Case Presentation: A 37-year-old woman with a history of HTN and ESRD due to preeclampsia now on hemodialysis presented to the hospital for two days of weakness, confusion, and fever. Notably, she had a recent history of blood cultures growing Acinetobacter for which she had received a course of antibiotics. Blood cultures taken at dialysis before admission grew Acinetobacter again and she was started on vancomycin and cefepime as an outpatient. On exam she was febrile, lethargic, and tachypneic with a diffuse erythematous rash. Labs were notable for pancytopenia and elevated liver enzymes. An initial diagnosis of sepsis due to bacteremia complicated by encephalopathy was made. Her dialysis catheter was deemed the likely source given her recurrent positive blood cultures. Her rash was suspected to be a drug reaction due to vancomycin received prior to admission. Based on sensitivities she was started on ampicillin/sulbactam for treatment of Acinetobacter. Her initial CT head was negative. CT chest and abdomen with IV contrast to evaluate for a localized nidus of infection demonstrated hepatosplenomegaly and diffuse retroperitoneal and pelvic lymphadenopathy. In light of her persistent tachypnea and concern for airway protection, she was transferred to the MICU for further monitoring and subsequently required intubation and vasopressors. While there her catheter was removed and a Shiley was placed. A lumbar puncture showed no obvious cause for her symptoms and her admission blood cultures were negative. Furthermore, she was noted to have a markedly elevated ferritin over 100,000 along with a lactate dehydrogenase of 3000. Concern for hemophagocytic lymphohistiocytosis (HLH) was raised and hematology was consulted. Due to a high H-score she was empirically started on high-dose dexamethasone. Subsequent lymph node biopsy showed aberrant T-cells suggestive of a neoplasm, and a bone marrow biopsy demonstrated hemophagocytosis. Soluble interleukin-2 receptor and CXCL9 were markedly elevated. She met diagnostic criteria for HLH and genetic testing was sent for further confirmation. She was subsequently started on etoposide. She eventually grew Stenotrophomonas in her sputum and blood and was treated with levofloxacin. While in the MICU, multiple attempts were made to wean sedation, however her encephalopathy persisted over her course. Video EEG and repeat CT head were negative. MRI head showed confluent areas of restricted diffusion in the bilateral parietal lobes, left insular cortex and left inferior frontal region. Together with intermittent hypertension, the neurology team was concerned for posterior reversible encephalopathy syndrome (PRES), possibly associated with her HLH. While still in the MICU she did not regain a mental status, became hemodynamically unstable, and ultimately expired.
Discussion: This case illustrates the importance of early recognition of HLH, especially in patients presenting with signs of diffuse inflammatory response. It also highlights anchoring bias given her positive outpatient blood cultures in the setting of a longstanding dialysis catheter. It is important to recall that even though HLH can mimic an infection, HLH can also be triggered by one. Additionally, there are cases with primary HLH and PRES mostly in children, but it will be important for clinicians to further investigate a possible link in adults as this can obscure the diagnostic picture.
Conclusions: While HLH may wear the mask of other diagnoses, suspicion of it is crucial in the critically ill to help alter outcomes.