Hematology — MCQs

Question 1: A 5-year-old boy presents with petechial bleeding and bruising on his torso and limbs. He has no other signs or symptoms and does not appear ill. His mother reports a gastrointestinal infection several weeks prior to the onset of petechiae and bruising. Complete blood count reveals thrombocytopenia (<20 x 10^9/L), with other parameters within the expected range for his age. Prothrombin time, partial thromboplastin time, and metabolic panels are all within the reference range. What is the expected outcome of this blood disorder?

• A. Complete resolution is expected. (Correct Answer)
• B. Survival rate is up to 70% depending on risk stratification.
• C. Lifelong disease dependent on factor VIII substitution.
• D. Lifelong disease dependent on factor IX substitution.

Explanation: ### Explanation The clinical presentation describes a classic case of **Immune Thrombocytopenic Purpura (ITP)**, the most common cause of isolated thrombocytopenia in children. **1. Why Option A is Correct:** In children, ITP typically follows a viral infection (respiratory or gastrointestinal) after a 1–4 week latent period. It is characterized by the sudden onset of petechiae and bruising in an otherwise healthy-appearing child. The hallmark is **isolated thrombocytopenia** (Platelets <100 x 10⁹/L) with normal PT, PTT, and hemoglobin. The prognosis is excellent; approximately **70–80% of children achieve complete spontaneous resolution** within 6 months, regardless of therapy. **2. Why the Other Options are Incorrect:** * **Option B:** This refers to the survival rates of pediatric malignancies like Acute Lymphoblastic Leukemia (ALL). While ALL presents with bruising, it typically involves "sick" symptoms (fever, bone pain), hepatosplenomegaly, and abnormalities in other cell lines (anemia/leukocytosis). * **Options C & D:** These describe **Hemophilia A (Factor VIII)** and **Hemophilia B (Factor IX)**. Hemophilias are coagulation factor deficiencies that present with deep tissue bleeds (hemarthrosis/hematomas) and a **prolonged aPTT**, rather than petechiae and isolated thrombocytopenia. **3. NEET-PG High-Yield Pearls:** * **Pathophysiology:** Anti-platelet antibodies (IgG) directed against GP IIb/IIIa or GP Ib/IX. * **Bone Marrow:** Not routinely required but would show **increased megakaryocytes** (compensatory). * **Management:** Observation is preferred if bleeding is minimal (dry purpura). If treatment is needed (wet purpura/active bleeding), **IVIG** or **Corticosteroids** are first-line. * **Chronic ITP:** Defined as thrombocytopenia persisting >12 months (occurs in ~20% of cases).