MULTIFOCAL MOTOR NEUROPATHY

Abstract

Introduction. Multifocal motor neuropathy (MMN) is a chronic autoimmune, multiple neuropathy with an isolated lesion of motor fibers, the development of asymmetric distal paresis with a predominant involvement of the hands. The disease is rare: the prevalence of MMN in the world is from 0.6-2.0 per 100 000 people. The disease is diagnosed 3-4 times more often in men. Isolated cases of the development of the disease in children are described. Epidemiological studies on the prevalence of MMN among the adult population in the Republic of Azerbaijan have not been conducted. The aim of the study. To highlight the features of the differential diagnostic series for suspected multifocal motor neuropathy. Case presentation. Patient A., aged 29, was admitted to our clinic with complaints of slowly progressive muscle weakness, numbness, parasthesia. During the study, tendon reflexes in the upper and lower extremities were reduced. To clarify the diagnosis, an ENMG examination of the peripheral nerves of the upper and lower extremities was prescribed. A patient on ENMG of the tibial nerve has signs of demyelination (decrease in the speed of propagation of excitation (ERV) to 33.2 m/s). In this regard, to differentiate from other polyneuropathies, the patient underwent ultrasound of the tibial nerve throughout its entire length. At the same time, segmental expansion of the tibial nerve and a decrease in echogenicity with obliteration of the cable structure due to the predominance of the type 3 interstitial component are detected on the right – asymmetric local structural changes. On the left – an increase in echogenicity due to the predominance of thickening of the interstitial component with an erased cable structure, thinning of the fascicular component - an asymmetric local structural change. Based on the nature of the lesion, the patient was diagnosed with multifocal motor neuropathy. A comprehensive examination of the patient, including, along with traditional ENMG and ultrasound, nerves, made it possible to reduce the time for making a diagnosis and start pathogenetic treatment of the patient in a timely manner. Timely prescribed immunoglobulin therapy made it possible to avoid further deterioration of the patient's condition and the risk of his disability. Discussion. The combination of clinical signs that meet the criteria for the disease,developed by the recommendations of the European Federation of Neurological Societies /Society of Peripheral Nerves (EFNS / PNS, 2010) for the study of MMN, as well as the results of instrumental diagnostic studies (ENMG and ultrasound), makes the diagnosis of multifocal motor neuropathy indisputable. Conclusion. Multifocal motor neuropathy is classified as an acquired autoimmune demyelinating multiple neuropathy, accompanied by damage to the myelin sheath of neurons, which in turn causes a violation of the conduction of nerve impulses along the motor nerves from the brain to the muscles. MRI of the brachial plexus (magnetic induction value > 1 T, imaging in standard T1 and T2 modes, as well as in STIR and DTI modes) without contrast agent injection is recommended for those patients with suspected MMN in whom ENMG results do not fully correspond to electrophysiological results MMN criteria (EFNS/PNS, 2010), in order to improve the reliability of the diagnosis. In the presented case, the patient's complaints were due to neurological symptoms. Despite the rarity of the disease and even rarer cases of damage to the nervous system (3-4 times more often in men), a neurologist should be wary of MMN, which contributes to timely diagnosis and the appointment of pathogenetic therapy.