# Hemophagocytic Lymphohistiocytosis: A Life-Threatening Hyperinflammatory Syndrome

## TL;DR

This paper presents a case of a man with two episodes of a rare, life-threatening immune condition called hemophagocytic lymphohistiocytosis (HLH), successfully treated with a specific anti-inflammatory drug.

## Contribution

The paper highlights the use of anakinra, an interleukin-1 receptor antagonist, in managing adult-onset HLH triggered by different underlying conditions.

## Key findings

- HLH was successfully treated with anakinra in two separate episodes in the same patient.
- HLH can be triggered by latent tuberculosis, parvovirus B19, and adult-onset Still’s disease.
- Early recognition and targeted immune therapy can improve outcomes in HLH patients.

## Abstract

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome resulting from uncontrolled immune activation. It can be triggered by infections, malignancies, or autoimmune conditions and is difficult to diagnose due to its nonspecific clinical presentation.

A male patient around 30 years old was admitted to the ICU in 2016 with severe diarrhea, vomiting, and abdominal pain. He developed pancytopenia requiring granulocyte colony-stimulating factor (G-CSF) support. Bone marrow aspiration and trephine revealed hemophagocytosis, with markedly elevated serum ferritin levels and a negative autoimmune workup apart from a positive anti-Ro antibody. The diagnosis of acquired HLH was established in the patient. Latent tuberculosis (TB) was treated empirically, and polymerase chain reaction (PCR) detected parvovirus B19. He was managed with high-dose dexamethasone after a hematology consultation and received intravenous immunoglobulin (IVIG).

A few years later, in 2022, the patient was readmitted with acute respiratory distress and bilateral pulmonary consolidations. He was diagnosed with adult-onset Still’s disease (AOSD) and secondary HLH. Imaging suggested fibrotic organizing pneumonia with a differential diagnosis of interstitial lung disease (ILD) or nonspecific interstitial pneumonitis (NSIP). Both episodes of HLH were successfully managed with interleukin-1 receptor antagonist therapy, i.e., anakinra.

This case demonstrates the complexity of HLH in adults. The first episode was likely to be triggered by the latent TB and parvovirus infection, and the second one by the AOSD. Both episodes were treated with anakinra, showing that targeting specific immune system chemicals can help manage HLH.

Clinicians should consider the possibility of HLH for patients who have low blood counts and widespread inflammation with an unclear cause, especially if they have known risk factors. Early recognition and prompt treatment with medicines that are targeted towards the immune system can save lives. It's also important to monitor these patients over time, as HLH can recur and may lead to long-term problems like lung damage.