Clinical Review

Atypical Features of COVID-19: A Literature Review



From the University of Florida College of Medicine, Division of Infectious Diseases and Global Medicine, Gainesville, FL.


  • Objective: To review current reports on atypical manifestations of coronavirus disease 2019 (COVID-19).
  • Methods: Review of the literature.
  • Results: Evidence regarding atypical features of COVID-19 is accumulating. SARS-CoV-2 can infect human cells that express the angiotensin-converting enzyme 2 receptor, which would allow for a broad spectrum of illnesses affecting the renal, cardiac, and gastrointestinal organ systems. Neurologic, cutaneous, and musculoskeletal manifestations have also been reported. The potential for SARS-CoV-2 to induce a hypercoagulable state provides another avenue for the virus to indirectly damage various organ systems, as evidenced by reports of cerebrovascular disease, myocardial injury, and a chilblain-like rash in patients with COVID-19.
  • Conclusion: Because the signs and symptoms of COVID-19 may occur with varying frequency across populations, it is important to keep differentials broad when assessing patients with a clinical illness that may indeed be COVID-19.

Keywords: coronavirus; severe acute respiratory syndrome coronavirus-2; SARS-CoV-2; pandemic.

Coronavirus disease 2019 (COVID-19), the syndrome caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was first reported in Wuhan, China, in early December 2019.1 Since then, the virus has spread quickly around the world, with the World Health Organization (WHO) declaring the coronavirus outbreak a global pandemic on March 11, 2020. As of May 21, 2020, more than 5,000,000 cases of COVID-19 have been confirmed, and more than 328,000 deaths related to COVID-19 have been reported globally.2 These numbers are expected to increase, due to the reproduction number (R0) of SARS-CoV-2. R0 represents the number of new infections generated by an infectious person in a totally naïve population.3 The WHO estimates that the R0 of SARS-CoV-2 is 1.95, with other estimates ranging from 1.4 to 6.49.3 To control the pathogen, the R0 needs to be brought under a value of 1.

A fundamental tool in lowering the R0 is prompt testing and isolation of those who display signs and symptoms of infection. SARS-CoV-2 is still a novel pathogen about which we know relatively little. The common symptoms of COVID-19 are now well known—including fever, fatigue, anorexia, cough, and shortness of breath—but atypical manifestations of this viral continue to be reported and described. To help clinicians across specialties and settings identify patients with possible infection, we have summarized findings from current reports on COVID-19 manifestations involving the renal, cardiac, gastrointestinal (GI), and other organ systems.


During the 2003 SARS-CoV-1 outbreak, acute kidney injury (AKI) was an uncommon complication of the infection, but early reports suggest that AKI may occur more commonly with COVID-19.4 In a study of 193 patients with laboratory-confirmed COVID-19 treated in 3 Chinese hospitals, 59% presented with proteinuria, 44% with hematuria, 14% with increased blood urea nitrogen, and 10% with increased levels of serum creatinine.4 These markers, indicative of AKI, may be associated with increased mortality. Among this cohort, those with AKI had a mortality risk 5.3 times higher than those who did not have AKI.4 The pathophysiology of renal disease in COVID-19 may be related to dehydration or inflammatory mediators, causing decreased renal perfusion and cytokine storm, but evidence also suggests that SARS-CoV-2 is able to directly infect kidney cells.5 The virus infects cells by using angiotensin-converting enzyme 2 (ACE2) on the cell membrane as a cell entry receptor; ACE2 is expressed on the kidney, heart, and GI cells, and this may allow SARS-CoV-2 to directly infect and damage these organs. Other potential mechanisms of renal injury include overproduction of proinflammatory cytokines and administration of nephrotoxic drugs. No matter the mechanism, however, increased serum creatinine and blood urea nitrogen correlate with an increased likelihood of requiring intensive care unit (ICU) admission.6 Therefore, clinicians should carefully monitor renal function in patients with COVID-19.


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