Pediatric Surgery — MCQs

Pediatric Surgery Indian Medical PG Practice Questions and MCQs

Question 191: Reversal of SMA and SMV relationship is seen in which condition?

A. Midgut Volvulus (Correct Answer)
B. Duodenal Atresia
C. Annular pancreas
D. Ileal Atresia

Explanation: **Explanation:** The reversal of the normal relationship between the Superior Mesenteric Artery (SMA) and Superior Mesenteric Vein (SMV) is a classic radiological hallmark of **Malrotation with Midgut Volvulus**. **1. Why Midgut Volvulus is correct:** In normal anatomy, the SMV lies to the **right** of the SMA. In malrotation, the normal 270° counter-clockwise rotation of the midgut fails to occur. This results in a narrow mesenteric base, allowing the bowel to twist around the SMA axis. On ultrasound or CT, this manifests as the **"Whirlpool Sign"** (vessels wrapping around each other) and the **reversal of the SMA/SMV relationship**, where the SMV is found to the **left** of the SMA. **2. Why other options are incorrect:** * **Duodenal Atresia:** Characterized by the "Double Bubble" sign on X-ray. It is a failure of recanalization, not a rotational anomaly. * **Annular Pancreas:** A congenital anomaly where pancreatic tissue encircles the second part of the duodenum, causing extrinsic obstruction. It does not involve mesenteric vessel transposition. * **Ileal Atresia:** An in-utero vascular accident leading to bowel discontinuity. While it presents with neonatal intestinal obstruction, the SMA/SMV relationship remains normal. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Upper GI Contrast Study (Barium Swallow/Meal). Look for the **"Corkscrew appearance"** of the distal duodenum/jejunum. * **Ladd’s Procedure:** The definitive surgical treatment. It involves detorsion (counter-clockwise), division of Ladd’s bands, broadening the mesentery, and performing an appendectomy. * **Ladd’s Bands:** Peritoneal bands crossing the duodenum from the cecum, causing extrinsic obstruction. * **Position of Bowel post-surgery:** Small bowel is placed on the right, and the large bowel is placed on the left.

Question 192: Which of the following statements is NOT true regarding pyloric stenosis?

A. Hypokalemia
B. Alkaline urine (Correct Answer)
C. Metabolic alkalosis
D. Hypochloremia

Explanation: In Infantile Hypertrophic Pyloric Stenosis (IHPS), the hallmark is non-bilious projectile vomiting, leading to a specific electrolyte derangement: **Hypochloremic Hypokalemic Metabolic Alkalosis with Paradoxical Aciduria.** ### Why "Alkaline Urine" is the Correct Answer (The False Statement) Initially, the kidney attempts to compensate for metabolic alkalosis by excreting bicarbonate ($HCO_3^-$) along with sodium. However, as vomiting continues, the body becomes volume-depleted. To conserve volume, the kidney activates the Renin-Angiotensin-Aldosterone System (RAAS). Aldosterone acts on the distal tubule to reabsorb Sodium ($Na^+$) at the expense of Hydrogen ($H^+$) and Potassium ($K^+$) ions. Despite the systemic alkalosis, the kidney excretes $H^+$ ions to save sodium, resulting in **acidic urine** (Paradoxical Aciduria). Therefore, "Alkaline urine" is incorrect. ### Analysis of Other Options * **C. Metabolic Alkalosis:** Loss of gastric hydrochloric acid ($HCl$) directly increases serum bicarbonate levels. * **D. Hypochloremia:** Direct loss of chloride ions in the vomitus. * **A. Hypokalemia:** Occurs due to both direct loss in vomitus and, more significantly, renal exchange where $K^+$ is excreted to conserve $Na^+$ under the influence of aldosterone. ### High-Yield Pearls for NEET-PG * **Diagnosis:** Best initial test is **Ultrasound** (Pyloric thickness >4mm, length >14mm). * **Clinical Sign:** "Olive-shaped" mass felt in the epigastrium. * **Radiology:** "String sign" or "Beak sign" on Barium swallow. * **Management:** Never a surgical emergency. **Resuscitate first** with Normal Saline (0.9%) + Potassium. Surgery (Ramstedt’s Myotomy) is performed only after correcting electrolytes.

