Thrombocytopenia in Children
Introduction to Thrombocytopenia in Children
Thrombocytopenia is defined as a platelet count below 150,000/μL. In children, it's a common hematological disorder that can result from various underlying conditions. The severity of thrombocytopenia is classified as:
- Mild: 100,000 - 150,000/μL
- Moderate: 50,000 - 99,000/μL
- Severe: <50,000/μL
Thrombocytopenia in children can be acute or chronic, and the etiology varies with age. Understanding the underlying cause is crucial for appropriate management and prognosis.
Etiology of Thrombocytopenia in Children
The causes of thrombocytopenia in children can be categorized into three main mechanisms:
- Decreased production:
- Congenital disorders (e.g., Wiskott-Aldrich syndrome, TAR syndrome)
- Bone marrow failure syndromes (e.g., aplastic anemia, Fanconi anemia)
- Viral infections (e.g., HIV, CMV, EBV)
- Nutritional deficiencies (e.g., vitamin B12, folate)
- Leukemia or other malignancies infiltrating the bone marrow
- Increased destruction:
- Immune thrombocytopenia (ITP) - most common cause in children
- Neonatal alloimmune thrombocytopenia
- Drug-induced thrombocytopenia
- Hemolytic uremic syndrome (HUS)
- Disseminated intravascular coagulation (DIC)
- Kasabach-Merritt phenomenon
- Sequestration:
- Hypersplenism (e.g., due to portal hypertension)
- Kasabach-Merritt phenomenon
The most common cause of acute thrombocytopenia in previously healthy children is immune thrombocytopenia (ITP), which accounts for approximately 50% of cases.
Clinical Presentation of Thrombocytopenia in Children
The clinical presentation of thrombocytopenia in children can vary widely, depending on the severity and underlying cause. Common signs and symptoms include:
- Petechiae: Small, pinpoint, round, and purple spots on the skin
- Purpura: Larger bruises
- Mucosal bleeding: Epistaxis (nosebleeds), gingival bleeding
- Easy bruising
- Prolonged bleeding from cuts or wounds
In severe cases, more serious bleeding can occur:
- Gastrointestinal bleeding
- Hematuria
- Menorrhagia in adolescent girls
- Intracranial hemorrhage (rare but life-threatening)
It's important to note that many children with mild to moderate thrombocytopenia may be asymptomatic and discovered incidentally on routine blood tests.
The presence of other symptoms (e.g., fever, weight loss, bone pain) may suggest underlying conditions such as infections or malignancies.
Diagnosis of Thrombocytopenia in Children
The diagnosis of thrombocytopenia in children involves a comprehensive approach:
- History and Physical Examination:
- Recent illnesses, medications, vaccinations
- Family history of bleeding disorders
- Presence and distribution of bleeding symptoms
- Signs of underlying systemic diseases
- Laboratory Tests:
- Complete blood count (CBC) with peripheral blood smear
- Reticulocyte count
- Coagulation studies (PT, aPTT, fibrinogen)
- Liver function tests
- Renal function tests
- Viral studies (e.g., HIV, hepatitis)
- Imaging Studies:
- Abdominal ultrasound to assess spleen size
- Chest X-ray if respiratory symptoms are present
- Bone Marrow Examination:
- Not routinely performed in acute ITP
- Indicated in cases of pancytopenia, suspected malignancy, or chronic thrombocytopenia
- Additional Tests:
- Antiplatelet antibody tests (not routinely recommended due to low sensitivity and specificity)
- Genetic testing for suspected inherited disorders
The diagnosis of ITP, the most common cause of thrombocytopenia in children, is often a diagnosis of exclusion after ruling out other causes.
Management of Thrombocytopenia in Children
The management of thrombocytopenia in children depends on the underlying cause, severity of thrombocytopenia, and presence of bleeding symptoms:
- Observation:
- Mild cases without significant bleeding may only require monitoring
- Educate parents and children about avoiding trauma and contact sports
- Treatment of Underlying Cause:
- Discontinuation of offending medications
- Treatment of infections
- Management of systemic diseases
- Specific Treatments for ITP:
- Corticosteroids (e.g., prednisone, methylprednisolone)
- Intravenous immunoglobulin (IVIG)
- Anti-D immunoglobulin (in Rh-positive patients)
- Thrombopoietin receptor agonists (e.g., eltrombopag, romiplostim) for chronic ITP
- Rituximab in refractory cases
- Splenectomy (rarely used in children, reserved for severe, chronic cases)
- Platelet Transfusions:
- Generally reserved for severe bleeding or prior to invasive procedures
- May be ineffective in ITP due to rapid destruction of transfused platelets
- Supportive Care:
- Avoidance of medications that affect platelet function (e.g., NSAIDs)
- Iron supplementation if anemia is present due to blood loss
- Psychosocial support for children and families
The choice of treatment should be individualized based on the child's age, severity of thrombocytopenia, bleeding symptoms, and quality of life considerations.
