Pediatric Surgery Basics — MCQs

Pediatric Surgery Basics Indian Medical PG Practice Questions and MCQs

Question 51: Which of the following is a true statement regarding congenital hypertrophic pyloric stenosis?

A. Typically presents at six months of age
B. Bilious vomiting is a common symptom
C. Metabolic alkalosis is frequently observed (Correct Answer)
D. Associated with hypokalemic acidosis

Explanation: **Explanation:** Congenital Hypertrophic Pyloric Stenosis (CHPS) is characterized by hypertrophy of the pyloric sphincter, leading to gastric outlet obstruction. **Why Option C is Correct:** The hallmark metabolic derangement in CHPS is **Hypochloremic, Hypokalemic, Metabolic Alkalosis with Paradoxical Aciduria**. Persistent vomiting of gastric contents leads to a significant loss of hydrochloric acid (HCl) and water. To compensate for the resulting alkalosis and dehydration, the kidneys attempt to conserve sodium and water. In the distal tubule, sodium is reabsorbed in exchange for hydrogen ions (leading to paradoxical aciduria) and potassium ions (leading to hypokalemia). **Why Other Options are Incorrect:** * **Option A:** CHPS typically presents between **3 to 6 weeks** of life. Presentation at six months is highly unusual. * **Option B:** The obstruction is proximal to the Ampulla of Vater; therefore, the vomiting is characteristically **non-bilious** and projectile. * **Option C vs D:** While hypokalemia is present, the primary acid-base disturbance is **alkalosis**, not acidosis. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Sign:** An "olive-shaped" mass palpable in the epigastrium (best felt after vomiting). * **Imaging:** Ultrasound is the gold standard (Pyloric muscle thickness >4mm, length >14mm). Barium swallow shows the **"String sign"** or **"Beak sign."** * **Management:** Initial priority is **fluid resuscitation** (Normal Saline with KCl). Definitive surgery is **Ramstedt’s Pyloromyotomy**. * **Association:** Often associated with the use of **Erythromycin** in the neonatal period.

Question 52: A child presents with bilious vomiting and a 'double bubble' sign on imaging. The mother also had a history of polyhydramnios during pregnancy. What is the most likely diagnosis?

A. Duodenal atresia (Correct Answer)
B. Hypertrophic pyloric stenosis
C. Alagille syndrome
D. Esophageal atresia

Explanation: ### Explanation **Correct Option: A. Duodenal Atresia** The clinical triad of **bilious vomiting**, a history of **maternal polyhydramnios**, and the classic **'double bubble' sign** on abdominal X-ray is pathognomonic for duodenal atresia. * **Pathophysiology:** Failure of recanalization of the duodenum during the 8th–10th week of gestation leads to complete obstruction. * **Imaging:** The 'double bubble' represents air trapped in the dilated stomach and the proximal duodenum, with no distal gas. * **Polyhydramnios:** Occurs because the fetus cannot swallow and absorb amniotic fluid due to the high intestinal obstruction. **Incorrect Options:** * **B. Hypertrophic Pyloric Stenosis:** Presents with **non-bilious** (projectile) vomiting, typically at 3–6 weeks of age. Imaging shows a 'string sign' or 'olive-shaped' mass, not a double bubble. * **C. Alagille Syndrome:** An autosomal dominant disorder characterized by neonatal cholestasis (jaundice) and bile duct paucity, associated with butterfly vertebrae and cardiac defects (Pulmonary stenosis). It does not cause acute intestinal obstruction. * **D. Esophageal Atresia:** Presents with drooling, choking, and cyanosis during feeding. While it is associated with polyhydramnios, the X-ray would show a coiled nasogastric tube in the esophageal pouch. **NEET-PG High-Yield Pearls:** 1. **Association:** Approximately 30% of infants with duodenal atresia have **Down Syndrome (Trisomy 21)**. 2. **Vomiting:** If the obstruction is distal to the Ampulla of Vater (most common), the vomit is **bilious**. 3. **Management:** Initial stabilization with an orogastric tube and IV fluids, followed by definitive surgery (**Duodenoduodenostomy** or Diamond-shaped anastomosis). 4. **Differential for Double Bubble:** Malrotation with midgut volvulus (requires urgent surgical exclusion) and Annular pancreas.

