society in Boston, US. Michael Rubinstein was the first to use plasmapheresis to treat an immune-related disorder when he saved the life of an adolescent boy with thrombotic thrombocytopenic purpura (TTP) at the Cedars of Lebanon Hospital in Los Angeles in 1959. The modern plasmapheresis process itself originated in the U.S. National Cancer Institute between 1963 and 1968, where investigators drew upon an old dairy creamer separation technology first used in 1878 and refined by Edwin Cohn 's centrifuge marketed in 1953. In 1965, Dr. Víctor Grifols-Lucas, brother of Josep Antoni Grifols-Lucas, patented

1440-554: The spinal cord . Such lesions can arise as a result of stroke , multiple sclerosis , spinal cord injury or other acquired brain injury . The resulting changes in muscle performance that can be wide and varied are described overall as upper motor neuron syndrome . Symptoms can include muscle weakness , decreased motor control including a loss of the ability to perform fine movements , increased vigor (and decreased threshold) of spinal reflexes including spasticity , clonus (involuntary, successive cycles of contraction/relaxation of

1480-414: The spinal cord to the level of the appropriate spinal nerve root. At this point, the upper motor neuron synapses with the lower motor neuron or interneurons within the ventral horn of the spinal cord , each of whose axons innervate a fiber of skeletal muscle. These neurons connect the brain to the appropriate level in the spinal cord, from which point nerve signals continue to the muscles by means of

1520-564: The supervision of the physician. Donors are screened at each donation for viral diseases that can be transmitted by blood, sometimes by multiple methods. For example, donations are tested for HIV by ELISA , which shows if they have been exposed to the disease, as well as by nucleic acid methods ( PCR or similar) to rule out recent infections that the ELISA test might miss and are also screened for hepatitis B and hepatitis C . Industry standards require at least two sets of negative test results before

1560-410: The upper motor neurons project out of the precentral gyrus travelling through to the brainstem, where they will decussate (intersect) within the lower medulla oblongata to form the lateral corticospinal tract on each side of the spinal cord . The fibers that do not decussate will pass through the medulla and continue on to form the anterior corticospinal tracts. The upper motor neuron descends in

1600-443: The way muscles fire. In MMN it will most likely reveal abnormalities suggesting that some percentage of the motor axons has been damaged. Laboratory testing for GM1 antibodies is frequently done, and can be very helpful if they are abnormal. However, since only a third of patients with MMN have these antibodies, a negative test does not rule out the disorder. Spinal fluid examination is not usually helpful. Multifocal motor neuropathy

#378621