Case 18

2018 ◽  
Author(s):  
Bashar Katirji
Keyword(s):  
Monoclonal Gammopathy ◽  
Compound Muscle Action Potential ◽  
Conduction Block ◽  
Demyelinating Polyneuropathy ◽  
Type I ◽  
Charcot Marie Tooth Disease ◽  
Immune Mediated ◽  
Muscle Action Potential ◽  
Unknown Significance ◽  
Distinguishing Features

Immune-mediated polyneuropathies are important to recognize since the majority of them are treatable. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the prototype of the acquired chronic demyelinating polyneuropathies. It should be distinguished from other acquired demyelinating polyneuropathy such as those associated with monoclonal gammopathy, myeloproliferative disorder, and myelin-associated glycoprotein. This case presents a patient with a chronic demyelinating polyneuropathy associated with monoclonal gammopathy of unknown significance. The discussion includes the clinical and electrodiagnostic criteria for CIDP and distinguishing features from axonal polyneuropathies, other acquired demyelinating polyneuropathies, and inherited demyelinating polyneuropathies such as Charcot-Marie-Tooth disease type I. The case also highlights the diagnostic criteria for conduction block and temporal dispersion based on analysis of compound muscle action potential amplitude, area, and duration.

Motor Nerve Conduction Studies

2016 ◽  
pp. 257-291
Author(s):  
Lyell K. Jones ◽  
James C. Watson
Keyword(s):  
Action Potential ◽  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Motor Nerve ◽  
Conduction Block ◽  
Neuromuscular Diseases ◽  
Muscle Action ◽  
Motor Nerve Conduction ◽  
Muscle Action Potential ◽  
Nerve Disease

A compound muscle action potential (CMAP) is the summated action potential recorded from muscle during a motor nerve conduction study (NCS). Motor NCSs with recording of CMAPs may be used for several purposes in assessing neuromuscular diseases, including providing objective measurements of the extent and localization of the cause of weakness; determining the underlying pathological abnormality, such as conduction block or slowing of conduction at a localized area of neurapractic injury; identifying the changes associated with Wallerian degeneration and regeneration in the motor nerve; and assisting (along with needle EMG) in distinguishing peripheral nerve disease from lower motor neuron disease, neuromuscular junction disease, and myopathies. This chapter will review the concepts and techniques of motor NCS and CMAP recording, will describe the technique and measurements, and will discuss the findings in various neuromuscular diseases.

scholarly journals A new method of superior vena cava isolation without phrenic nerve injury by longitudinal ablation parallel to the phrenic nerve: a case report

2020 ◽  
Vol 4 (5) ◽  
pp. 1-4
Author(s):  
Tomoyuki Arai ◽  
Rintaro Hojo ◽  
Takeshi Kitamura ◽  
Seiji Fukamizu
Keyword(s):  
Superior Vena Cava ◽  
Phrenic Nerve ◽  
Compound Muscle Action Potential ◽  
Superior Vena ◽  
Conduction Block ◽  
Vena Cava ◽  
Major Complication ◽  
Muscle Action Potential ◽  
The Right

Abstract Background Superior vena cava (SVC) isolation has improved the outcomes of paroxysmal atrial fibrillation (AF) originating from the SVC. However, right phrenic nerve (PN) injury is a major complication of this procedure. Therefore, in cases where the right atrium (RA)-SVC conduction site is near the PN, tremendous care is required to prevent PN injury. Case summary Repeated SVC isolation was performed due to the recurrence of SVC-triggered AF. The RA-SVC activation map revealed that the partial conduction block line was detected, and the propagation broke through the gap at the course of the PN site from the RA to the SVC. Since the course of the PN identified at high-output pacing was wide, the SVC was isolated by making longitudinal lines on both sides of the PN in a cranial direction, except for where low-output pacing captured, confirming compound muscle action potential to detect PN injury. Eventually, the SVC was successfully isolated without PN injury, and the sinus rhythm was maintained without antiarrhythmic drugs during a 14-month follow-up period. Conclusion Superior vena cava isolation was difficult depending on the course of the PN, and some methods to avoid PN injury were reported. However, this method can facilitate safe and effective SVC isolation with the conventional system, including the cases with AF foci located on the course of the PN.

scholarly journals Analysis of compound muscle action potential in patients with chronic inflammatory demyelinating polyneuropathy and Charcot-Marie-Tooth disease type 1A

2021 ◽  
Vol 8 (2) ◽  
pp. 114-121
Author(s):  
Onur Akan ◽  
Canan Emir
Keyword(s):  
Peroneal Nerve ◽  
Tibial Nerve ◽  
Chronic Inflammatory Demyelinating Polyneuropathy ◽  
Compound Muscle Action Potential ◽  
Disease Type ◽  
Muscle Action ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Muscle Action Potential ◽  
Tooth Disease

Objective: To provide an additional contribution to the differential diagnosis of Charcot-Marie-Tooth disease type 1A (CMT1A) and chronic inflammatory demyelinating polyneuropathy (CIDP)  by analyzing distal duration and proximal/distal amplitude and duration ratios on different nerves in these diseases that show demyelinating peripheral neuropathy features. Material and Methods: We retrospectively reviewed the electromyography (EMG) findings of patients aged 18-80 years who were followed up with a diagnosis of acquired and hereditary demyelinating type polyneuropathy in the neuromuscular diseases outpatient clinic in our center. We analyzed the distal CMAP duration and amplitude, proximal and distal compound muscle action potential, and duration ratios on each nerve in the patient groups, separately. Results: The CIDP group had significantly longer Peroneal nerve distal duration than the CMT1A group (p=0.04). Median, ulnar, and tibial nerve distal durations were similar between the groups (p=0.84, p=0.86, and p=0.13, respectively). The median nerve, ulnar nerve, and peroneal nerve proximal/distal amplitude ratios were not different between the CMT1A and CIDP groups (p=0.99, p=0.38, and p=0.16, respectively). The tibial nerve proximal/distal amplitude ratio in the CIDP group was lower than in the CMT1A group (p=0.003). Median, ulnar, peroneal, and tibial nerve proximal/distal duration ratios were statistically similar among the groups (p=0.21, p=0.66, p=0.62, and p=0.46, respectively). Conclusion: This study may help to improve the management of challenging patients where there is an overlap between hereditary and inflammatory neuropathies. The different electrodiagnostic models of various acquired and hereditary demyelinating polyneuropathies should be clinically recognized.

Sign in / Sign up

Export Citation Format

Share Document