How common are neurological symptoms in patients with Covid-19 infection?

Although we usually think of it as primarily a respiratory tract disease, neurological manifestations with Covid-19 are not at all uncommon,1-6 occurring in over one-third of hospitalized patients with Covid-19 according to one medRxiv report.1

In a Chinese study1 involving 214 hospitalized patients with Covid-19, 36.4% had 1 or more neurological symptoms, with the majority involving the central nervous system (CNS) (25.0%), of which the most common complaints were dizziness (17%) and headache (13.0%). Some patients (9.0%) had cranial nerve/peripheral nerve complaints of which the most common were difficulty with taste (hypogeusia) (6.0%) and sense of smell (hyposmia) (5.0%).  A fewer number of patients had impaired consciousness, acute cerebrovascular disease (including ischemic stroke and cerebral hemorrhage). Although not strictly-speaking a neurological manifestation, the study also reported “muscle injury” in ~20.0% of patients     (defined as myalgia plus CK >200 IU/L).

Descriptions of Covid-19 encephalopathy, including one associated with acute hemorrhagic necrotizing process, are also beginning to appear in the literature.3-5 Reports of “Neuro-Covid-19 units” in Italy further underlines the common occurrence of neurological symptoms in these patients.6

More than one mechanism for neurological complications in Covid-19 are likely,  including:1-2

  1. Direct viral invasion into the CNS which could explain the associated headache, high fever, vomiting, convulsions, and consciousness disorders. Some have reported normal CSF parameters but a report of PCR positive CSF suggests direct injury from the virus itself.2 Covid-19 virus may gain access to the CNS through direct invasion of neuronal pathways (eg. olfactory nerve given recent reports of difficulty with sense of smell) or through blood circulation.
  2. Indirect CNS injury through extreme systemic derangements such as hypoxia, or immune/inflammatory response-related injury (eg, through cytokines, hypercoagulability related to infection). Some have also posited that binding of Covid-19 virus to ACE2 may cause abnormally elevated blood pressure and increase the risk of cerebral hemorrhage.2

The fact that Covid-19 is so versatile and affects the nervous system as well shouldn’t surprise us. Neurological complications have been reported with couple of other related respiratory Coronaviruses such as those of SARS and MERS.2


Bonus pearl: Did you know that as early 1970-80s some coronaviruses were shown to cause “nasoencephalopathy” when injected intranasally in mice with subsequent spread to the CNS through the olfactory nerve?7 Maybe we shouldn’t be too surprised that sense of smell is impaired in some Covid-19 patients. If we could only stop the virus at the nose!

Liked this post? Download the app on your smart phone and sign up below to catch future pearls right into your inbox, all for free!

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.



  1. Mao L, Wang M, Chen S, et al. Neurological manifestations of hospitalized patients with COVID-19 in Wuhan, China: a retrospective case series study.
  2. Wu Y, Xu X, Chen Z, et al. Nervous system involvement after infection with COVID-19 and other coronaviruses. Brain, Behavior, and Immunity 2020, March 30.
  3. Xiang et al. 2020. First case of 2019 novel Coronavirus disease with encephalitis. ChinaXiv, T202003 (2020), p. 00015 (obtained from reference 2).
  4. Poyiadji N, Shain G, Noujaim D, et al. COVID-19-associated acute hemorrhagic necrotizing encephalopathy: CT and MRI features. Radiology 2020
  5. Filatov A, Sharma P, Hindi F, et al. Neurological complications of coronavirus (COVID-19): encephalopathy. Cureus 12(3): e7352. DOI 10.7759/cureus.7352
  6. Talan J. COVID-19: Neurologists in Italy to Colleagues in US: Look for poorly-defined neurologic conditions in patients with the Coronavirus. Neurology Today 2020, March 27.
  7. Perlman S, Jacobsen G, Afifi A. Spread of a neurotropic murine Coronavirus into the CNS via the trigeminal and olfactory nerves. Virology 1989;170:556-560

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

How common are neurological symptoms in patients with Covid-19 infection?

Should I consider Powassan virus (POWV) in my patient with acute encephalitis?

POWV is a neuroinvasive arbovirus transmitted by Ixodes ticks (similar to Lyme disease). It has been reported in Canada, Russia and, increasingly, in northeastern states and Great lakes region of United States1. Although many cases occur during warmer months, nearly 30% of cases reported from New York occurred during November, December and January 2.  Rather remarkably, POWV may be transmitted within 15 minutes of a tick bite in contrast to the agent of Lyme disease which typically takes at least 48 hours2!

The most common clinical presentation is a febrile illness associated with encephalitis, meningoencephalitis or aseptic meningitis.  Seizures, focal deficits, aphasia, and dysarthria have been reported2. Typically, cerebrospinal fluid shows lymphocytic pleocytosis, normal glucose, and normal or mildly elevated protein.  Electroencephalography (EEG) reveals generalized slow wave activity and MRI of the brain may suggest microvascular ischemia or demyelinating disease in the parietal or temporal lobes. Collectively, the clinical presentation may resemble those seen in herpes simplex virus encephalitis. 

POWV disease carries 10% mortality with severe neurological sequelae in 50% of survivors4.  Despite lack of effective treatment, POWV should be considered in the differential diagnosis of acute encephalitis in endemic areas.



  1. CDC.  
  2. El Khoury MC, Camargo JF, White JL. Potential role of deer tick virus in Powassan encephalitis cases in Lyme disease-endemic areas of New York, USA. Emerg Infect Dis 2013;19:1928-33.
  3. CDC.
  4. Hermance ME, Thanagamai S. Tick saliva enhances Powassan virus transmission to the host, influencing its dissemination and the course of disease. J Virol 2015; 89:7852-60.
Should I consider Powassan virus (POWV) in my patient with acute encephalitis?