Pediatric Surgery — MCQs

Pediatric Surgery Indian Medical PG Practice Questions and MCQs

Question 21: Hypochloremic alkalosis is a complication of which of the following conditions?

A. Congenital pyloric stenosis
B. Vomiting (Correct Answer)
C. Haematemesis
D. Aspirin intoxication

Explanation: **Explanation:** The core physiological mechanism behind **hypochloremic hypokalemic metabolic alkalosis** is the loss of gastric secretions. Gastric juice is rich in hydrochloric acid (HCl) and potassium. **1. Why Vomiting is Correct:** When a patient vomits (specifically non-bilious vomiting), there is a significant loss of **Hydrogen (H+)** and **Chloride (Cl-)** ions. * **Alkalosis:** The loss of H+ ions leads to a rise in serum pH (metabolic alkalosis). * **Hypochloremia:** The loss of Cl- leads to low serum chloride. * **The Renal Response:** To compensate for the loss of fluid, the kidneys activate the Renin-Angiotensin-Aldosterone System (RAAS). Aldosterone causes sodium reabsorption at the expense of potassium and hydrogen excretion in the distal tubule, leading to **hypokalemia** and **paradoxical aciduria** (a classic NEET-PG favorite). **2. Analysis of Other Options:** * **Congenital Pyloric Stenosis (A):** While this condition *causes* hypochloremic alkalosis, it does so **via the mechanism of vomiting**. In the context of this question, "Vomiting" is the more direct physiological cause. However, in many clinical scenarios, these two are synonymous. * **Haematemesis (C):** This refers to vomiting blood. While it involves vomiting, the primary concern is acute blood loss and potential shock, not the specific electrolyte pattern of pure gastric juice loss. * **Aspirin Intoxication (D):** Salicylate poisoning typically causes a mixed acid-base disorder: early **respiratory alkalosis** (due to hyperventilation) followed by **high anion gap metabolic acidosis**. **High-Yield Clinical Pearls:** * **Paradoxical Aciduria:** In severe depletion, the kidney excretes H+ instead of Na+ to conserve volume, making the urine acidic despite systemic alkalosis. * **Fluid of Choice:** The treatment for this condition is **0.9% Normal Saline** (to replace Chloride and Volume) with added **Potassium**. * **Pyloric Stenosis:** Always remember it presents as **non-bilious, projectile vomiting** in an infant (3–6 weeks old) with a palpable "olive-shaped" mass.

Question 22: Which of the following is a better prognostic factor for operation of biliary duct obstruction in a newborn?

A. No passage of bile
B. Size of ductule > 200 micron (Correct Answer)
C. Weight of baby > 3 kg
D. Preterm baby

Explanation: **Explanation:** The question refers to the surgical management of **Biliary Atresia (BA)**, specifically the **Kasai portoenterostomy**. The prognosis of this procedure depends heavily on the histological characteristics of the biliary remnants at the porta hepatis. **1. Why Option B is Correct:** The most significant histological predictor of successful bile drainage after a Kasai procedure is the **diameter of the biliary ductules** found within the fibrous tissue at the porta hepatis. According to the landmark studies by Chandra and Altman: * **Ductules > 200 microns:** Associated with the best prognosis and excellent bile flow. * **Ductules 150–200 microns:** Associated with fair prognosis. * **Ductules < 150 microns:** Associated with poor outcomes and failure of bile drainage. **2. Why Other Options are Incorrect:** * **Option A (No passage of bile):** This is a clinical sign of obstruction/failure, not a favorable prognostic factor. * **Option C & D (Weight/Preterm status):** While the general health and maturity of the baby affect surgical risk, they are not specific prognostic markers for the success of the biliary reconstruction itself. The **age at the time of surgery** is a much more critical factor than birth weight (ideally performed before 60 days of life). **High-Yield Clinical Pearls for NEET-PG:** * **Investigation of Choice:** HIDA scan (shows no excretion into the bowel). * **Gold Standard Diagnosis:** Intraoperative Cholangiogram (IOC). * **Kasai Procedure:** Also known as Hepatic Portoenterostomy. * **The "Rule of 8":** Success rates for Kasai are highest if performed before 8 weeks (60 days) of age. Beyond 90 days, the success rate drops significantly due to established secondary biliary cirrhosis. * **Most common cause** of pediatric liver transplantation is Biliary Atresia.

