General Surgery Principles Practice Questions

Q: Non-bilious vomiting is typically seen in which of the following conditions?

Hypertrophic pyloric stenosis. **Explanation:** The key to distinguishing between types of pediatric intestinal obstruction lies in the anatomical relationship to the **Ampulla of Vater** (where the common bile duct enters the second part of the duodenum). **1. Why Hypertrophic Pyloric Stenosis (HPS) is correct:** In HPS, there is hypertrophy of the pyloric sphincter muscle, causing a functional gastric outlet obstruction. Because the obstruction is **proximal** to the Ampulla of Vater, the gastric contents (milk/formula) cannot mix with bile. Therefore, the hallmark clinical presentation is **non-bilious, projectile vomiting** in an infant typically aged 3–6 weeks. **2. Why the other options are incorrect:** * **Duodenal Atresia:** The obstruction most commonly occurs distal to the Ampulla of Vater. Thus, it typically presents with **bilious vomiting** within the first 24–48 hours of life. It is classically associated with the "double bubble" sign on X-ray. * **Meconium Ileus:** This is a distal small bowel obstruction (terminal ileum) often associated with Cystic Fibrosis. Since the blockage is far distal to the bile duct, the vomitus is **bilious**. * **Necrotising Enterocolitis (NEC):** This is an inflammatory/ischemic necrosis of the bowel. It presents with abdominal distension, bloody stools, and **bilious** gastric residuals or vomiting. **Clinical Pearls for NEET-PG:** * **Metabolic Profile in HPS:** Hypochloremic, hypokalemic, metabolic alkalosis with paradoxical aciduria. * **Physical Exam:** A palpable "olive-shaped" mass in the epigastrium. * **Ultrasound (Investigation of Choice):** Look for pyloric muscle thickness >4mm and pyloric canal length >14mm. * **Treatment:** Ramstedt’s Pyloromyotomy (after correcting electrolyte imbalances).

Q: Calot's triangle is an important landmark for which anatomical structure?

Cystic artery. **Explanation:** The **Triangle of Calot** (Cystic Triangle) is a critical surgical landmark used during cholecystectomy to ensure the safe identification and ligation of structures before gallbladder removal. The **cystic artery** is the primary structure found within the boundaries of this triangle, making it the correct answer. **Boundaries of Calot’s Triangle:** * **Superiorly:** Inferior surface of the liver. * **Medially:** Common Hepatic Duct (CHD). * **Laterally:** Cystic duct. **Why the other options are incorrect:** * **Cystic duct:** This forms the **lateral boundary** of the triangle, rather than being a structure contained within it. * **Common bile duct (CBD):** The CBD is located inferior to the junction of the cystic duct and CHD. Mistaking the CBD for the cystic duct is a major cause of biliary injury during surgery. * **Hepatic vein:** These veins drain directly into the IVC and are located deep within the liver parenchyma, far from the biliary tree. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mascagni’s Lymph Node (Lund’s Node):** This is the sentinel lymph node of the gallbladder, often found within Calot’s triangle. It becomes enlarged in cholecystitis. 2. **Moynihan’s Hump:** A tortuous right hepatic artery may enter Calot’s triangle (caterpillar turn), increasing the risk of accidental ligation. 3. **Critical View of Safety (CVS):** Modern surgical teaching emphasizes the "Critical View of Safety" rather than just identifying Calot's triangle to prevent CBD injuries. 4. **Content Variation:** While the original description by Calot (1891) used the cystic artery as a boundary, the modern surgical definition (Hepatobiliary Triangle) places the **cystic artery** as the key content.

Q: Catgut is preserved in which of the following solutions?

Isopropyl alcohol. **Explanation:** **Catgut** is a natural, absorbable surgical suture derived from the submucosa of sheep intestine or the serosa of bovine intestine. Because it is composed of collagen, it is highly susceptible to hydration and bacterial degradation. 1. **Why Isopropyl Alcohol is Correct:** Catgut is preserved in a solution of **90% Isopropyl alcohol** (often with a small percentage of water or conditioning agents like glycerol). The primary reason is to maintain the **tensile strength** and **pliability** of the suture. Alcohol prevents the collagen fibers from swelling or becoming macerated, which would happen if stored in a purely aqueous solution. It also maintains the sterility of the suture material within its foil packet. 2. **Why Other Options are Incorrect:** * **Glutaraldehyde (A):** This is a high-level disinfectant (e.g., Cidex) used for cold sterilization of endoscopes and heat-sensitive instruments, not for suture preservation. * **Iodine (C):** While iodine is used to treat "Chromic Catgut" to delay absorption or as an antiseptic, the liquid medium in the packet remains alcohol-based. * **Cetrimide (D):** This is a quaternary ammonium disinfectant used for wound cleaning and skin preparation, not for the long-term storage of biological sutures. **High-Yield Clinical Pearls for NEET-PG:** * **Absorption:** Catgut is absorbed by **proteolysis** (enzymatic degradation) and triggers a significant inflammatory tissue reaction. * **Absorption Time:** Plain catgut loses tensile strength in 7–10 days; Chromic catgut (treated with chromic acid salts) lasts 14–21 days. * **Contraindication:** Never use catgut in biliary or urinary tracts, as it can act as a nidus for **stone formation** (calculogenesis). * **Handling:** Catgut should be used immediately after removal from the packet; if it dries out, it becomes brittle and loses its handling properties.

