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Difficulty: MediumHematology and Oncology

A 34-year-old woman presents to the clinic with a 2-day history of pinpoint red rashes on her lower extremities and bleeding from her gums when brushing her teeth. She reports having a mild upper respiratory infection two weeks ago but is otherwise healthy. She takes no medications and has no personal or family history of bleeding disorders. Vital signs are within normal limits. Physical examination reveals diffuse petechiae over the bilateral shins and ankles. There is no palpable hepatosplenomegaly, and no lymphadenopathy is appreciated. Neurologic examination is unremarkable.

Laboratory results are as follows:
Hemoglobin: 12.5 g/dL12.5 \text{ g/dL}
Leukocyte count: 7,500/mm37,500/\text{mm}^3
Platelet count: 14,000/mm314,000/\text{mm}^3
Prothrombin time: 11 seconds11 \text{ seconds}
Activated partial thromboplastin time: 28 seconds28 \text{ seconds}
Creatinine: 0.8 mg/dL0.8 \text{ mg/dL}

A peripheral blood smear shows enlarged platelets but no schistocytes or blasts. What is the most appropriate next step in management?

  1. Administer high-dose oral corticosteroidsAnswer
  2. B
    Initiate emergency therapeutic plasma exchange
  3. C
    Perform a bone marrow aspiration and biopsy
  4. D
    Observe with repeat laboratory testing in one week
  5. E
    Transfuse one unit of pooled platelets

Answer

Administer high-dose oral corticosteroids
The correct answer is to administer high-dose oral corticosteroids. This patient presents with primary immune thrombocytopenia (ITP), an autoimmune disorder characterized by IgG autoantibodies directed against platelet membrane glycoproteins (e.g., GPIIb/IIIa). This leads to increased platelet destruction by splenic macrophages and isolated thrombocytopenia. The diagnosis is clinical and supported by isolated thrombocytopenia, normal coagulation times, and a peripheral smear showing large platelets (indicating increased bone marrow production) without schistocytes. In adult patients, treatment is indicated if there is active bleeding or if the platelet count is <30,000/mm3< 30,000/\text{mm}^3. First-line therapy consists of high-dose glucocorticoids (such as dexamethasone or prednisone), which may be combined with intravenous immunoglobulin (IVIG) if a rapid increase in platelet count is required.

Step-by-Step Solution

1
Analyze the clinical presentation and laboratory findings.
The patient has isolated thrombocytopenia (14,000/mm314,000/\text{mm}^3) with normal hemoglobin, leukocytes, and coagulation studies. The peripheral smear shows large platelets without schistocytes.
To differentiate between potential causes of thrombocytopenia, such as ITP, TTP, DIC, and bone marrow failure.
2
Establish the most likely diagnosis.
The diagnosis is primary immune thrombocytopenia (ITP), triggered by a recent viral infection.
The isolated low platelet count, mucocutaneous bleeding, lack of splenomegaly, and absence of microangiopathic hemolytic anemia fit the classic presentation of ITP.
3
Determine the indication for treatment.
Treatment is indicated because the platelet count is <30,000/mm3< 30,000/\text{mm}^3 and the patient is experiencing active mucosal bleeding (gums).
Patients with ITP who have platelets <30,000/mm3< 30,000/\text{mm}^3 or significant clinical bleeding are at high risk for severe hemorrhage and require therapy.
4
Select the appropriate first-line therapy.
High-dose glucocorticoids (e.g., dexamethasone or prednisone) are selected.
Corticosteroids reduce autoantibody production and decrease splenic macrophage destruction of antibody-coated platelets, making them the standard initial treatment for ITP.

Key Concept

Diagnosis and management of primary immune thrombocytopenia (ITP)
Estimated Time:1m 0s
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Topics

Hematology and Oncology

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