COVID-19 associated phrenic nerve mononeuritis: a case series.

This study characterised the hemidiaphragm elevation on 3-month interval chest X-rays (CXRs) of patients post COVID-19 pneumonia. 467 CXRs were screened; 19 (4.1%) had an elevated hemidiaphragm. There were 15 (3.2%) patients of interest with new hemidiaphragm elevation, persisting on average 7 months post COVID-19 diagnosis. Symptomatic patients underwent diaphragm ultrasound (n=12), pulmonary function test (n=10), muscle function test (n=6) and neurophysiology (n=5), investigating phrenic nerve function. Ultrasound demonstrated reduced/paradoxical diaphragmatic movements in eight; four of eight had reduced thickening fraction. Neurophysiology peripheral limb studies did not support the differential diagnoses of critical illness neuropathy/myopathy. We propose that, in selected patients, COVID-19 may cause phrenic nerve mononeuritis.

Terminal Anatomy of Phrenic Nerve: A Deeper Look at Diaphragm Innervation Patterns.

BACKGROUND: Traumatic brachial plexus injuries are devastating lesions, and neurotization is an usually elected surgical therapy. The phrenic nerve has been harvested as a motor fibers donor in brachial plexus neurotization, showing great results in terms of motor reinnervation. Unfortunately, these interventions lack solid evidence regarding long-term safety and possible late respiratory function sequelae, raising crescent concerns after the COVID-19 pandemic onset and possibly resulting in reduced propensity to use this technique. The study of the distal anatomy of the phrenic nerves may lead to a better understanding of their branching patterns, and thus the proposition of surgical approaches that better preserve patient respiratory function. METHODS: Twenty-one phrenic nerves in 10 formalized cadavers were scrutinized. Prediaphragmatic branching patterns were inspected through analysis of the distance between the piercing site of the nerve at the diaphragm and the cardiac structures, number of divisions, and length from the point where the main trunk emits its branches to the diaphragm. RESULTS: The main trunk of the right phrenic nerve reaches the diaphragm near the inferior vena cava and branches into 3 major divisions. The left phrenic nerve reaches the diaphragm in variable locations near the heart, branching into 2-5 main trunks. Moreover, we noticed a specimen presenting 2 ipsilateral parallel phrenic nerves. CONCLUSIONS: The right phrenic nerve presented greater consistency concerning insertion site, terminal branching point distance to this muscle, and number of rami than the left phrenic nerve.

[Parsonage-Turner syndrome following severe SARS-CoV-2 infection]. / Syndrome de Parsonage-Turner compliquant une infection sévère à SARS-CoV-2.

INTRODUCTION: Complications following COVID-19 are starting to emerge; neurological disorders are already described in the literature. CASE REPORT: This case is about a 20-year old male with a severe COVID-19, hospitalized in a Reanimation and Intensive Care Unit with an Acute Respiratory Distress Syndrome, thromboembolic complication and secondary bacterial infection. This patient had a non-specific neurological disorder with a pseudobulbar palsy, (MRI, ENMG and lumbar puncture were normal), associated 4 months later with persistent left shoulder motor deficit and respiratory failure. Respiratory and neurological check-up led to a diagnosis of the Parsonage-Turner syndrome or neuralgic amyotrophy affecting C5-C6 nerve roots, the lateral pectoral and phrenic nerves at the origin of the scapular belt, amyotrophy and left diaphragm paralysis. CONCLUSIONS: This case shows that persistant dyspnoea after COVID 19 infection should lead to a search for a diaphragmatic cause which is not always the result of Reanimation Neuropathy but may also indicate a neuralgic amyotrophy. It is the fourth case of neuralgic amyotrophy following COVID-19. This brings the medical community to consider the risk of diaphragm paralysis apart from critical illness polyneuropathy. Respiratory muscle evaluation and diaphragmatic ultrasound should be considered in case of persistent dyspnoea.

Diaphragm and Phrenic Nerve Ultrasound in COVID-19 Patients and Beyond: Imaging Technique, Findings, and Clinical Applications.

The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung disease, prolonged ventilation, phrenic nerve injury, neuromuscular disease, and central nervous system pathology. In light of the global pandemic of coronavirus disease 2019 (COVID-19), there has been growing interest in the utility of ultrasound for evaluation of respiratory symptoms including lung and diaphragm sonography. Diaphragm ultrasound can be utilized to diagnose diaphragm dysfunction, assess severity of dysfunction, and monitor disease progression. This article reviews diaphragm and phrenic nerve ultrasound and describes clinical applications in the context of COVID-19.

Phrenic nerve study as outcome in clinical trials for amyotrophic lateral sclerosis.

Introduction: Respiratory tests are fundamental for monitoring respiratory function in ALS, and essential in clinical trials. Slow vital capacity (SVC) was canceled in some countries to prevent COVID-19 transmission. We aimed to test phrenic nerve motor responses as an option to SVC in clinical trials. Methodology: Patients followed-up in our unit were selected respecting inclusion criteria used elsewhere: possible/probable/definite disease; onset-age 18-80years; disease duration from disease duration ≤24months; body mass index (BMI)>20kg/m2; respiratory subscore of the revised ALS functional rating scale (ALSFRS-R)≥11; upright SVC ≥ 70%. We added normal phrenic responses (meanPhrenAmpl, ≥0.4mV). All patients were on riluzole. SVC and meanPhrenAmpl were recorded at study entry (T0) and 24 weeks later (T1). Decays were determined. Sample size was calculated for a treatment effect of 30% on the decay rate. Results: We included 317 ALS patients (191 males, 225 spinal-onset), mean onset-age 59.9 ± 10.7 (31-80)years, mean onset BMI 25.48 ± 3.2 (20.1-35)kg/m2, mean disease duration 10.5 ± 5.6 (1-24)months, mean ALSFRS-R 41.54 ± 4.3 (22-47) and respiratory subscore 11.83 ± 0.38 (11-12). MeanPhrenAmpl and SVC were weakly but significantly correlated at T0 and T1. At T1, MeanPhrenAmpl decayed 16.94 ± 16.45% and SVC 13.5 ± 16.86%. For the proposed drug effect, 174 and 272 patients would be needed to recruit using respectively meanPhrenAmpl and SVC decline as the primary outcome measurement (accepting no dropouts). Discussion: Contrary to SVC, meanPhrenAmpl is non-volitional and not associated with aerosolization risk. Lower recruitment number (98 patients less) would be needed, translating shorter inclusion period, trial length and costs, and probable lower missed data rate. MeanPhrenAmp is an alternative test in ALS clinical trials.

Erythropoietin as candidate for supportive treatment of severe COVID-19.

In light of the present therapeutic situation in COVID-19, any measure to improve course and outcome of seriously affected individuals is of utmost importance. We recap here evidence that supports the use of human recombinant erythropoietin (EPO) for ameliorating course and outcome of seriously ill COVID-19 patients. This brief expert review grounds on available subject-relevant literature searched until May 14, 2020, including Medline, Google Scholar, and preprint servers. We delineate in brief sections, each introduced by a summary of respective COVID-19 references, how EPO may target a number of the gravest sequelae of these patients. EPO is expected to: (1) improve respiration at several levels including lung, brainstem, spinal cord and respiratory muscles; (2) counteract overshooting inflammation caused by cytokine storm/ inflammasome; (3) act neuroprotective and neuroregenerative in brain and peripheral nervous system. Based on this accumulating experimental and clinical evidence, we finally provide the research design for a double-blind placebo-controlled randomized clinical trial including severely affected patients, which is planned to start shortly.