All the following can cause metabolic acidosis with a high anion gap Except:

Correct Answer: C

Rationale: Renal tubular acidosis causes normal anion gap metabolic acidosis, not high anion gap metabolic acidosis.

Correct Answer: D

Rationale: Surfactant therapy reduces the risk of pneumothorax and mortality but does not significantly reduce BPD rates. The other options are benefits of surfactant therapy.

Correct Answer: C

Rationale: Achondroplasia is a genetic disorder caused by a mutation in the FGFR3 gene, not a chromosomal abnormality. Prader-Willi syndrome, X-linked hydrocephalus, and Treacher Collins syndrome are chromosomal or genetic disorders.

Correct Answer: C

Rationale: An increased anion gap metabolic acidosis is caused by acid accumulation, such as in salicylate toxicity, where excess acids like lactate and ketones contribute to the gap.

Correct Answer: D

Rationale: Dennie-Morgan folds are characteristic infraorbital creases seen in children with atopic dermatitis or allergic rhinitis.