Kasabach-Merritt syndrome is a vascular tumor disorder associated with platelet-consuming coagulopathy and thrombocytopenia. Treatment of the disease has been experimental to date. Interferons and corticosteroids have shown promise in many cases.
What is Kasabach-Merritt syndrome?
Kasabach-Merritt syndrome is also called hemangioma–thrombocytopenia syndrome and corresponds to a rare blood disorder. Hemangiomas and a coagulopathy with platelet consumption characterize the clinical picture. Symptomatic coagulopathy is also called disseminated intravascular coagulation. It is a potentially life-threatening condition of excessive blood clotting that consumes clotting factors and causes a tendency to bleed. This phenomenon is one of the vasculopathies. The direct consequence is thrombocytopenia, i.e. a reduced platelet count. Medicine understands this as concentrations below 150,000 platelets per µl. 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 medical science recognized the hemangiomas within this syndrome as aggressive giant hemangiomas. Therefore, the term hemangioma-thrombocytopenia syndrome is actually incorrect.
Causes
The prevalence of Kasabach-Merritt syndrome is not yet known. However, the condition is considered rare. Because of this rarity, the syndrome has not been conclusively studied. The etiology of the disease is also largely unknown. Currently, there is speculation about genetic correlations, as seems to be suggested by the familial clustering of cases of the disease observed to date. Originally, the syndrome was classified as an infantile tumor disorder. Although the hemangiomas of Kasabach-Merritt syndrome are not tumors of infancy, symptomatic tumor-like symptoms are not in dispute. Because of this classification of the syndrome, a genetic predisposition is all the more likely. However, like other tumors, genetic disposition alone probably does not trigger the onset of the disease. Probably, external factors such as environmental toxins are added to the genetic factors as a causative basis.
Symptoms, complaints, and signs
Patients with Kasabach-Merritt syndrome exhibit planar vascular tumors that may extend over entire extremities. Thrombosis occurs in the giant hemangiomas, causing thrombocytopenia and consumptive coagulopathy with resultant bleeding tendency. Neither the clinical symptoms nor the histological characteristics of the vascular tumors have resembled those of hemangiomas. Scientists currently suspect tuft angiomas or caposiform hemangioendotheliomas behind the tumors. The immunologic GLUT1 response of the tumors, unlike that of infantile vascular tumors, is always negative. Despite the coagulopathy, Kasabach-Merritt syndrome does not correspond to chronic intravascular coagulopathy, which impedes flow in malformations of the veins or lymphatics. Also, the coagulopathies of malignant angiosarcomas and fibrosarcomas should not be confused with those of Kasabach-Merritt syndrome.
Diagnosis and Course of the Disease
The symptomatology of Kasabach-Merritt syndrome is considered unique. GLUT1 reaction and detection of thrombocytopenia by vascular tumors are important steps in the diagnosis. However, to date, the diagnosis cannot be confirmed beyond doubt because of the unknown etiology of the tumors. Direct detection is not possible because of the lack of background knowledge. In diagnosis and subsequent treatment, it is important to distinguish chronic intravascular coagulopathies from malformations or angiosarcomas and fibrosarcomas. This differentiation is decisive for the course of the disease, since only in this way a promising therapy is possible. The prognosis for patients with Kasabach-Merritt syndrome has improved considerably in recent years. Nevertheless, the disease still takes a lethal course in about ten percent of cases. After recovery, however, the rate of recurrence is extremely low. Permanent tissue damage is also rare.
Complications
Kasabach-Merritt syndrome usually results in the development of tumors, which occur primarily in the vessels of the extremities.These can continue to spread, affecting and destroying healthy tissue as well. In most cases, Kasabach-Merritt syndrome leads to an increased tendency to bleed. Even simple and minor injuries can cause severe 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, pain at rest at night can lead to sleep problems and thus to a general irritability of the affected person. The quality of life is limited by Kasabach-Merritt syndrome. Unfortunately, there is no specific treatment for Kasabach-Merritt syndrome. For this reason, complications do not occur. The symptoms can be partially limited with the help of medication. Likewise, the tumors can be removed and limited by radiation. However, whether the patient’s life expectancy is reduced by the syndrome cannot be universally predicted.
When should you see a doctor?
A physician is needed as soon as the affected person suffers from disturbances in blood flow. If there is an increased tendency to bleed, abnormalities in the heart rhythm or palpitations, a visit to the doctor is advised. If bleeding is generally difficult to stop and even minor injuries result in severe blood loss, this is considered unusual. A visit to the doctor is necessary so that the cause of the developments can be determined. If serious disturbances occur, such as a feeling of pressure in the organism, dizziness or interruptions of consciousness, a doctor must be consulted. In the event of a loss of consciousness, an ambulance service must be alerted immediately. At the same time, first aid measures must be initiated by persons present to ensure the survival of the person affected. 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 may be indications of a disorder present in the affected person. If the complaints persist over a longer period of time, a check-up visit to a doctor should be made. If there is general weakness, malaise or lack of energy, a visit to the doctor is recommended. If performance levels drop or physical activities can no longer be performed as usual, a doctor is needed.
