In a 3 year old child, most common cause of hepatitis B is?

HPSSC Staff Nurse - 2021

Child Health Nursing (Pediatrics)

Medium

Appeared in: HPSSC Staff Nurse - 2021

Explanation

Perinatal transmission (mother-to-child) is the leading cause of Hepatitis B infection in young children globally.
The risk of an acute HBV infection becoming chronic is highest when acquired at birth, at approximately 90%.
Therefore, a 3-year-old child diagnosed with Hepatitis B most likely contracted a chronic infection from their mother during the perinatal period.
Infection in the newborn is often asymptomatic, so it may not be diagnosed until later in childhood.

Option A: While a pin prick (percutaneous injury) can transmit HBV, it is a much less frequent cause of chronic infection in a 3-year-old compared to the high probability of perinatal transmission.
Option B: Transmission via saliva is considered inefficient. While possible through close household contact (e.g., sharing toothbrushes), it is not the primary mode of transmission and is far less common than the perinatal route.
Option D: Due to rigorous screening of donated blood for Hepatitis B surface antigen (HBsAg), the risk of acquiring HBV from a blood transfusion is extremely low in most countries today.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hepatitis B transmission routes in children as background academic context rather than a clinical decision trigger.
This concept underscores the critical importance of prenatal screening for HBsAg in all pregnant women to identify those at risk of transmitting the virus.
For infants born to HBsAg-positive mothers, immediate post-exposure prophylaxis with both the Hepatitis B vaccine and Hepatitis B Immune Globulin (HBIG) within 12 hours of birth is crucial to prevent transmission.
Chronic Hepatitis B acquired in childhood significantly increases the risk of developing cirrhosis and hepatocellular carcinoma (liver cancer) later in life.

How to Approach the Question

First, identify the key elements of the question: the patient is a '3-year-old child', the disease is 'Hepatitis B', and the question asks for the 'most common cause'.
The age of the patient is a major clue. An infection in a very young child often points to congenital or perinatal origins.
Recall the different transmission routes of Hepatitis B: parenteral (blood), perinatal (mother-to-child), and sexual/mucous membrane contact.
Critically, remember the relationship between age at infection and the risk of chronicity. The younger the person, the higher the risk the infection becomes chronic.
Synthesize these facts: A 3-year-old with HBV most likely has a chronic infection that was acquired at birth, where the risk of chronicity is highest (~90%).
Evaluate the other options: Blood transfusions are now very safe, and other routes like pinpricks or saliva are statistically less common for this age group than perinatal transmission.

Concept Tested & Keywords

Concept Tested: Hepatitis B transmission routes in children
Stem keywords: 3 year old child, hepatitis B, most common cause
Lead-in keywords: most common cause
Clinical cues: The patient's age (3 years old) is a critical clue, pointing towards an infection acquired earlier in life that has become chronic.

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