Category: Critical Care
Keywords: HLH, Hemophagocytic Lymphohistiocytosis (PubMed Search)
Posted: 3/31/2020 by Kim Boswell, MD
(Updated: 4/20/2024)
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Please see Part I from 12/24/19 for information about causes and symptoms.
Diagnosis:
The diagnosis of HLH is challenging, as it often mimics sepsis or other critical illness. A high index of suspicion is vital and early treatment, imperative.
Diagnostic criteria in adults include 5 of 8 of the following:
(based on the Hscore: https://www.mdcalc.com/hscore-reactive-hemophagocytic-syndrome#use-cases)
· Presence of known immunosuppression
· Fever >38.5
· Splenomegaly or hepatomegaly
· Cytopenias
· Ferritin elevation (usually markedly elevated)
· Elevated triglycerides
· Low fibrinogen level
· ALT elevation
Immunologic testing:
· CD25 levels are elevated
· NK cell activity is low or absent
In adults, highly elevated ferritin levels (>10,000) are highly suggestive of HLH.
Elevated LDH, Ddimer, and multisystem organ dysfunction (especially CNS) is common.
Immunologic testing should not delay treatment if other lab values suggestive of HLH.
Treatment:
Given the high mortality rate, treatment should be initiated if the symptoms are suggestive of HLH. In the setting of a critically ill individual, hematology consultation is warranted for treatment guidance as treatment is based on lab values and clinical picture. Treatment usually starts with high dose , IV steroids (dexamethasone) and may include chemotherapeutic agents, such as Etoposide. For those patients with CNS involvement, intrathecal chemotherapy is usually a mainstay of treatment
