Scrub Typhus Complicated by Acute Respiratory Distress Syndrome and Haemophagocytic Lymphohistiocytosis in a Young Patient

摘要

Scrub typhus is an endemic rickettsial disease causing vasculitis involving the small vessels of the body. Haemophagocytic Lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterised by excessive unbalanced cytokine release. An 11-year-old child presented with high grade fever with chills and rigors with respiratory distress. Chest X-ray showed right-sided consolidation. Serological tests for H1N1, Immunoassay for HIV, Montoux test were negative, BACTEC was sterile and CBNAAT of gastric aspirate was normal. Anti Nuclear Antibody and Anti ds-DNA tests were also negative. Rickettsial serology was positive for Scrub typhus, by IgM ELISA. The bone marrow examination showed macrophages with phagocytosis of erythrocytes, lymphocytes and platelets. A diagnosis of HLH was given. Flow cytometry revealed CD4 expression by 42.6% of T-cells and CD8 expression by 99.4% of T-cells leading to a reversal of CD4/CD8 ratio of 1:2. The patient did not respond to treatment and died soon after.Early diagnosis of scrub typhus and its complications is essential as prognosis of the patient depends on time to start of treatment.