The first case of Streptococcus intermedius brain abscess with hemophagocytic histiocytosis

Background Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening immune syndrome associated with an excessive systemic inflammatory response. Viral infection caused HLH is the most common secondary HLH, but there are relatively few reports of HLH caused by bacterial infection. The present study is the first case of HLH caused by Streptococcus intermedia meningitis. Case presentation The patient is an 11-year-old and 9-month-old boy. The main symptoms are fever, headache, and vomiting. The imaging finding of the brain is cerebritis and brain abscess. The cerebrospinal fluid (CSF) routine test showed increased nucleated cells, but the smear and culture of CSF were negative. The metagenomics next-generation sequencing (mNGS) of CSF detected Streptococcus intermedius, and the body temperature of the children returned to normal after antibiotic treatment according to etiology. One week later, the child developed fever again, with Kawasaki disease-like manifestations. After high-dose immunoglobulin therapy, the body temperature returned to normal again. The routine blood test showed a progressive decrease in leukocytes and platelets, and bone marrow biopsy detected histiocytes phagocytosed blood cells. Then infection-associated hemophagocytic syndrome (IAHS) was diagnosed, high-dose methylprednisolone and sequential therapy were given and the patient's recovery was encouraging. Conclusions Our case shows that HLH can also be secondary to Streptococcus intermediate infection, and early bone marrow biopsy is the golden standard for HLH diagnosis. mNGS can improve the detection sensitivity for pathogens when traditional pathogenic tests are negative. Conventional chemotherapy regimens may not be required for IAHS when high-dose glucocorticoids and immunoglobulin therapy are effective.