UMEM Educational Pearls

Category: Airway Management

Title: Hemophagocytic Lymphohistiocytosis (HLH)

Keywords: HLH, Hemophagocytic Lymphohistiocytosis (PubMed Search)

Posted: 12/24/2019 by Kim Boswell, MD
Click here to contact Kim Boswell, MD

Hemophagocytic Lymphohistiocytosis (HLH) – Part I

A rare, but important disease that is becoming more widely recognized and more frequently diagnosed. This disease, while uncommon, is rapidly progressive and caries a high mortality rate.

Causes are not completely understood, but involve abnormal activation of the immune response due to a failure of the typical downregulation in hyperinflammatory processes.

Two types exist:

            Congenital/Familial – genetic predisposition which usually requires a triggering event to occur

            Acquired – occurs in adults with no known predisposition (often have underlying genetic predispositions) – triggering events include infections , immunodeficiency, rheumatologic disorders, and malignancy in addition to many others.

Diagnosis is challenging due to the wide variety of symptoms and constellation of symptoms, which often mimic more common infections/sepsis presentations.  Common symptoms include the following:

  • Fever – 95 percentSplenomegaly – 89 percent 
  • Bicytopenia – 92 percent (most often anemia and thrombocytopenia) 
  • Hypertriglyceridemia or hypofibrinogenemia – 90 percent

Symptoms can, and do, occur in any body system – rashes, conjunctivitis, DIC, LFT abnormalities,  hypotension/shock, and respiratory failure are all common concomitant findings in the presentation of HLH

More on the specific diagnosis and treatment to follow in part II...

References

McClain KL. Clinical features and diagnosis of hemophagoctyic lymphohistiocytosis. UpToDate.Waltham, MA:UpToDate Inc. https://www.uptodate.com (Accessed on December 24, 2019.)