Question 23: For an 8-year-old child with temporomandibular joint (TMJ) ankylosis, what is the treatment of choice?

A. Gap arthroplasty
B. Condylectomy
C. Gap arthroplasty with costochondral grafting (Correct Answer)
D. Treatment not required

Explanation: ### Explanation **Correct Option: C. Gap arthroplasty with costochondral grafting** The management of TMJ ankylosis in children is distinct from adults due to the ongoing need for facial growth. In an 8-year-old child, the primary goals are to release the ankylosis, prevent recurrence, and **restore the growth center**. The **costochondral graft (CCG)** is the gold standard because the cartilaginous cap of the rib acts as a growth center, mimicking the function of the mandibular condyle. This helps in maintaining the vertical height of the ramus and prevents future facial asymmetry or micrognathia (bird-face deformity) as the child grows. **Why other options are incorrect:** * **Gap Arthroplasty (A):** While this involves removing the ankylotic bone to create a gap, it does not replace the lost growth center. In children, this leads to a high rate of recurrence (re-ankylosis) and progressive mandibular shortening. * **Condylectomy (B):** This is the surgical removal of the condyle. It is insufficient for ankylosis management as it does not address the extensive bony mass often present and fails to provide a functional replacement for growth. * **Treatment not required (D):** TMJ ankylosis is a surgical emergency in pediatric patients to prevent permanent facial deformity, dental malocclusion, and life-threatening obstructive sleep apnea. **Clinical Pearls for NEET-PG:** * **Kaban’s Protocol:** The standard surgical protocol for pediatric TMJ ankylosis includes aggressive resection, ipsilateral coronoidectomy, and reconstruction with a costochondral graft. * **Most common cause:** In India, trauma (falls) is the most common cause of TMJ ankylosis, followed by infections (otitis media). * **Complication of CCG:** The most significant risk unique to costochondral grafting is **overgrowth** of the graft, which can lead to late-onset facial asymmetry. * **Post-op Care:** Early and aggressive physiotherapy is mandatory to prevent re-ankylosis.

Question 24: A 5-year-old male child presents with a single testis in the scrotum. Examination reveals the contralateral testis is palpable in the inguinal canal. What is the recommended management?

A. Orchiopexy (Correct Answer)
B. Observation until puberty
C. Orchidectomy
D. Androgen administration

Explanation: **Explanation:** The clinical presentation describes **Undescended Testis (Cryptorchidism)**. In this case, the testis is palpable in the inguinal canal, confirming it is not absent but has failed to reach the scrotum. **1. Why Orchiopexy is correct:** Orchiopexy is the gold standard treatment for undescended testis. The primary goals are to preserve fertility (germ cell maturation begins at 6 months), reduce the risk of testicular torsion, and allow for easier screening for testicular malignancy (which is 40 times more common in undescended testes). Current guidelines recommend surgery between **6 to 12 months of age**. Since this child is 5 years old, immediate surgical intervention is mandatory to prevent further germ cell degradation. **2. Why other options are incorrect:** * **Observation until puberty:** Spontaneous descent is rare after 6 months of age. Delaying surgery until puberty significantly increases the risk of infertility and makes the detection of malignancy difficult. * **Orchidectomy:** This is reserved for cases where the testis is atrophic, non-viable, or if the patient is post-pubertal with a normal contralateral testis. In a 5-year-old, every effort is made to salvage the testis. * **Androgen administration:** Hormonal therapy (hCG or GnRH) has a very low success rate and is generally not recommended as a primary treatment, especially for palpable inguinal testes. **NEET-PG High-Yield Pearls:** * **Most common site:** Inguinal canal. * **Ideal age for surgery:** 6–12 months (latest by 18 months). * **Most common complication post-orchiopexy:** Testicular atrophy. * **Malignancy risk:** Orchiopexy does *not* eliminate the risk of malignancy but makes the testis accessible for examination. The most common tumor in an undescended testis is **Seminoma**. * **Investigation of choice:** Clinical examination is paramount. For non-palpable testes, **Diagnostic Laparoscopy** is the gold standard.

