HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS, FAMILIAL TYPE
FHLH types 1, 2, 3, 4 and 5; FHL; HLH; HPLH; Familial Erythrophagocytic Lymphohistiocytosis; Erythrophagocytic Lymphohistiocytosis; Familial Histiocytic Retulosis
Familial Hemophagocytic Lymphohistiocytosis (FHLH) is a rare, genetic disease that is caused by mutations in the perforin 1 (PRF1) gene. FHLH is characterized by uncontrolled activation of the immune system. The T cells, macrophages and overproduced inflammatory cytokines infiltrate the liver, spleen, bone marrow and central nervous system resulting in a multi-system disorder. The highly stimulated and ineffective immune response threatens the life of the individual and may lead to death unless appropriate and timely treatment is provided. Symptoms include: prolonged high fever, enlargement of the spleen (splenomegaly), jaundice, engulfment and destruction of blood cells in the bone marrow and other tissues. It commonly appears in infants and during early childhood, although it can appear in all age groups. FHLH can be triggered by infections, viruses such as Epstein-Barr, rheumatic diseases and malignancies.
TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
A molecular diagnosis confirms the disease. Clinical evaluation of fever and splenomegaly, and blood tests which measure high triglycerides, ferritin, transaminases, bilirubin, coagulation time and decreased fibrinogen.
ICD-9: 288.4 Hemophagocytic syndromes
ONSET AND PROGRESSION
FHLD is uniformly fatal if not treated. The prognosis is varied for those receiving treatment. The median survival time is 2 -6 months after diagnosis. Even with treatment, approximately 21-26% of individuals with FHLD can be expected to survive 5 years. Remission is always temporary, as the disease inevitably returns. Without treatment, the uncontrolled inflammatory response leads to sustained neutropenia and death from bacterial or fungal infections as well as from cerebral dysfunction.
Individuals with FHLD often receive treatment for the symptoms of this disease. Treatment may include antibiotic therapy for any infection and immunologic treatment for immune disorders. Some individuals are treated with stem cell or bone marrow transplants. The response to treatment is variable.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for Evaluation: Complete medical history and physical examination with a description of findings. Laboratory studies measuring high triglycerides, ferritin, transaminases, bilirubin, coagulation time and decreased fibrinogen.
Suggested Listings for Evaluation:
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114.07 A, B or C
Need to differentiate Familial HLH from Acquired or Secondary HLH which has a very good prognosis.