UMEM Educational Pearls

Category: Critical Care

Title: Hemophagocytic Lymphohistiocystosis (HLH) Part II

Keywords: HLH, Hemophagocytic Lymphohistiocytosis (PubMed Search)

Posted: 3/31/2020 by Kim Boswell, MD (Updated: 10/21/2020)
Click here to contact Kim Boswell, MD

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

References