no longer supports your web browser (Internet Explorer version 9 or lower). See what browsers we support.


Pictures of COVID-19 and disease information have been excerpted from VisualDx clinical decision support system as a public health service. Additional information, including symptoms, diagnostic pearls, differential diagnosis, best tests, and management pearls, is available in VisualDx.

How VisualDx Works Media Kit

VisualDx Blog: Coronavirus (COVID-19): What You Need to Know

Click here for the full clinical write-up and images in VisualDx

May 20, 2020.


The situation is rapidly changing. Refer to the US Centers for Disease Control and Prevention (CDC) (Information for Healthcare Professionals) for the most current information.

Clinicians should immediately implement recommended infection prevention and control practices if a patient is suspected of having COVID-19. Minimize the number of personnel that interact with a suspected or positive COVID-19 patient and record all personnel who have entered the room.

Per the CDC, health care providers should immediately notify their local or state health department in the event of the identification of a person under investigation (PUI) for COVID-19. See Diagnostic Pearls and Best Tests for more information on evaluating and reporting suspected cases.

Per the CDC:

  • Preferred Personal Protective Equipment (PPE): Adhere to Standard, Contact, and Airborne Precautions, including the use of Eye Protection (ie, gowns, gloves, NIOSH-certified disposable N95 respirator, eye protection).
  • Acceptable Alternative Personal Protective Equipment (PPE): Adhere to Standard, Contact, and Droplet Precautions, including the use of Eye Protection (ie, gowns, gloves, facemask [non-N95], eye protection) for COVID+ or COVID PUI patients not undergoing aerosol-generating procedures (intubation, extubation, bilevel positive airway pressure [BiPAP], continuous positive airway pressure [CPAP], etc). N95 or higher respirators should be used in the setting of aerosol-generating procedures.

  • Isolate the patient under investigation for COVID-19 in an Airborne Infection Isolation Room (AIIR) for aerosol-generating procedures, if available.

The CDC has also provided interim guidance (as of April 13) on infection prevention and control to reduce facility risk, isolate symptomatic patients as soon as possible, and protect health care personnel.

Contrary to CDC recommendations, the World Health Organization (WHO) does not recommend use of Airborne Precautions unless the patient is undergoing high-risk interventions for aerosolization (intubation, induced sputum, etc). Currently, all US providers should follow CDC recommendations.

Finally, it is imperative that providers caring for patients being evaluated for or found to have COVID-19 practice regular hand hygiene before and after patient contact. 

About COVID-19

Coronavirus disease 2019 (COVID-19), previously known as 2019 novel coronavirus (2019-nCoV), is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new coronavirus and the responsible agent for an outbreak of pneumonia cases in Wuhan City, Hubei Province, China, initially reported to the World Health Organization on December 31, 2019, and reportedly linked to a large seafood and animal market. Coronaviruses are a family of viruses, some of which cause infection in humans and others in animals such as camels, cats, and bats. When animal coronaviruses evolve, on rare occasion they can become infectious to and spread between humans (a zoonotic infection) as has occurred with Middle East respiratory syndrome (MERS) and SARS. This animal-to-human spread has been postulated to have occurred with SARS-CoV-2 with subsequent person-to-person transmission.

Person-to-person spread in the community is occurring in many countries, including the United States. The virus is transmitted primarily via infectious secretions (respiratory droplets and sputum) between individuals in close contact (within about 6 feet). It is possible that, in addition, the virus can be transmitted by saliva, urine, and stool. Transmission of SARS-CoV-2 from asymptomatic or pre-symptomatic persons has been reported.

Clinical features primarily include fever and symptoms of lower respiratory tract illness (eg, cough, shortness of breath), although many patients also report associated gastrointestinal complaints (nausea, vomiting). Reported cases have ranged from mild to severe; some cases have been fatal. Some individuals with infection can be relatively asymptomatic.

