A 16-year-old female adolescent develops swelling at the anterior aspect of the neck with difficulty of the swallowing. Examination reveals a firm, nontender diffuse goiter with a pebble-like surface. Her mother has had a thyroid disease in early adulthood. Of the following, the MOST valuable test to confirm the diagnosis is

Correct Answer: D

Rationale: Hashimoto thyroiditis, suggested by goiter and family history, is confirmed by elevated antithyroid peroxidase antibodies. Function tests (D) assess impact, while scan (A), biopsy (B), and ultrasound (C) are less specific initially.

Correct Answer: A

Rationale: Renal osteodystrophy is usually due to secondary hyperparathyroidism. Alendronate sodium is used in adult osteoporosis, not renal osteodystrophy, which requires phosphate binders or vitamin D analogs.

Correct Answer: D

Rationale: Metabolic disorders in neonates typically present with lethargy, poor tone, poor feeding, and seizures due to metabolic derangements. Hyperthermia is less characteristic, as these infants often have hypothermia from energy failure, making it the exception.

Correct Answer: C

Rationale: Galactosemia’s renal tubular dysfunction causes a normal-anion-gap hyperchloremic metabolic acidosis due to impaired bicarbonate reabsorption, consistent with proximal tubulopathy.

Correct Answer: A

Rationale: Hyperammonemia treatment includes ammonia scavengers (B), dialysis (C, D, E), but IV glucose alone doesn’t remove ammonia, though it prevents catabolism; it’s not a primary treatment here.