Kasabach-Merritt syndrome

Kasabach-Merritt Syndrome

Kasabach-Merritt syndrome (KMS) is a rare and potentially life-threatening condition characterized by a combination of a vascular tumor, thrombocytopenia, and consumptive coagulopathy. It is most commonly associated with certain types of vascular tumors, such as kaposiform hemangioendothelioma and tufted angioma.

Pathophysiology

Kasabach-Merritt syndrome occurs when a vascular tumor traps and destroys platelets, leading to thrombocytopenia. The tumor also consumes clotting factors, resulting in a coagulopathy. This can lead to severe bleeding complications. The exact mechanism involves the sequestration of platelets within the abnormal vascular channels of the tumor, as well as the activation of the coagulation cascade.

Clinical Presentation

Patients with Kasabach-Merritt syndrome typically present with a rapidly enlarging vascular lesion, often accompanied by signs of thrombocytopenia such as petechiae, purpura, or bleeding. The lesion is usually a deep, soft tissue mass that may be associated with overlying skin changes. The condition is most commonly seen in infants and young children.

Diagnosis

The diagnosis of Kasabach-Merritt syndrome is based on clinical findings, laboratory tests, and imaging studies. Laboratory tests typically show thrombocytopenia and evidence of coagulopathy, such as prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT). Imaging studies, such as ultrasound or MRI, can help identify the vascular tumor and assess its extent.

Treatment

Treatment of Kasabach-Merritt syndrome involves managing the underlying vascular tumor and correcting the coagulopathy. Options include:

• Corticosteroids: Often used as first-line therapy to reduce the size of the tumor and improve platelet counts.
• Vincristine: A chemotherapeutic agent that can be effective in shrinking the tumor.
• Interferon-alpha: Used in some cases to reduce tumor size.
• Surgical intervention: May be necessary if the tumor is accessible and causing significant complications.
• Embolization: A procedure to block the blood supply to the tumor, reducing its size and activity.

Prognosis

The prognosis of Kasabach-Merritt syndrome varies depending on the size and location of the tumor, as well as the response to treatment. Early diagnosis and intervention are crucial to prevent severe complications.

Also see

• Thrombocytopenia
• Coagulopathy
• Vascular tumors
• Kaposiform hemangioendothelioma
• Tufted angioma