During a physical examination, the nurse observes spoon-shaped nails (koilonychia). Which condition should the nurse suspect?

Rationale: A. While chronic hypoxia can cause changes in nail appearance, such as clubbing (rounded, bulbous fingertips with nails curving downward), it does not cause spoon-shaped nails. Therefore, chronic hypoxia is incorrect. B. Spoon-shaped nails, or koilonychia, are a classic sign of iron deficiency anemia. In this condition, the nails become thin, concave, and may have raised ridges, resembling a spoon. This occurs due to impaired hemoglobin production and associated tissue hypoxia, which affects nail formation. Other signs of iron deficiency anemia may include pallor, fatigue, brittle hair, and glossitis (smooth, sore tongue). C. Edema causes swelling of soft tissues in the extremities, including around the nails, but it does not produce the concave, spoon-shaped appearance characteristic of koilonychia. D. Hyperthyroidism may cause nail thinning, brittle nails, or onycholysis (separation of the nail from the nail bed), but it does not cause spoon-shaped nails.