Please Remove Adblock
Adverts are the main source of Revenue for DoveMed. Please remove adblock to help us create the best medical content found on the Internet.

Kasabach-Merritt Syndrome

Last updated Oct. 22, 2018

Approved by: Maulik P. Purohit MD, MPH

Kasabach-Merritt Syndrome (KMS) is a rare, life-threatening condition affecting the ability of blood to clot, which is observed in newborns and infants. The cause of the condition is not well-established.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Hemangioma Thrombocytopenia Syndrome
  • Kasabach-Merritt Phenomenon
  • KMS (Kasabach-Merritt Syndrome)

What is Kasabach-Merritt Syndrome? (Definition/Background Information)

  • Kasabach-Merritt Syndrome (KMS) is a rare, life-threatening condition affecting the ability of blood to clot, which is observed in newborns and infants. The cause of the condition is not well-established
  • In this syndrome, there is a formation of vascular tumors accompanied by decreased platelets (thrombocytopenia) in the peripheral blood (but not in the bone marrow), leading to a bleeding disorder
  • The vascular tumor, such as Kaposiform hemangioendothelioma or tufted angioma, may grow at a fast rate in locations that include the trunk, upper and lower extremities, retroperitoneum, cervical and facial regions
  • Kasabach-Merritt Syndrome can result in severe internal bleeding due to reduced number of platelets in blood
  • It can be a lethal condition, if prompt treatment is not undertaken (which may include blood transfusion and surgery in some cases) on an urgent basis

Who gets Kasabach-Merritt Syndrome? (Age and Sex Distribution)

  • Kasabach-Merritt Syndrome is an infrequent disorder that is observed in newborns, infants, and very young children
  • Both male and female genders are affected, though some studies show that there is a higher prevalence in males
  • There is no racial, ethnic, or geographical predilection observed

What are the Risk Factors for Kasabach-Merritt Syndrome? (Predisposing Factors)

  • The risk factors for Kasabach-Merritt Syndrome are not well known

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Kasabach-Merritt Syndrome? (Etiology)

  • The exact cause of Kasabach-Merritt Syndrome is unknown. Research is currently being performed to identify the relevant causative factors
  • However, the formation of the vascular tumors can cause platelet clumping in large quantities, resulting in decreased number of circulating platelets in blood
  • Platelets are very vital components for the formation of blood clots. Uncontrolled bleeding may occur if platelet count decreases, which can be fatal
  • The vascular tumors causing KMS may include the following:
    • Kaposiform hemangioendothelioma
    • Tufted angioma

What are the Signs and Symptoms of Kasabach-Merritt Syndrome?

The signs and symptoms associated with Kasabach-Merritt Syndrome may include:

  • Formation of vascular tumors (abnormal blood vessels), which grow rapidly. These tumors can be multiple and affect any part of the body
  • If these are present on the skin, red spots may be seen
  • It can cause pain in the affected region
  • There may be easy bruising and wounds that cause low platelet levels in blood
  • Low platelet count resulting in uncontrolled bleeding can occasionally cause anemia

The signs and symptoms of the vascular tumors causing KMS may include the following:

  • Kaposiform hemangioendothelioma:
    • It appears in the soft tissues of the limbs, head and neck region, or retroperitoneum (abdomen)
    • Infants less than 2 years are mostly affected by this tumor
    • They usually shrink with time, but does not disappear completely
  • Tufted angioma:
    • They usually affect children before the age of 5 years
    • It can be very painful
    • It can appear as brown, purple, or red skin lesions

How is Kasabach-Merritt Syndrome Diagnosed?

Kasabach-Merritt Syndrome may be diagnosed using the following tools:

  • Complete physical exam and evaluation of medical history: A child is suspected of having Kasabach-Merritt Syndrome when it presents with the following conditions:
    • Vascular tumor growth
    • Bleeding disorders
    • Easy bruising
  • Complete blood count (CBC) with differential
  • Blood test to check fibrinogen levels
  • Imaging studies such as ultrasound, CT, MRI scan of the affected regions
  • Angiography of the affected region
  • Tissue biopsy: A biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Kasabach-Merritt Syndrome?

The complications of Kasabach-Merritt Syndrome are generally linked to the part of the body where bleeding may take place, such as bleeding into the brain can cause a stroke. The other complications may include:

  • Severe anemia due to heavy loss of blood
  • Disseminated intravascular coagulation (DIC)
  • Severe internal bleeding can potentially result in fatalities

How is Kasabach-Merritt Syndrome Treated?

Treatment of Kasabach-Merritt Syndrome may have to be considered on an emergency basis, since a lack of prompt treatment may result in death. The treatment may involve the expertise of specialists that include pediatricians, hematologists, dermatologists, surgeons, and radiologists.

The treatment measures may include:

  • Stabilization of the vital signs through intensive care treatment including intravenous fluids
  • A blood transfusion may be necessary, since KMS is treated by administering platelets to the patients
  • Use of medications such as systemic steroids, interferon alpha, cyclophosphamide, vincristine, etc.
  • A complete surgical excision of vascular tumors may not be possible in all cases, since they may be multiple in numbers
  • Arterial embolization of the tumor is used to provide temporary relief from the symptoms, and reduce blood loss during ‘tumor removal’ surgical procedure
  • Follow-up care with regular screening and check-ups are important

How can Kasabach-Merritt Syndrome be Prevented?

Currently, there is no effective prevention of Kasabach-Merritt Syndrome available.

What is the Prognosis of Kasabach-Merritt Syndrome? (Outcomes/Resolutions)

  • The prognosis of Kasabach-Merritt Syndrome depends upon the severity of the signs and symptoms, the numbers, sizes, and locations of the vascular tumors. Generally, the prognosis of KMS is guarded
  • Early diagnosis and urgent treatment may result in positive outcomes. A majority of individuals will require intensive care treatment in a hospital setting
  • Fatalities may arise, if there is severe bleeding in the GI tract or brain (resulting in a massive stroke). The overall death rate from KMS is around 30%, which means that 1 in 3 individuals may not survive this blood disorder

Additional and Relevant Useful Information for Kasabach-Merritt Syndrome:

  • Kaposiform hemangioendothelioma is an infrequent and aggressive childhood tumor, involving the blood vessels

The following article link will help you understand Kaposiform hemangioendothelioma:


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Nov. 12, 2015
Last updated: Oct. 22, 2018