Preventive measures:

  • Every person should wash hands often; the CDC recommends washing with soap and water for at least 20 seconds, or using an alcohol-based hand sanitizer if soap and water are not available.
  • Per the CDC, mitigation strategies to control transmission of the disease and protect individuals at increased risk for severe illness (including older adults and persons of any age with underlying health conditions) include physical distancing measures such as staying at home and avoiding gatherings or other situations of potential exposures, including travel, and generally maintaining distance (approximately 6 feet or 2 meters) from others when possible. Mitigation strategies can be scaled up or down depending on evolving local circumstances.
  • The CDC recommends wearing cloth face coverings in public settings where other physical distancing measures are difficult to maintain (eg, grocery stores, pharmacies), particularly where significant community transmission is occurring.

Look For

Information to define the spectrum of clinical illness attributed to COVID-19 is still being gathered. The incubation period is estimated to be between 2 and 14 days after exposure, with an estimated median incubation period of about 4-5 days.

Emergency warning signs for COVID-19 include trouble breathing, persistent pain or pressure in the chest, new confusion or inability to arouse, and bluish lips or face.

Signs and symptoms of illness vary, and some people with COVID-19 infection can be relatively asymptomatic. Most patients, however, will experience one or more of the following over the course of disease:

  • Fever
  • Cough
  • Fatigue
  • Anorexia
  • Dyspnea
  • Sputum production
  • Myalgias

Other signs and symptoms include chills, repeated shaking with chills, arthralgia, sore throat, headache, confusion, rhinorrhea, hemoptysis, vomiting, and diarrhea. Anosmia or ageusia preceding the onset of respiratory symptoms has also been reported. See below for further discussion of variant presentations.

multisystem inflammatory syndrome potentially linked to COVID-19 has been reported in children and young adults; clinical features include Kawasaki-like and toxic shock syndrome-like presentations.

Little is known about primary COVID-19 infection in children at present. It seems to most commonly manifest as a mild respiratory illness or be asymptomatic. Severe primary COVID-19 illness in children has been uncommonly reported. In a multicenter cross-sectional study of 48 children admitted to US and Canadian pediatric intensive care units for COVID-19, over 80% had significant preexisting comorbidities. Early hospital outcomes were better in children than adults.

In the analysis of more than 1000 patients admitted to the hospital with laboratory-confirmed COVID-19 infection in China, laboratory findings included the following (with laboratory scores being worse in patients with severe illness):

  • Lymphocytopenia (83.2%)
  • Thrombocytopenia (36.2%)
  • Leukopenia (33.7%)
  • Most patients had elevated C-reactive protein.

On admission, chest CT image abnormalities were detected in 86.2% of patients. The most common abnormalities were ground-glass opacity (56.4%) and bilateral patchy shadowing (51.8%). Additional imaging details are below.

Some patients initially presented without fever and without abnormal radiologic findings.

The median duration of hospitalization was 12 days (mean 12.8), and most patients (91.1%) received a diagnosis of pneumonia. Other complications included acute respiratory distress syndrome (ARDS) (3.4%) and shock (1.1%). Uncommon complications were acute kidney injury, acute cardiac injury (cardiomyopathy), secondary infection, and rhabdomyolysis.

Gastrointestinal symptoms of COVID-19:

While the majority of symptomatic COVID-19 patients present with respiratory symptoms of cough, shortness of breath and sore throat, a unique subgroup of COVID-19 patients with low severity disease present with primarily digestive symptoms. In one study, up to 23% of patients with COVID-19 confirmed by PCR testing presented with digestive symptoms (diarrhea, nausea, and vomiting and/or abdominal pain) alone. Up to 30% of patients with standard COVID-19 illness marked primarily by respiratory symptoms will have concurrent gastrointestinal symptoms including diarrhea, nausea, and vomiting and/or abdominal pain. In those with diarrhea, symptoms can last for 1-14 days (5 days on average). In some cases, digestive symptoms such as diarrhea can be the initial presenting symptoms of COVID-19 in patients who may later develop respiratory symptoms or fever. In one study, only 3% of patients had only gastrointestinal symptoms. Patients with digestive symptoms appear to have a longer duration between symptom onset and viral clearance and are more likely to have fecal samples positive for SARS-CoV-2 compared with those with respiratory symptoms.

COVID-19-associated coagulopathy:

COVID-19-associated coagulopathy is primarily characterized by elevations in fibrinogen and D-dimer levels. These elevations are generally in parallel with elevations in inflammatory markers such as C-reactive protein. Other markers of coagulation such as PT and PTT are not generally elevated, and platelet counts are only mildly low (100K range), unlike standard sepsis-associated disseminated intravascular coagulation (DIC). Some COVID-19 patients can progress to a more fulminant DIC picture with severe tissue damage.