Question 53: A 4-year-old male child is admitted to the hospital with severe vomiting. Radiographic examination and history taking reveals that the boy suffers from an annular pancreas. Which of the following structures is most typically obstructed by this condition?

A. Pylorus of the stomach
B. First part of the duodenum
C. Second part of the duodenum (Correct Answer)
D. Third part of the duodenum

Explanation: **Explanation:** **Annular pancreas** is a rare congenital anomaly resulting from the failure of the **ventral pancreatic bud** to rotate properly behind the duodenum. Instead, the bifid ventral bud migrates in opposite directions, encircling the duodenum and forming a ring of pancreatic tissue that causes extrinsic compression. * **Why Option C is correct:** The ventral pancreatic bud normally rotates around the **second (descending) part of the duodenum** to fuse with the dorsal bud. In annular pancreas, this ring specifically constricts the second part of the duodenum, typically **extrinsic to the Ampulla of Vater**. This leads to symptoms of high intestinal obstruction, such as postprandial vomiting (which may be non-bilious or bilious depending on the exact site relative to the ampulla). **Analysis of Incorrect Options:** * **Option A (Pylorus):** The pylorus is proximal to the pancreatic development site. Obstruction here is characteristic of Hypertrophic Pyloric Stenosis (HPS), not pancreatic anomalies. * **Option B (First part):** The first part of the duodenum is intraperitoneal and superior to the pancreatic head; it is not involved in the rotational path of the ventral bud. * **Option D (Third part):** The third (horizontal) part of the duodenum is located inferiorly and is more commonly compressed by the Superior Mesenteric Artery (SMA Syndrome), not the pancreas. **NEET-PG High-Yield Pearls:** 1. **Embryology:** Caused by the failure of the **ventral bud** to rotate 270° posteriorly. 2. **Associations:** Strongly associated with **Down Syndrome (Trisomy 21)**, duodenal atresia, and malrotation. 3. **Radiology:** Classically presents with the **"Double Bubble Sign"** on X-ray (air in the stomach and proximal duodenum). 4. **Management:** The surgical treatment of choice is **Duodenoduodenostomy** (bypassing the obstruction) rather than dividing the pancreatic ring, to avoid pancreatic fistulas.

Question 54: A 3-week-old child presents with projectile postprandial vomiting and is diagnosed with hypertrophic pyloric stenosis. Congenital hypertrophic pyloric stenosis is associated with which of the following acid-base and electrolyte disturbances?

A. Hypokalemic acidosis
B. Hypokalemic alkalosis (Correct Answer)
C. Hyperkalemic acidosis
D. Hyperkalemic alkalosis

Explanation: **Explanation:** In Hypertrophic Pyloric Stenosis (HPS), the hallmark metabolic derangement is **Hypochloremic Hypokalemic Metabolic Alkalosis**. **1. Why Hypokalemic Alkalosis is correct:** * **Vomiting:** The infant loses gastric juice rich in Hydrochloric acid (HCl) and water. The loss of H+ ions directly causes **metabolic alkalosis**. * **Chloride Loss:** Loss of Cl- leads to a compensatory increase in bicarbonate (HCO3-) retention by the kidneys to maintain electrical neutrality, worsening the alkalosis. * **Renal Compensation & Hypokalemia:** Initially, the kidney tries to excrete HCO3- along with Na+. However, as the child becomes dehydrated (volume depleted), the RAAS (Renin-Angiotensin-Aldosterone System) is activated. To conserve Na+ and water, the kidney begins excreting K+ and H+ in exchange for Na+. This leads to **hypokalemia**. * **Paradoxical Aciduria:** In severe cases, to save the last bits of K+, the kidney excretes H+ ions into the urine despite systemic alkalosis. **2. Why other options are incorrect:** * **Acidosis (A & C):** HPS involves the loss of acid (HCl). Acidosis would occur in conditions involving the loss of base (e.g., severe diarrhea) or tissue hypoxia (lactic acidosis). * **Hyperkalemia (C & D):** Potassium is lost both through vomiting (minor) and primarily through renal excretion in exchange for sodium during dehydration. Hyperkalemia is typically seen in renal failure or adrenal insufficiency. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** 3–6 week old male, non-bilious projectile vomiting, and a palpable "olive-shaped" mass in the epigastrium. * **Diagnosis:** Ultrasound is the investigation of choice (Pyloric thickness >4mm, length >14mm). * **Management:** HPS is a **medical emergency, not a surgical one**. Correct electrolytes and dehydration first (using 0.45% or 0.9% NS with KCL) before performing **Ramstedt’s Myotomy**.

