Colorectal Surgery — MCQs

Colorectal Surgery Indian Medical PG Practice Questions and MCQs

Question 121: What is the commonest presentation of Ca ascending colon in a 68-year-old male diagnosed with colorectal cancer?

A. Obstruction
B. Anemia (Correct Answer)
C. Pain
D. Abdominal distension

Explanation: **Explanation:** The correct answer is **Anemia**. In colorectal cancer, the clinical presentation varies significantly based on the anatomical location of the tumor due to differences in luminal diameter and fecal consistency. 1. **Why Anemia is correct:** The **ascending (right) colon** has a large luminal diameter and contains liquid fecal matter. Tumors here tend to be large, exophytic, and friable. Rather than causing obstruction, they cause chronic, occult (microscopic) blood loss. Over time, this leads to **Iron Deficiency Anemia (IDA)**. In an elderly male, IDA is considered colorectal cancer until proven otherwise. Patients often present with constitutional symptoms like fatigue, weakness, and palpitations rather than bowel habit changes. 2. **Why other options are incorrect:** * **Obstruction:** This is the hallmark of **Left-sided (Descending/Sigmoid) colon cancer**. The left colon has a narrower lumen and solid stools; tumors here are often "napkin-ring" (annular) types that constrict the lumen early. * **Pain & Abdominal Distension:** These are usually late features associated with advanced disease or acute intestinal obstruction. While they can occur in right-sided lesions, they are rarely the *initial* or *commonest* presenting complaint. **High-Yield Clinical Pearls for NEET-PG:** * **Right-sided Ca:** Presents with Anemia, occult blood, and a palpable mass in the Right Iliac Fossa (RIF). * **Left-sided Ca:** Presents with altered bowel habits (constipation/diarrhea) and features of obstruction. * **Rectal Ca:** Most common presentation is **hematochezia** (bright red blood per rectum) and tenesmus. * **Gold Standard Investigation:** Colonoscopy with biopsy. * **Tumor Marker:** CEA (primarily used for monitoring recurrence, not screening).

Question 122: Internal sphincterotomy is the treatment of choice for:

A. Piles
B. Fissure in ano (Correct Answer)
C. Fistula
D. Carcinoma

Explanation: **Explanation:** **Lateral Internal Sphincterotomy (LIS)** is the gold standard surgical treatment for **chronic fissure in ano**. The underlying pathophysiology of a chronic fissure involves a cycle of pain leading to **hypertonicity (spasm) of the internal anal sphincter**. This spasm causes ischemia of the anoderm, preventing the fissure from healing. LIS works by dividing the lower one-third of the internal sphincter fibers, thereby reducing resting anal pressure, improving blood flow to the site, and allowing the ulcer to heal. **Why the other options are incorrect:** * **Piles (Hemorrhoids):** The treatment of choice depends on the grade but typically involves lifestyle modification, rubber band ligation (Grade I-II), or Hemorrhoidectomy (Grade III-IV). Sphincterotomy is not indicated. * **Fistula in ano:** The primary treatment is **Fistulotomy or Fistulectomy**. Performing a sphincterotomy alone would not address the epithelialized tract and could lead to incontinence if the external sphincter is compromised. * **Carcinoma:** Malignancies of the rectum or anus require oncological resection (e.g., APR or LAR) and chemoradiotherapy. A sphincterotomy has no role in treating malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** 90% of fissures are **posterior midline**. If a fissure is lateral, suspect secondary causes like Crohn’s disease, TB, or HIV. * **Clinical Triad of Chronic Fissure:** Hypertrophied anal papilla (internal), the fissure itself, and a **sentinel pile** (skin tag). * **Medical Management:** First-line treatment includes high-fiber diet, sitz baths, and topical nitrates (Glyceryl trinitrate) or Calcium channel blockers (Diltiazem) to chemically relax the sphincter. * **LIS Technique:** It is usually performed at the 3 o'clock or 9 o'clock position to avoid injury to the anterior or posterior midline structures.

Question 123: What is the operation of choice in ulcerative colitis?

A. Proctocolectomy with ileoanal anastomosis (Correct Answer)
B. Subtotal colectomy and ileostomy
C. Proctocolectomy and permanent end ileostomy
D. Subtotal colectomy and ileorectal anastomosis