Question 193: What is the most common presentation of Meckel's diverticulum?

A. Lower GI bleeding (Correct Answer)
B. Upper GI bleeding
C. Diarrhea
D. Abdominal pain

Explanation: **Explanation:** Meckel’s diverticulum is the most common congenital anomaly of the gastrointestinal tract, resulting from the failure of the **vitellointestinal duct** to obliterate. **Why Lower GI Bleeding is Correct:** The most common clinical presentation, especially in the pediatric population, is **painless lower gastrointestinal bleeding**. This occurs because approximately 50% of symptomatic Meckel’s diverticula contain **ectopic gastric mucosa**. This ectopic tissue secretes acid, leading to ulceration of the adjacent ileal mucosa (which lacks protective mechanisms against acid). The resulting hemorrhage typically presents as "currant jelly" or brick-red stools. **Why Other Options are Incorrect:** * **Upper GI Bleeding:** Meckel’s diverticulum is located in the distal ileum (lower GI tract); therefore, bleeding manifests as hematochezia or melena, not hematemesis. * **Diarrhea:** This is not a classic feature of Meckel’s. While inflammatory processes (Meckel’s diverticulitis) may cause altered bowel habits, it is not the primary presentation. * **Abdominal Pain:** While pain occurs in cases of diverticulitis or intussusception (where the diverticulum acts as a lead point), **painless** bleeding remains the most frequent presentation overall. **High-Yield Clinical Pearls for NEET-PG:** * **The Rule of 2s:** 2% of the population, 2 inches long, 2 feet from the ileocecal valve, 2 types of ectopic tissue (Gastric > Pancreatic), and presents before age 2. * **Investigation of Choice:** **Technetium-99m pertechnetate scan** (Meckel’s scan), which identifies the ectopic gastric mucosa. * **Complications:** In adults, intestinal obstruction is more common, whereas, in children, bleeding is the most common symptom. * **Littre’s Hernia:** When a Meckel’s diverticulum is present within a hernial sac.

Question 194: What is an uncommon complication of Meckel's diverticulum?

A. Intussusception
B. Diverticulitis
C. Malignancy (Correct Answer)
D. Increased bleeding

Explanation: **Explanation:** Meckel’s diverticulum is the most common congenital anomaly of the gastrointestinal tract, resulting from the failure of the vitellointestinal duct to obliterate. While it is often asymptomatic, complications occur in about 4% of cases. **Why Malignancy is the Correct Answer:** Malignancy is the **rarest** complication of Meckel’s diverticulum, occurring in less than 0.5% to 3% of symptomatic cases. When it does occur, the most common histological type is **Carcinoid tumor**, followed by adenocarcinoma and leiomyosarcoma. Due to its extreme rarity compared to inflammatory or obstructive complications, it is considered the "uncommon" choice. **Analysis of Incorrect Options:** * **Increased Bleeding (Option D):** This is the **most common** presentation in children. It occurs due to acid secretion from ectopic gastric mucosa, leading to ulceration of the adjacent ileal mucosa (painless hematochezia). * **Intussusception (Option A):** This is a common cause of intestinal obstruction in patients with Meckel’s. The diverticulum acts as a lead point, causing the ileum to invaginate into the colon. * **Diverticulitis (Option B):** This mimics acute appendicitis and is a frequent complication in adults. It occurs due to obstruction of the diverticular lumen by a fecolith or foreign body. **NEET-PG High-Yield Pearls:** * **Rule of 2s:** 2% of the population, 2 inches long, 2 feet from the ileocaecal valve, 2 types of ectopic tissue (Gastric > Pancreatic), and presents before age 2. * **Investigation of Choice:** Meckel’s Scan (Technetium-99m pertechnetate scan) – detects ectopic gastric mucosa. * **Most common presentation in adults:** Intestinal obstruction. * **Most common presentation in children:** Painless lower GI bleeding (Brick-red/Currant jelly stools).