Question 55: A child presented with projectile, forcible, non-bilious vomiting. What is the most likely diagnosis?

A. Pyloric stenosis (Correct Answer)
B. Large bowel obstruction
C. Hirschsprung's disease
D. Ileal obstruction

Explanation: ### Explanation **Correct Answer: A. Pyloric Stenosis** The hallmark of **Infantile Hypertrophic Pyloric Stenosis (IHPS)** is **projectile, non-bilious vomiting**. This occurs because the hypertrophy of the pyloric sphincter creates a mechanical gastric outlet obstruction. Since the obstruction is proximal to the Ampulla of Vater (where bile enters the duodenum), the vomitus contains only gastric contents and no bile. It typically presents in infants aged 3–6 weeks. **Why the other options are incorrect:** * **B. Large bowel obstruction:** This presents with significant abdominal distension and late-onset vomiting which is usually **feculent** (not projectile). * **C. Hirschsprung’s disease:** This is a functional distal bowel obstruction. It presents with failure to pass meconium within 48 hours and **bilious vomiting** due to the distal nature of the obstruction. * **D. Ileal obstruction:** Any obstruction distal to the second part of the duodenum (like ileal atresia or midgut volvulus) will result in **bilious vomiting**, as the gastric contents mix with bile before being expelled. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Projectile non-bilious vomiting, palpable **"olive-shaped" mass** in the epigastrium, and visible gastric peristalsis (left to right). * **Metabolic Abnormality:** Hypochloremic, hypokalemic **metabolic alkalosis** with paradoxical aciduria (frequently tested). * **Diagnosis:** Ultrasound is the investigation of choice (look for pyloric muscle thickness >4mm or length >14mm). * **Treatment:** The definitive surgery is **Ramstedt’s Pyloromyotomy**, but the immediate priority is always correcting fluid and electrolyte imbalances.

Question 56: The abdominal mass in congenital hypertrophic pyloric stenosis in a newborn child can be best palpated where?

A. In the midepigastric area (Correct Answer)
B. In the right hypochondriac quadrant
C. In the umbilical area
D. During feeding

Explanation: **Explanation:** **Congenital Hypertrophic Pyloric Stenosis (CHPS)** is characterized by hypertrophy and hyperplasia of the muscular layers of the pylorus, leading to a functional gastric outlet obstruction. **Why Option A is Correct:** The classic physical finding in CHPS is a firm, mobile, non-tender, olive-shaped mass (the "olive"). Anatomically, the pylorus is located in the **midepigastric area**, slightly to the right of the midline. To palpate it effectively, the clinician must relax the abdominal wall (often using a sugar teat) and palpate deeply in the epigastrium, usually above and to the right of the umbilicus. **Why Other Options are Incorrect:** * **Option B:** While the pylorus is slightly right of the midline, the **right hypochondrium** is typically occupied by the liver and gallbladder. The pyloric mass is more central/epigastric. * **Option C:** The **umbilical area** is too low. The stomach and pylorus are upper abdominal structures. * **Option D:** While visible gastric peristalsis (left to right) is best seen *during* or after feeding, the mass itself is best palpated when the stomach is **empty** (e.g., after vomiting or via a nasogastric tube) to prevent the distended stomach from obscuring the pylorus. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** Non-bilious, projectile vomiting in a 3–6 week old infant. * **Metabolic Profile:** Hypochloremic, hypokalemic metabolic alkalosis with paradoxical aciduria (frequently tested). * **Diagnosis:** Ultrasound is the gold standard (Pyloric muscle thickness >4mm, length >14mm). * **Radiology:** "String sign" or "Beak sign" on barium swallow. * **Management:** Initial resuscitation with Normal Saline (0.9% NaCl), followed by **Ramstedt’s Pyloromyotomy**.

Question 57: Regarding pectus excavatum, all are true except?

