Which statement by the mother of an 18-month-old would lead the nurse to believe that the child should be referred for further evaluation for developmental delay?

A.While cystic fibrosis is characterized by a high concentration of sodium chloride in sweat due to defective chloride channels, this is not the cause of the barrel chest and clubbing of the fingers.

B.The barrel chest and clubbing of the fingers are often seen in children with cystic fibrosis due to chronic hypoxia (lack of oxygen). Chronic lung infections, airway obstruction, and respiratory insufficiency associated with cystic fibrosis lead to prolonged low oxygen levels, which can result in these physical changes.

C.Decreased respiratory capacity, often due to the chronic respiratory issues associated with cystic fibrosis, can result in a barrel chest (increased chest diameter due to air trapping) and clubbing of the fingers (a sign of chronic hypoxia).

D.Decreased respiratory capacity (due to thick mucus and airway obstruction) does contribute to chronic respiratory issues in cystic fibrosis, but the direct cause of the barrel chest and clubbing is the chronic lack of oxygen (hypoxia) rather than decreased capacity alone. The changes in the chest and fingers are a result of prolonged oxygen deprivation.

A. “My child has a vocabulary of approximately 20 words.”

This statement indicates language development, and an 18-month-old with a vocabulary of approximately 20 words is within the expected range. It's a positive indicator of language acquisition.

B. “My child is still thumb sucking.”

Thumb sucking is a common self-soothing behavior in infants and toddlers. While it's a normal behavior, it typically decreases with age. Thumb sucking alone may not necessarily be a cause for concern unless it persists significantly and interferes with other aspects of development.

C. “My child seems to be quite wary of strangers.”

Stranger anxiety is a normal developmental stage, and many children exhibit wariness or fear of unfamiliar people around the age of 18 months. It is considered a typical response and not necessarily indicative of developmental delay.

D. “My child is able to stand but is not yet taking steps independently.”

At 18 months, most children are expected to be walking independently. The inability to take independent steps might be a concern for gross motor skill development. While some variation is normal, a delay in achieving this milestone might prompt further evaluation to rule out any underlying developmental issues.