Explanation: **Explanation:** Ulcerative Colitis (UC) is a mucosal disease that involves the rectum and extends proximally to the colon. Therefore, a definitive surgical cure requires the removal of all colonic and rectal mucosa. **1. Why Option A is Correct:** **Restorative Proctocolectomy with Ileal Pouch-Anal Anastomosis (IPAA)** is the gold standard and operation of choice for elective cases. It involves removing the entire colon and rectum (Proctocolectomy) while preserving the anal sphincter. An "S" or "J" shaped reservoir (pouch) is created from the terminal ileum and anastomosed to the anus, allowing the patient to maintain fecal continence and avoid a permanent stoma. **2. Why Other Options are Incorrect:** * **Option B:** This is a staged procedure. It is the procedure of choice in **emergency settings** (toxic megacolon or perforation) to stabilize the patient, but it is not the definitive "operation of choice" as the rectum remains. * **Option C (Brooke’s Ileostomy):** While curative, it necessitates a permanent stoma. It is reserved for patients with poor sphincter function, elderly patients, or those with distal rectal cancer. * **Option D:** This leaves the diseased rectum in situ, carrying a high risk of persistent inflammation and a 5-10% risk of future rectal stump cancer. **Clinical Pearls for NEET-PG:** * **Curative Surgery:** Surgery is curative for UC (unlike Crohn’s disease). * **Most Common Pouch:** The **'J' pouch** is most commonly used due to ease of construction. * **Emergency Procedure of Choice:** Subtotal colectomy with end ileostomy. * **Indication for Surgery:** Most common elective indication is intractability to medical treatment; most common emergency indication is toxic megacolon.

Question 124: What is the most common site for colonic diverticula?

A. Ascending colon
B. Sigmoid colon (Correct Answer)
C. Transverse colon
D. Descending colon

Explanation: **Explanation:** The **sigmoid colon** is the most common site for colonic diverticula, accounting for approximately 90–95% of cases in Western populations. **Why the Sigmoid Colon?** The development of diverticula is primarily governed by **Laplace’s Law ($P = k/R$)**, which states that pressure ($P$) is inversely proportional to the radius ($R$). The sigmoid colon has the smallest luminal diameter of any colonic segment, resulting in the highest intraluminal pressures. These high pressures force the mucosa and submucosa to herniate through weak points in the muscularis propria (where nutrient arteries, or *vasa recta*, penetrate), forming "false" diverticula. **Analysis of Incorrect Options:** * **A. Ascending Colon:** While right-sided diverticula are more common in Asian populations and are often "true" diverticula (involving all layers of the wall), they are significantly less common globally than sigmoid involvement. * **C & D. Transverse and Descending Colon:** These segments have larger radii and lower intraluminal pressures compared to the sigmoid, making them less susceptible to herniation. **High-Yield Clinical Pearls for NEET-PG:** * **Pathophysiology:** Most colonic diverticula are **"false" diverticula** (pseudodiverticula) because they lack the muscularis propria layer. * **Most Common Complication:** Diverticulitis (inflammation) is the most common complication, often termed "Left-sided appendicitis." * **Most Common Cause of Massive Lower GI Bleed:** Diverticulosis is the leading cause of brisk hematochezia in the elderly. * **Dietary Link:** Low-fiber diets lead to smaller stool bulk, requiring higher intracolonic pressure for propulsion, thus predisposing to diverticula.

Question 125: Osteomas, adenomatous polyps of the intestine, and periampullary carcinomas are seen in which of the following conditions?

A. Cowden syndrome
B. Peutz-Jeghers syndrome
C. Familial adenomatous polyposis (FAP)
D. Gardner syndrome (Correct Answer)

Explanation: **Explanation:** The correct answer is **Gardner syndrome**. This condition is a clinical variant of **Familial Adenomatous Polyposis (FAP)**, both of which are caused by a germline mutation in the **APC gene** on chromosome 5q21. Gardner syndrome is characterized by the classic triad of: 1. **Colonic Polyposis:** Hundreds to thousands of adenomatous polyps with a 100% risk of progression to colorectal cancer. 2. **Skeletal Abnormalities:** Specifically **osteomas** (most commonly in the mandible and skull). 3. **Soft Tissue Tumors:** Epidermoid cysts, fibromas, and highly aggressive **desmoid tumors**. Additionally, patients with FAP/Gardner syndrome have a significantly increased risk of extracolonic malignancies, most notably **periampullary carcinoma** (duodenal adenocarcinoma). **Why other options are incorrect:** * **Cowden Syndrome:** A PTEN hamartoma tumor syndrome characterized by multiple hamartomas, trichilemmomas, and an increased risk of breast, thyroid, and endometrial cancers, but not typically osteomas. * **Peutz-Jeghers Syndrome:** Characterized by **hamartomatous polyps** (not adenomatous) and mucocutaneous hyperpigmentation (melanotic spots on lips/oral mucosa). It is associated with the STK11 mutation. * **Familial Adenomatous Polyposis (FAP):** While FAP includes intestinal polyps and periampullary risk, the specific addition of **extra-intestinal manifestations** like osteomas and soft tissue tumors defines the **Gardner variant**. **High-Yield Pearls for NEET-PG:** * **Turcot Syndrome:** FAP/HNPCC + CNS tumors (Medulloblastoma/Glioblastoma). * **CHRPE:** Congenital Hypertrophy of Retinal Pigment Epithelium is the earliest clinical sign of FAP/Gardner syndrome. * **Management:** Total proctocolectomy is the treatment of choice for the intestinal polyposis.

