A female pediatric patient is brought to the ED for evaluation of a swollen left arm. She is otherwise well, and your exam reveals that she is able to walk well, she speaks in phrases, and she demonstrates stranger anxiety. What is the MOST likely developmental stage of this female?

A 15-year-old female presents to the ED with crampy abdominal pain and brisk vaginal bleeding. She states that her last menstrual period was "about 3 months ago." Vital signs at triage include a heart rate of 150 beats per minute, respiratory rate of 36 respirations per minute, and blood pressure of 90/60 mmHg. She appears pale, with dry lips. She is with a friend who drove her to the ED. She states that her mother is at work and can't be disturbed. She has no other guardian. What is the MOST appropriate next step? 

The greatest incidence of bacteremia occurs in children in which age group? 

A 2-month-old infant is brought to the ED by his young parents, who says he is "very sick." He cried most of the night, and this morning he seemed very sleepy and wouldn't wake up to take his bottle. His vital signs include a temperature of 35.4°C, respiratory rate of 72 respirations per minute, and heart rate of 192 beats per minute. His feet and hands are quite cool, and his radial pulse is not palpable. What is the MOST likely diagnosis? 

A 3-week-old infant was brought to the ED by his mother and grandmother with a concern of vomiting. He was fine yesterday, but this morning he was fussy and started crying a lot. About 2 hours prior to presentation to the ED he started vomiting, and at triage he was noted to have an episode of bilious emesis. He is awake and alert on exam, but his lips are dry and he is tachycardic with a heart rate of 190. What is the MOST likely diagnosis?