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Introduction:

This case study will examine a patient with a rare and disabling movement disorder. The primary objective of this essay seeks to criti-cally analyse and discuss the neuroscience nursing care and interventions of multifocal motor neuropathy. Firstly, the patients’ clinical presentation, past medical history and the underlying pathophysiology of multifocal mo-tor neuropathy will be comprehensively ex-plored and the epidemiology, etiology and the patients’ risk factors will be identified. Sec-ondly, relevant diagnostic investigations will be examined with the goal of identifying the interrelationship between the patient’s health background and risk factors. Lastly, the nurs-ing management and treatment for the patient will be discussed with a holistic approach, taking into consideration the social, ethical and psychological effects of the disorder.

The key aspects that will be discussed in this paper will be addressed with the utmost im-portance placed on maintaining patient confi-dentiality.

Case Study:

A 65-year-old female, who will be referred to as Mrs Smith, was admitted to the ward with a history of multifocal motor neuropathy first diagnosed in 2010 after experiencing left hand wasting. A nerve conduction study this admission revealed motor block. She had a history of hypertension and a previous hip

replacement, otherwise the patient was gen-erally well. The patient’s current symptoms included limited use of both hands/fingers due to significant weakness, pain in hands, ulnar muscle wastage and bilateral foot drop. The patient had been receiving a mainte-nance dose 22.5g intravenous immunoglobu-lin (IVIg) every 4 weeks with a loading dose of 120mg once a year. The current admission on the ward was for a five-day course of 120mg of IVIg.

Multifocal motor neuropathy (MMN) is a slow, progressive motor disorder in which the de-myelination of motor axons occurs (Nowacek & Teener, 2012). The likely etiology of MMN is an autoimmune attack on the motor nerves (Lawson & Arnold, 2014). MMN is an ac-quired disorder that is associated with elevat-ed levels of antibodies to ganglioside GM1 (anti-GM1) and immunoglobulin M (IgM) anti-bodies (Léger, Guimarães-Costa & Iancu Fer-foglia, 2015). Studies reveal the link between the presence of IgM anti-GM1 antibodies in approximately 50% of MMN patients (Vlam et al. 2015; Lawson & Arnold, 2014)

Abstract

Multifocal motor neuropathy is a rare and chronic movement disorder associated with the progres-sive weakening of the patient’s limbs. This case study examines the clinical presentation, findings, treatment, and outcome of a female patient treated with intravenous immunoglobulin therapy. The case study illustrates the important role the neuroscience nurse plays in the care and treatment of a patient with a complex disorder.

Keywords: multifocal motor neuropathy, movement disorders, intravenous immunoglobin.

Questions or comments about this article should be directed to Madeline Bone Email address: madelinebone96@gmail.com

DOI: 10.21307/ajon-2017-011

Copyright © 2018ANNA

Multifocal Motor Neuropathy: A clinical case study

Madeline A Bone 1.

1Bachelor of Nursing Student, University of Tasmania

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GM1 is found universally in the body, howev-er is most abundant in peripheral motor nerves (Lawson & Arnold, 2014). GM1 is re-sponsible for numerous functions including paranodal stabilisation and ion channel clus-tering (Lawson & Arnold, 2014). Disruptions to these functions results in conduction fail-ure across the paranodal regions causing a cascading effect on the action potential prop-agation and leading to conduction failure in the peripheral nerves (Lawson & Arnold, 2014). The abundance of GM1 is found in the myelin of motor nerves compared to the sen-sory nerves, which may provide insight into why MMN does not affect sensory nerve function (Lawson & Arnold, 2014). The pro-gressive nature of the disorder is due to auto-antibodies binding to GM1 gangliosides, acti-vating the classical complement system path-way and causing nerve damage by initiating the complement membrane attack complex within the peripheral nerves (Yuki, Watanabe, Nakajima & Spath, 2010).

MMN is a chronic disorder that tends to mim-ic the more fatal form of movement disorders, motor neuron disease (Lawson & Arnold, 2014). A recent study revealed one third of patients are given an initial diagnosis of mo-tor neuron disease (MND), with further test-ing eventually ruling MND out (Dimachkie, Barohn & Katz, 2013). MMN is considered a benign disease, however the functional im-pairment can have a serious effect on the patient’s quality of life (Cats et al. 2010). The prevalence of MMN is estimated to affect 1-2 in 100,000 individuals (Meuth & Kleinschnitz, 2010). A study has revealed the mean age for onset of symptoms is approximately 40 years old. (Meuth & Kleinschnitz, 2010). As in Mrs Smith’s case, the upper extremities are usually the first to be affected and most often the presenting symptom (Latov, 2014). The nerves that are most commonly affected are the ulnar, median and radial nerves, with pa-tients presenting with difficulty extending the fingers and wrist and a reduced hand grip (Lawson & Arnold, 2014). This is in line with Mrs Smith’s initial symptoms. The patient currently has restricted movement in both hands as well as weakness in her arms and lower limbs. MMN causes muscle atrophy which is relatively mild in the early stages of the disease and worsens as the disease pro-gresses (Berger, McCallus & Lin, 2013). The specific cause of this disorder is still not known. A known risk factor is gender, with