Question 195: Watson criteria is used for what?

A. Treatment for tracheoesophageal fistula (Correct Answer)
B. Diagnosis of tracheoesophageal fistula
C. Diagnosis of peptic ulcer
D. Prognosis of esophageal cancer

Explanation: **Explanation:** The **Watson Criteria** (also known as the Watson classification) is a clinical guideline used to determine the surgical management strategy for **Tracheoesophageal Fistula (TEF)** and Esophageal Atresia (EA). It categorizes infants based on their birth weight and the presence of pneumonia, which are the two most critical predictors of surgical outcome. * **Why Option A is correct:** The criteria guide the **treatment** approach (Primary vs. Staged repair). * **Group A:** Weight >2.5 kg and no pneumonia (Immediate primary repair). * **Group B:** Weight 1.8–2.5 kg or mild pneumonia (Delayed primary repair). * **Group C:** Weight <1.8 kg or severe pneumonia (Staged repair: Gastrostomy followed by delayed repair). * **Why other options are incorrect:** * **B:** Diagnosis of TEF is clinical (inability to pass a stiff NG tube) and radiological (coiled tube on X-ray), not based on Watson criteria. * **C & D:** These are unrelated to pediatric surgery. Peptic ulcers use the Forrest or Johnson classifications, and esophageal cancer uses TNM staging. **High-Yield Clinical Pearls for NEET-PG:** 1. **Waterston vs. Spitz:** While Waterston was the traditional criteria, the **Spitz Classification** is now more commonly used as it focuses on birth weight (<1500g) and **Major Congenital Heart Disease** as the primary prognostic factors. 2. **Most common type:** Type C (Esophageal atresia with distal fistula) is the most common (85%). 3. **VACTERL Association:** Always screen for other anomalies (Vertebral, Anal, Cardiac, TEF, Renal, Limb). 4. **Investigation of choice:** Plain X-ray (Babygram) showing a coiled NG tube in the upper pouch. If air is seen in the stomach, it confirms a distal fistula.

Question 196: According to Moore's classification of omphalocole (examphalos), type I umbilical defect is less than what size in cm?

A. 0.5
B. 2.5 (Correct Answer)
C. 3.5
D. 4.5

Explanation: **Explanation:** Moore’s classification is a clinical grading system used to categorize the severity of an omphalocele (examphalos) based on the diameter of the umbilical defect. This classification is crucial for determining the surgical approach and predicting the risk of associated anomalies. * **Correct Answer (B):** According to Moore’s classification, a **Type I defect** (also known as a small omphalocele or omphalocele of the cord) is defined as having an umbilical defect diameter of **less than 2.5 cm**. These are typically small hernias into the base of the umbilical cord and often contain only loops of the small intestine. * **Incorrect Options (A, C, D):** These values do not align with the standardized Moore’s criteria. A **Type II defect** (Giant Omphalocele) is defined as a defect **greater than 2.5 cm** in diameter. These larger defects often contain the liver and have a higher association with pulmonary hypoplasia and chromosomal abnormalities. **High-Yield Clinical Pearls for NEET-PG:** * **Omphalocele vs. Gastroschisis:** Omphalocele is a midline defect covered by a sac (amnion and peritoneum), whereas gastroschisis is usually to the right of the umbilicus and has no sac. * **Associated Anomalies:** Omphalocele is highly associated with other malformations (up to 50-70%), most notably **Beckwith-Wiedemann Syndrome** (macroglossia, gigantism, hypoglycemia) and **Pentalogy of Cantrell**. * **Management:** Type I defects can often be closed primarily. Type II (Giant) defects may require staged closure using a Silastic silo (Schuster’s procedure) to prevent abdominal compartment syndrome.

Question 197: What is the most important reason for placing an alveolar bone graft in a cleft palate patient?