A. Gross cardiovascular system dysfunction (Correct Answer)
B. Decrease in lung capacity
C. Cosmetic deformity
D. Depression in chest

Explanation: **Explanation:** **Pectus Excavatum** (Funnel Chest) is the most common congenital chest wall deformity, characterized by a posterior depression of the sternum and adjacent costal cartilages. **Why Option A is the Correct Answer (The "Except"):** While Pectus Excavatum can cause a displacement of the heart to the left and a slight decrease in stroke volume during intense exercise, it **rarely leads to gross cardiovascular system dysfunction**. Most patients remain hemodynamically stable. Significant cardiac failure or life-threatening dysfunction is not a standard feature of the condition, making this statement false. **Analysis of Other Options:** * **Option B (Decrease in lung capacity):** True. The inward displacement of the sternum reduces the intrathoracic volume, leading to a restrictive pattern on pulmonary function tests (decreased Total Lung Capacity and Vital Capacity). * **Option C (Cosmetic deformity):** True. This is the most common reason for presentation. The deformity can lead to significant body image issues and psychological distress, especially during adolescence. * **Option D (Depression in chest):** True. This is the hallmark physical finding of the condition (sternal "hollow"). **High-Yield Clinical Pearls for NEET-PG:** * **Haller Index:** Used to quantify severity via CT scan (Transverse diameter / Anteroposterior diameter). A score **>3.25** is considered severe and often warrants surgery. * **Associated Conditions:** Frequently associated with **Marfan Syndrome**, Ehlers-Danlos, and Scoliosis. * **Surgical Management:** * **Nuss Procedure:** Minimally invasive approach using a retrosternal metal bar (current gold standard). * **Ravitch Procedure:** Open surgery involving cartilage resection. * **Symptoms:** Most are asymptomatic at rest but may experience dyspnea or chest pain during strenuous exercise.

Question 58: What is true about cystic hygroma?

A. It most commonly presents in the posterior triangle of the neck.
B. Sclerosing agents can be useful in its management.
C. Pre-operative MRI is crucial for surgical planning. (Correct Answer)
D. Surgery is not always indicated.

Explanation: **Cystic Hygroma (Cystic Lymphangioma)** is a benign congenital malformation of the lymphatic system, resulting from the failure of lymphatics to communicate with the venous system. ### **Explanation of Options** * **Option C (Correct):** Pre-operative MRI is the gold standard for surgical planning. Cystic hygromas are notorious for infiltrating deep tissue planes, wrapping around vital neurovascular structures (like the carotid sheath or facial nerve), and extending into the mediastinum. MRI provides superior soft-tissue contrast compared to CT, allowing the surgeon to map the exact extent of the lesion to minimize complications during excision. * **Option A:** While the neck is the most common site (75-80%), it most frequently presents in the **anterior triangle**, not the posterior triangle. * **Option B:** Sclerotherapy (using agents like OK-432, Bleomycin, or Doxycycline) is highly effective for **macrocystic** lesions. However, it is less effective for microcystic variants. While "useful," the question structure in competitive exams often prioritizes the "most crucial" clinical step or a definitive diagnostic requirement. * **Option D:** While some small, asymptomatic lesions can be observed, surgery or intervention is **almost always indicated** due to the risk of rapid enlargement, secondary infection, or life-threatening airway compromise (especially in cervical lesions). ### **High-Yield Clinical Pearls for NEET-PG** * **Transillumination:** Cystic hygromas are characteristically **brilliantly transilluminant** (unlike hemangiomas). * **Association:** Frequently associated with chromosomal anomalies, most notably **Turner Syndrome** (45, XO) and Down Syndrome. * **Classification:** Divided into Macrocystic (>2cm) and Microcystic (<2cm) types. * **Complications:** Sudden increase in size usually indicates **intralesional hemorrhage** or infection. * **Treatment of Choice:** Complete surgical excision is the definitive treatment, provided vital structures can be preserved.

Question 59: When can an X-ray detect congenital anorectal malformation?

