Overview
Definition:
Thrombocytopenia is defined as a platelet count below the normal range, typically <150,000/µL
In pediatrics, it can be transiently caused by viral infections or be a manifestation of immune-mediated destruction, as seen in Immune Thrombocytopenia (ITP).
Epidemiology:
Viral-associated thrombocytopenia is common, often asymptomatic or mild, occurring in 10-20% of children with significant viral infections
Primary ITP incidence in children is estimated at 1-2 per 100,000 per year, with a bimodal peak in young children (2-5 years) and adolescents.
Clinical Significance:
Distinguishing between benign viral-induced thrombocytopenia and potentially serious ITP is crucial for appropriate management, avoiding unnecessary treatments, and preventing complications like severe bleeding
This differentiation impacts patient outcomes and management strategies, making it a high-yield topic for DNB and NEET SS preparation.
Clinical Presentation
Symptoms:
Petechiae
Purpura
Ecchymoses
Epistaxis
Gingival bleeding
Hematuria
Melena
Severe bleeding (e.g., intracranial hemorrhage) is rare but possible
Symptoms of underlying viral illness may be present, such as fever, rash, pharyngitis, or gastrointestinal upset
Children with ITP may be asymptomatic initially.
Signs:
Low platelet count (<150,000/µL) on CBC
Normal or slightly elevated white blood cell count
Normal or slightly elevated hemoglobin and hematocrit
Normal coagulation profile (PT, aPTT)
Splenomegaly may be present in ITP but is uncommon
Absence of fever or presence of fever related to viral infection
Normal physical examination apart from bleeding manifestations.
Diagnostic Criteria:
For ITP: Isolated thrombocytopenia (platelet count <100,000/µL) with normal white blood cell and red blood cell counts, and normal coagulation studies, in the absence of other identifiable causes of thrombocytopenia (e.g., drugs, toxins, other systemic illnesses, or specific viral infections that directly cause significant thrombocytopenia)
Criteria for viral-associated thrombocytopenia often relies on temporal association with a clear viral prodrome and rapid resolution after the viral illness subsides.
Diagnostic Approach
History Taking:
Detailed history of recent viral illness (fever, rash, URI symptoms)
Timeline of onset of thrombocytopenia and bleeding symptoms
History of recurrent bleeding or previous low platelet counts
Family history of bleeding disorders or ITP
Medication history (including recent vaccinations)
Recent exposure to infectious agents
Absence of other systemic symptoms suggestive of other causes of thrombocytopenia.
Physical Examination:
Thorough assessment for bleeding manifestations: petechiae, purpura, ecchymoses, mucosal bleeding (gingival, epistaxis), hematuria, rectal bleeding
Examine for signs of infection (fever, rash, pharyngitis)
Palpate for splenomegaly or hepatomegaly
Assess for any signs of systemic illness that might suggest other causes of thrombocytopenia (e.g., lymphadenopathy in leukemia)
Rule out signs of trauma or abuse.
Investigations:
Complete Blood Count (CBC) with differential and peripheral smear: Essential to confirm thrombocytopenia and assess morphology of platelets and other cell lines
Platelet count <150,000/µL
Peripheral smear may show large platelets in ITP, but is often normal in viral thrombocytopenia
Coagulation profile (PT, aPTT): Should be normal in both conditions to rule out consumptive coagulopathies
Viral serologies: May be considered if specific viral etiology is suspected but often not necessary for initial differentiation
Bone marrow aspiration: Rarely indicated in typical childhood ITP or viral thrombocytopenia unless diagnosis is uncertain, to rule out aplastic anemia, leukemia, or other bone marrow disorders
Antiplatelet antibodies: Not routinely used for diagnosis in children, as they are neither sensitive nor specific.
Differential Diagnosis:
Viral-associated thrombocytopenia
Immune Thrombocytopenia (ITP)
Drug-induced thrombocytopenia
Hemolytic Uremic Syndrome (HUS)
Thrombotic Thrombocytopenic Purpura (TTP)
Disseminated Intravascular Coagulation (DIC)
Congenital amegakaryocytic thrombocytopenia
Bone marrow failure syndromes (e.g., aplastic anemia, leukemia)
Connective tissue diseases.