A. To improve pronunciation
B. To improve breathing efficiency
C. To create an eruptive pathway for the permanent canine (Correct Answer)
D. To improve feeding efficiency

Explanation: In patients with a cleft involving the alveolus, there is a deficiency of bone in the maxillary arch. The primary objective of an **Alveolar Bone Graft (ABG)** is to provide structural support for the dental arch and facilitate the natural eruption of teeth. ### Why Option C is Correct The **permanent maxillary canine** typically erupts between ages 9 and 12. In a cleft patient, the lack of bone at the cleft site prevents the canine from erupting into its proper position, often leading to impaction or eruption into the palate. By performing a bone graft (usually a secondary graft using autologous iliac crest bone) when the canine root is **one-half to two-thirds formed**, surgeons create a solid bony bridge. This allows the canine to migrate through the graft, stabilizing the dental arch and providing bone for future orthodontic movements or implants. ### Why Other Options are Incorrect * **Option A:** While palatoplasty (repair of the soft palate) is crucial for speech and velopharyngeal competence, the alveolar bone graft itself has a negligible impact on pronunciation. * **Option B:** Breathing efficiency is related to the nasal airway and septal deviations, which are addressed via rhinoplasty or septoplasty, not alveolar bone grafting. * **Option D:** Feeding issues are primarily managed in infancy using specialized nipples or early lip/palate repair. By the time a bone graft is performed (mixed dentition stage), feeding is no longer a primary concern. ### High-Yield Clinical Pearls for NEET-PG * **Timing:** The "Gold Standard" for secondary alveolar bone grafting is during **mixed dentition (ages 7–11 years)**, specifically before the eruption of the permanent canine. * **Donor Site:** The **iliac crest** is the most common source of autogenous cancellous bone for this procedure. * **Other Benefits:** ABG also helps in closing residual oronasal fistulas and provides support to the alar base of the nose.

Question 198: What is the primary surgical treatment for congenital hydrocephalus?

A. Ventriculoperitoneal (V-P) shunt (Correct Answer)
B. Acetazolamide
C. Glycerine
D. Furosemide

Explanation: ### Explanation **Primary Surgical Treatment: Ventriculoperitoneal (V-P) Shunt** Congenital hydrocephalus is characterized by an abnormal accumulation of cerebrospinal fluid (CSF) within the cerebral ventricles, leading to increased intracranial pressure (ICP). The **Ventriculoperitoneal (V-P) shunt** is the gold-standard surgical treatment. It works by diverting excess CSF from the lateral ventricles of the brain into the peritoneal cavity, where it is absorbed into the systemic circulation. This mechanical bypass effectively reduces ICP and prevents progressive neurological damage and macrocephaly. **Analysis of Incorrect Options:** * **Acetazolamide (B) & Furosemide (D):** These are pharmacological agents used to decrease CSF production (Acetazolamide inhibits carbonic anhydrase). While they may be used as temporary measures in post-hemorrhagic hydrocephalus or while awaiting surgery, they are **not** primary or definitive treatments for congenital hydrocephalus. * **Glycerine (C):** This is an osmotic agent used to acutely lower intracranial pressure in emergencies (similar to Mannitol). It does not address the underlying obstructive or communicative pathology of hydrocephalus and is not a long-term surgical solution. **Clinical Pearls for NEET-PG:** * **Most Common Complication:** Shunt infection (most commonly *Staphylococcus epidermidis*) and shunt obstruction. * **Alternative Surgery:** **Endoscopic Third Ventriculostomy (ETV)** is an alternative for obstructive (non-communicating) hydrocephalus, avoiding the need for a foreign body (shunt). * **Classic Presentation:** "Setting-sun" eye sign, bulging fontanelle, and cracked-pot sign (Macewen's sign) on percussion. * **Most Common Cause:** Aqueductal stenosis is the most frequent cause of congenital obstructive hydrocephalus.

Question 199: The Blalock-Taussing shunt is performed between which two structures?

