What is Kasabach-Merritt Syndrome?

Medicine understands the Kasabach-Merritt syndrome as a vascular tumor disease that is associated with a platelet-consuming coagulation disorder and thrombocytopenia. The treatment of the disease has so far been experimental. Interferons and corticosteroids have shown promise in many cases.

What is Kasabach-Merritt Syndrome?

Those affected often suffer from fever and severe pain in the extremities. This pain can also spread to other areas and cause pain there as well. See AbbreviationFinder for abbreviations related to Kasabach-Merritt Syndrome.

The Kasabach-Merritt syndrome is also called hemangioma thrombocytopenia syndrome and corresponds to a rare blood disease. Blood sponges and a coagulation disorder with thrombocyte consumption characterize the clinical picture. The symptomatic coagulation disorder is also called disseminated intravascular coagulation.

This is a potentially life-threatening condition of excessive blood clotting that depletes clotting factors and causes a tendency to bleed. This phenomenon is one of the vasculopathies. The direct result is thrombocytopenia, i.e. a reduced number of platelets. As such, medicine understands concentrations below 150,000 platelets per µl.

The Kasabach-Merritt syndrome was first described by K. Merritt and H. Kasabach in the 20th century as a syndrome with hemangiomas and consumption coagulopathy. It was not until the 1990s that medicine recognized the hemangiomas associated with this syndrome as aggressive giant hemangiomas. The term hemangioma thrombocytopenia syndrome is therefore actually incorrect.


The prevalence of Kasabach-Merritt syndrome is not yet known. However, the disease is considered rare. Because of this rarity, the syndrome has not yet been fully researched. The etiology of the disease is also largely unknown. There is currently speculation about genetic connections, which seems to be obvious given the family history of cases of the disease that has been observed so far.

The syndrome was originally classified as an infantile tumor disease. Although the hemangiomas of Kasabach-Merritt syndrome are not tumors of childhood, there is no doubt that they are symptomatic of tumorous symptoms. Because of this classification of the syndrome, a genetic disposition is all the more likely. Like other tumors, however, the genetic disposition alone probably does not trigger the onset of the disease. Presumably, external factors such as environmental toxins are added to the genetic factors as a causal basis.

Symptoms, Ailments & Signs

Patients with Kasabach-Merritt syndrome have flat vascular tumors that can extend over entire extremities. Thrombosis occurs in the giant hemangiomas, causing thrombocytopenia and consumption coagulopathy with a resulting tendency to bleed. Neither the clinical symptoms nor the histological characteristics of vascular tumors are similar to those of hemangiomas.

Science currently suspects tufted angiomas or Kaposiform hemangioendothelioma behind the tumors. The immunological GLUT1 reaction of the tumors is, unlike that of infantile vascular tumors, always negative. Despite the coagulopathy, the Kasabach-Merritt syndrome does not correspond to a chronic intravascular coagulopathy, which impedes the flow in malformations of the veins or lymphatics. The coagulopathies of malignant angiosarcomas and fibrosarcomas should also not be confused with those of Kasabach-Merritt syndrome.

Diagnosis & course of disease

The symptoms of Kasabach-Merritt syndrome are considered unique. The GLUT1 reaction and the detection of thrombocytopenia due to vascular tumors are important diagnostic steps. However, due to the unknown etiology of the tumours, the diagnosis cannot yet be definitively confirmed. Direct proof cannot be provided as there is currently a lack of background knowledge.

In diagnostics and subsequent treatment, it is particularly important to distinguish between chronic intravascular coagulopathies and malformations or angiosarcomas and fibrosarcomas. This distinction decides on the course of the disease, since this is the only way to achieve a promising therapy. The prognosis for patients with Kasabach-Merritt syndrome has improved significantly in recent years. Nevertheless, the disease is still fatal in around ten percent of cases. However, after recovery, the rate of recurrence is extremely low. Permanent tissue damage is also rare.


The Kasabach-Merritt syndrome usually leads to the formation of tumors, which mainly occur in the vessels of the extremities. These can continue to spread, infecting and destroying healthy tissue. In most cases, Kasabach-Merritt syndrome leads to an increased tendency to bleed. Even simple and minor injuries can lead to heavy bleeding, which is usually more difficult to stop than usual.

Those affected often suffer from fever and severe pain in the extremities. This pain can also spread to other areas and cause pain there as well. Furthermore, rest pain at night can lead to sleep disorders and thus to general irritability of the person concerned. The quality of life is limited by the Kasabach-Merritt syndrome.

Unfortunately, there is no specific treatment for Kasabach-Merritt syndrome. For this reason, there are no complications. The symptoms can be partially reduced with the help of medication. The tumors can also be removed and restricted by radiation. However, whether the patient’s life expectancy is reduced by the syndrome cannot be universally predicted.

When should you go to the doctor?

A doctor is needed as soon as the person concerned suffers from circulatory disorders. If you have an increased tendency to bleed, abnormal heart rhythm or heart palpitations, a doctor’s visit is advisable. If bleeding is difficult to stop in general and severe blood loss occurs even with minor injuries, this is considered unusual. A visit to the doctor is necessary so that the cause of the developments can be determined.

