A health condition in which a person experiences bleeding and clotting problems due to two types of tumors called kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) is known as Kasabach-Merritt syndrome (KMS). People with this condition may have reduced levels of platelets, low clotting proteins, and low red blood cell count. Early detection and prompt treatment are vital. Doctors usually treat KMS with options to prevent bleeding problems and surgery to remove the tumors.
In other words, KMS is a rare complication of two types of tumors that negatively affect infants. They are vascular tumors that are made up of blood vessels. About 70% of babies who are born with KHE and 10% born with TA will develop KMS. Furthermore, KMS is considered a medical emergency, and without immediate treatment, it can be fatal. Those who develop it often have problems with clotting proteins and platelets, and may also develop anemia, which significantly reduces oxygen levels in the blood. Sometimes, KMS is called Kasabach-Merritt phenomenon (KMP).
What Are The Symptoms of Kasabach-Merritt Syndrome?
Children who develop this condition usually experience different symptoms, depending on which part of the body is affected. For instance, the tumor may develop under the child’s skin, on their arms, legs, trunk, neck, or face. Check some general symptoms below:
- Fatigue (extreme tiredness)
- Hemorrhage
- A large, growing purplish or reddish mass with poorly defined borders
- Reddened or darkened areas of skin that often look like scaly patches
- Lesions with small red or purple spots
- About 10% of children with KMS have tumors inside the body, and they cannot be seen
- Fussiness
- Irritability
Immediately contact your healthcare professional if any of the symptoms listed above occur. Early diagnosis and prompt treatment are essential.
Causes
This condition occurs due to certain tumors that cause problems with bleeding and clotting. When a tumor appears, it affects platelets and red blood cells (in some cases). Usually, red blood cells die too quickly because odd blood vessels from the tumor cause damage to them. At the same time, small clots may form inside the affected blood vessels. This process occurs continuously, which may leave your child with reduced levels of platelets and clotting proteins.
What Happens if Kasabach-Merritt Syndrome is Left Untreated?
Babies who develop KMS may also experience some complications, especially if the condition is not detected in the early stages. Check some complications below:
- Life-threatening hemorrhage – This complication may cause spontaneous intracranial hemorrhages, which significantly increase the mortality rates (about 30%).
- Consumptive coagulopathy and DIC – Prolonged trapping and destruction of platelets may lead to disseminated intravascular coagulation (DIC) and severe acquired hypofibrinogenemia.
- Pleural and pericardial effusion
- Heart failure
- Infections and sepsis – Some people with KMS may develop ulceration and skin breakdown, which allows bacteria to enter the body.
- Joint problems – Without immediate treatment, KMS may cause hemarthrosis (repetitive bleeding into joints), hemophilia-like arthropathy, chronic pain, lymphedema, and mobility problems.
This document does not contain a full list of complications, but you can consult with your doctor about measures to reduce the risk or even prevent them. Unfortunately, it is not always possible to prevent KMS because some babies develop tumors inside the body that cannot be seen.
Diagnosis
Most of the time, doctors diagnose KMS before 12 months of age. When doctors suspect a tumor that may cause KMS, they will perform some imaging tests to examine the tissue inside the body. These include ultrasound, X-ray, CT (computerized tomography) scan, and MRI (magnetic resonance imaging) scan. They may also perform different blood tests to check for abnormal blood cell count and clotting problems. For example, complete blood count (CBC), partial thromboplastin time (PTT), prothrombin time (PT) test, fibrinogen test, and D-dimer test.
Treatment
Commonly, physicians recommend different options for babies with KMS because it depends on several factors. Examples include the severity and location of the tumor, existing health problems, age, gender, and preferences. Typically, the treatment goal is to prevent bleeding and clotting problems and remove the tumor. Check some options often recommended by doctors below:
Medicines
These include:
- Sirolimus – This medication is recommended by doctors to starve the tumor of nutrients it requires to grow. Sometimes, it is taken along with a steroid medicine.
- Vincristine – This is a chemotherapy medication that can help destroy the tumor when Sirolimus does not work. Unfortunately, Vincristine may cause some adverse reactions. Consult with your healthcare professional before choosing this medicine.
Procedures
- Surgery – This treatment is often recommended for babies with small tumors only.
- Embolization – During this procedure, surgeons will block blood vessels that supply the tumor, causing it to die.
- Radiation therapy – This is another cancer treatment that may help shrink a large tumor before surgery. However, it may also cause adverse reactions.
Supportive Care
Some people with KMS may need the following treatment options to reduce the risk of major blood loss. Check some examples below:
- Cyroprecipitate
- Fresh frozen plasma
- Platelet and blood transfusions
Frequently Asked Questions
When should I see my healthcare professional?
If you notice your child has internal bleeding signs, including irregular heartbeat, slow reflexes or movement, or breathing problems, immediately call 911 or go to the nearest emergency room (ER). Otherwise, it may lead to serious complications (such as death).
What can I expect if my child has Kasabach-Merritt syndrome?
Generally, the mortality rate is about 30%, which means that 3 out of 10 babies with KMS will die. Usually, the prognosis is worse in babies with internal tumors. However, there are some new medicines (such as Sirolimus) that help more children with KMS survive.
What liver disease is associated with Kasabach-Merritt syndrome?
Commonly, KMS is associated with giant liver hemangioma, which occurs more commonly among children than adults. The primary treatments for children with this liver disease are liver resection, enucleation, and liver transplantation.
Can adults develop Kasabach-Merritt syndrome?
Kasabach-Merritt syndrome occurs almost exclusively in infants and young children, especially during the first year of life. Although extremely rare, a few cases have been reported in older children and adults. In these uncommon situations, the condition is usually associated with kaposiform hemangioendothelioma or tufted angioma.
Is Kasabach-Merritt syndrome inherited?
No. KMS is not considered an inherited genetic disorder and usually does not run in families. It develops as a complication of specific vascular tumors rather than being passed from parents to children. In most cases, there is no known way to prevent it.
Can Kasabach-Merritt syndrome be cured?
Many children improve significantly when the underlying tumor responds to treatment. Medications such as sirolimus or vincristine, along with surgery or embolization when appropriate, can control the tumor and resolve the clotting abnormalities. However, long-term follow-up is important because some tumors may recur or require additional treatment.
Why are platelet transfusions not always given immediately?
Although platelet counts are often very low, platelet transfusions are usually reserved for severe bleeding, preparation for surgery, or other life-threatening situations. This is because transfused platelets can become trapped inside the tumor, potentially promoting its growth or increasing clotting activity. Your child’s healthcare team will determine when platelet transfusions are necessary.
How long does treatment for Kasabach-Merritt syndrome usually last?
The duration of treatment varies depending on the size and location of the tumor and how well it responds to therapy. Some children require medication for several months, while others may need treatment for a year or longer. Regular blood tests and imaging studies help doctors determine when treatment can be safely reduced or stopped.
What specialists are involved in treating Kasabach-Merritt syndrome?
Because KMS is a complex condition, treatment often involves a healthcare team. This may include pediatric hematologists, oncologists, dermatologists, interventional radiologists, pediatric surgeons, and intensive care specialists. Working together, these healthcare professionals develop an individualized treatment plan for each child.
What follow-up care does a child need after recovering from Kasabach-Merritt syndrome?
Children who recover from KMS usually need regular follow-up visits to monitor for tumor recurrence, bleeding or clotting abnormalities, medication side effects, and overall growth and development. Follow-up appointments may include physical examinations, blood tests, and imaging studies to ensure the condition remains under control. Ask your healthcare provider if you have any other questions.
