Category: Critical Care
Keywords: HLH, Hemophagocytic Lymphohistiocytosis (PubMed Search)
Please see Part I from 12/24/19 for information about causes and symptoms.
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
· Ferritin elevation (usually markedly elevated)
· Elevated triglycerides
· Low fibrinogen level
· ALT elevation
· 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.
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