science

Kasabach–Merritt syndrome

Kasabach–Merritt syndrome is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Kasabach–Merritt syndrome rather than just read about it. In short: Kasabach–Merritt syndrome (KMS), also known as hemangioma with thrombocytopenia, is a rare disease, usually of infants, in which a vascular tumor leads to decreased platelet counts and sometimes other bleeding problems, which can be life-threatening. It is also known as hemangioma thrombocytopenia syndrome.

Key takeaways

Kasabach–Merritt syndrome belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
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Reproduce the core statement of Kasabach–Merritt syndrome from memory before moving on to harder problems.

Reference excerpt

Kasabach–Merritt syndrome (KMS), also known as hemangioma with thrombocytopenia, is a rare disease, usually of infants, in which a vascular tumor leads to decreased platelet counts and sometimes other bleeding problems, which can be life-threatening. It is also known as hemangioma thrombocytopenia syndrome. It is named after Haig Haigouni Kasabach and Katharine Krom Merritt, the two pediatricians who first described the condition in 1940.

Signs and symptoms 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 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.

Pathophysiology Kasabach–Merritt syndrome is usually caused by a hemangioendothelioma or other vascular tumor, often present at birth. Although these tumors are relatively common, they only rarely cause Kasabach–Merritt syndrome. When these tumors are large or are growing rapidly, sometimes they can trap platelets, causing severe thrombocytopenia. The combination of vascular tumor and consumptive thrombocytopenia defines Kasabach–Merritt syndrome. Tumors can be found in the trunk, upper and lower extremities, retroperitoneum, and in the cervical and facial areas. This consumptive coagulopathy also uses up clotting factors, such as fibrinogen which may worsen bleeding. The coagulopathy can progress to disseminated intravascular coagulation and even death. Hemolytic anemia secondary to microangiopathic destruction (physical damage) of the RBCs can be expressed as mild, moderate, or severe.

Diagnosis The diagnostic workup is directed by the presenting signs and symptoms, and can involve:

blood counts, clotting studies, and other laboratory testing imaging tests (ultrasound, CT scan, MRI, sometimes angiography, and rarely nuclear medicine scans) Biopsy of the tumor is contraindicated due to risk of bleeding. Patients uniformly show severe thrombocytopenia, low fibrinogen levels, high fibrin degradation products (due to fibrinolysis), and microangiopathic hemolysis.

Management Management of Kasabach–Merritt syndrome, particularly in severe cases, can be complex and require the joint effort of multiple subspecialists. This is a rare disease with no consensus treatment guidelines or large randomized controlled trials to guide therapy.

Supportive care Patient with Kasabach–Merritt syndrome can be extremely ill and may need intensive care. They are at risk of bleeding complications including intracranial hemorrhage. The thrombocytopenia and coagulopathy are managed with platelet transfusions and fresh frozen plasma, although caution is needed due to the risk of fluid overload and heart failure from multiple transfusions. The possibility of disseminated intravascular coagulation, a dangerous and difficult-to-manage condition, is concerning. Anticoagulant and antiplatelet medications can be used after careful assessment of the risks and benefits.

Definitive treatment Generally, treatment of the underlying vascular tumor results in resolution of Kasabach–Merritt syndrome. If complete surgical resection is feasible, it provides a good opportunity for cure (although it can be dangerous to operate on a vascular tumor in a patient prone to bleeding, even with appropriate surgical subspecialists involved). If surgery is not possible, various other techniques can be used to control the tumor:

embolization (by interventional radiology) can limit the tumor's blood supply external compression bandages can have similar effects certain medications, including: corticosteroids alpha-interferon chemotherapy (e.g. vincristine) radiation therapy has been used, often successfully, but now is avoided whenever possible due to the risk of long-term adverse effects (e.g. risk for future cancer).

Prognosis Kasabach–Merritt syndrome has a mortality rate of about 30%. For patients that survive the acute disease, supportive care may be required through a gradual recovery.Furthermore, patients may need care from a dermatologist or plastic surgeon for residual cosmetic lesions or an otolaryngologist for head & neck/airway involvement. On long-term followup, most patients have skin discoloration and/or mild disfiguration from the dormant tumor.

Illustrations

Worked examples

Example 1 — a first encounter with Kasabach–Merritt syndrome

Start with the simplest possible case. Write down what Kasabach–Merritt syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Kasabach–Merritt syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Kasabach–Merritt syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Kasabach–Merritt syndrome

In research: Kasabach–Merritt syndrome appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Kasabach–Merritt syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Kasabach–Merritt syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Coagulopathies, Dermal and subcutaneous growths, Rare syndromes, so understanding it makes those chapters shorter.
In everyday life: Look for Kasabach–Merritt syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Kasabach–Merritt syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kasabach–Merritt syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Kasabach–Merritt syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kasabach–Merritt syndrome in simple terms?

Why does Kasabach–Merritt syndrome matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Kasabach–Merritt syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Kasabach–Merritt syndrome.