# A Case Report of Aggressive Post-Infectious Hemophagocytic Lymphohistiocytosis in an Immunocompetent Adult

## TL;DR

This case report highlights a rare aggressive immune disorder in an adult, emphasizing the need for early diagnosis and treatment to improve outcomes.

## Contribution

The case underscores the importance of early suspicion and treatment of HLH in adults using updated diagnostic criteria.

## Key findings

- HLH can present aggressively in immunocompetent adults with non-specific symptoms.
- Timely treatment with etoposide and steroids is critical for survival, even without bone marrow confirmation.
- The HScore criteria offer a broader diagnostic scope compared to older pediatric-focused criteria.

## Abstract

Hemophagocytic lymphohistiocytosis (HLH) is an acute inflammatory syndrome triggered by immune events such as infections, inflammation, autoimmune diseases, and malignancies. Initial presentations can range from vague symptoms to infectious features such as fever. Given its aggressive nature, timely diagnosis and immediate treatment are crucial to achieving optimal patient outcomes. Recently, the HLH score (HScore) criteria have been applied as diagnostic criteria, offering a broader scope compared to the previous HLH-2004 score, which was primarily based on pediatric populations. The standard treatment for decades has involved the combination of etoposide and high-dose steroids, and it is recommended to initiate treatment as soon as possible, even in the absence of a bone marrow test or when there is suspicion of the diagnosis. In this case presentation, we aim to underscore the significance of maintaining a high level of suspicion for HLH and the importance of promptly initiating treatment.