About kasabach-merritt syndrome

What is kasabach-merritt syndrome?

Kasabach-Merritt phenomenon (KMP) is a rare condition that is associated with a coagulopathy with features including profound thrombocytopenia (low platelets), hypofibrinogenemia (low fibrinogen), and anemia. This phenomenon is only associated with two rare vascular tumors: kaposiform hemangioendotheliomas and tufted angiomas. This condition can be life-threatening secondary to the risk of bleeding and progression to DIC (disseminated intravascular coagulopathy).

What are the symptoms for kasabach-merritt syndrome?

Initially a vascular lesion is usually noted on the skin which can be firm and hard (indurated). Areas of tiny red dots (petechiae) can appear around the lesion or on other parts of the body. If the vascular lesion is internal, these petechiae and bruising can be seen on the skin. Bruising and spontaneous bleeding can also occur. The tumors are not hemangiomas. They usually present in young infants, less than three months of age, but have also been reported in the toddler age group. These tumors occur in the extremities, chest, neck, abdomen and pelvis. They infiltrate across tissue and can be aggravated by interventions, infection and trauma. When the tumors associated with KMP are internal such as in the chest or abdomen, they can cause significant illness and can be life-threatening due to bleeding. Internal lesions can take a longer time to diagnose.

What are the causes for kasabach-merritt syndrome?

The cause of KMP is unknown. It is believed to be secondary to sequestration or trapping of platelets and proteins into the tumor. These tumors are made up of abnormal endothelial cells (spindle cells) and abnormal lymphatic tissue. It is unclear why the KMP occurs and if it is caused by the spindle cells or the lymphatic component. A cause for the tumor (KHE and or TA) is also unknown but possibly secondary to a change in a gene in the tissue involved (somatic gene mutation).

What are the treatments for kasabach-merritt syndrome?

The focus is treating the underlying tumor. Treatment of these tumors is best done at centers familiar with these tumors or who have an interdisciplinary vascular anomaly center. Medical management has included corticosteroids, interferon, chemotherapeutic agents such as vincristineaspirin, and antiplatelet drugs such as Ticlopidine. Sometimes a combination of medications has been used. Other adjuvant therapies have included interventional embolization. If the lesion can be surgically removed, that is the treatment of choice.

In 2013, a consensus statement was published as a result on an interdisciplinary meeting that stated vincristine and steroids were the first line treatment for KHE/TA with KMP. Since that statement there have been a significant number of papers published regarding the use of sirolimus for the treatment of these tumors with impressive results especially in improving KMP. A series of 10 patients with KHE and KMP were treated with sirolimus in a prospective FDA sponsored phase II study and all responded. (1RO1FD-03712). About 50% of patients need to remain on a low dose of sirolimus to prevent reoccurrence of symptoms such as pain. Follow-up studies are needed to evaluate this medication as a treatment for KMP.

What are the risk factors for kasabach-merritt syndrome?

The primary risk factor for kasabach-merritt syndrome is a blood-clotting disorder called thrombocytopenia, which is the condition of having low amounts of platelets in your blood.

  • A low platelet count can be caused by various medical conditions, including autoimmune disorders like lupus and rheumatoid arthritis.
  • Being an immunosuppressed patient (such as someone with HIV).
  • People with kasabach-merritt syndrome tend to be younger than 50 years old, but the condition can occur at any age.
  • People who have had a previous cancer diagnosis or have been treated with chemotherapy are at higher risk for developing this condition.
  • The condition is most often seen in people who are on bed rest or have had an injury or surgery that prevented them from moving around for a long time, such as after surgery.
  • The clots can travel to other parts of the body, including the lungs, kidneys and brain.
  • Recent surgery or trauma (e.g., a broken bone)
  • Infection (e.g., pneumonia)
  • Smoking cigarettes
  • Exposure to certain medications (e.g., chemotherapy)
  • Having lung cancer

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