Differential Diagnosis for Hemophagocytic Lymphohistiocytosis (HLH) vs. Macrophage Activation Syndrome (MAS)
- Single most likely diagnosis:
- HLH: The presence of clear HLH activity in the bone marrow strongly supports this diagnosis, as it is a key diagnostic criterion for HLH. HLH is a rare, life-threatening condition characterized by excessive immune activation and tissue damage.
- Other Likely diagnoses:
- MAS: Although MAS is closely related to HLH and shares many clinical and laboratory features, the presence of clear HLH activity in the bone marrow may lean more towards HLH. However, MAS can still be considered, especially if there are underlying conditions such as autoimmune disorders or infections that could trigger MAS.
- Infection-associated hemophagocytosis: This condition can mimic HLH or MAS and should be considered, especially if there is evidence of an underlying infection.
- Do Not Miss diagnoses:
- Sepsis: Sepsis can present with similar clinical features to HLH or MAS, including fever, organ dysfunction, and coagulopathy. It is crucial to rule out sepsis, as it requires prompt and specific treatment.
- Malignancy: Certain malignancies, such as lymphoma or leukemia, can cause secondary HLH. Missing a diagnosis of malignancy could have severe consequences.
- Rare diagnoses:
- Langerhans cell histiocytosis: This rare disorder can cause hemophagocytosis and should be considered, especially if there are other systemic symptoms or radiographic findings suggestive of LCH.
- Erdheim-Chester disease: This rare histiocytic disorder can cause hemophagocytosis and should be considered if there are other characteristic features, such as bone lesions or cardiovascular involvement.