0071643192.pdf

HEMATOLOGY, ONCOLOGY, ALLERGY,

AND IMMUNOLOGY

■ Platelet transfusion if

■ Life-threatening hemorrhage and abnormal platelet level or function

■ Platelets <10,000/μL for bleeding prophylaxis, except in ITP, TTP, HIT

IDIOPATHICTHROMBOCYTOPENICPURPURA

Idiopathic thrombocytopenic purpura is thrombocytopenia without an under-

lying causative disease or offending medication. Platelets are removed prema-

turely by reticuloendolethial system. Peak incidence occurs in children (2–6 years

old) and adults (20–50 years old). Acute ITP is more common in children and

chronic ITP is more common in adults. Platelet counts of <20,000/mm^3 may

cause life-threatening hemorrhage.

SYMPTOMS/EXAM

■ In children, often follows a viralinfection

■ Petechiae, gingival bleeding, epistaxis, menorrhagia, GI bleeding, intra-

cranial hemorrhage

DIAGNOSIS

■ Isolated thrombocytopenia on CBC

■ Peripheral smear with a small number of well-granulated platelets

■ Bone marrow biopsy shows no primary bone marrow disorder.

TREATMENT

■ Treatment is reserved for severe bleeding with platelets <50,000/mm^3 or

platelet count <10,000/mm^3 without bleeding.

■ For children, treatment is usually conservative since the majority have a

favorable outcome. Children should avoid physical activity or NSAIDs.

TABLE 9.7. Common Causes of Thrombocytopenia

Decreased bone marrow production Marrow infiltration

Drugs

Toxins

Infection

Increased platelet destruction Immunologic

Idiopathic thrombocytopenic purpura (ITP)

Collagen vascular disease (eg, systemic lupus

erythematosus [SLE])

Leukemia, lymphoma

Drug-induced (eg, heparin)

Infection (typically viral)

Mechanical

Thrombotic thrombocytopenic purpura

Hemolytic uremic syndrome

Disseminated intravascular coagulation

HELLP syndrome

Vasculitis

Splenic sequestration Hypersplenism

ITP is the most common

hemorrhagic disease in

children. It is usually self-

limited, resolving in weeks to

months.