Review Question - QID 210485

A 3-year-old girl is brought in by her parents to her pediatrician for concerns about their child’s behavior. Since the parents started taking their child to daycare, they have become concerned that their daughter has not been behaving like other children her age. Most notably, she seldom responds when her name is called at home or at daycare. Additionally, she has been getting in trouble with the day care staff for not following directions but instead demanding to play with the train set at all times. She has been asked numerous times to share the toys, but the patient does not play with the other children. The parents state that the patient was born vaginally following a normal pregnancy, and the patient had been meeting developmental milestones all along. While she does not speak much, she is able to construct sentences up to 4-5 words. On exam, the patient’s temperature is 98.2°F (36.8°C), blood pressure is 106/60 mmHg, pulse is 76/min, and respirations are 14/min. The patient does not cooperate with gross or fine motor testing, but she appears to have no trouble running around the room and draws very detailed trains with crayons. While drawing and standing, she frequently makes flapping motions with her hands. The patient has ample vocabulary, but speaks in a singsong voice mostly to herself and does not engage during the exam. Which of the following is the most likely diagnosis?