Treatment and therapy
Regression of hemangiomas is the primary goal in therapy for Kasabach-Merritt syndrome. The bleeding tendency also decreases after the vascular tumors have regressed. Unfortunately, therapeutic success is unpredictable in the symptomatic setting, and thus treatment is more like an empirical matter. Accordingly, many experimental options are available. Besides treatment via laser surgery, radiological embolization of the tumors can take place. Drug therapies with interferon or steroid are also conceivable. Transfusions are available for the treatment of thrombocytopenia, and fibrinolysis inhibitors are available for the treatment of fibrinolysis. Meanwhile, some of the above treatment options have emerged in the scientific community as more helpful and others as less successful. To date, treatments with systemic corticosteroids have shown the most success. Drugs in this group include alpha-2a and alpha-2b interferons, as well as vincristine, for example. This immunosuppression alleviates the symptoms, but does not usually make them disappear. Anticoagulation is achieved by the administration of ticlopidine or aspirin. If the tumors can be removed surgically, this removal should be given priority. Removal of the tumors relieves the patient of all symptoms. Embolization or irradiation of the tumors is less promising than surgical removal. Substitution of platelets does not take place, because thrombocytopenia has been aggravated in this way in the past. The risk of intestinal bleeding increases in this way. However, substitution must take place immediately before tumor surgery.
Outlook and prognosis
The prospects for successful treatment in Kasabach-Merritt syndrome are much better today than in the past. The rarely occurring hemangioma-throbocytopenia syndrome can be better treated today thanks to new findings.What remains difficult, however, is that Kasabach-Merritt syndrome occurs postnatally and in early infancy. This reduces the possibility of using strong medications or performing a successful surgical intervention in the first days of life. The vascular tumors associated with Kasabach-Merritt syndrome must be clearly differentiated from other conditions with similar symptoms before treatment is initiated for therapy to be effective. The therapeutic success rate is unpredictable even with treatment with systemic corticosteroids, alpha-2a and alpha-2b interferon, anticoagulants, and drugs such as aspirin or vincristine. The outlook is better in Kasabach-Merritt syndrome if the vascular tumor can be removed. Possible, but quite rare, are radiation or embolization of the tumors. Thanks to improved treatment options, only about 10 percent of babies with Kasabach-Merritt syndrome die today. However, the syndrome leaves certain after-effects despite successful treatment. Pseudo-fibrosis or muscular problems are possible, for example. Thus, Kasabach-Merritt syndrome is one of the rare early childhood diseases that can be better managed today. What the prospects are in the future, and whether medical genetic engineering can improve anything in the survival prognosis in Kasabach-Merritt syndrome, no one can say at present.
Prevention
The body of research on Kasabach-Merritt syndrome is so far too limited to provide promising preventive measures. If the disease is indeed genetic, prevention is almost impossible anyway.
Follow-up
In most cases, the options and measures for aftercare in Kasabach-Merritt syndrome are severely limited, so those affected by this disease are primarily dependent on a rapid diagnosis with 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. As a rule, self-healing cannot occur in this case. Since Kasabach-Merritt syndrome is a genetic disease, the affected person should first undergo genetic testing and counseling if he or she wishes to have children. The treatment of Kasabach-Merritt syndrome is usually carried out with the help of various surgical procedures. In any case, the affected person should rest and take care of his body after the operation. Here, efforts or other stressful and physical activities should be refrained from in order not to put unnecessary strain on the body. The support and help of friends and family is also very important and can, above all, prevent depression or other psychological upsets. However, in many cases, due to the disease, the life expectancy of the affected person is significantly reduced or otherwise negatively affected.
What you can do yourself
Individuals diagnosed with Kasabach-Merritt syndrome must seek medical treatment immediately. Accompanying medical therapy, some measures can be taken to speed up the healing process. First of all, it is important to pay attention to unusual symptoms and accompanying symptoms. The medication is usually not optimally adjusted at the beginning and must be adjusted by the doctor several times until the desired effect is achieved. The patient can support this process by keeping a detailed diary of complaints and by consulting closely with the doctor. At the same time, the patient should take it easy. This is particularly important in the case of advanced disease. Otherwise, the immune system may be overloaded, which can lead to serious complications. In a severe course, the patient should consult a therapist. Talking to a professional can work through any fears, making it easier to deal with the disease. In addition, the therapist can establish contact with other sufferers or a self-help group. Parallel to therapeutic treatment, the lifestyle must be adapted, because patients with Kasabach-Merritt syndrome are usually no longer able to perform physically or mentally strenuous activities.
