Correct: B — Pyloric stenosis. Repeated loss of HCl and K+ from gastric contents causes hypochloremic, hypokalemic metabolic alkalosis. Classic presentation: non-bilious projectile vomiting at 3–6 weeks, olive-shaped mass. Confirm with ultrasound; treat with pyloromyotomy.

Correct: C. Umbilical hernias <2 cm in children typically close by age 4–5. Watchful waiting is appropriate. Taping/coins are NOT recommended. Refer if still open after age 5, defect >2 cm, or incarceration occurs.

Correct: C — Duodenal atresia. The "double bubble" (air in stomach + dilated duodenum) is pathognomonic. Associated with Down syndrome. Pyloric stenosis = non-bilious vomiting. Treat surgically.

Correct: B — Intussusception. Most common abdominal emergency ages 6 months–3 years. Classic: colicky pain + currant-jelly stool + sausage-shaped mass. Ultrasound confirms (target sign). Air enema is diagnostic and therapeutic (80–90% success).

Correct: C — Hirschsprung disease. Congenital absence of ganglion cells in the distal colon. Confirmed by rectal biopsy. Associated with Down syndrome. Treatment: surgical pull-through.

Correct: C. Recurrent UTIs in young children warrant evaluation for vesicoureteral reflux (VUR). VCUG is the gold standard. VUR increases risk of renal scarring. AAP also recommends VCUG after the FIRST febrile UTI in children <2 years.

Correct: C — Testicular torsion is a urological emergency. Salvage rate: 100% if repaired within 6 hours, <10% after 24 hours. Absent cremasteric reflex is the most reliable sign. Do NOT delay for imaging if clinical picture is clear. Treat with emergent surgical detorsion + bilateral orchiopexy.

Correct: B — PSGN. Occurs 1–3 weeks post-pharyngitis (3–6 weeks post-impetigo). Hallmarks: hematuria, edema, HTN, RBC casts, low C3, elevated ASO titer. Most recover fully. No specific treatment (supportive).

Correct: C. A communicating hydrocele (patent processus vaginalis; size fluctuates with activity) does not resolve spontaneously and risks hernia. Refer for elective surgical repair. Never aspirate. Non-communicating hydroceles in infants <1 year may be observed.

Correct: C. Orchiopexy by 12–18 months preserves fertility and reduces malignancy risk (seminoma). Most descent occurs by 3–6 months of age. This child is already past the window — urgent referral to urology is warranted.

Correct: B. NSAIDs are first-line — they inhibit prostaglandin synthesis (COX inhibition), reducing uterine contractions. Start 1–2 days before menses for best effect. Combined OCPs are second-line if NSAIDs are inadequate.

Correct: C — Female Athlete Triad: energy deficiency + menstrual dysfunction + low bone density. Suppressed GnRH pulsatility leads to low LH/FSH and estrogen. Manage: increase caloric intake, reduce exercise, calcium/vitamin D for bone protection.

Correct: C — CAIS. 46,XY + androgen receptor mutation: normal breasts (estrogen from testes), absent pubic/axillary hair, absent uterus/cervix. Intra-abdominal testes must be removed post-puberty (malignancy risk). MRKH has 46,XX with absent uterus but normal pubic hair.

Correct: C — Imperforate hymen. Menses accumulate behind the hymen (hematocolpos), presenting as a bulging blue/purple membrane at the introitus with cyclic pain. Uterus/ovaries are normal. Treatment: surgical hymenectomy. Do NOT aspirate in office.

Correct: B — PCOS in adolescents. Combined OCPs regulate cycles and reduce androgens. Metformin is added if insulin resistance/metabolic syndrome is present. Lifestyle modification is also essential. Clomiphene is for fertility only.

Correct: B. Secondary dysmenorrhea has identifiable causes: endometriosis (most common in adolescents), fibroids, adenomyosis, PID. Progressive, develops after menarche. Partial NSAID response only; treat the underlying cause (often requires laparoscopy for diagnosis).

Correct: B. Normal menarche occurs 2–3 years after thelarche. Primary amenorrhea = no menses by age 15 WITH secondary sexual characteristics, OR no breast development AND no menses by age 13. This girl is still within normal range. Reassure and continue monitoring.

Correct: B. Total and free testosterone are the key labs for hyperandrogenism in PCOS. Also check LH:FSH ratio, fasting glucose, lipids, and HbA1c for metabolic syndrome screening. 17-OHP rules out congenital adrenal hyperplasia (must be in differential).

Correct: B — Turner syndrome (45,X). Features: short stature, webbed neck, shield chest, primary amenorrhea, ovarian dysgenesis. GH therapy in childhood for height; estrogen replacement for pubertal induction and bone health (usually started at 11–13 years). Cardiac and renal anomalies must also be monitored.

Correct: C. Hypothalamic amenorrhea from energy deficiency (anorexia) requires treating the root cause — weight restoration. OCPs do NOT adequately protect bone in this setting (no substitute for estrogen from ovarian recovery). Refer to eating disorder specialist + nutritionist + psychiatry. Calcium and vitamin D are adjuncts.