FORTUNATELY, NOT A TTP (THROMBOTIC THROMBOCYTOPENIC PURPURA). A CASE OF COVID INFECTION WITH EXTREME THROMBOCYTOPENIA (PLATELETS 5K/UL) AND SEVERE DEFICIENCY OF ADAMTS 13 (<2 %) WITHOUT TTP SYMPTOMS AND WITHOUT NEED FOR PLASMAPHERESIS

ABSTRACT

CASE 54-year-old female presented with 1 week of generalized weakness, headache, congestion, cough with dark- colored phlegm, and several days of decreased smell and taste. She was unvaccinated and had positive sick contacts. Patient tested positive for Covid and found to have severe thrombocytopenia with platelets of 5K/uL, very rare schistocytes on smear, and no other notable abnormalities. She received platelet transfusion and was treated for presumed immune thrombocytopenia with IVIG and dexamethasone. The patient had no petechiae, bleeding, or other symptoms concerning for secondary TMA, notably TTP. The platelet count was 93 K/uL by day 5 and she was discharged home. Later that day her ADAMTS13 test resulted at <2% and the ADAMTS13 antibody was elevated. The patient was asked to return to the hospital for monitoring of TTP symptoms. She reported improvement in her weakness. Her thrombocytopenia and oxygen saturation remained normal. Bilateral lower extremity ultrasound showed no lower extremity VTE. On the day of discharge, 10 days after her original thrombocytopenia identified, she had a platelet count of 373 K/uL and repeated ADAMTS13 of 14.8%. IMPACT/DISCUSSION: ADAMTS13 is known as von Willebrand factor (VWF) protease as it cleaves prothrombotic and highly adhesive to platelets ultra-large multimers of VWF into smaller multimers, thus modulating VWF activity and regulating the adhesive function. A severe deficiency of ADAMTS13 characterizes TTP, a rare but potentially fatal disorder associated with thrombosis due to accumulation of prothrombotic ultra-large VWF multimers. There are literature reports of TTP and TTP-like syndromes in Covid-19. It is speculated that in COVID-19, the excess of VWF released in response to endothelial activation likely exhausts the available reserves of ADAMTS13, which may then propagate formation of microthrombi in different organs. We report an extreme thrombocytopenia, marked decrease of ADAMTS 13 and elevated ADAMTS13 antibodies, which would be confirmative evidence of TTP should our patient have clinical features of it. Our patient did not have fever, neurologic abnormalities, renal dysfunction, or active hemolysis. She was followed in outpatient clinic after the discharge. The platelet count recovered and ADAMTS 13 trended up without need for plasmapheresis. Our case is a good example of a fortunate outcome without any complications despite threatening presenting criteria. CONCLUSION: Covid-19 associated endothelial stimulation and damage could mimic a life-threatening disorder without expected fatal complications. On the other hand, it can ultimately lead to the most severe form of thrombotic microangiopathy, TTP, for which the mortality rate is close to 90%. It is hard to know which outcome to expect in different circumstances. Therefore, it is crucial for physicians to promptly recognize clinical picture of TTP as treatment is lifesaving.