Question 25: What is the most commonly used shunt in the management of hydrocephalus?

A. Ventriculoatrial shunt
B. Ventriculoperitoneal shunt (Correct Answer)
C. Ventriculopericardial shunt
D. Ventriculopleural shunt

Explanation: **Explanation:** The primary goal in treating hydrocephalus is to divert excess cerebrospinal fluid (CSF) from the cerebral ventricles to another body cavity where it can be absorbed. **Ventriculoperitoneal (VP) Shunt** is the most commonly used procedure because the peritoneum provides a large surface area for fluid absorption and can accommodate long lengths of tubing. This is particularly advantageous in pediatric patients, as the extra tubing allows for the child’s physical growth without requiring immediate surgical revision. It is technically simpler to perform and has a lower risk of life-threatening complications compared to vascular shunts. **Analysis of Incorrect Options:** * **Ventriculoatrial (VA) Shunt:** This was historically common but is now a second-line option. It carries risks of serious systemic complications, including endocarditis, "shunt nephritis" (immune-complex glomerulonephritis), and pulmonary hypertension. * **Ventriculopleural Shunt:** Used as a backup when the peritoneum is unsuitable (e.g., due to extensive adhesions). It is rarely used in children under age 7 because the pleural space has limited absorptive capacity, leading to symptomatic pleural effusion. * **Ventriculopericardial Shunt:** A very rare salvage procedure used only when other sites (peritoneum, atrium, pleura) are exhausted. **Clinical Pearls for NEET-PG:** * **Most common complication:** Shunt infection (most commonly *Staphylococcus epidermidis*). * **Most common cause of shunt failure:** Mechanical obstruction (usually at the proximal/ventricular end). * **Alternative:** Endoscopic Third Ventriculostomy (ETV) is the preferred treatment for obstructive (non-communicating) hydrocephalus to avoid shunt-related complications.

Question 26: What is the most common cause of a mass in the posterior mediastinum in children?

A. Rhabdomyosarcoma
B. Duplication cyst of the esophagus
C. Lymphoma
D. Neuroblastoma (Correct Answer)

Explanation: **Explanation:** In the pediatric population, the mediastinum is divided into anterior, middle, and posterior compartments. The **posterior mediastinum** is the most common site for mediastinal masses in children, and the vast majority (approx. 90%) of these are **neurogenic tumors**. **Neuroblastoma** is the most common cause of a posterior mediastinal mass in children. These tumors arise from the sympathetic chain ganglia. While neuroblastomas are more common in the abdomen (adrenal gland), thoracic neuroblastomas generally have a better prognosis. **Analysis of Incorrect Options:** * **A. Rhabdomyosarcoma:** This is the most common soft tissue sarcoma in children, but it typically presents in the head and neck, genitourinary tract, or extremities, rarely as a primary mediastinal mass. * **B. Duplication cyst of the esophagus:** While these are classic posterior mediastinal lesions, they are much less common than neurogenic tumors. * **C. Lymphoma:** Lymphomas (Hodgkin and Non-Hodgkin) are the most common cause of masses in the **anterior and middle mediastinum** in children, not the posterior compartment. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 1/3rds:** In children, 1/3 of mediastinal masses are malignant; in adults, 1/3 are malignant. * **Neuroblastoma Markers:** Elevated urinary catecholamines (VMA/HVA) and N-myc amplification (poor prognostic factor). * **Dumbbell Tumor:** Neuroblastomas can extend through the intervertebral foramina into the spinal canal, presenting with neurological symptoms. * **Imaging:** MRI is the investigation of choice to evaluate spinal canal involvement in posterior mediastinal masses.

