Diagnosis of CSS in COVID-19
There is no standard for the diagnosis of CSS related to COVID-19, so further clinical and laboratory investigations are needed. The basic principles for consideration of CSS in COVID-19 are the following presentations:
  1. A rapid or sudden regression of multiple organ functions (cardiac, liver or renal injury).
  2. The elevation of systematic inflammatory biomarkers (such as CRP, erythrocyte sedimentation rate and serum ferritin).
  3. A significant decrease of lymphocyte counts.
  4. The elevation of cytokines, such as IL-1β, IL-2R, IL-6, IP-10, MCP-1, TNF-α and IFN-γ.
Clinicians should keep highly alert on the possibility of CSS under these circumstances. However, that CSS is highly heterogeneous and may present with unspecific syndromes, the diagnosis of CSS in COVID-19 is very challenging and the development of a specific diagnostic test that helps to make the diagnosis of CSS earlier is a high priority for future research [12].
The inflammatory disorders in COVID-19 have been reported in many studies. COVID-19 causes a decrease of lymphocyte count and an increase of C reactive protein (CRP), especially in severely ill patients. The major subtypes of T lymphocytes (T cell) (CD3+ CD4+ T cell and CD3+ CD8+ T cells) are reduced in the COVID-19 and are significantly lower in the severe cases. Other immune cells, B cell and natural killer (NK) cell, have more inconsistency in recent studies[13].