Prognosis of Thrombocytopenia in Children
The prognosis of thrombocytopenia in children varies depending on the underlying cause:
- Acute ITP:
- Excellent prognosis with spontaneous resolution in 70-80% of children within 6 months
- Low risk of serious bleeding complications (<1%)
- Chronic ITP (lasting >12 months):
- Occurs in 20-30% of children with ITP
- Many will eventually recover, but some may have persistent thrombocytopenia into adulthood
- Drug-induced thrombocytopenia:
- Usually resolves within 1-2 weeks after discontinuation of the offending drug
- Infection-associated thrombocytopenia:
- Generally improves with resolution of the underlying infection
- Inherited thrombocytopenias:
- Prognosis varies depending on the specific disorder
- May require lifelong management
Long-term follow-up is important, especially for children with chronic thrombocytopenia, to monitor for complications and adjust treatment as needed. The overall quality of life for most children with thrombocytopenia is generally good, especially with proper management and education.
Thrombocytopenia in Children
- QUESTION: What is the definition of thrombocytopenia in children?
ANSWER: Platelet count below 150,000/µL - QUESTION: Which of the following is NOT a common cause of thrombocytopenia in newborns?
ANSWER: Iron deficiency anemia - QUESTION: What is the most common cause of thrombocytopenia in children?
ANSWER: Viral infections - QUESTION: Which of the following is a hereditary cause of thrombocytopenia?
ANSWER: Wiskott-Aldrich syndrome - QUESTION: What is the primary mechanism of thrombocytopenia in disseminated intravascular coagulation (DIC)?
ANSWER: Increased consumption of platelets - QUESTION: Which of the following is NOT a typical finding in immune thrombocytopenia?
ANSWER: Splenomegaly - QUESTION: What is the most serious complication of severe thrombocytopenia in children?
ANSWER: Intracranial hemorrhage - QUESTION: Which of the following medications can cause drug-induced thrombocytopenia?
ANSWER: Heparin - QUESTION: What is the typical platelet count threshold for spontaneous bleeding?
ANSWER: Less than 10,000/µL - QUESTION: Which of the following is NOT a typical feature of thrombocytopenia in children?
ANSWER: Joint pain - QUESTION: What is the most common cause of thrombocytopenia in pregnancy?
ANSWER: Gestational thrombocytopenia - QUESTION: Which of the following conditions can cause both thrombocytopenia and hemolytic anemia?
ANSWER: Hemolytic uremic syndrome (HUS) - QUESTION: What is the primary mechanism of thrombocytopenia in hypersplenism?
ANSWER: Increased sequestration of platelets in the spleen - QUESTION: Which of the following is NOT a typical finding in the peripheral blood smear of patients with thrombotic thrombocytopenic purpura (TTP)?
ANSWER: Giant platelets - QUESTION: What is the role of ADAMTS13 testing in diagnosing TTP?
ANSWER: To confirm severe deficiency of ADAMTS13 enzyme activity - QUESTION: Which of the following is a potential cause of pseudo-thrombocytopenia?
ANSWER: EDTA-induced platelet clumping - QUESTION: What is the most common viral infection associated with thrombocytopenia in children?
ANSWER: Epstein-Barr virus (EBV) infection - QUESTION: Which of the following is NOT a typical feature of neonatal alloimmune thrombocytopenia?
ANSWER: Gradual onset over several days - QUESTION: What is the primary treatment for heparin-induced thrombocytopenia?
ANSWER: Discontinuation of heparin and initiation of alternative anticoagulation - QUESTION: Which of the following conditions is associated with large platelets on peripheral blood smear?
ANSWER: Bernard-Soulier syndrome - QUESTION: What is the role of bone marrow examination in evaluating thrombocytopenia?
ANSWER: To assess for primary bone marrow disorders or infiltrative processes - QUESTION: Which of the following is NOT a typical finding in aplastic anemia?
ANSWER: Isolated thrombocytopenia - QUESTION: What is the most common cause of thrombocytopenia in patients with chronic liver disease?
ANSWER: Hypersplenism - QUESTION: Which of the following is a potential complication of severe thrombocytopenia during surgery?
ANSWER: Excessive bleeding - QUESTION: What is the primary mechanism of thrombocytopenia in vitamin B12 deficiency?
ANSWER: Ineffective thrombopoiesis - QUESTION: Which of the following is NOT a typical finding in thrombocytopenia associated with systemic lupus erythematosus (SLE)?
ANSWER: Normal complement levels - QUESTION: What is the role of thrombopoietin receptor agonists in treating chronic immune thrombocytopenia?
ANSWER: To stimulate platelet production - QUESTION: Which of the following is a potential cause of thrombocytopenia in critically ill children?
ANSWER: Sepsis - QUESTION: What is the most appropriate initial management for mild, asymptomatic thrombocytopenia in children?
ANSWER: Observation and close monitoring - QUESTION: Which of the following is NOT a typical indication for platelet transfusion in children with thrombocytopenia?
ANSWER: Asymptomatic patient with platelet count of 70,000/µL
