A 60-year-old man with isaacs mertens-syndrome a rare entity

G Tharani,G Yuvarani,K Kamatchi

doi:10.3329/bjms.v20i3.52819

Abstract

Isaacs-mertens syndrome also known as neuromyotonia is a rare neuromuscular disorder caused by hyperexcitability and continuous firing of axons of the nerve that innervate the muscle fibers. It is an immune-mediated disorder with elevated antibody level against voltage gated potassium channels (VGKC). Symptoms include progressive muscle weakness, continuously twitching muscles (myokymia), cramping, increased sweating and delayed muscle relaxation. This is a case report of a 60-year-old man who presented with pain and weakness of right lower limb for 3 months, which gradually became worse to involve both the lower and upper limbs. NCS revealed to have motor neuropathy and EMG showed fibrillations and fasciculations with positive sharp waves. After which he was diagnosed with Isaacs-mertens syndrome and was followed up for 8 weeks with medications and physiotherapy management. Bangladesh Journal of Medical Science Vol.20(3) 2021 p.691-693

Highlights

Isaacs – Mertens Syndrome referred as acquired neuromyotonia, is an autoimmune disease caused by hyper-excitability of the motor nerves and activation of muscle fibres owing to autoantibodies directed against the VGKCs on peripheral nerves.1Jacob Isaac Merten first delineated it in 1961.2Clinically it is characterized by continuous, spontaneous, widespread muscle twitching, muscle stiffness, cramps, pseudo myotonia, pseudotetany and at times muscle hypertrophy, mild muscular weakness, parasthesias and numbness that gradually develops between 15 to 60 years.[3]
The excessive and spontaneous muscle activity persists throughout sleep, attributed to hyperexcitability of terminal parts of motor nerve fiber, possibly as a result of a partial loss of motor innervation and compensatory collateral sprouting of surviving axons measured as high-frequency repetitive discharges of varying waveforms in EMG.Differential diagnosis includes hereditary neuromyotonia or myokymia syndromes, crampfasciculation syndrome, motor neuron diseases (progressive spinal muscle atrophy, neuropathy, amyotrophic lateral sclerosis (ALS) and tetanus.[4]
A 60-year-old man with isaacs mertens-syndrome a rare entity symptoms for 2 months but had no relief; instead, his symptoms began to worsen and became more dependent in his activities of daily living. Doctors thought it as Amyotrophic lateral sclerosis, but electrophysiological studies and immunological studies confirmed the presence of Isaacs-Mertens Syndrome and was under immune-therapy and was referred to the physiotherapy department for further management

Summary

Introduction

Isaacs – Mertens Syndrome referred as acquired neuromyotonia, is an autoimmune disease caused by hyper-excitability of the motor nerves and activation of muscle fibres owing to autoantibodies directed against the VGKCs on peripheral nerves.1Jacob Isaac Merten first delineated it in 1961.2Clinically it is characterized by continuous, spontaneous, widespread muscle twitching, muscle stiffness, cramps, pseudo myotonia, pseudotetany and at times muscle hypertrophy, mild muscular weakness, parasthesias and numbness that gradually develops between 15 to 60 years.[3]. The symptoms began 9 months prior to the first day of assessment He took some Ayurveda medicines for his. A 60-year-old man with isaacs mertens-syndrome a rare entity symptoms for 2 months but had no relief; instead, his symptoms began to worsen and became more dependent in his activities of daily living. Doctors thought it as Amyotrophic lateral sclerosis, but electrophysiological studies and immunological studies confirmed the presence of Isaacs-Mertens Syndrome and was under immune-therapy and was referred to the physiotherapy department for further management. Patient was encouraged to perform Breathing exercises for 2 times a day for 8weeks daily to maintain the respiratory function

Discussion

Conclusion