Question 27: What is the most common organ involved in blunt abdominal trauma in a child?

A. Spleen (Correct Answer)
B. Kidney
C. Small intestine
D. Liver

Explanation: **Explanation:** In pediatric blunt abdominal trauma (BAT), the **Spleen** is the most commonly injured solid organ. This susceptibility is due to several anatomical factors in children: the rib cage is more compliant and provides less protection, the spleen is relatively larger in proportion to the abdominal cavity compared to adults, and the supporting ligaments are less developed, allowing for greater mobility and shearing forces during deceleration. **Analysis of Options:** * **A. Spleen (Correct):** Statistically the most frequent organ injured. Most pediatric splenic injuries are managed non-operatively (NOM) due to the thick splenic capsule in children and the risk of Overwhelming Post-Splenectomy Infection (OPSI). * **B. Kidney:** While frequently injured in children due to less perirenal fat and a lower position in the abdomen, it ranks behind the spleen and liver in frequency. * **C. Small Intestine:** This is the most common **hollow viscus** organ injured, often associated with "seat belt syndrome" or lap-belt injuries, but it is less common than solid organ injuries. * **D. Liver:** The liver is the **second most common** solid organ injured. While liver injuries have a higher mortality rate due to potential major vascular involvement, the spleen remains the most frequent. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of BAT in children:** Motor vehicle accidents (as a pedestrian or passenger). * **Kehr’s Sign:** Referred pain to the left shoulder, indicative of splenic rupture/diaphragmatic irritation. * **Management Gold Standard:** Hemodynamically stable children are managed **non-operatively**, regardless of the grade of injury seen on CT. * **Lap-belt Injury Triad:** Abdominal wall ecchymosis, hollow viscus injury (small bowel), and Lumbar spine fracture (Chance fracture).

Question 28: Sacroccygeal teratoma is an embryological remnant of which structure?

A. Neural tube
B. Allantois
C. Notochord
D. Primitive streak (Correct Answer)

Explanation: **Explanation:** **Sacrococcygeal Teratoma (SCT)** is the most common congenital tumor in newborns. It originates from the **Primitive Streak**, specifically from the **Hensen’s node** (primitive knot). During the third week of gestation, the primitive streak is responsible for gastrulation (forming the three germ layers). Normally, the streak disappears, but if pluripotent cells persist in the sacrococcygeal region, they can develop into a teratoma containing derivatives of all three germ layers (ectoderm, mesoderm, and endoderm). **Analysis of Incorrect Options:** * **Neural tube:** This structure gives rise to the central nervous system. Defects here lead to conditions like spina bifida or myelomeningocele, not teratomas. * **Allantois:** This is an embryonic duct involved in early fluid exchange and bladder development. Its remnant is the urachus; failure of its obliteration leads to urachal cysts or fistulae. * **Notochord:** This serves as the primitive axis of the embryo. Remnants of the notochord give rise to a **Chordoma**, a malignant bone tumor usually found in the clivus or sacrum, but not a teratoma. **High-Yield Clinical Pearls for NEET-PG:** * **Epidemiology:** More common in females (4:1 ratio). * **Altman Classification:** Type I (mostly external) is the most common; Type IV (entirely internal/presacral) has the highest risk of malignancy. * **Diagnosis:** Often detected on prenatal ultrasound; elevated **Alpha-fetoprotein (AFP)** is a marker for yolk sac components (malignancy). * **Management:** Surgical excision is the treatment of choice. **Crucial Step:** The **Coccyx must be removed** along with the tumor to prevent a high rate of recurrence.

Question 29: In intussusception, what does the term 'intussuscipiens' refer to?

