Thrpmbocytopenia And Thrombocytosis Flashcards
are small pinpoint hemorrhages about 1 mm in diameter
Petechiae
about 3 mm in diameter and generally round
purpura
are 1 cm or larger and usually irregular in shape
ecchymoses
Abnormalities in platelet production can result from
mega- karyocyte hypoplasia in the bone marrow or ineffective throm- bopoiesis.
Lack of adequate bone marrow megakaryocytes (mega- karyocytic hypoplasia) is seen in a wide variety of congenital disorders, including
Fanconi anemia (pancytopenia),
thrombocytopenia with absent radius (TAR) syndrome,
May-Hegglin anomaly,
Wiskott-Aldrich syndrome,
Bernard-Soulier syndrome
is a rare autosomal dominant disorder whose exact frequency is unknown. Large platelets (20 mm in diameter) are present on the peripheral blood film, and Döhle-like bodies are present in neutrophils and occasionally in monocytes.
May-Hegglin anomaly
The disorder is characterized by abnormally enlarged or misshapen platelets.
May-Hegglin anomaly
Mutations in the MYH9 gene that en- codes for nonmuscle myosin heavy chain (a cytoskeletal protein in platelets) have been reported.1 This mutation may be respon- sible for the abnormal size of platelets in this disorder.
May-Hegglin anomaly
Three other disorders involving mutations of the MYH9 gene have been reported:
Sebastian syndrome,
Fechtner syndrome, and
Epstein syndrome
is inherited as an autosomal dominant disorder characterized by large platelets, thrombocytopenia, and granulocytic inclusions
Sebastian syndrome
Similar abnormalities with Sebastian syndrome and are accompanied by deafness, cataracts, and nephritis.
Fechtner syndrome
large platelets are associated with deafness, ocular problems, and glomerular nephritis
Epstein syndrome
is a rare autosomal recessive disorder char- acterized by severe neonatal thrombocytopenia and congeni- tal absence or extreme hypoplasia of the radial bones of the forearms with absent, short, or malformed ulnae and other orthopedic abnormalities.
TAR syndrome
