3 Clinical Characteristics

3.1 Clinical Manifestations

Based on current epidemiological investigations, the incubation period of COVID-19 is ranged between 1 to 14 days, and generally within 3 to 7 days.

Fever, fatigue and dry coughing are considered the main clinical manifestations, but symptoms such as stuffy nose, runny nose,pharyngalgia, myalgia and diarrhea are relatively less common. In severe cases, dyspnea and/or hypoxemi a usually occurs after one week of disease onset, and the worse can rapidly progresses to acute respiratory distress syndrome, septic shock, metabolic acidosis hard to correct, and hemorrhage and coagulation dysfunction, multiple organ failure, etc. It’s worth noting that patients with severe or critical illness may have a moderate to low fever,or no fever at all.

Mild cases only present with light fever, mild fatigue and so on without manifestation of pneumonia.

From the cases treated currently, most of the patients have a favorable prognosis. The elderly and people with chronic underlying diseases usually have poor prognosis while cases with relatively mild symptoms are common in children.

3.2 Laboratory Examination

In the early stage of COVID-19, a normal or decreased total white blood cell count and a decreased lymphocyte count can be found in patients. In addition, increased value of liver enzymes, LDH, muscle enzymes and myoglobin can occur in some patients; and raised level of troponin can be seen in some critically ill patients. In most cases, the laboratory tests show a raised C-reactive protein value and erythrocyte sedimentation rate but a normal procalcitonin value. Among severe patients, D-dimer value is increased and peripheral blood lymphocytes decreased persistently. In addition, elevated values of inflammatory factors are accompanied with in severe and critical patients.

The nucleic acid of 2019-nCoV can be detected in biological specimens such as nasopharyngeal swabs, sputum, other lower respiratory tract secretions, blood and feces.

To improve the positive rate of nucleic acid detection, it is recommended to collect and retain sputum in general patients besides those performed with tracheal intubation(lower respiratory tract secretions should be collected);and all the specimens should be sent and tested as fast as possible.

3.3 Chest Imaging

In the early stage of COVID-19, the images show that there are multiple small patched shadows and interstitial changes, especially in the lung periphery. As the disease progresses, the images of these patients further develop into multiple ground glass shadows and infiltration shadows in both lungs. In severe cases, lung consolidation may occur. It is seldom to find pleural effusion in patients with COVID-19.