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Emergency And Acute Medicine – Idiopathic Thrombocytopenic Purpura
Basics
Description Idiopathic thrombocytopenic purpura (ITP) is isolated thrombocytopenia without an identifiable cause and with normal other cell lines. Incidence is approximately 2–5 per 100,000 per year. Acute ITP commonly affects children, with about 80% recovering within 8 weeks with or without therapy. Chronic ITP occurs mainly in adults, particularly young women, and often requires treatment to achieve remission. Refractory chronic ITP is characterized by fluctuating platelet counts and poor response to therapy.
Etiology
Immune-mediated platelet destruction due to autoantibodies, primarily IgG, leading to splenic and hepatic macrophage clearance. Some patients lack detectable autoantibodies, suggesting T-cell–mediated cytotoxicity. Complement activation may contribute. Decreased platelet production may occur in chronic or refractory disease. Eradication of Helicobacter pylori has been associated with platelet recovery in some patients.
Diagnosis
Signs And Symptoms
History: Mucocutaneous bleeding is most common, including epistaxis, gingival bleeding, menorrhagia, and conjunctival hemorrhage. Gastrointestinal bleeding, hemarthrosis, hematuria, and hematomas are uncommon. Pediatric cases often follow viral illness by 2–3 weeks. Adults typically have insidious onset; up to one-quarter are asymptomatic.
Physical exam: Petechiae and nonpalpable purpura are common. Spleen size is normal; splenomegaly suggests an alternate diagnosis. Intracranial hemorrhage is the most serious complication and leading cause of death, with risk increasing with age.
Essential Workup
Diagnosis of exclusion. CBC with differential and peripheral smear. PT and PTT if bleeding. Renal and liver function tests. Type and screen if bleeding. Pregnancy test when appropriate. Consider HIV testing.
Diagnosis Tests And Interpretation
Labs: Isolated thrombocytopenia with increased mean platelet volume. Normal RBC and WBC morphology. Normal coagulation studies and liver function.
Imaging: Noncontrast CT head if headache, neurologic deficits, trauma, or concern for intracranial hemorrhage.
Procedures: Bone marrow biopsy in patients >60 years, atypical cases, refractory disease, or prior to splenectomy. Antibody testing is not clinically useful.
Differential Diagnosis
Bone marrow failure or infiltration, splenic sequestration, thrombotic microangiopathies, disseminated intravascular coagulation, HELLP syndrome, valvular disease, and drug-induced thrombocytopenia.
Treatment
Prehospital And Initial Stabilization ABCs with attention to airway in severe mucosal bleeding or CNS hemorrhage. Establish IV access. Control bleeding with direct pressure.
Emergency Department Management Management depends on platelet count, bleeding severity, duration, age, and comorbidities. Observation is appropriate for children without bleeding or profound thrombocytopenia. Life-threatening bleeding requires high-dose IV corticosteroids, IVIG, and platelet transfusions (given after steroids or IVIG). Platelet transfusions alone are often ineffective. Aminocaproic acid may be considered for mucosal bleeding.
Medication
First line: High-dose glucocorticoids (dexamethasone 40 mg daily or prednisone 1–2 mg/kg/day), IVIG 1–2 g/kg for critical bleeding or urgent platelet rise, Anti-D immunoglobulin in Rh-positive patients.
Second line: Immunosuppressive agents, rituximab, thrombopoietin receptor agonists, or splenectomy for refractory disease.
Pregnancy Considerations
Differentiate from gestational thrombocytopenia and HELLP syndrome. Maternal platelet count does not predict neonatal thrombocytopenia. Mode of delivery is based on obstetric indications. Neonates should be screened and treated if thrombocytopenic.
Follow-Up And Disposition
Admission Criteria Life-threatening bleeding, any bleeding with platelets <20,000 />micro;L, asymptomatic patients with platelets <20,000 />micro;L and unreliable follow-up.
Discharge Criteria Asymptomatic patients or minor bleeding with platelets >30,000/µL.
Follow-Up Recommendations Hematology follow-up is required in all cases.
Key Points And Cautions
Exclude pseudothrombocytopenia before diagnosis. Spontaneous bleeding is uncommon until platelets fall below 10,000/µL. Intracranial hemorrhage risk increases with age and mandates urgent evaluation.