men being twice as likely to develop the dis-order than women (Sutedja, 2010). Mrs Smith does not have any past history or risk factors that would indicate that she would be at risk of developing the disorder.

To correctly diagnose Mrs Smith, she under-went nerve conduction studies. Nerve con-duction studies are considered the gold standard, as the test can identify multifocal partial conduction blocks (Meuth & Klein-schnitz, 2010). Motor conduction blocks are defined as a decrease of action potentials recorded from a specific or group of muscles subsequent to proximal nerve stimulation as compared with distal nerve stimulation (Lawson & Arnold, 2014). MMN affects the multifocal partial conduction blocks on motor nerves, but not sensory nerves, which is why MMN affects the movement of the limbs but has no sensory impairment (Yuki, Watanabe, Nakajima & Spath, 2010). An international study has revealed 80% of MMN patients have conduction blocks detected in the ulnar nerves and 77% detected in median nerves (Cats et al. 2010). Mrs Smith underwent fur-ther diagnostic imaging including a computed tomography scan (CT) of the brain and com-prehensive blood tests which showed no evi-dence of disease. However, the nerve con-duction study revealed a motor block in the ulnar and median nerves which confirmed the diagnosis of MMN.

Mrs Smith had managed the disorder for nearly a decade with effective treatment op-tions allowing her to maintain independence. The treatment Mrs Smith had been receiving for the past 6 years was intravenous immu-noglobulin therapy (IVIg). MMN has no known cure, however therapies, such as im-munoglobulin therapy, aim to reduce motor deficits, slow down ongoing axonal degener-ation and promote remyelination (Léger, Guimarães-Costa & Iancu Ferfoglia, 2015). IVIg is a solution manufactured from human plasma protein (Australian Red Cross, 2018). It contains typical IgG antibodies with a broad spectrum of antibody activity and is used to treat patients requiring antibody replacement as well as autoimmune, hematological and neurological disorders (Australian Red Cross, 2018). The mechanism of action of IVIg is not fully understood, however it is thought the antibodies work against the mechanisms of the classical complement pathway in order to

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prevent the membrane attack (Stangel et al. 2016). IVIg neutralises pathogenic antibod-ies, inhibits antibody production by B cells and suppresses inflammatory mediators pro-duced by T cells (Léger, Guimarães-Costa & Iancu Ferfoglia, 2015). Several studies prove that IVIg has a beneficial long-term effect on muscle strength, however it is not able to pre-vent a small decrease in muscle strength and increase of axon loss as the disorder pro-gresses (Nobile-Orazio & Gallia, 2013; Léger et al. 2008). A retrospective study of 40 pa-tients with MMN found that 68% of patients were dependent on long-term maintenance IVIg infusions to stabilise their motor condi-tion (Léger, Guimarães-Costa & Iancu Fer-foglia, 2015). Most patients will become less responsive to IVIg therapy over time and will therefore require higher and more frequent doses to achieve the result (Lawson & Ar-nold, 2014). Similarly, another study revealed that patients who did not receive IVIg treat-ment suffered more severe weakness and had further progression of axon loss in com-parison to those patients who received IVIg treatment (Jovanovich & Karam, 2015).

The effectiveness of IVIg treatment is de-pendent on how soon after diagnosis treat-ment is commenced. A recent international study found that 94% of the 88 MMN pa-tients’ examined responded positively to IVIg treatments (Jovanovich & Karam, 2015). The 6% of MMN patients who did not respond to the treatment had been diagnosed with the disorder later and their symptoms had be-come advanced (Jovanovich & Karam, 2015). Furthermore, the dosage strength and frequency of infusions plays a significant role in the effectiveness of treatment (Léger et al. 2008).

