Reviewed and revised 11 July 2014
- Haemophagocytic lymphohistiocytosis (HLH) may be inherited (AR; 5 subtypes, aka familial HLH) or acquired;
- may mimic severe sepsis, consider in apparent sepsis without source
- likely under-diagnosed in ICU
- HLH arising secondary to EBV or other viral infection is commonly termed X-linked lymphoproliferative disease (XLP)
- a hyperimmune state characterised by pathological and uncontrolled macrophage and T-cell activation from cytokine production
- can be primary or secondary (congenital typically presents as shock and acidosis in infancy or early childhood)
- may be triggered by infection, malignancy or rheumatological disease
Molecular diagnosis consistent with HLH: pathologic mutations of PRF1,UNC13D, Munc18-2, Rab27a, STX11, SH2D1A, or BIRC4
Five of these eight criteria:
- Cytopenia of two or more cell lines (i.e. Hb <90 g/L, platelets <100 x 10E9/L, neutrophils <1 x 10E3/L)
- Either elevated triglycerides or low fibrinogen
- Histopathological evidence of hemophagocytosis (on either bone marrow, spleen or lymph node biopsy)
- Serum ferritin > 500 mcg/mL (often much higher in HLH: ferritin > 3000 ng/mL as concerning for HLH and ferritin > 10 000 as highly suspicious (96% specific))
- Low or absent NK cell activity (by flow cytometry, if available)
- Soluble CD25 > 2400 U/mL
- Treatment of the underlying cause
- Chemotherapy may be required in severe cases (e.g. etoposide, dexamethasone, and cyclosporine)
- Platelet transfusion as indicated
- Supportive care: pneumocystis jiroveci prophylaxis, fungal prophylaxis, intravenous immunoglobulin supplementation, and neutropenic precautions
References and Links
- Allen CE, Yu X, Kozinetz CA, et al. Highly elevated ferritin levels and the diagnosis of hemophagocytic lymphohistiocytosis. Pediatr Blood Cancer. 2008;50:1127–1129. PMID: 18085676
- Besset S, Schnell D, Azoulay E. Hemophagocytic lymphohistiocytosis mimicking septic shock. Chest 2012 Mar;141(3):835. PMID 22396580 [Free Full Text]
- Jordan MB, Allen CE, Weitzman S, Filipovich AH, McClain KL: How I treat hemophagocytic lymphohistiocytosis. Blood 2011, 118:4041–4052. [Free Full Text]
- Raschke RA, and Garcia-Orr R. Original Research. Critical Care. Hemophagocytic Lymphohistiocytosis. A Potentially Underrecognized Association With Systemic Inflammatory Response Syndrome, Severe Sepsis, and Septic Shock in Adults. Chest 2011; 140 (4): 933-938. PMID: 21737492 [Free Full Text]
- Strauss R, Neureiter D, Westenburger B, Wehler M, Kirchner T, Hahn EG (2004) Multifactorial risk analysis of bone marrow histiocytic hyperplasia with hemophagocytosis in critically ill medical patients–a postmortem clinicopathologic analysis. Crit Care Med 32:1316–1321. PMID: 15187513
FOAM and web resources
- Maryland CC Project — HLH… the White Whale of Hematology! (2014)
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.