Transient abnormal myelopoiesis (TAM) causing multiple organ failure

Abstract

Objective. To review all neonates admitted to our intensive care unit (ICU) with Transient Abnormal Myelopoiesis (TAM) – a self-limiting congenital myeloproliferative disorder seen in association with Down's syndrome. We have become concerned that in neonates requiring intensive care, TAM may not be self-limiting in its course resulting in a poor prognosis.

Method. A retrospective review of neonates admitted to our intensive care unit (ICU) with TAM and trisomy 21 between 1996 and 2000. Clinical presentation, disease progression and laboratory findings were recorded to identify any prognostic features.

Results. Four cases of TAM and trisomy 21 were admitted. All four presented within the 1st week of life in respiratory failure secondary to pulmonary hypertension. All were hydropic and showed evidence of hyperviscosity. Median white cell count at presentation was 282, range 56–471×10⁹/l. All excepting one were treated with exchange transfusion and low dose cytarabine. Three died of multi-organ failure in spite of aggressive treatment. Post mortem examination of the infants confirmed the diagnoses and showed multiple thrombo-emboli in the lungs and livers.

Conclusion. In infants with TAM requiring ICU, the severity of illness produced by this 'self-limiting' disease is striking and the resultant morbidity and mortality has not been reported previously. The markers for fatal outcome versus spontaneous resolution of TAM are not clear. In a dysmorphic, hydropic neonate with a high white cell count TAM should be suspected and early, aggressive exchange transfusion and simultaneous chemotherapy should be started.