Mrs Smith was admitted to the ward for a dose of 120g IVIg over five days. The Clinical use of Intravenous Immunoglobulin in Aus-tralia Guidelines recommend IVIg be given initially at a 2g/kg dosage over two to five days (Australia Red Cross, 2018). This ratio accurately correlates with Mrs Smiths’ weight and the prescribed dose of 120g of IVIg. A loading dose is common practice among practitioners internationally and is then followed by maintenance doses of 0.4-1g/kg every two to four weeks (Australia Red Cross, 2018; Schaika et al. 2006). Mrs Smith had been receiving maintenance doses of

22.5g IVIg every four weeks, however in the last few months she had reported her symp-toms becoming more severe. In response, her IVIg dose was increased to 24.5g.

As a registered nurse, working within the neuroscience department, progressive motor disorders are not uncommon and the regis-tered nurse needs to be able to provide the highest quality of care for these patients. It is important the neuroscience nurse under-stands the pathophysiology behind the disor-der, as well as the correct administration of IVIg. IVIg must be given under strict proto-cols, ensuring the six patient rights are com-pleted with two nurses and cross checks of the product, dose and rate. Reactions to IVIg are most likely to occur within the first hour of the infusion, therefore the patient must be closely monitored and the patient’s vital signs checked regularly (Australian Red Cross, 2018). Common adverse reactions the neuro-science nurse must be aware of include headaches, chills or fever, nausea and vomit-ing. Mild allergic reactions may occur such as skin rash and mild changes to heart rate or blood pressure. The neuroscience nurse must be aware of severe reactions that may occur during transfusion such as; anaphylax-is, haemolysis, thromboembolic events or aseptic meningitis (Hahn et al. 2013). IVIg can have a negative effect of the patient’s renal function, therefore Mrs Smiths’ renal function should have been checked prior to commencing the infusion and continued to be monitored over the course of five days (Lawson & Arnold, 2014).

Along with closely monitoring the patient’s vital signs during and after the IVIg infusion; the role of the neuroscience nurse is to accu-rately monitor upper and lower limb strength, movement and sensation. The neuroscience nurse must also help with mobility and meal assistance. It is the role of the neuroscience nurse caring for a patient with MMN to advo-cate for that patient and provide a multidisci-plinary approach to care, involving the physi-otherapist and a social worker or discharge planner if the patient is struggling to manage with their disability. Mrs Smith lived alone and was mobilising with a four-wheel walker. An occupational therapist offered to assess her living conditions to implement further aids within the house, however she declined the services. Patients with MMN are faced with

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not only the physical challenges that are at-tributed to the disorder, but the psychological and social effects can negatively affect the patient’s quality of life. In 2016, a large inter-national study revealed 75% of MMN pa-tient’s felt exhausted and left with no energy to complete day time tasks, as well as 59% stating they were embarrassed by their limita-tions (Katz, Lewis & Spatafora, 2017).

Reflection:

Caring for patients such as Mrs Smith allows for improved clinical skills and an in depth knowledge of IVIg infusions, which will bene-fit future patients and provide fellow col-leagues with a resource of information re-garding the expected benefits, risks and nursing interventions that are associated with IVIg infusions.

Conclusion:

MMN is a rare disorder that purely effects motor function. However, due to the disabling and incurable nature of the condition, pa-tients may struggle with emotional and psy-chological issues. The correlation between MMN risk factors and Mrs Smith’s medical history was weak, with the patient’s age be-ing the only known risk factor for her develop-ing the disorder. There is strong evidence to suggest that early treatment of MMN is the most important factor in long term functional outcome. Fortunately, Mrs Smith was treated early and has been responding well to IVIg treatment.

Acknowledgement

The author acknowledges the generosity of ‘Mrs Smith’ in providing permission to write this case study.

Conflict of interest

The author declares no conflicts of interest.

References:

Australian Red Cross (2018) ‘Criteria for the clinical use of intravenous immunoglobulin in Australia’, Australian Red Cross, viewed 3

August 2018, https://transfusion.com.au/blood_products/fractionated_plasma/ivig.

Berger, M., McCallus, D & Lin, C. (2013). ‘Rapid and reversible responses to IVIG in autoimmune neuromuscular diseases sug-gest mechanisms of action involving competi-tion with functionally important autoantibod-ies’, Journal of the Peripheral Nervous Sys-tem, Vol. 18, pp.275-296.

Cats, E., van der Pol, W., Piepers, S., Franssen, H., Jacobs, B., van den Berg-Vos, R., Kuks, J., van Doorn, P., van Engelen, B., Verschuuren, J., Wokke, J., Veldink, J & van den Berg, L. (2010). ‘Correlates of outcome and response to IVIg in 88 patients with mul-tifocal motor neuropathy’, American Academy of Neurology, Vol. 75, pp.818-825.

