Although the prevalence of thrombocytopenia (condition in which you have a low blood platelet count) at the time of admission of a patient with COVID-19 was already known, it has now also been demonstrated at a late stage. A new study at Union Hospital, in Wuhan, China, suggests that 11.8% of hospitalized patients suffer from late thrombocytopenia (delayed-phase thrombocytopenia is defined as thrombocytopenia begins or worsens after 14 days post symptoms appearance) and that in rare cases it can lead to death.
In these late stages, delayed phase thrombocytopenia in COVID-19 is prone to develop in elderly patients (71.9% in over 60-years-old patients) or patients with low lymphocyte count on admission. Similarly, late thrombocytopenia is related to a longer stay in the hospital and a higher amount of ICU admissions. All this, and according to the data provided by the study, implies a worse clinical result compared to those without delayed-phase thrombocytopenia.
Furthermore, hematopoietic system can also be affected by COVID-19. Delayed phase nadir platelet counts demonstrated a high and significantly negative linear correlation with B cell percentages and serum IL-6 levels. The study also presented bone marrow aspiration pathology of three patients with delayed phase thrombocytopenia, showing impaired maturation of megakaryocytes. Speculating that the delayed phase platelet destruction might be mediated by antibodies, and suggesting immunoregulatory treatment in severe patients to improve outcomes. The present descriptive data suggested an association between delayed-phase thrombocytopenia and antiviral immune, which highlight rationality for immunoregulatory treatment.
Finally, study suggests that, although most of the delayed-phase thrombocytopenia lasted less than 7 days, implying the delayed-phase thrombocytopenia is transient, doctors need to pay attention to the delayed-phase thrombocytopenia especially at 3-4 weeks after symptom onset, which is the median time for delayed-phase thrombocytopenia occurrence. This knowledge may help doctors to timely apply immunoregulatory treatment, and thus improve outcomes.
Link to the paper: https://doi.org/10.1101/2020.04.11.20059170
Editorial Disclaimer: information published during the 2020 COVID-19 pandemic may be updated frequently to reflect the dynamic nature of current understanding.