A Case of Pyrexia of Unknown Origin Diagnosed as Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease that is even rarer in the adult population. It requires a high degree of suspicion from the treating physician, and if diagnosed early, patients might have a survival benefit from this highly fatal condition. HLH is a disorder of immune regulation where the hyperactivity of cytokines attacks different cells, which leads to multiple organ dysfunctions. Varying presentations and similarities with other diseases make diagnosis difficult. Familial HLH is commonly seen in the pediatric population, while acquired or secondary HLH is seen in adults. Secondary HLH is commonly triggered by neoplasms, infections, rheumatological diseases, and other autoimmune diseases. Here is a case of HLH that presented as chronic undiagnosed fever. In this case report, we have discussed in detail this disease, its presentation, investigations, treatment, and other important information that will help practicing doctors better diagnose and treat HLH patients.

Epidemiology and Outcomes of Neonatal Hemophagocytic Lymphohistiocytosis

OBJECTIVES

Neonatal hemophagocytic lymphohistiocytosis (HLH) is a rare entity. The objective of the study was to describe the prevalence, clinical characteristics, interventions and outcomes of neonates diagnosed with HLH in the United States.

METHODS

A retrospective analysis of 2009, 2012, and 2016 Kids' Inpatient Database was performed. Neonates discharged/died with a diagnosis of HLH were identified and analyzed.

RESULTS

Among 11,130,055 discharges, 76 neonates had a diagnosis of HLH. Fifty-two percent (95% CI: 38.6-63.6) were males and 54% (95% CI: 39.7-68.5) were white. Herpes simplex infection was present in 16% (95% CI: 9.2-28.1). 24.4% (95% CI: 14.5-37.9) received chemotherapy, 11.5% (95% CI: 5.2-23.6) IVIG and 3.6% (95% CI: 0.8-14.4) allogenic hemopoietic stem cell transplantation. Organ dysfunction was commonly seen and severe sepsis was documented in 26.6% (95% CI: 16.4-39.9). Median LOS was 16 (IQR 7-54) days. The mortality was 42% (95% CI: 30.8-55).

CONCLUSIONS

HLH is a rare diagnosis and carries a high mortality in neonates. Herpes simplex virus is the most common infection associated with neonatal HLH. HLH should be considered in the differential diagnosis in neonates presenting with multi-organ dysfunction or sepsis.

Adult hemophagocytic lymphohistiocytosis causing multi organ dysfunction in a patient with multiple autoimmune disorders: when the immune system runs amok

We report a case of several autoimmune disorders eventually presenting as severe multi organ dysfunction syndrome caused by adult hemophagocytic lymphohistiocytosis (HLH). Clinical and laboratory tests might lead to fatal misinterpretation without awareness of its diagnostic evaluation, as HLH shares common features with sepsis and immune‐mediated systemic inflammatory response syndromes.