The diagnosis of MAS requires the simultaneous presence of 1 clinical criterion + at least 2 laboratory criteria. Bone marrow aspiration for evidence of macrophage hemophagocytosis may be required in doubtful cases. This diagnostic criteria may not be powerful enough to distinguish MAS from particular infectious complications |
Clinical criteria |
1. Fever (>38 °C) |
2. Hepatomegaly (≥3 cm below the costal arch) |
3. Splenomegaly (≥3 cm below the costal arch) |
4. Hemorrhagic manifestations (purpura, easy bruising, or mucosal bleeding) |
5. Central nervous system dysfunction (irritability, disorientation, lethargy, headache, seizures, or coma) |
Laboratory criteria |
1. Cytopenia affecting 2 or more cell lineages (white blood cell count ≤ 4000, hemoglobin ≤ 9 mg/dL, or platelet count ≤ 150,000/mm³ |
2. Increased aspartate aminotransferase (>40 units/L) |
3. Increased lactate dehydrogenase (>567 units/L) |
4. Hypofibrinogenemia (fibrinogen ≤ 1.5 g/L) |
5. Hypertriglyceridemia (triglycerides > 178 mg/dL) |
6. Hyperferritinemia (ferritina > 500 mcg/L) |
Histopathologic criterion |
Evidence of macrophage hemophagocytosis in the bone marrow aspirate |