(850) A Rare Case of Ehrlichiosis Complicated by Secondary HLH and Super-Refractory Status Epilepticus

Introduction: Secondary hemophagocytic lymphohistiocytosis (HLH) is a rare and potentially life-threatening hyperinflammatory condition, often precipitated by infections. Ehrlichiosis, a tick-borne illness, has been reported to cause HLH. While both Ehrlichiosis and HLH can lead to neurological symptoms and, in rare instances, seizures, there are no reported cases of Ehrlichiosis with secondary HLH resulting in status epilepticus in pediatric patients.

Description: A 6-year-old boy with recent tick bites was admitted to Arkansas Children’s Hospital with two-day history of headache, fever, and altered mental status who was found to have serum PCR positive for Ehrlichia chaffeensis. He was treated with doxycycline. He briefly showed improvement in mental status before developing seizure activity which quickly progressed into status epilepticus requiring intubation. His seizures were refractory to first and second line antiepileptic therapies and required infusions of midazolam, ketamine, and eventually pentobarbital to achieve seizure control. Cerebral spinal fluid studies revealed pleocytosis with elevated protein. Brain MRI demonstrated mild volume loss. Lab work revealed hyperferritinemia, hypertriglyceridemia, elevated soluble IL-2, anemia, thrombocytopenia, and hypofibrinogenemia consistent with secondary HLH. Despite receiving appropriate antibiotic coverage, his hyperinflammatory state continued to deteriorate, requiring the initiation of anakinra and dexamethasone. He successfully weaned off the pentobarbital infusion six days after the seizure onset. Subsequently, he was extubated and discharged for rehabilitation.

Discussion: Secondary HLH is a rare condition consisting of hypercytokinemia due to excessive lymphocyte-mediated activation of macrophages and histiocytes as a result of an infection, autoimmune disorder, or malignancy. CNS involvement in secondary HLH is rare and can be challenging to control. Status epilepticus is a rare and difficult-to-suppress complication CNS involved HLH. After undergoing immunomodulation therapy, our patient experienced a successful recovery. Arkansas has the highest incidence of Ehrlichiosis in the United States. Ehrlichiosis needs to be high on the differential for pediatric patients presenting with fever and altered mental status.