A 4-week-old infant is brought to the emergency department by his parents with violent vomiting. It started about 3 days ago and has slowly gotten worse. He vomits after most feedings but seems to keep some formula down. His mother notes that he is eager to feed between episodes and seems to be putting on weight. Other than an uncomplicated course of chlamydia conjunctivitis, the infant has been healthy. He was born at 39 weeks gestation via spontaneous vaginal delivery. He is up to date on all vaccines and is meeting all developmental milestones. The physical exam is significant for a palpable mass in the right upper quadrant. What is the first-line confirmatory diagnostic test and associated finding?

Abdominal ultrasound; elongated pyloric channel and muscle hypertrophy

Barium upper GI series; GE junction and portion of the stomach in thorax

Air enema; filling defect and coil spring sign

Barium upper GI series; bird beak sign and corkscrewing

Abdominal X-ray; ‘double bubble’ sign

A 68-year-old man is brought to the emergency department because of fever, progressive weakness, and cough for the past five days. He experienced a similar episode 2 months ago, for which he was hospitalized for 10 days while visiting his son in Russia. He states that he has never fully recovered from that episode. He felt much better after being treated with antibiotics, but he still coughs often during meals. He sometimes also coughs up undigested food after eating. For the last 5 days, his coughing has become more frequent and productive of yellowish-green sputum. He takes hydrochlorothiazide for hypertension and pantoprazole for the retrosternal discomfort that he often experiences while eating. He has smoked half a pack of cigarettes daily for the last 30 years and drinks one shot of vodka every day. The patient appears thin. His temperature is 40.1°C (104.2°F), pulse is 118/min, respirations are 22/min, and blood pressure is 125/90 mm Hg. Auscultation of the lungs shows right basal crackles. There is dullness on percussion at the right lung base. The remainder of the physical examination shows no abnormalities. Laboratory studies show: Hemoglobin 15.4 g/dL Leukocyte count 17,000/mm3 Platelet count 350,000/mm3 Na+ 139 mEq/L K+ 4.6 mEq/L Cl- 102 mEq/L HCO3- 25 mEq/L Urea Nitrogen 16 mg/dL Creatinine 1.3 mg/dL An x-ray of the chest shows a right lower lobe infiltrate. Which of the following is the most likely explanation for this patient's symptoms?

Weak tone of the lower esophageal sphincter

Unrestricted growth of pneumocytes with invasion of the surrounding tissue

Uncoordinated contractions of the esophagus

Formation of a tissue cavity containing necrotic debris

A 12-year-old patient with esophageal varices is managed by the procedure shown in the image. All of the following statements regarding this condition are true except:

This is the definitive treatment

Gastric balloon is inflated with 400 mL of air

Esophageal balloon is inflated with 40 mm Hg pressure of air

Should be kept inflated for a maximum of 24-48 hours

Neonatal surgical emergencies for USMLE Step 2 CK: High-Yield Surgery Lessons

👶 Tiny Tummies, Big Trouble

📌 VACTERL association: Vertebral, Anal atresia, Cardiac, TracheoEsophageal fistula, Renal, Limb defects.

Condition	Pathophysiology Pearl	Classic Presentation
CDH	Herniation (Bochdalek > Morgagni) → pulmonary hypoplasia.	Scaphoid abdomen, respiratory distress, bowel sounds in chest.
TEF	Failed foregut separation (Type C most common).	Choking/coughing with feeds, NG tube coils, gastric air bubble.
Gastroschisis / Omphalocele	G: Defect lateral to umbilicus, no sac. O: Midline defect, sac, associated anomalies.	Visible bowel (uncovered/covered).
Malrotation w/ Volvulus	Abnormal rotation → Ladd's bands, midgut volvulus.	Sudden bilious vomiting in a well-appearing neonate.
Duodenal Atresia	Failure of duodenal recanalization.	"Double bubble" sign on X-ray, bilious vomiting.
NEC	Ischemia & inflammation in premature infants.	Abdominal distension, bloody stools, pneumatosis intestinalis.

⭐ ~30% of infants with duodenal atresia have Down syndrome (Trisomy 21). Conversely, ~5% of infants with Down syndrome have duodenal atresia.

🩺 Diagnosis - Peeking Inside Problems

Initial Workup:
- Abdominal X-ray (AXR): First-line for any neonatal abdominal distress.
- Contrast Studies: Definitive for specific conditions.

Pathognomonic Findings:
- CDH: Bowel loops in chest on CXR/AXR.
- TEF: Coiled NG tube in esophageal pouch.
- NEC: ⭐ Pneumatosis intestinalis (air in bowel wall).
- Hirschsprung: Transition zone on contrast enema.

Neonatal X-ray: Duodenal Atresia "Double Bubble" Sign

⭐ Bilious emesis in a neonate is malrotation with midgut volvulus until proven otherwise. This is a true surgical emergency requiring immediate evaluation with an upper GI series.

🔪 Management - Scalpels & Support

Initial stabilization is paramount before any surgical intervention.

Malrotation w/ Volvulus: Emergent laparotomy for Ladd's procedure. Detorse bowel, lyse Ladd's bands, place cecum in LLQ, appendectomy.
Congenital Diaphragmatic Hernia (CDH): Intubate, NG decompression. Delayed repair after cardiopulmonary stabilization (managing pulmonary hypertension).
Gastroschisis: Cover bowel with sterile silo/wrap. Aggressive IV fluid resuscitation for massive losses. Staged surgical closure.

⭐ In CDH, avoid bag-mask ventilation. It insufflates the herniated bowel, worsening respiratory compromise by further compressing the hypoplastic lungs.

🚧 Complications - Post-Op Perils

Short Gut Syndrome: After massive bowel resection (NEC, atresia, volvulus). Leads to malabsorption, TPN dependence, and cholestasis.
Adhesions → SBO: A universal long-term risk following any neonatal laparotomy. Presents with bilious emesis and abdominal distension.
GERD: Extremely common post-TEF repair due to esophageal dysmotility. Can cause strictures and recurrent aspiration.
Neurodevelopmental Delay: Risk in severe cases (e.g., CDH, gastroschisis) from perinatal stress, hypoxia, or prolonged hospitalization.

⭐ Post-TEF repair, GERD is a near-universal complication, often requiring long-term management with PPIs or fundoplication.

⚡ Biggest Takeaways

Bilious vomiting in a neonate is malrotation with volvulus until proven otherwise; diagnose with an upper GI series.

Duodenal atresia presents with a "double-bubble" sign on X-ray and is strongly associated with Down syndrome.

Necrotizing enterocolitis (NEC) in premature infants shows pneumatosis intestinalis (air in bowel wall).

Congenital diaphragmatic hernia (CDH): Intubate immediately for respiratory distress; avoid bag-mask ventilation.

Gastroschisis is a defect without a sac; omphalocele is midline and covered by a sac.

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