Dr K K Aggarwal

President CMAAO, HCFI and Past national President IMA

Coronavirus disease 2019 (COVID-19) can be categorized into three based on the severity of illness: Early infection, pulmonary phase and hyperinflammatory phase.

Early infection is the first stage of the illness. The patient has only mild constitutional symptoms such as fever (>99.6⁰F), dry cough, headache and diarrhea. At this stage, laboratory tests show lymphopenia and increased levels of PT, d-dimer and LDH.

Undetected or untreated, the patient moves into the next stage of the illness, the pulmonary phase.  The patient develops shortness of breath and hypoxia (PaO2/FiO2 <300mmHg). Lab tests reveal transamnitis and low to normal procalcitonin. Chest imaging will show an abnormal CT.

The hyperinflammation phase or the third stage is the critical stage characterized by acute respiratory distress syndrome (ARDS), systemic inflammatory response syndrome (SIRS) and /shock and cardiac failure. The inflammatory markers (CRP, IL-6, D-dimer, ferritin), troponin, NT-proBNP levels are raised indicative of poor prognosis.

Since COVID-19 is a new disease, there is no specific antiviral drug for its treatment. Potential therapies are being explored.

• Besides symptomatic management and oxygen, old drugs such as chloroquine, hydroxychloroquine, azithromycin, are being repurposed as treatment for COVID-19.
• The investigational antiviral drug remdesivir is undergoing phase 3 clinical trial for safety and efficacy in treatment of hospitalized COVID-19 patients.
• In critical patients, rescue treatment with convalescent plasma transfusions is another therapeutic option.
• Anti-inflammatory agents like corticosteroids, human immunoglobulin, 1L-6 inhibitors, IL-2 inhibitors, JAK inhibitors in the later phase of the disease to control or modulate the host inflammatory response.

In case of any infection, the host reacts by initiating an immune response to fight of the infection in the early phase (“viral response phase”). In the later stages of the illness (“host inflammation response phase”), the host may have an exaggerated or out of control immune response to the trigger, which is the COVID-19 virus infection. This is called “cytokine storm”. At this stage, the virus is deadly and is responsible for the critical condition of the patient and is often fatal. Tests for inflammatory markers (CRP, IL-6, D-dimer, ferritin), troponin, NT-proBNP levels can detect the presence of cytokine storm.