For three years her skin ulcers and pain would flare, then vanish, stumping doctors. Her daughter, a nurse, finally figured it out.

Kimberly Ho, a newly minted nurse at Children’s National Medical Center just off a 12-hour overnight shift, struggled to focus on a presentation about working with sexually traumatized children and adolescents.

As the picture of a skin infection flashed on the screen, the 22-year-old snapped to attention.

The instructor was recounting the story of a teenage patient who had been given an incorrect diagnosis by a doctor in training — a breach of hospital protocol that had caused an uproar. The lecture, aimed at new staff members, emphasized the importance of working within the chain of command. The girl’s actual diagnosis was largely beside the point — except to Ho.