Hemophagocytic Lymphohistiocytosis (HLH): What's the Calm Before the Storm?

Introduction: Hemophagocytic lymphohistiocytosis (HLH) results from life-threatening immune system overactivation, often misdiagnosed due to nonspecific symptoms1. Urgent immunosuppression is essential to manage hyperinflammation, and emapalumab may be necessary in cases that deteriorate Case Description: 59-year-old male on dialysis presented with abdominal pain, weakness, and shortness of breath, was hypertensive, anemic, had thrombocytopenia. A CT scan revealed liquid stool in the intestines, with no significant thickening of the bowel wall, required NG tube placement and hemodialysis. Next day, he exhibited fever, lethargy, and worsening encephalopathy. Lab results revealed elevated LDH 5410 and a reticulocyte count of 3.2, low haptoglobin <10, and high ferritin levels > 26,000. H-score of 170 suggested a 40-54% probability of HLH, led to initiation of empiric steroids. Infectious workup prompted treatment for C. difficile diarrhea and intubation for worsening sepsis. Later elevated IL-2 receptor levels 3143 were noted. Unfortunately, he deteriorated and suffered cardiac arrest, becoming unresponsive despite resuscitation efforts. Tragically, he passed away before getting Etoposide. Discussion: HLH is a serious condition with primary and secondary forms, later related to infections, autoimmune disorders, or malignancies1 Diagnosis requires meeting five out of eight criteria described1. Presentation mimics infections involves hyperinflammation and rapid deterioration2. Ferritin levels above 7,500-10,000 ng/ml greatly enhance specificity2. Distinguishing HLH from infectious diseases is crucial because treatment strategies differ3. Immunosuppressive therapy, especially with concurrent infections, can be risky; thus, the focus should be on managing infections, often starting with corticosteroids and possibly using IVIG2,3. Etoposide and dexamethasone reduce proinflammatory cytokines, while emapalumab targets interferon-γ for resistant patients4,5. C. difficile infections, often linked to antibiotic use, can lead to severe complications6. Rarely, HLH patients have developed C. difficile infections, as seen in cases involving EBV-associated T-cell lymphoma and ulcerative colitis with CMV infection7,8. Both patients tragically lost their lives, like our patient, underscoring the need for vigilant diagnosis, a multidisciplinary approach, and timely initiation of immunosuppression in this context.