Dimachkie, M., Barohn, J & Katz, J. (2013). ‘Multifocal Motor Neuropathy, Multifocal Ac-quired Demyelinating Sensory and Motor Neuropathy and Other Chronic Acquired De-myelinating Polyneuropathy Vari-ants’, Neurologic Clinics, Vol. 31, No. 2: pp.533–555.

Hahn, A., Beydoun, S., Lawson, V., Oh, M., Empson, V., Leibl, H., Ngo, Y., Gelmont, D & Koski, C. (2013). ‘A controlled trial of intrave-nous immunoglobulin in multifocal motor neu-ropathy’, Journal of peripheral nervous sys-tem, Vol. 18, No. 4: pp.321-330.

Jovanovich, E & Karam, C. (2015). ‘Human immune globulin infusion in the management of multifocal motor neuropathy’, Degenerative Neurological and Neuromuscular Disease, Vol. 2016, No. 6: pp.1-12.

Katz, J., Lewis, R & Spatafora, D. (2017). ‘First Global Multifocal Motor Neuropathy (MMN) Quality of Life (QOL) Patient Survey Identifies Needs in Education and Treat-ment’, Neurology, Vol. 13, No. 16: pp. 1-15.

Latov, N. (2014). ‘Diagnosis and treatment of chronic acquired demyelinating polyneuropa-thies’, NEUROLOGY, Vol. 10, pp.435-442.

Lawson, V & Arnold, W. (2014). ‘Multifocal motor neuropathy: a review of pathogenesis, diagnosis, and treatment’, Neuropsychiatric Disease and Treatment, Vol. 10, pp.567-576.

Léger, J., Guimarães-Costa, R & Iancu Fer-foglia, R. (2015). ‘The pathogenesis of multi-focal motor neuropathy and an update on current management options’, Therapeutic Advances in Neurological Disorders, Vol. 8, No .3: pp.109-122.

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Léger, J., Viala, K., Cancalon, F., Maisonobe, T., Gruwez, B., Waegemans, T & Bouche, P. (2008). ‘Intravenous immunoglobulin as short- and long-term therapy of multifocal motor neuropathy: a retrospective study of re-sponse to IVIg and of its predictive criteria in 40 patients’, Journal of Neurology Neurosur-gery Psychiatry, Vol. 79, pp.93-96.

Meuth, S & Kleinschnitz, C. (2010). ‘Multifocal Motor Neuropathy: Update on Clinical Characteristics, Pathophysiological Concepts and Therapeutic Options’, Europe-an Neurology, Vol. 63, pp.193-204.

Nobile-Orazio, E & Gallia, F. (2013). ‘Multifocal Motor Neuropathy: Current Thera-pies and Novel Strategies’, Drugs, Vol. 73, No. 5: pp.397-406.

Nowacek, D & Teener, J. (2012). ‘Multifocal Motor Neuropathy’, Seminars in Neurology, Vol. 32, pp.500-505.

Schaika, I., Boucheb, P., Illac, I., Le´gerb, J., Van den Berghd, P., Cornblathe, D., Eversf, E., Haddeng, R., Hughesh, R., Koskii, C., Nobile-Orazioj, E., Pollardk, J., Sommerl, C & van Doorn, P. (2006). ‘European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of multifo-cal motor neuropathy’, European Journal of Neurology, Vol. 13, pp.802-808.

Stangel, M., Gold, R., Pittrow, D., Baumann, U., Borte, M., Fasshauer, M., Hensel, M., Huscher, D., Reiser, M & Sommer, C. (2016). ‘Treatment of patients with multifocal motor neuropathy with immunoglobulins in clinical

practice: the SIGNS registry’, Therapeutic Advances in Neurological Disorders, Vol. 9, No. 3: pp.165–179.

Sutedja, N. (2010). ‘Risk factors for motor neuron diseases, genes, environment and lifestyle’, Utrecht University, Rotterdam, The Netherlands.

Vlam, L., Stam, M., Jager, W., Cats, E., van den Berg, L & van der Pol, W. (2015). ‘Cytokine profiles in multifocal motor neurop-athy and progressive muscular atrophy’, Journal of Neuroimmunology, Vol. 286, pp.1-4.

Yuki, N., Watanabe, H., Nakajima, T & Spath, P. (2010). ‘IVIG blocks complement deposi-tion mediated by anti-GM1 antibodies in mul-tifocal motor neuropathy’, Journal of Neurolo-gy Neurosurgery Psychiatry, Vol. 82, pp.87-91