Q: What is the most common lesion found in the middle mediastinum?

Congenital cyst. **Explanation:** The mediastinum is traditionally divided into anterior, middle, and posterior compartments. The **middle mediastinum** contains the heart, pericardium, great vessels, trachea, and major bronchi. **Why "Congenital Cyst" is correct:** Congenital cysts are the most common primary lesions of the middle mediastinum. These include **bronchogenic cysts** (most common), pericardial cysts, and enteric cysts. They arise from abnormal budding of the primitive foregut during embryogenesis. On imaging, they typically appear as well-circumscribed, fluid-filled masses near the carina or paratracheal region. **Analysis of Incorrect Options:** * **Lipoma (A):** While lipomas can occur anywhere in the mediastinum, they are rare and most frequently found in the anterior mediastinum or cardiophrenic angles. * **Aneurysm (B):** Aortic aneurysms are common vascular pathologies of the middle mediastinum; however, they are categorized as vascular abnormalities rather than primary mediastinal "lesions" or tumors. * **Germ Cell Tumour (D):** These (along with the "4 Ts": Thymoma, Teratoma, Thyroid, and Terrible Lymphoma) are the hallmark lesions of the **Anterior Mediastinum**. **High-Yield Clinical Pearls for NEET-PG:** * **Anterior Mediastinum:** Most common site for mediastinal masses overall. Most common lesion: **Thymoma**. * **Middle Mediastinum:** Most common lesion: **Congenital/Bronchogenic Cyst**. Lymphadenopathy (sarcoid, lymphoma, or metastasis) is also frequently seen here. * **Posterior Mediastinum:** Most common lesion: **Neurogenic tumours** (e.g., Schwannoma, Neurofibroma). * **Imaging Gold Standard:** Contrast-Enhanced Computed Tomography (CECT) is the investigation of choice for characterizing mediastinal masses.

Q: Which tumour is not typically found in the anterior mediastinum?

Neurofibroma. ### Explanation The mediastinum is anatomically divided into compartments, each associated with specific characteristic pathologies. The **anterior mediastinum** is the space bounded by the sternum anteriorly and the pericardium/great vessels posteriorly. #### Why Neurofibroma is the Correct Answer **Neurofibroma** is a nerve sheath tumor. In the mediastinum, neurogenic tumors (including neurofibromas, schwannomas, and ganglioneuromas) are almost exclusively found in the **posterior mediastinum**, arising from the paravertebral sympathetic chain or intercostal nerves. Therefore, it is not a typical finding in the anterior compartment. #### Analysis of Incorrect Options (The "4 Ts" of Anterior Mediastinum) The differential diagnosis for an anterior mediastinal mass is classically remembered by the mnemonic **"The 4 Ts"**: * **Thymic Tumours (Option B):** The most common primary anterior mediastinal neoplasm in adults (e.g., Thymoma, Thymic carcinoma). * **Teratoma (Option A):** Represents Germ Cell Tumors (GCTs). Mature teratomas are the most common GCTs found in this region. * **Thyroid Tumours (Option C):** Specifically "Retrosternal Goiter." Ectopic thyroid tissue or an extension of a cervical goiter frequently occupies the superior-anterior mediastinum. * **"Terrible" Lymphoma:** The fourth "T," often presenting with bulky lymphadenopathy. #### NEET-PG High-Yield Pearls * **Most common mediastinal mass overall:** Neurogenic tumors (but specifically in the **posterior** compartment). * **Most common anterior mediastinal mass:** Thymoma. * **Imaging Gold Standard:** Contrast-Enhanced CT (CECT) is the investigation of choice to delineate the compartment and characteristics of the mass. * **Myasthenia Gravis Association:** Approximately 15% of patients with Myasthenia Gravis have a thymoma, while 65-75% have thymic hyperplasia.

Q: Which one of the following conditions can complicate as hyperchloremic acidosis?

