Kasabach–Merritt phenomenon: a single centre experience

Abstract

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.

Clinical Review: Management of Adult Kasabach-Merritt Syndrome Associated with Hemangiomas

“…Platelet counts in KMS can be alarmingly low, but lifethreatening hemorrhages are rarely seen [3]. The half-life of platelets is very short due to intra-lesion trapping and destruction, leading to its ineffectiveness.…”

“…Similar to platelets, use of cryoprecipitate and fresh frozen plasma for the correction of hypofibrinogenemia and coagulopathy should be given sparingly, and their use should be limited to: active bleeding, before surgical procedures, platelet count <10,000/μL or fibrinogen < 1 g/dL [3,38]. Recombinant factor VIIa can be used in active and uncontrolled bleeding [39].…”

“…All these factors are known targets of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) [3]. Clinical effectiveness of corticosteroids in management of KMS has been validated in multiple clinical trials [3,9,19,[48][49][50][51].…”

“…KMS is a rare presentation in adults, and its exact incidence is unknown. In terms of pediatric literature, TA and KHE are rare, with incidence of KHE estimated at 0.07/1000, 000 children per year [2,3]. The incidence of KMS in patients with KHE and TA are 70% and 10% respectively [4,5].…”

“…The incidence of KMS in patients with KHE and TA are 70% and 10% respectively [4,5]. TA and KHE share several histopathologic similarities, while TA is a benign tumor characterized by tufts of capillaries within the dermis, [3,4] KHE tends to be locally aggressive tumor that may involve superficial or deep soft tissues [4,6]. In the adult population, KMS is seen most often as a complication from hemangiomas [7], hemagiomatosis [4] or angiosarcoma [8].…”