A mother notes her 6-week-old son’s umbilical cord is still attached. His activity and intake are normal; there has been no illness or fever. Delivery was at term without problems. His examination is notable for a cord without evidence of separation and a shallow, 0.5-cm ulceration at the occiput without discharge or surrounding erythema. Mother declares that the “sore,” caused by a scalp probe, has been slowly healing since birth and was deemed unremarkable at his 2-week checkup. Which of the following is consistent with this child’s likely diagnosis?

The parents of a 2-year-old girl bring their child to you for the first time. The child was born at term after an uncomplicated pregnancy and delivery, and her neonatal course was uneventful. She sat without support at 6 months of age, pulled to a stand at 10 months, and walked at 14 months. She has a 10-word vocabulary, can drink from a cup, and feeds herself with a spoon. A previous child in the family died at age 5 years from “heart trouble.” On physical examination, you note lower extremity contractures, hand stiffness, somewhat coarse facial features, and hepatosplenomegaly. The child’s growth is within normal limits, and her examination is otherwise normal. Which of the following is the most appropriate next step to diagnose this child’s condition?

A 6-year-old previously healthy child presents with bilateral lower limb weakness and absent reflexes. She had had URTI about a week prior.  MRI of the lumbosacral spine showed enhanced spinal roots. What is the most appropriate therapy?

 A 14-year-old girl has abdominal pain approximately weekly. During these episodes, she has multiple bowel movements that are looser than her usual stools. She relates that she feels better after she has a bowel movement. She has had no fever, rectal bleeding, or mucus in her stool. She has not lost weight. Her physical examination is normal. The best next step in the evaluation of her abdominal pain is

A 6-year-old boy presents with seizures and learning difficulties. His parents have noticed multiple hypopigmented patches over his trunk since infancy. On examination, he has three hypomelanotic macules on his back, a shagreen patch over his lower back, and periungual fibromas on his toes. His head circumference is in the 90th percentile. Fundoscopy reveals no abnormalities.

Brain MRI shows multiple subependymal nodules and cortical tubers.

Which of the following is the most likely additional finding in this child?

Which of the following is true about epilepsy syndromes?

An adolescent presents with recurrent palpitations. ECG shows short PR interval and delta waves. Which drug should be avoided?

A 3-month-old exclusively breastfed infant has persistent watery diarrhoea for 3 weeks, poor weight gain, and perianal excoriations. Stool is acidic (pH 4.5), and reducing substances are positive. Which of the following is the most likely cause?

A neonate diagnosed with classic galactosemia is started on lactose-free formula. Which of the following complications may still occur despite early and adequate dietary management?

The following are normal findings in a paediatric ECG EXCEPT:

A 6-year-old with a history of incomplete Hib vaccination presents with fever, drooling, and stridor. He refuses to lie flat. CSF is normal, but blood culture grows Gram-negative coccobacilli. What is the most likely diagnosis?

A 3-year-old with fever and neck stiffness has CSF with 500 WBC/mm³ (60% lymphocytes), normal glucose, and no organisms. What virus is most likely?

A newborn receives AZT prophylaxis after birth to an HIV-positive mother. At 2 weeks, HIV DNA PCR is positive. What is the most urgent next step?

A 7-year-old obese child presents with loud snoring, behavioural issues at school, and daytime fatigue. Which of the following is the gold standard test for diagnosis?

A previously healthy 4-year-old develops severe pneumonia with high fever, leukocytosis, and persistent hypoxia despite antibiotics. Chest imaging reveals cavitary lesions in the affected lobe. Which organism is most often implicated in necrotizing pneumonia in children?