Ureterosigmoidostomy. **Explanation:** **Hyperchloremic Metabolic Acidosis (Normal Anion Gap Acidosis)** occurs when there is a loss of bicarbonate ($HCO_3^-$) from the body, which is compensated by an increase in serum chloride ($Cl^-$) to maintain electroneutrality. **1. Why Ureterosigmoidostomy is Correct:** In this surgical procedure, the ureters are diverted into the sigmoid colon. The colonic mucosa is exposed to urine for prolonged periods. The intestinal epithelium actively reabsorbs chloride ions from the urine in exchange for bicarbonate ions (via the $Cl^-/HCO_3^-$ exchanger). This chronic loss of bicarbonate into the urine and excessive absorption of chloride leads to **Hyperchloremic Metabolic Acidosis**. **2. Analysis of Other Options:** * **Vomiting:** Causes loss of gastric $HCl$, leading to **Hypochloremic Metabolic Alkalosis**. * **Ileoplasty:** While urinary diversions using ileal segments (like an Ileal Conduit) can cause similar electrolyte shifts, the surface area and contact time in a sigmoid diversion are significantly higher, making Ureterosigmoidostomy the classic textbook association for this complication. * **Diarrhea:** While diarrhea *does* cause hyperchloremic metabolic acidosis (due to loss of alkaline intestinal secretions), **Ureterosigmoidostomy** is the more specific surgical complication often tested in this context. *Note: In many clinical scenarios, both B and D are correct, but B is the classic surgical "high-yield" answer.* **Clinical Pearls for NEET-PG:** * **Mnemonic for Normal Anion Gap Acidosis (USED CARP):** **U**reterosigmoidostomy, **S**aline infusion, **E**ndocrine (Addison’s), **D**iarrhea, **C**arbonic anhydrase inhibitors, **A**mmonium chloride, **R**enal tubular acidosis, **P**ancreatic fistula. * **Ureterosigmoidostomy** is rarely performed today due to this metabolic risk and the long-term risk of **adenocarcinoma** at the site of anastomosis.

Q: True about malignant melanoma?

Lymphatic spread. **Explanation:** **Malignant Melanoma** is a highly aggressive cutaneous malignancy arising from melanocytes. **1. Why Option A is Correct:** The most common route of initial metastasis for malignant melanoma is via the **lymphatics** to regional lymph nodes. While hematogenous spread occurs later (leading to distant metastases in the lungs, liver, and brain), the predictable lymphatic progression is the basis for staging and surgical management. **2. Why Other Options are Incorrect:** * **Option B:** Lymph node biopsy (specifically Sentinel Lymph Node Biopsy - SLNB) is **not always done**. It is generally indicated for intermediate-thickness lesions (Breslow thickness 0.8 mm to 4.0 mm) or thinner lesions with high-risk features (e.g., ulceration). It is not required for *in situ* melanoma or very thin lesions (<0.8 mm). * **Option C:** Modern surgical practice has shifted away from routine **Completion Lymph Node Dissection (CLND)** even if the sentinel node is positive. Large trials (MSLT-II) showed that CLND improves regional control but does not improve overall survival compared to nodal observation with ultrasound. * **Option D:** While **Microsatellitism** (microscopic nests of tumor cells near the primary lesion) is a known pathological feature and a poor prognostic indicator, it is a *feature* of the disease rather than a defining "true" statement in the context of general surgical principles compared to the primary mode of spread. **High-Yield Clinical Pearls for NEET-PG:** * **Breslow Depth:** The most important prognostic factor (measured from the granular layer to the deepest tumor cell). * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variegation, Diameter >6mm, Evolving. * **Commonest Site:** Back in men; Lower limbs in women. * **Most Common Subtype:** Superficial Spreading Melanoma. * **Most Aggressive Subtype:** Nodular Melanoma.

Question 1

Non-bilious vomiting is typically seen in which of the following conditions?

Accepted Answer

Hypertrophic pyloric stenosis

Answer

Meconium ileus

Answer

Duodenal atresia

Answer

Necrotising enterocolitis

Question 2

What is the most common site for chest tube insertion in a case of pleural effusion?

Accepted Answer

7th intercostal space, midaxillary line

Answer

2nd intercostal space, midclavicular line

Answer

5th intercostal space, midclavicular line

Answer

None of the above

Question 3

Calot's triangle is an important landmark for which anatomical structure?

Accepted Answer

Cystic artery

Answer

Cystic duct

Answer

Common bile duct

Answer

Hepatic vein

Question 4

Catgut is preserved in which of the following solutions?

Accepted Answer

Isopropyl alcohol

Answer

Glutaraldehyde

Answer

Iodine

Answer

Cetrimide

Question 5

What is the most common lesion found in the middle mediastinum?

Accepted Answer

Congenital cyst

Answer

Lipoma

Answer

Aneurysm

Answer

Germ cell tumour

Question 6

Which statement is true regarding a hydatid cyst of the lung?

Accepted Answer

More common in lower lobes.

Answer

Never ruptures.

Answer

Calcification is common.

Answer

Always associated with a cyst in the liver.

Question 7

Which tumour is not typically found in the anterior mediastinum?

Accepted Answer

Neurofibroma

Answer

Teratoma

Answer

Thymic tumours

Answer

Thyroid tumours

Question 8

Which one of the following conditions can complicate as hyperchloremic acidosis?

Accepted Answer

Ureterosigmoidostomy

Answer

Vomiting

Answer

Ileoplasty

Answer

Diarrhoea

Question 9

Which of the following is most ideal when sealing a vessel?

Accepted Answer

Continuous low-voltage waveforms

Answer

Continuous high-voltage waveforms

Answer

Intermittent low-voltage waveforms

Answer

Intermittent high-voltage waveforms

Question 10

True about malignant melanoma?

Accepted Answer

Lymphatic spread

Answer

Lymph node biopsy is always done

Answer

Block dissection is done when sentinel node is involved

Answer

Microsatellitism

General Surgery Principles — MCQs

General Surgery Principles — MCQs

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