Kasabach-Merritt phenomenon (KMP) is characterised by thrombocytopenia, microangiopathic haemolytic anaemia and consumptive coagulopathy that can lead to life-threatening bleeding, in the context of an enlarging vascular tumour (1). KMP usually develops in infancy and is associated with significant morbidity and mortality. Potentially fatal complications associated with KMP include haemorrhage, cardiac failure and invasion of vital structures by the lesion. The mortality rate is reported as high as 30% (2). The first case of KMP was reported in 1940 by Kasabach and Merritt, who described a case of consumptive coagulopathy associated with a hemangioma (3). However, it is now recognised that KMP is usually associated with Kaposiform hemangioendothelioma (KHE) and tufted angioma, rather than the classic involuting hemangioma of infancy (4).Fortunately, KMP is rare, affecting <1% of all children with vascular tumours. The optimum treatment of KMP has not been established, and its management can be very difficult. It often involves a multimodal approach, with many disciplines involved. In this article, we review the experience of managing KMP in a single institution. AbstractObjective: Kasabach-Merritt phenomenon (KMP) can lead to life-threatening bleeding, and its optimum treatment has not been established. We review the experience of managing KMP in a single institution. Methods: A retrospective chart review on all children with KMP treated at the Hospital for Sick Children, Toronto, over an 18 yr period was carried out. Results: All 15 patients had profound thrombocytopenia and hypofibrinogenemia at presentation, half had bleeding symptoms, and three had cardiac failure. All patients received corticosteroids. Five responded to steroids alone, given for an average of 13 wk, increasing platelets to >20 · 10 9 ⁄ L at a mean of 6.2 d and fibrinogen >1 g ⁄ dL at 25.6 d. Ten patients received at least one other therapeutic modality in addition to steroids, including vincristine, interferon, anti-platelet agents and pentoxifylline. Five patients received vincristine, for a mean of 6 wk, with two patients responding. Eight patients received interferon, for a mean of 4 months, with two patients responding. Overall, the mean time to increasing platelets >20 · 10 9 ⁄ L was 56 d, to >150 · 10 9 ⁄ L was 88 d and fibrinogen >1 g ⁄ dL 49 d. Ten patients showed a partial response to embolisation, with a mean of 2.8 procedures performed. Thrombotic complications occurred in 7%. Twelve patients remain alive, with relapse in six patients, all treated successfully. One patient died, and two patients have been lost to follow-up. Conclusion: KMP is a rare condition, with significant morbidity and mortality. The therapeutic approach should include a multidisciplinary team and consensus on guidelines.

Paget-Schroetter syndrome or effort-related upper extremity deep vein thrombosis is a rare condition that usually afflicts young healthy individuals, most commonly males. The cause is multifactorial but almost always involves extrinsic compression of the subclavian vein at the thoracic inlet, causing venous stenosis from repetitive trauma. The diagnosis of this condition may be difficult, and its delay may contribute to potential complications including thrombosis progression, pulmonary embolism, thrombosis recurrence, and post-thrombotic syndrome. Similarly, the best therapeutic option has not been established and in the lack of evidence-based guidelines, treatment may be extremely challenging especially in children, in whom long-term complications can be particularly disabling.

Sulfhemoglobinemia is a rare disorder characterized by the presence of sulfhemoglobin in the blood. It is typically drug-induced and may cause hypoxia, end-organ damage, and death through oxygen deprivation. We present here a case of non-drug-induced sulfhemoglobinemia in a 7-day-old preterm infant complicated by hemolytic anemia. Microbiota compositional analysis of fecal samples to investigate the origin of hydrogen sulphide revealed the presence of Morganella morganii at a relative abundance of 38% of the total fecal microbiota at the time of diagnosis. M morganii was not detected in the fecal samples of 40 age-matched control preterm infants. M morganii is an opportunistic pathogen that can cause serious infection, particularly in immunocompromised hosts such as neonates. Strains of M morganii are capable of producing hydrogen sulphide, and virulence factors include the production of a diffusible a-hemolysin. The infant in this case survived intact through empirical oral and intravenous antibiotic therapy, probiotic administration, and red blood cell transfusions. This coincided with a reduction in the relative abundance of M morganii to 3%. Neonatologists should have a high index of suspicion for intestinal pathogens in cases of non-drug-induced sulfhemoglobinemia and consider empirical treatment of the intestinal microbiota in this potentially lethal condition.

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