COVID-19 Latest: Cambridge University Physicians Discover New Emerging Neurologic Complication Called Mononeuritis Multiplex In Severe COVID-19 Patients
: Doctors at Cambridge University Hospital NHS Foundation Trust have reported that a significant proportion of patients with severe COVID-19 disease who required intensive care developed unanticipated disabling neurological deficits that were related to a neurological condition known as mononeuritis multiplex.
The research findings are published on a preprint server and are currently being peer reviewed. https://www.medrxiv.org/content/10.1101/2020.07.19.20149898v2
The neurological condition mononeuritis multiplex or multifocal neuropathy is a form of peripheral neuropathy that involves inflammation of two or more different nerve areas. It can cause asymmetrical sensory and motor damage in multiple parts of the body.
Dr Stephen Sawcer the corresponding author and Professor from the Department of Clinical Neurosciences, Cambridge Biomedical Campus said that it is expected that many survivors of severe disease who need to be supported with long-term mechanical ventilation may be left with significant Intensive Care Unit – Acquired Weakness (ICUAW).
He told Thailand Medical News, “However, in our post-COVID-19 follow up clinic, we have found that, as well as the anticipated global weakness related to loss of muscle mass, a significant proportion of these patients also have disabling focal neurological deficits relating to an axonal mononeuritis multiplex.”
The study team says this unexpected complication of severe COVID-19 could have significant long-term impacts on outcomes for many patients and profound implications in terms of their rehabilitation needs.
Schematic homuncular illustration of the sensory and motor deficits arising from the multiple mononeuropathies present in eleven patients recovering from severe COVID-19. * denote those neuropathies which were unequivocally confirmed electrophysiologically. Hatched shading indicates posterior muscle groups (hamstrings and triceps). In those neuropathies listed as sciatic there was involvement of both common peroneal and tibial divisions.
The researchers strongly recommend that COVID-19 survivors who have ICUAW undergo detailed neurological assessment since many are likely also to have the focal neurological deficits.
The study team have found that among patients attending the hospital’s post-COVID-19 follow-up clinic, a significant number not only experience the global symmetric weakness related to loss of muscle mass and strength, but also significant neurological deficits related to multifocal neuropathy.
It was observed that eleven (16%) of 69 survivors who had been discharged from intensive care after receiving prolonged mechanical ventilation (average period 31 days) had this type of neuropathy. The team says that in many cases, the global symmetrical weakness observed had initially been assumed to be related to critical illness neuropathy. However, a detailed neurophy
siological assessment identified axonal sensorimotor mononeuropathies, and critical illness neuropathy was only seen in one patient.
It was found that the nerve involvement was often random, with some nerve fascicles (which are made up of bundles of axons) more significantly affected than others. Three patients underwent ultrasound scanning, which showed widespread thickening of the nerves that had been affected.
Interestingly one patient with bilateral femoral neuropathies underwent an MRI scan that revealed the presence of bilateral psoas hematoma, which is a complication of extracorporeal membrane oxygenation (ECMO). ECMO is a type of respiratory support that involves blood being pumped to a heart-lung machine where carbon dioxide is removed and oxygen added before blood is returned back to the body.
According to the researchers however, “this finding did not explain the upper limb nor the sciatic neuropathies.”
Another patient with bilateral sciatic nerve lesions also underwent an MRI scan, but the nerves appeared normal, and an MRI scan of the brachial plexus in another patient showed that the nerves were normal.
The study team says that to date, 102 patients with COVID-19 have been treated in the hospital’s intensive care units. Forty-four have been discharged; 14 have been moved to other hospitals; 11 are still recovering, and 33 have died. Since not all patients have been discharged, additional cases of mononeuropathy may still emerge in the weeks to come, the team adds.
Dr Sawcer said, “This series highlights an important neurological complication of COVID-19, which detrimentally affects the long-term outcomes of patients and markedly influences their rehabilitation needs. Given that this complication is evident in a significant proportion of the patients discharged from the intensive care units of a single hospital (16% in our cohort of treated patients), the rehabilitation burden globally could be substantial.”
The study team also points out that, since cases of ICUAW will be expected, the focal deficits observed here may also go unrecognized.
The researchers acknowledge that overall, the number of affected patients is small and that their observations have not involved a comparative group. However, the clinical features are “striking” and have important implications for patients’ outcomes and their rehabilitation.
Dr Sawcer said,
“We strongly urge detailed neurological assessment of patients with post-COVID-19 ICUAW, especially those with asymmetric weakness, as we suspect that many such patients are likely to have focal deficits resulting from their COVID-19 illness.”
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