COVID-19: Clinical sciences

COVID-19 is a respiratory infection caused by SARS-CoV-2, a highly contagious virus that primarily spreads via respiratory droplets. Once in the respiratory tract, the virus replicates and causes symptoms similar to the common cold, while in some cases, the virus causes a robust inflammatory response that can produce life-threatening illness. Based on clinical manifestations, COVID-19 can be mild, moderate, severe, or critical.

Now, if your patient presents with chief concerns suggesting COVID-19, you should first perform an ABCDE assessment to determine if your patient is unstable. If the patient is unstable, stabilize their airway, breathing, and circulation. This might require you to intubate the patient and provide mechanical ventilation. Also, don’t forget to obtain IV access and place your patient on continuous vital sign monitoring including heart rate, blood pressure, and pulse oximetry.

Once you stabilize the patient, obtain a focused history and physical exam; but also labs, such as a SARS-CoV-2 test; an arterial blood gas, or ABG; a CMP; inflammatory markers, including CRP and ESR; as well as D-dimer, BNP, troponin, and lactate. You should also obtain a chest X-ray and ECG.

Typically, patients report respiratory symptoms, such as cough, rhinorrhea, nasal congestion, as well as shortness of breath, and difficulty breathing. They may also report new loss of taste or smell. Often, systemic symptoms like headache, fatigue, myalgia and fever, are associated. Some patients may also experience gastrointestinal symptoms like nausea, vomiting, or diarrhea. Additionally, patient history can reveal a known SARS-CoV-2 exposure.

On physical exam, you can find evidence of respiratory distress, such as hypoxemia, as well as rales or rhonchi on auscultation, and accessory muscle use and retractions. In severe cases, your patient can be hypotensive as well!

As for labs, these will reveal a positive SARS-CoV-2 test. The ABG and CMP can show respiratory alkalosis; and CRP and ESR are typically elevated. Depending on the severity of the illness, the patient could also have elevated D-dimer, BNP, troponin, or lactate levels.

Now, the chest X-ray typically shows ill-defined, patchy, ground glass opacities that are predominantly peripheral and typically affect the lower lobes, but keep in mind that in some cases, it may not show abnormalities. Finally, the ECG could show heart rate or rhythm abnormalities, as well as ischemic changes such as ST segment depression or T wave inversions.

Now, here’s a clinical pearl! Some medications used to treat COVID-19 can prolong the QTc interval, so having an initial ECG is important to help trend and ensure the QTc interval does not become too prolonged. They can also increase liver enzymes, so having baseline and follow-up liver function tests is important to monitor for hepatotoxicity.

Okay, at this point, you can diagnose critical COVID-19! Often, these patients require aggressive respiratory support, so based on the patient’s degree of respiratory distress, you can start either the high-flow nasal cannula, noninvasive ventilation, invasive ventilation, or even ECMO.

All patients should receive systemic corticosteroids, as well as an immunomodulator to decrease inflammatory-mediated injury; but also remdesivir to directly target the virus. Next, put all patients on a prophylactic dose of anticoagulation, often preferably low molecular weight heparin, since COVID-19 can cause thrombotic complications. Finally, if your patient is hypotensive, start vasopressors to maintain adequate blood pressure and organ perfusion.

Now, here’s a clinical pearl to keep in mind! Monoclonal antibodies against SARS-CoV-2 have been shown to provide clinical benefit in treating COVID-19, but their efficacy depends on the viral strain.