Three cases of acute distal demyelinating neuropathy with recovery

Post COVID-19 Guillain-Barre syndrome presents as sensory dominant neuropathy with reversible conduction failure

Guillain-Barré syndrome (GBS) has several clinical variants. The sensory presentations of GBS are atypical but well-recognized. We report a patient who presented with predominantly sensory symptoms associated with reversible conduction failure (RCF). RCF is a well-defined neurophysiological abnormality noted mainly in axonal GBS and may be misinterpreted as evidence of demyelination. A 25-year-old woman presented 2 weeks after a coronavirus 2019 infection with acute sensory symptoms, distal allodynia, mild weakness, and mild hyporeflexia in her upper limbs. A nerve conduction study (NCS) showed delayed motor distal latencies, and lumbar puncture confirmed cytoalbuminologic dissociation. After excluding other etiologies, she was diagnosed with GBS, treated with an IV immunoglobulin course, and showed remarkable recovery. Results of a repeat NCS were consistent with RCF and confirmed the presence of axonal GBS. Increased awareness of sensory GBS and RCF is expected to improve the diagnosis and management of atypical GBS presentations.

New evidence for secondary axonal degeneration in demyelinating neuropathies

Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.

Chronic Inflammatory Demyelinating Polyneuropathy: Time to Maximal Recovery in Patients Receiving Intravenous Immunoglobulin Therapy

BACKGROUND

The response of chronic inflammatory demyelinating polyneuropathy (CIDP) to intravenous immunoglobulins (IVIgs) treatment is well established. However, it remains unclear whether patients not responding to two IVIg treatments or those whose condition stabilizes (ICE trial) may benefit from additional doses. We aim to identify the time period required to reach maximal strength gains from IVIg treatment.

METHODS

Retrospective chart review of 14 patients with CIDP was performed. Change in handgrip (HG), Knee extension (KE), elbow flexion, and dorsiflexion was analyzed with a dynamometer during IVIg therapy. Strength improvements in Nm or kg, cumulative grams (g) of IVIg, and time in days required for maximal strength recovery were determined per function (± standard error of the mean). Ancillary therapy was recorded for all patients.

RESULTS

Improvements in strength of each function were significant (p < 0.05). Earliest improvement was in HG (137.07 ± 21.23) and latest in KE (238.15 ± 38.9). Majority of patients improved by 200 days of therapy. HG required the lowest cumulative grams of IgG (561.71 ± 97.21) and KE the most (798 ± 120.7).

CONCLUSION

Our study has demonstrated the effectiveness of multiple treatments with IVIg to reach significant improvement in strength. Different muscle groups manifested different time dependency, reflecting the requirement of variable amounts of IVIg. Improvement was identified on an ongoing basis, with therapy lasting between 20.2 and 37.3 weeks, requiring between 562 and 798 g of IVIg.