Objective: To improve the understanding of clinical manifestations, diagnostic criteria and therapeutic measures of hemophagocytic lymphohistiocytosis (HLH) with viral encephalitis onset.

Methods: This paper reports the diagnosis and treatment of a case diagnosed as hemophagocytic lymphohistiocytosis complicated with viral encephalitis symptoms onset admitted to the department of neurology. Based on literature review, the etiology, classification, clinical manifestations, diagnostic criteria and treatment of hemophagocytic syndrome were discussed.

Results: One young patient complained of fever and headache, and his condition progressed rapidly, resulting in infectious shock and disseminated intravascular coagulation. After laboratory examination and multidisciplinary discussion, the patient was diagnosed as hemophagocytic lymphohistiocytosis. Dexamethasone, gamma globulin, anti-infection, platelet transfusion and other treatments were given, and the patient was discharged with fully recovery.

Conclusion: Hemophagocytic lymphohistiocytosis is an overactive inflammatory response syndrome caused by abnormal immune regulation that can occur at all ages, and it can be life-threatening. To improve the understanding of the clinical manifestations, diagnostic criteria and treatment measures of HLH is helpful for early diagnosis and appropriate treatment.