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Characterized by the association of a vascular tumor
with thrombocytopenia and coagulopathy. Histologically, it is either a
kaposiform hemangioendothelioma or a tuft angioma, not a hemangioma.
++
Hemangioma-Thrombocytopenia Syndrome.
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Approximately 300 cases have been reported in the
literature since 1940. Slightly more frequent in females. No racial
predilection.
++
Unknown; seems to be more frequent in Asia.
++
Ecchymotic tumor develops on a vascular lesion; it
usually starts in the neonatal period and grows very quickly; tumoral growth
is accompanied by thrombocytopenia and hypofibrinogenemia. This disseminated
intravascular coagulation (DIC) picture is secondary to entrapment of
platelets within the vascular tumor.
++
The triad of thrombocytopenia, coagulopathy, and a
vascular tumor should be highly suggestive.
++
Enlarging hemangioma-like lesion, mainly
cutaneous (especially on the extremities) but also visceral. DIC (decreased
platelets and fibrinogen, presence of increased d-dimers). Often
inoperable. Treatment options: vincristine, interferon-α, steroids,
ticlopidine with aspirin, or radiotherapy. Untreated Kasabach-Merritt
syndrome has a 10 to 37% mortality rate.
++
Examine for airway involvement.
Check complete blood count (platelet count), coagulation profile, bleeding time, and
cross-match for blood even for minor surgical procedures.
++
Potential difficult airway if
oropharyngeal or neck involvement is present. Anticipate the need for blood
products to treat anemia and/or coagulopathy. Do not transfuse platelets because
they will immediately be trapped within the tumor with an ensuing increase in
size. Effect of chemotherapy on the cardiac and respiratory system must
be considered.
++
No specific pharmacological
implications with this condition; however, patients treated with
chemotherapy and corticosteroids (perioperative stress dose) must be prepared for anesthesia
accordingly. Avoid nonsteroidal antiinflammatory drugs secondary to their effects on
platelets.
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Congenital Hemangiomas: Share many similarities with
Kasabach-Merritt syndrome, but without the coagulation disorders; they usually
regress between 5 and 9 years of age.
++
Klippel-Trenaunay Syndrome: Congenital arteriovenous malformation
usually located on a single extremity resulting in skeletal and soft tissue
hypertrophy.
David TJ: Hemangioma with thrombocytopenia (Kasabach-Merritt syndrome).
Arch Dis Child 58:1022, 1953.
Enjolras O, Wassef M, Mazoyer E, et al: Infants with Kasabach-Merritt
syndrome do not have “true” hemangiomas.
J Pediatr 130:631, 1997.
[PubMed: 9108863]
Maguiness S, Guenther L: Kasabach-Merritt syndrome.
J Cutan Med Surg 6:335, 2002.
[PubMed: 11951132]