Hematological disorders associated with Covid-19

The Covid-19, the pandemic disease caused by Novel Corona Virus (SARS-CoV2) has a plethora of hematological disorders that form the leading cause of morbidity and mortality associated with this illness.

To start with, one of the early hallmarks of Covid-19 is a drop in White Cell Count (TLC) and particularly that of Lymphocytes. The platelets drop too. The virus also leads to Co-agulopathy, a disruption in the clotting mechanism of the blood. This disruption can result in excessive clotting or bleeding throughout the body’s blood vessels leading to DIC (Disseminated Intravascular Coagulation). Overactive clotting factors and proteins lead to this potentially fatal condition. These thromboembolic phenomena i.e. clot in the veins and sometimes in arteries can cause thrombosis or embolism across different organs of the body and in the lungs is called pulmonary embolism, or blood supply cut-off in solid organs like the Liver, Kidney or brain leading to a multi-organ failure. This phenomenon is seen in as much as 30% of patients admitted with severe Covid-19 disease. The troubling factor is that it is unclear if the conventional anti-coagulation therapy, even with increasing doses, is helping to improve outcomes in the affected.

One may have heard of the term “Cytokine Storm” during Covid-19. Cytokines are proteins that are secreted by the different white blood cells in response to an outside antigen. This is to defend the body against it. However, Covid-19 induces a huge, disproportionate response when these cytokines are released in large quantities into the tissues resulting in fluid logging. For example, fluid logging in the lungs causes blockage of airways resulting in patient gasping for breath, to ARDS (Acute Respiratory Distress Syndrome) to death.

To detect these abnormalities of dysfunction of the blood vessel endothelium, we perform a bunch of tests including d-dimer, Fibrinogen, and coagulation profile like Prothrombin time, Partial Thromboplastin Time and we look for elevated clotting factors like vWF Ag and Factor VIII. Blood thinning agents are then instituted to control these coagulation disturbances.

While all this sounds alarming, one should remember that the low risk patients are not even hospitalized, and when a patient exhibits signs of moderate to high risk, all relevant tests are run in a good ICU equipped to manage Covid-19 and therapies instituted to retard the progress of the disease. Anti-coagulation therapy may be in place for a month (minimum) to 3 months in such patients. It is indeed a long haul and even with the best of care, mortality is a possibility, making Covid-19 a dreaded disease. However, according to our Indian experience, fewer than 2% of Covid-19 patients die, far lower than the 5-6% mortality in the western world. This is a good situation we find ourselves in and it could be a topic for another time!

About Author: Dr Niti Raizada, Director – Medical Oncology and Hemato-Oncology, Fortis Hospital, Bengaluru.