Basics
Description Idiopathic thrombocytopenic purpura (ITP) is isolated thrombocytopenia without an identifiable cause and with normal other cell lines. Incidence is approximately 2–5 per 100,000 per year. Acute ITP commonly affects children, with about 80% recovering within 8 weeks with or without therapy. Chronic ITP occurs mainly in adults, particularly young women, and often requires treatment to achieve remission. Refractory chronic ITP is characterized by fluctuating platelet counts and poor response to therapy.
Etiology
Immune-mediated platelet destruction due to autoantibodies, primarily IgG, leading to splenic and hepatic macrophage clearance. Some patients lack detectable autoantibodies, suggesting T-cell–mediated cytotoxicity. Complement activation may contribute. Decreased platelet production may occur in chronic or refractory disease. Eradication of Helicobacter pylori has been associated with platelet recovery in some patients.
Diagnosis
Signs And Symptoms
History: Mucocutaneous bleeding is most common, including epistaxis, gingival bleeding, menorrhagia, and conjunctival hemorrhage. Gastrointestinal bleeding, hemarthrosis, hematuria, and hematomas are uncommon. Pediatric cases often follow viral illness by 2–3 weeks. Adults typically have insidious onset; up to one-quarter are asymptomatic.
Physical exam: Petechiae and nonpalpable purpura are common. Spleen size is normal; splenomegaly suggests an alternate diagnosis. Intracranial hemorrhage is the most serious complication and leading cause of death, with risk increasing with age.
Essential Workup
Diagnosis of exclusion. CBC with differential and peripheral smear. PT and PTT if bleeding. Renal and liver function tests. Type and screen if bleeding. Pregnancy test when appropriate. Consider HIV testing.
Diagnosis Tests And Interpretation
Labs: Isolated thrombocytopenia with increased mean platelet volume. Normal RBC and WBC morphology. Normal coagulation studies and liver function.
Imaging: Noncontrast CT head if headache, neurologic deficits, trauma, or concern for intracranial hemorrhage.
Procedures: Bone marrow biopsy in patients >60 years, atypical cases, refractory disease, or prior to splenectomy. Antibody testing is not clinically useful.
Differential Diagnosis
Bone marrow failure or infiltration, splenic sequestration, thrombotic microangiopathies, disseminated intravascular coagulation, HELLP syndrome, valvular disease, and drug-induced thrombocytopenia.
Treatment
Prehospital And Initial Stabilization ABCs with attention to airway in severe mucosal bleeding or CNS hemorrhage. Establish IV access. Control bleeding with direct pressure.
Emergency Department Management Management depends on platelet count, bleeding severity, duration, age, and comorbidities. Observation is appropriate for children without bleeding or profound thrombocytopenia. Life-threatening bleeding requires high-dose IV corticosteroids, IVIG, and platelet transfusions (given after steroids or IVIG). Platelet transfusions alone are often ineffective. Aminocaproic acid may be considered for mucosal bleeding.
Medication
First line: High-dose glucocorticoids (dexamethasone 40 mg daily or prednisone 1–2 mg/kg/day), IVIG 1–2 g/kg for critical bleeding or urgent platelet rise, Anti-D immunoglobulin in Rh-positive patients.
Second line: Immunosuppressive agents, rituximab, thrombopoietin receptor agonists, or splenectomy for refractory disease.
Pregnancy Considerations
Differentiate from gestational thrombocytopenia and HELLP syndrome. Maternal platelet count does not predict neonatal thrombocytopenia. Mode of delivery is based on obstetric indications. Neonates should be screened and treated if thrombocytopenic.
Follow-Up And Disposition
Admission Criteria Life-threatening bleeding, any bleeding with platelets <20,000 />micro;L, asymptomatic patients with platelets <20,000 />micro;L and unreliable follow-up.
Discharge Criteria Asymptomatic patients or minor bleeding with platelets >30,000/µL.
Follow-Up Recommendations Hematology follow-up is required in all cases.
Key Points And Cautions
Exclude pseudothrombocytopenia before diagnosis. Spontaneous bleeding is uncommon until platelets fall below 10,000/µL. Intracranial hemorrhage risk increases with age and mandates urgent evaluation.
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