Unraveling the mystery of Covid-19 cytokine storm: From skin to organ systems

Abstract

COVID-19 is a global pandemic that emerged from Wuhan, China. Besides pneumonia and acute respiratory distress syndrome, the disease leads to multisystem involvement in the form of myocarditis, arrhythmias, cardiac arrest, gastrointestinal symptoms, hypoxemic brain injury, acute liver, and renal function impairment. There are also reports of cutaneous lesions in form of urticarial and maculopapular rashes, chilblain like fingers and toes (covid feet), livedoid vasculopathy, and chicken-pox like or varicelliform vesicles. Clinically, many of these skin lesions are likely secondary to occlusion of small to medium blood vessels due to microthrombi formation or due to viral laden antigen-antibody immune complexes; and same explanation may hold true for possible hypoxemic injury simultaneously occurring in other vital organs like lungs, heart, brain, and kidneys. The histopathology, immunoflorescence and RT-PCR analysis of skin biopsies can provide useful insights for ascertaining the pathogenesis of this complex viral syndrome. Apparently, it is interplay of disarmed cellular immunity and over-activated humoral immunity that culminates in end-organ changes. The morbidity and mortality can be significantly reduced by upgrading the cellular immunity and downgrading the humoral response; along with prevention of hypoxemic and reperfusion injuries by using antivirals, immunomodulators, antioxidants, anti-platelets, and anticoagulants in judicious and phased manner.

Keywords: Covid; Covid feet; cytokine storm.

FIGURE 1

Flowchart explaining how the SARS‐CoV‐2 virus attacks the nasopharynx and gains entry into lung, gastrointestinal system, and blood vessels due to abundant presence of ACE2 receptors. Cell mediated immunity is disarmed by atrophy and destruction of lymph nodes, thymus, spleen, and liver. Blood vessels in lung are easy target due to presence of ACE2 receptors initiating cascade of micro‐thrombi formation, immune complex deposition, and exaggerated humoral immune response leading to subsequent hypoxemic injury to various vital organs