Background
Clinical spectrum of immunoglobulin M (IgM) monoclonal gammopathy varies from IgM monoclonal gammopathy of unknown significance (IgM-MGUS) to hematological malignancies. We evaluated the clinical features, electrophysiological characteristics, and prognosis of patients with peripheral neuropathy associated with IgM monoclonal gammopathy (PN-IgM MG).
Methods
We retrospectively evaluated 25 patients with PN-IgM MG. Peripheral neuropathy was classified as axonal, demyelinating, or undetermined, based on electrophysiological studies. We classified the enrolled patients into the IgM-MGUS and malignancy groups, and compared the clinical and electrophysiological features between the groups.
Results
Fifteen patients had IgM-MGUS and 10 had hematologic malignancies (Waldenström’s macroglobulinemia: two and B-cell non-Hodgkin’s lymphoma: eight). In the electrophysiological evaluation, the nerve conduction study (NCS) criteria for demyelination were met in 86.7% of the IgM-MGUS group and 10.0% of the malignancy group. In particular, the distal latencies of the motor NCS in the IgM-MGUS group were significantly prolonged compared to those in the malignancy group (median, 9.1 ± 5.1 [IgM-MGUS], 4.2 ± 1.3 [malignancy], p = 0.003; ulnar, 5.4 ± 1.9 [IgM-MGUS], 2.9 ± 0.9 [malignancy], p = 0.001; fibular, 9.3 ± 5.1 [IgM-MGUS], 3.8 ± 0.3 [malignancy], p = 0.01; P-posterior tibial, 8.3 ± 5.4 [IgM-MGUS], 4.4 ± 1.0 [malignancy], p = 0.04). Overall treatment responses were significantly worse in the malignancy group than in the IgM-MGUS group (p = 0.004), and the modified Rankin Scale score at the last visit was higher in the malignancy group than in the IgM-MGUS group (2.0 ± 1.1 [IgM-MGUS], 4.2 ± 1.7 [malignancy], p = 0.001), although there was no significant difference at the initial assessment.
Conclusions
The risk of hematological malignancy should be carefully assessed in patients with PN-IgM MG without electrophysiological demyelination features.

Ultrasonography is currently being developed as a tool for evaluating peripheral neuropathy. It is one of the painless and least-invasive methods of medical diagnostic testing that yields anatomic views of the nerves and their surrounding structures. Here I first describe the equipment settings and technique for nerve ultrasound along with typical sonographic findings for normal nerves. I then address frequently used parameters for nerve measurements that facilitate diagnoses of focal and generalized neuropathies.

Citations

• A soft, scalable and adaptable multi-contact cuff electrode for targeted peripheral nerve modulation
  Valentina Paggi, Florian Fallegger, Ludovic Serex, Olivier Rizzo, Katia Galan, Alice Giannotti, Ivan Furfaro, Ciro Zinno, Fabio Bernini, Silvestro Micera, Stéphanie P. Lacour
  Bioelectronic Medicine.2024;[Epub]     CrossRef

Background
Peripheral nerve injury rarely occurs in patients with rhabdomyolysis. Based on our experience and previous reports, we consider prolonged immobilization a risk factor for the development of peripheral neuropathy in rhabdomyolysis patients.
Methods
This study analyzed 28 patients with rhabdomyolysis due to prolonged immobilization. We analyzed their demographic and laboratory data, clinical and imaging findings, and outcomes, and compared these factors between patients with and without neuropathy.
Results
Seven of the 28 patients had peripheral neuropathy, including sciatic neuropathy or lumbosacral plexopathy. Compared to those without neuropathy, the patients with neuropathy were younger (p = 0.02), had higher peak creatine kinase (CK) levels (p = 0.02), had higher muscle uptake in bone scans (p = 0.03), and more frequently exhibited abnormal muscle findings in computed tomography (CT) (p = 0.004).
Conclusions
Patients with prolonged immobilization-induced rhabdomyolysis and neuropathy had higher CK levels, increased uptake on bone scans, and more-frequent abnormal muscles on CT than those without neuropathy. These findings indicate that peripheral neuropathy is more likely to develop in patients with severe muscle injury.

Citations

• Crushing Muscles: A Case Study on Rhabdomyolysis, Renal Failure, and Compartment Syndrome Triggered by Pre-Workout Supplement Abuse
  Faryal Altaf, Vedangkumar Bhatt, Sindhaghatta Venkatram, Gilda Diaz-fuentes
  Cureus.2024;[Epub]     CrossRef
• Foot drop secondary to rhabdomyolysis: improved foot dorsiflexion and gait after neurolysis and distal nerve transfer—a case series and literature review
  Rahul K Nath, Chandra Somasundaram
  Journal of Surgical Case Reports.2023;[Epub]     CrossRef
• A Rare Complication of Rhabdomyolysis: Peripheral Neuropathy
  Chidinma Ejikeme, Ramez Alyacoub, Sherif Elkattawy, Tanya Shankar, Ruhin Yuridullah
  Cureus.2021;[Epub]     CrossRef