Development of DIC in COVID-19 is an extremely concerning finding, as it is associated with extremely poor prognosis. In one study, 71% of non-survivors from COVID-19 infection met DIC criteria compared with only 0.4% of survivors. Marked D-dimer elevation (3- to 4-fold elevation) at admission as well as elevation over time were also associated with high mortality. Despite this, therapeutic anticoagulation is not indicated in the absence of documented venous thromboembolism or atrial fibrillation. The efficiency of therapeutic anticoagulation is presently under study, but a prophylactic dose of low molecular weight heparin (LMWH) is recommended for all hospitalized patients with COVID-19.

Despite the development of coagulopathy, COVID-19 infection is only rarely complicated by bleeding.

COVID-19-associated cytokine release syndrome:

In addition to the bilateral diffuse alveolar injury that marks severe cases of COVID-19, these cases demonstrate a sustained decrease in lymphocytes compared with more mild cases as well as increased levels of inflammatory cytokines such as interleukin (IL)-6, IL-10, IL-2, and interferon (IFN)-γ. This "cytokine storm" results in the development of cytokine release syndrome (CRS), which is characterized by a marked increase in vascular permeability with the development of severe vasoplegia and systemic hypotension, noncardiogenic pulmonary edema, and persistent fevers.

Skin manifestations of COVID-19 (not a common finding):

A Spanish study of 375 patients with confirmed and clinically suspected cases of COVID-19 highlighted 5 main cutaneous presentation patterns.

  • "Pseudo-chilblains" on the acral surfaces, including erythema, edema, vesiculation, and purpura of the hands and feet. Lesions may be painful, itchy, or asymptomatic. The term "COVID toes" has also been used to describe these lesions, and feet have been noted to be affected more frequently than hands. These manifestations occurred in younger individuals late in disease course and usually followed a milder illness. PCR is often negative in these patients, and the timing of onset has been touted as one explanation.
  • A vesicular eruption with lesions all in the same stage (as opposed to chickenpox). In some cases, vesicles coalesce and become hemorrhagic. This manifestation occurred predominantly in middle-aged patients with moderate disease severity and lasted around 10 days. Itch was a common associated symptom.
  • An urticarial eruption.
  • A maculopapular eruption. Also classed in this group were some cases with a perifollicular distribution, some that were erythema multiforme-like, some that were pityriasiform, and some that manifested secondary purpura as well. For both the urticarial and maculopapular eruptions, itch was frequent, and patients tended to present with more severe disease. Rash was present at the onset of other symptoms and lasted about 6-8 days.
  • Livedo or necrotic lesions. Transient livedo was seen in milder illness, but fixed livedo and necrosis were seen in an older age group with severe disease.

Other less frequent findings included a purpuric flexural exanthem and an enanthem.


  • A review article highlighting the role of chest CT in early detection and management of COVID-19 reports that typical chest CT findings include multifocal bilateral ground glass opacities with patchy consolidations, peripheral subpleural distribution, and posterior part or lower lobe predilection. Less commonly, crazy-paving pattern or air bronchogram sign was observed. Pure consolidation, reversed halo sign, or pleural effusion was uncommonly detected.
  • Pure ground glass opacity lesions can be an early presentation of COVID-19 pneumonia.
  • Chest CT is superior to chest x-ray in early detection of COVID-19 pneumonia, but both have low specificity for the diagnosis.

medical illustration of moderate presentation of covid-19

medical illustration of moderate presentation of covid-19

medical illustration of severe presentation of covid-19

medical illustration of critical presentation of covid-19

chest x-ray showing progression of covid-19

chest x-ray of covid-19 showing ground glass oapcities

chest x-ray of covid-19 showing diffuse bilateral consolidations

chest x-ray of covid-19 showing progression

Unlock Your Unlimited Access to VisualDx. Start your 30 day free trial. Cancel at any time.

VisualDx is trusted for diagnostic decision support in over 2,300 hospitals, large clinics, and medical schools across the globe.

Start your 30 day free trial