Acute Neurologic Manifestations of Respiratory Viruses

Understanding the pathophysiology of COVID-19 and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that causes the disease has demonstrated the complexity of acute respiratory viruses that can cause neurologic manifestations. This article describes the most common respiratory viruses that have neurologic manifestations, with a focus on SARS-CoV-2 and COVID-19.

In vitro and in vivo studies have better elucidated the neurotropism of various respiratory viruses. Understanding host cell receptors that mediate viral binding and entry not only demonstrates how viruses enter host cells but also provides possible mechanisms for therapeutic interventions. Elucidation of SARS-CoV-2 binding and fusion with host cells expressing the angiotensin-converting enzyme 2 (ACE2) receptor may also provide greater insights into its systemic and neurologic sequelae. Respiratory virus neurotropism and collateral injury due to concurrent inflammatory cascades result in various neurologic pathologies, including Guillain-Barré syndrome, encephalopathy, encephalitis, ischemic stroke, intracerebral hemorrhage, and seizures.

Numerous respiratory viruses can infect the cells of the peripheral and central nervous systems, elicit inflammatory cascades, and directly and indirectly cause various neurologic manifestations. Patients with neurologic manifestations from respiratory viruses are often critically ill and require mechanical ventilation. Neurologists and neurointensivists should be familiar with the common neurologic manifestations of respiratory viruses and the unique and still-evolving sequelae associated with COVID-19.