When should a child receive the first dose of the hepatitis B virus (HBV) vaccine if the mother is hepatitis B surface antigen (HBsAg) negative?

Correct Answer: B

Rationale: If the mother is HBsAg negative, it is recommended that the child receives the first dose of the hepatitis B vaccine at birth before discharge from the hospital. This is to provide early protection against the hepatitis B virus. The second dose of the vaccine is typically given at the first well-child visit, and the third dose is usually administered at a later date. The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention and the Committee on Infectious Diseases of the American Academy of Pediatrics govern the recommendations for immunization, including the hepatitis B virus vaccine. Choice A is incorrect as the first dose should ideally be given at birth. Choice C is incorrect as waiting until 6 months of age may leave the child vulnerable to infection during the early months of life. Choice D is incorrect as the hepatitis B vaccine is recommended for all newborns, especially if the mother is HBsAg negative, to prevent transmission of the virus.

Correct Answer: C

Rationale: Neonates have a large surface area relative to their weight, which makes them prone to heat loss to the environment, leading to thermoregulation issues. The underdeveloped kidney affecting urine concentration (Choice A) is unrelated to the thermal regulation process. While a flexed posture can help retain heat (Choice B), it does not outweigh the impact of the large body surface area in neonates. Although subcutaneous fat (Choice D) provides insulation, in neonates, the large body surface area is more significant in contributing to heat loss than the fat's insulating properties.

Correct Answer: C

Rationale: Low-set ears in a neonate suggest major abnormalities and should prompt further evaluation. The correct alignment of the top of the pinnae of the ear with the outer canthus of the eye is crucial. Nystagmus, an involuntary eye movement, is common in newborns and often resolves on its own. Epstein pearls, small cysts on the hard palate, are insignificant and disappear over time. A positive Babinski reflex is normal in infants up to 1 year of age. Therefore, the presence of low-set ears is the most concerning finding that requires immediate attention.

Correct Answer: C

Rationale: When a parent's infant is born with physical defects, understanding the psychological reactions is crucial. The reaction is often similar to the grief experienced when facing the death of a child. Parents need to grieve for the loss of the expected child and adapt to the needs of a child with physical defects. The grief process typically involves stages like shock, frustration, and anger, which can last for years. Denial during the shock phase is not maladaptive but can help parents cope initially. Additionally, parents are sensitive to the behavior of health professionals, whose interactions can significantly influence the parents' reactions to the infant. Therefore, recognizing the similarity of the psychological reaction to grief is an important consideration in understanding how parents cope with their infant's physical defects.

Correct Answer: D

Rationale: The correct answer is D, 'Small for gestational age.' A small for gestational age, or small-for-date, infant is any child whose intrauterine growth rate was slowed and whose birth weight falls below the 10th percentile on intrauterine growth curves. Choices A and B, 'Postterm' and 'Postmature,' refer to infants born after 42 weeks of gestational age regardless of birth weight, and do not specifically address growth rate. Choice C, 'Low birth weight,' refers to infants with a birth weight less than 2500 g (5.5 pounds) regardless of gestational age, which is a different classification compared to being small for gestational age.