If there are serious disorders such as a feeling of pressure in the organism, dizziness or loss of consciousness, a doctor must be consulted. In the event of a loss of consciousness, an emergency service must be alerted immediately. At the same time, first-aid measures are to be initiated by those present to ensure the survival of the person concerned. If discoloration of the skin, bruising or increased bruising occur without a comprehensible reason, a doctor must be informed of the observations.

Permanently low blood pressure, cold limbs or an overall pale complexion can be indications of an existing disorder in the person concerned. If the symptoms persist for a longer period of time, you should see a doctor for a check-up. If you experience general weakness, feeling unwell or lack of energy, a doctor’s visit is recommended. If the performance level drops or if physical activities can no longer be carried out as usual, a doctor is needed.

Treatment & Therapy

The regression of the hemangiomas is the primary goal in the treatment of Kasabach-Merritt syndrome. The tendency to bleed also decreases after the vascular tumors have receded. Unfortunately, the success of therapy cannot be predicted with the symptoms and the treatment is more of an empirical matter. Accordingly, many test options are available. In addition to treatment with laser surgery, radiological embolization of the tumors can take place.

Drug therapies with interferon or steroids are also conceivable. Transfusions are available to treat thrombocytopenia and fibrinolysis inhibitors to treat fibrinolysis. In the meantime, science has shown that some of the treatment options mentioned are more helpful and others less successful. So far, treatments with systemic corticosteroids have shown success most frequently. In addition to alpha-2a and alpha-2b interferons, drugs in this group include, for example, vincristine.

This immunosuppression alleviates the symptoms, but usually does not make them go away. The coagulation inhibition occurs through the administration of ticlopidin or aspirin. If the tumors can be surgically removed, this removal should be given priority. Removal of the tumors removes all symptoms from the patient. Embolization or radiation of the tumors are less promising than surgical removal. A substitution of the thrombocytes does not take place, since the thrombopenia has intensified in the past. This increases the risk of intestinal bleeding. However, the substitution must take place immediately before a tumor operation.

Outlook & Forecast

The prospects for successful treatment of Kasabach-Merritt Syndrome are much better today than they used to be. Thanks to new findings, the rarely occurring hemangioma-thrombocytopenia syndrome can now be better treated. However, it is still difficult that the Kasabach-Merritt syndrome occurs after birth and in early childhood. This reduces the possibility of using strong drugs or performing a successful surgical procedure in the first few days of life.

The vascular tumors associated with Kasabach-Merritt syndrome must be clearly differentiated from other diseases with similar symptoms before treatment is initiated in order for therapy to be effective. The therapeutic success rate is not predictable even with treatment with systemic corticosteroids, alpha-2a and alpha-2b interferon, anticoagulants, and drugs such as aspirin or vincristine. The prospects for Kasabach-Merritt syndrome are better if the vascular tumor can be removed. Radiation or embolization of the tumors are possible, but very rare.

Thanks to improved treatment options, only about 10 percent of babies with Kasabach-Merritt syndrome die today. Despite successful treatment, the syndrome leaves certain after-effects. Pseudo-fibrosis or muscular problems are possible, for example. This makes the Kasabach-Merritt syndrome one of the rare diseases in early childhood that are easier to deal with today. Nobody can say at the moment what the prospects are like in the future and whether medical genetic engineering can improve the survival prognosis in Kasabach-Merritt syndrome.


The research on Kasabach-Merritt syndrome is so far too little for promising preventive measures to be available. If the disease is actually genetic, prevention is hardly possible anyway.


In most cases, the possibilities and measures of aftercare for Kasabach-Merritt syndrome are severely limited, so that those affected by this disease are primarily dependent on a quick diagnosis and subsequent treatment. This is the only way to prevent further complications, so ideally a doctor should be consulted at the first signs and symptoms of the disease.

Usually, self-healing cannot occur. Since Kasabach-Merritt syndrome is a genetic disease, the person concerned should first have a genetic examination and counseling if they wish to have children. Kasabach-Merritt syndrome is usually treated with the help of various surgical procedures. The person concerned should definitely rest after the procedure and take care of their body.

Here, exertion or other stressful and physical activities should be avoided in order not to unnecessarily burden the body. The support and help of friends and family is also very important and can, above all, prevent depression or other mental upsets. In many cases, however, the life expectancy of those affected is significantly reduced or otherwise negatively affected due to the disease.

You can do that yourself

People diagnosed with Kasabach-Merritt Syndrome must seek immediate medical attention. In addition to medical therapy, some measures can be taken to accelerate the healing process.

The first thing to do is to look out for unusual symptoms and side effects. The medication is usually not optimally adjusted at the beginning and has to be adjusted several times by the doctor until the desired effect is achieved. The patient can support this process by keeping a detailed complaint diary and by keeping in close contact with the doctor. At the same time, the patient should take it easy. This is particularly important in the case of an advanced disease. Otherwise, the immune system can become overloaded, which can lead to serious complications.

If the course is severe, the patient should consult a therapist. In a conversation with a specialist, any fears can be worked through, which makes it easier to deal with the disease. In addition, the therapist can establish contact with other sufferers or a self-help group. In parallel to the therapeutic treatment, lifestyle must be adjusted, because patients with Kasabach-Merritt syndrome are usually no longer able to carry out physically or mentally strenuous activities.

Kasabach-Merritt Syndrome