A. Immediately after birth
B. 24-48 hours after birth (Correct Answer)
C. 48-72 hours after birth
D. After 72 hours

Explanation: ### Explanation The correct timing for an X-ray (specifically the **Invertogram** or Rice-Wangensteen projection) in a neonate with an anorectal malformation (ARM) is **24–48 hours after birth**. **1. Why 24–48 hours is correct:** The primary goal of the X-ray is to determine the level of the rectal pouch relative to the pelvic floor (High vs. Low anomaly). Immediately after birth, the gastrointestinal tract is collapsed. It takes time for swallowed air to traverse the entire length of the bowel and reach the distal-most end of the rectal pouch. Furthermore, the **anal sphincter mechanism** in a newborn has high tone initially; it requires roughly 18–24 hours for the meconium to soften and the air pressure to overcome this tone to reach the distal end. Performing the X-ray earlier may result in a "false high" reading, leading to unnecessary complex surgeries. **2. Why other options are incorrect:** * **Immediately after birth (Option A):** Air has not yet reached the distal rectum. The distance between the skin marker and the gas shadow will be falsely increased. * **48–72 hours / After 72 hours (Options C & D):** While the air would certainly be present, waiting this long delays diagnosis and increases the risk of bowel distension, vomiting, and aspiration. Clinical management (like a colostomy or anoplasty) should ideally be initiated within the first 48 hours. **3. High-Yield Clinical Pearls for NEET-PG:** * **Invertogram Technique:** The baby is held upside down for 3–5 minutes before the X-ray. A radio-opaque marker (coin) is placed at the anal dimple. * **Key Landmark:** The **PC line** (Pubococcygeal line) and **M-line** are used to classify the level of the lesion. * **Prone Cross-Table Lateral View:** This is now often preferred over the classic invertogram as it is less stressful for the neonate and provides similar diagnostic accuracy. * **VACTERL Association:** Always screen for other anomalies (Vertebral, Anal, Cardiac, Tracheo-Esophageal, Renal, Limb) in cases of ARM.

Question 60: What is the initial imaging of choice for suspected acute appendicitis in children?

A. Ultrasound (USG) (Correct Answer)
B. Magnetic Resonance Imaging (MRI)
C. Contrast-Enhanced Computed Tomography (CECT)
D. X-ray

Explanation: **Explanation:** The diagnosis of acute appendicitis in children is primarily clinical; however, when imaging is required, **Ultrasound (USG)** is the **initial imaging of choice**. **1. Why Ultrasound is Correct:** Children are highly sensitive to ionizing radiation. USG is non-invasive, cost-effective, and avoids radiation exposure (ALARA principle—As Low As Reasonably Achievable). In pediatric patients, the abdominal wall is thinner and there is less omental fat, which often allows for better visualization of the appendix compared to adults. A positive finding typically shows a non-compressible, blind-ended tubular structure >6 mm in diameter. **2. Why Other Options are Incorrect:** * **CECT (Option C):** While CECT is the most sensitive and specific modality (the "Gold Standard" for accuracy), it is reserved as a **second-line** investigation if USG is inconclusive. This is due to the high radiation dose and potential risks of IV contrast. * **MRI (Option B):** MRI is highly accurate and avoids radiation, but it is not the "initial" choice due to high costs, lack of universal availability, and the potential need for sedation in young children. * **X-ray (Option D):** Plain radiographs are non-specific. While they may show a fecalith (appendicolith) in 10% of cases or signs of perforation, they cannot reliably diagnose or rule out appendicitis. **Clinical Pearls for NEET-PG:** * **ALARA Principle:** Always prioritize USG over CT in children to prevent secondary malignancies. * **Most common cause of pediatric acute abdomen:** Acute Appendicitis. * **Classic Sign:** Migratory pain to the Right Iliac Fossa (RIF) and rebound tenderness (McBurney’s point). * **Scoring System:** The **Alvarado Score** (MANTRELS) or the **Pediatric Appendicitis Score (PAS)** are used to risk-stratify patients.

Practice by Chapter

Surgical Conditions of the Newborn

Practice Questions

Congenital Diaphragmatic Hernia

Practice Questions

Esophageal Atresia and Tracheoesophageal Fistula

Practice Questions

Intestinal Atresia and Stenosis

Practice Questions

Malrotation and Volvulus

Practice Questions

Hirschsprung's Disease

Practice Questions

Anorectal Malformations

Practice Questions

Biliary Atresia

Practice Questions

Abdominal Wall Defects

Practice Questions

Inguinal Hernia and Hydrocele

Practice Questions

Intussusception

Practice Questions

Appendicitis in Children

Practice Questions

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