A. The inner invaginated segment
B. The middle layer of the invaginated segment
C. The receiving or outer bowel segment (Correct Answer)
D. The entire intussuscepted mass

Explanation: ### Explanation Intussusception is the telescoping of one segment of the gastrointestinal tract into an adjacent segment. To understand the anatomy, it is essential to distinguish between the two primary components: 1. **Intussusceptum (The "In" part):** This is the proximal segment of the bowel that invaginates or slides into the distal segment. 2. **Intussuscipiens (The "Recipient" part):** This is the distal, outer segment that receives the invaginated portion. **Why Option C is Correct:** The term **Intussuscipiens** is derived from the Latin *suscipere*, meaning "to receive." In the pathology of intussusception, it acts as the sheath or the outer container that holds the prolapsed inner segment. **Analysis of Incorrect Options:** * **Option A & B:** These refer to the **Intussusceptum**. The intussusceptum itself consists of three layers (an entering inner layer, a returning middle layer, and the apex), but collectively they form the invaginated segment, not the receiving one. * **Option D:** The entire mass is simply referred to as the **Intussusception**. ### NEET-PG High-Yield Clinical Pearls: * **Most Common Site:** Ileocolic (specifically at the ileocecal valve). * **Classic Triad:** Intermittent abdominal pain, "currant jelly" stools (blood and mucus), and a palpable sausage-shaped mass (usually in the right upper quadrant). * **Dance’s Sign:** An empty feeling in the Right Iliac Fossa (RIF) due to the migration of the cecum. * **Diagnosis of Choice:** Ultrasound (shows the **"Target" or "Donut" sign** in transverse view and the **"Pseudokidney" sign** in longitudinal view). * **Management:** Non-operative reduction using **Hydrostatic (saline/barium) or Pneumatic (air) enema** is the first-line treatment in stable patients. Surgical intervention is required if there are signs of peritonitis or gangrene.

Question 30: A neonate presents with respiratory distress and excessive salivation. The mother had a history of polyhydramnios. What is the initial investigation?

A. Chest X-ray
B. Nasogastric tube insertion followed by chest X-ray (Correct Answer)
C. Endoscopy
D. Contrast study

Explanation: This question describes the classic presentation of **Esophageal Atresia (EA)** with or without **Tracheoesophageal Fistula (TEF)**. ### **Explanation of the Correct Answer** The triad of maternal polyhydramnios (due to the fetus's inability to swallow amniotic fluid), excessive salivation/drooling, and respiratory distress (due to aspiration or fistula) is highly suggestive of EA. The **initial investigation** of choice is the attempt to pass a wide-bore (10 Fr), stiff **radiopaque nasogastric (NG) or orogastric tube**. In cases of EA, the tube will meet resistance and "coil" in the upper esophageal pouch. A subsequent **Chest X-ray** (including the abdomen) confirms the diagnosis by showing the tube coiled in the neck or upper mediastinum. The X-ray also helps identify the presence of bowel gas, which indicates a distal TEF. ### **Why Other Options are Incorrect** * **A. Chest X-ray alone:** While an X-ray is necessary, it must be performed *with* the NG tube in situ to visualize the level of atresia. A plain film alone may be non-specific. * **C. Endoscopy:** This is invasive, unnecessary for the initial diagnosis, and carries a high risk of respiratory compromise in a distressed neonate. * **D. Contrast study:** This is generally **contraindicated** as the initial step due to the high risk of aspiration of contrast into the lungs, leading to chemical pneumonitis. It is only reserved for rare cases of "H-type" fistulas. ### **High-Yield Clinical Pearls for NEET-PG** * **Most Common Type:** Type C (85%) – Proximal atresia with distal fistula. * **Gasless Abdomen:** Seen in Type A (Pure Atresia) and Type B (Proximal fistula). * **Associated Anomalies:** **VACTERL** association (Vertebral, Anal, Cardiac, TEF, Renal, Limb) is present in 50% of cases. Echocardiography is mandatory before surgery to rule out a right-sided aortic arch. * **Definitive Management:** Surgical ligation of the fistula and primary end-to-end anastomosis.

Practice by Chapter

Neonatal Physiology

Practice Questions

Congenital Anomalies Overview

Practice Questions

Neonatal Intestinal Obstruction

Practice Questions

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

Practice Questions

Biliary Atresia

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Pediatric Tumors

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Congenital Diaphragmatic Hernia

Practice Questions

Pediatric Trauma

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