“Covid-19 A New Viral Trigger to Hemophagocytic Lymphohistiocytosis?”

1. Summary We report a case of patient with COVID-19 pneumonia who had prolong course in critical care unit and developed clinical and laboratory features of Hemophagocytic Lymphohistiocystosis (HLH) supported by findings on bone marrow. Patient received supportive treatment and IL-6 inhibitor but developed multiorgan failure and could not revive back to life. HLH is life threatening condition with rapid course and can lead to multiorgan failure and death. This case highlights the importance of fact that HLH can lead to significant morbidity and mortality in critically ill patient with COVID-19 pneumonia and it warrants early evaluation in these patients. 2. Introduction Nearly 4.2 million [1] people are affected by Coronavirus (SARSCoV2 or COVID-19) worldwide since the new virus emerged in china late in 2019. Although the majority of patients are suffering from mild disease, a significant number of patients sill requires intensive care management [2]. It is not clear yet why the virus manifests itself as life threatening and deadly in some patients. Whether the direct viral infection or the abnormal hyperimmune response is the main cause of mortality is still an area of ongoing research. Secondary Hemophagocytic Lymphohistiocystosis (HLH) is one such example of life threatening and excessive immune activation leading to tissue destruction and multiorgan failure [3]. HLH has been described in the past in association with rheumatological disorders [4, 5] and certain viral infections such as Epstein-Barr virus (EBV) [5]. Various scores have been validated for the prediction of HLH in clinically relevant context. One such score is the H score [6] as summarized in (Table 1). Table 1: The Hscore [8] Parameter No. of points (criteria for scoring) Known underlying immunosuppressiona 0 (no) or 18 (yes) Temperature (°C) 0 (<38.4), 33 (38.4–39.4), or 49 (>39.4)