A. Subclavian artery and pulmonary vein
B. Subclavian vein and pulmonary artery
C. Aorta and pulmonary artery (Correct Answer)
D. Aorta and pulmonary vein

Explanation: The **Blalock-Taussig (BT) shunt** is a palliative surgical procedure used to increase pulmonary blood flow in cyanotic heart diseases with decreased pulmonary perfusion, most notably **Tetralogy of Fallot (TOF)**. ### **Explanation of the Correct Answer** The fundamental goal of a BT shunt is to create a communication between the **systemic circulation (Aorta/its branches)** and the **pulmonary circulation (Pulmonary Artery)**. * **Classic BT Shunt:** Historically involved an end-to-side anastomosis between the **Subclavian Artery** (a branch of the aorta) and the **Pulmonary Artery**. * **Modified BT Shunt:** Currently the standard practice, it uses a synthetic GORE-TEX graft to connect the **Subclavian Artery** to the **Pulmonary Artery**. Since the subclavian artery is a direct continuation of the systemic output, the shunt effectively connects the **Aorta to the Pulmonary Artery**, allowing deoxygenated blood a second chance to reach the lungs. ### **Why Other Options are Incorrect** * **Options A & D (Pulmonary Vein):** The goal is to send blood to the lungs for oxygenation. Connecting to the pulmonary vein (which carries already oxygenated blood to the heart) would not improve oxygenation. * **Option B (Subclavian Vein):** Connecting a vein to an artery would not provide the high-pressure gradient necessary to drive sufficient blood flow into the pulmonary system. ### **NEET-PG High-Yield Pearls** * **Indication:** Primarily used for "Blue Babies" (TOF, Pulmonary Atresia, Tricuspid Atresia). * **Classic vs. Modified:** The classic shunt sacrificed the subclavian artery (leading to weak pulses in the arm); the modified shunt preserves it using a graft. * **Complication:** Horner’s syndrome (due to sympathetic chain injury) and chylothorax. * **Other Shunts to Remember:** * **Waterston Shunt:** Ascending Aorta to Right Pulmonary Artery. * **Potts Shunt:** Descending Aorta to Left Pulmonary Artery. * **Glenn Shunt:** Superior Vena Cava to Right Pulmonary Artery.

Question 200: Swenson's operation is performed for which condition?

A. Hirschsprung disease (Correct Answer)
B. Crohn's stricture dilation
C. Biliary atresia
D. Choledochal cyst

Explanation: **Explanation:** **Hirschsprung Disease (HD)** is the correct answer. It is a congenital condition characterized by the absence of ganglion cells (Auerbach’s and Meissner’s plexuses) in the distal colon, leading to functional obstruction. **Swenson’s procedure** was the first definitive pull-through operation described for HD. It involves a complete proctosectomy and resection of the aganglionic segment, followed by an end-to-end anastomosis of the normal ganglionic proximal colon to the anal canal. **Analysis of Incorrect Options:** * **Crohn’s stricture dilation:** This is typically managed via endoscopic balloon dilation or surgical stricturoplasty (e.g., Heineke-Mikulicz or Finney stricturoplasty), not pull-through procedures. * **Biliary atresia:** The gold standard surgical treatment is the **Kasai portoenterostomy**, which involves connecting the liver hilum to a Roux-en-Y loop of the jejunum. * **Choledochal cyst:** Management involves excision of the cyst followed by biliary reconstruction, usually via **Roux-en-Y Hepaticojejunostomy**. **High-Yield Clinical Pearls for NEET-PG:** * **Other Pull-through Procedures for HD:** * **Duhamel:** Retrorectal pull-through (leaves the aganglionic rectum in situ). * **Soave:** Endorectal pull-through (stripping the mucosa and pulling the colon through a muscular cuff). * **Diagnosis:** The gold standard is a **Rectal Suction Biopsy** showing absence of ganglion cells and increased acetylcholinesterase activity. * **Radiology:** Barium enema classically shows a "transition zone" between the narrow aganglionic segment and the dilated proximal colon.

Practice by Chapter

Neonatal Physiology

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Congenital Anomalies Overview

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Neonatal Intestinal Obstruction

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Necrotizing Enterocolitis

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Hirschsprung's Disease

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Anorectal Malformations

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Pediatric Hernias

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Pyloric Stenosis

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Biliary Atresia

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Pediatric Tumors

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Congenital Diaphragmatic Hernia

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Pediatric Trauma

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