In 3 cases of severe
multiple organ failure due to
hemophagocytic lymphohistiocytosis (HLH) in children, the authors demonstrate the utility of continuous
hemofiltration in attenuating the consequences of excess
cytokine activity, with
therapy titrated to the degree of
lactic acidosis. HLH was diagnosed in 3 encephalopathic children with
multiple organ failure, elevated
ferritin (49,396-237,582 pmol/L; or 21,983-105,733 ng/mL), elevated serum
triglyceride, and depressed cell lines. One had a known
malignancy, one had EBV-associated lymphoproliferative disease, and one was previously healthy. Continuous
hemofiltration was initiated, with the ultrafiltrate production rate and countercurrent
dialysate flow titrated to
metabolic acidosis as reflected by the serum
lactate (maximum 3.5 mmol/L or 31.6 mg/dL).
Hemofiltration was titrated upward until
lactic acidosis resolved, through clearance of
lactate or interruption of excess
cytokine-driven activity; maximum prescription was 2000 mL/h ultrafiltrate production plus 2500 mL/h
dialysate flow. Stability was achieved with
hemofiltration, then substantial resolution occurred with treatment according to the HLH-94 protocol (
dexamethasone,
cyclosporin,
VP-16, intrathecal
methotrexate). One child succumbed to
candidiasis. Another made a full recovery. A third succumbed to his primary
malignancy. HLH should be suspected in unexplained or unresolving
multiple organ failure. Titration of
hemofiltration based on measurable parameters of cellular metabolism (e.g.,
lactate, base deficit) may stabilize the child with
metabolic acidosis long enough to allow proper diagnosis and institution of definitive
therapy.
Hemofiltration is not a panacea but rather a stabilizing mechanism, with poorly understood effects on interstitial water and solute flux, that facilitates recovery over weeks, not days.