Management
Initial Management:
For suspected viral-associated thrombocytopenia: Conservative management with close observation
Advise on avoiding contact sports and activities that may lead to injury
Ensure adequate hydration and rest
For suspected ITP: Assess bleeding severity
Mild bleeding may be managed with observation and reassurance
Moderate to severe bleeding or very low platelet counts (<10,000-20,000/µL) warrant intervention
Strict avoidance of aspirin and NSAIDs is crucial for both.
Medical Management:
For ITP: First-line therapy typically includes corticosteroids (e.g., Prednisolone 1-2 mg/kg/day orally for 2-4 weeks, then tapered) or Intravenous Immunoglobulin (IVIG) (1 g/kg as a single dose or divided over 2 days) for patients with significant bleeding or very low platelet counts
Second-line options include Rituximab, thrombopoietin receptor agonists (TPO-RAs like Eltrombopag - use with caution in children), or splenectomy in refractory cases
Viral-associated thrombocytopenia generally does not require specific medical treatment beyond supportive care, as it is self-limiting.
Surgical Management:
Splenectomy is considered a last resort in refractory ITP cases after failure of medical management, but is very rarely indicated in children
It is not a treatment for viral-associated thrombocytopenia.
Supportive Care:
Close monitoring of platelet counts and bleeding status
Patient and family education regarding signs of significant bleeding and when to seek medical attention
Avoidance of intramuscular injections where possible
Ensure adequate nutritional intake
Prompt treatment of any underlying severe viral infection if present.
Complications
Early Complications:
For ITP: Intracranial hemorrhage (rare but life-threatening)
Severe mucocutaneous bleeding
For viral thrombocytopenia: Usually asymptomatic or mild bleeding
Severe bleeding is uncommon.
Late Complications:
For ITP: Chronic ITP (platelet count remains low despite treatment)
Increased risk of bleeding during surgery or trauma
For viral thrombocytopenia: Generally none
it is a transient, self-limiting condition.
Prevention Strategies:
For viral-associated thrombocytopenia: Prevention focuses on general hygiene and vaccination against common viral illnesses
For ITP: Prevention of complications involves prompt diagnosis and appropriate management to maintain safe platelet levels and prevent bleeding episodes
Careful monitoring and adherence to treatment protocols are key.
Prognosis
Factors Affecting Prognosis:
For childhood ITP: Most children (about 80%) achieve spontaneous remission within 6-12 months
Factors associated with chronic ITP include older age at diagnosis, severe bleeding at presentation, and very low initial platelet counts
For viral-associated thrombocytopenia: Excellent prognosis
platelet counts typically normalize within days to weeks as the viral infection resolves.
Outcomes:
The majority of children with acute ITP have a favorable outcome with spontaneous recovery
For viral-induced thrombocytopenia, the outcome is generally excellent with complete resolution of the low platelet count.
Follow Up:
Children with ITP require regular follow-up to monitor platelet counts, assess for bleeding, and adjust treatment as needed
Those with transient viral thrombocytopenia typically require only short-term follow-up until platelet normalization.
Key Points
Exam Focus:
Key differentiator: Temporal association with viral illness and rapid resolution favors viral
Isolated thrombocytopenia with exclusion of other causes favors ITP
Management is conservative for viral
corticosteroids/IVIG for symptomatic ITP
Spontaneous remission is common in childhood ITP.
Clinical Pearls:
Always check the peripheral smear for platelet morphology and other cell lines
A normal coagulation profile is critical in the workup
Remember that a viral prodrome can precede the onset of ITP, making differentiation challenging initially
Do not treat asymptomatic, mild thrombocytopenia in the context of a clear viral illness unless platelet counts are critically low.
Common Mistakes:
Over-investigating or over-treating viral-associated thrombocytopenia
Failing to consider ITP in a child with persistent thrombocytopenia after a viral illness
Not adequately assessing bleeding severity in suspected ITP
Using aspirin or NSAIDs in a patient with thrombocytopenia.