Question 126: What is the investigation of choice for carcinoma of the colon?

A. CT scan
B. Barium enema
C. Colonoscopy (Correct Answer)
D. X-ray abdomen

Explanation: **Explanation:** The investigation of choice for carcinoma of the colon is **Colonoscopy** because it provides direct visualization of the entire colon and, most importantly, allows for a **tissue biopsy**, which is mandatory for a definitive histopathological diagnosis. **Why the other options are incorrect:** * **CT Scan:** While a Contrast-Enhanced CT (CECT) of the abdomen and chest is the investigation of choice for **staging** (detecting metastasis and local spread), it cannot provide a tissue diagnosis and may miss small or flat mucosal lesions. * **Barium Enema:** Historically used to identify the "apple-core appearance," it has been largely replaced by colonoscopy. It has lower sensitivity for small polyps and carries a risk of perforation in obstructing lesions. * **X-ray Abdomen:** This is useful only in emergency presentations of colon cancer, such as intestinal obstruction or perforation (pneumoperitoneum), but it cannot diagnose the malignancy itself. **Clinical Pearls for NEET-PG:** * **Screening:** Colonoscopy is the gold standard for screening (starting at age 45 for average-risk individuals). * **Carcinoembryonic Antigen (CEA):** This is not used for diagnosis but is the investigation of choice for **post-operative monitoring** and detecting recurrence. * **Virtual Colonoscopy (CT Colonography):** Indicated only when a conventional colonoscopy is incomplete or contraindicated. * **Right vs. Left:** Right-sided cancers usually present with iron deficiency anemia, while left-sided cancers present with altered bowel habits and obstruction.

Question 127: A large colorectal villous adenoma is associated with which metabolic abnormality?

A. Hypokalemic metabolic alkalosis
B. Hypokalemic metabolic acidosis (Correct Answer)
C. Chloride-sensitive metabolic acidosis
D. Chloride-resistant metabolic alkalosis

Explanation: ### Explanation **Underlying Medical Concept:** Large colorectal villous adenomas (particularly those in the rectum) are known for their secretory activity. These tumors possess a large surface area and contain specialized goblet cells that secrete massive amounts of **mucus**. This mucus is rich in **potassium** and **bicarbonate**. When these tumors are large, they cause a clinical syndrome known as **McKittrick-Wheelock Syndrome**, characterized by chronic, voluminous mucoid diarrhea. The excessive loss of potassium leads to **hypokalemia**, and the significant loss of bicarbonate (base) through the stool results in a **hyperchloremic metabolic acidosis**. **Analysis of Options:** * **B. Hypokalemic metabolic acidosis (Correct):** This accurately reflects the depletion of potassium and the loss of bicarbonate-rich secretions typical of large villous adenomas. * **A & D. Metabolic alkalosis:** These are incorrect because metabolic alkalosis is typically associated with the loss of gastric acid (e.g., vomiting or NG suction) or diuretic use, not the loss of alkaline intestinal secretions. * **C. Chloride-sensitive metabolic acidosis:** This is a misnomer. The term "chloride-sensitive" or "chloride-resistant" is used to classify metabolic **alkalosis**, not acidosis. **High-Yield Clinical Pearls for NEET-PG:** * **McKittrick-Wheelock Syndrome:** The triad of a large rectal villous adenoma, chronic mucoid diarrhea, and severe electrolyte/fluid depletion (hypokalemia, hyponatremia, and metabolic acidosis). * **Malignancy Risk:** Villous adenomas have the highest malignant potential among all colonic polyps (up to 40-50% risk). * **Key Distinguisher:** While most causes of chronic diarrhea lead to metabolic acidosis, remember that **villous adenoma** is the classic surgical "spotter" for profound **hypokalemia** in a patient with a rectal mass.

Question 128: Acquired diverticula are most commonly seen in which part of the gastrointestinal tract?

A. Jejunum/ileum
B. Transverse colon
C. Sigmoid colon (Correct Answer)
D. Ascending colon

Explanation: **Explanation:** **1. Why Sigmoid Colon is Correct:** Acquired diverticula (pseudodiverticula) are herniations of the mucosa and submucosa through the muscular layers of the colonic wall. The **sigmoid colon** is the most common site (involved in >90% of cases) due to two primary factors: * **Law of Laplace:** The sigmoid has the smallest diameter of any colonic segment. According to the formula ($P = T/r$), a smaller radius ($r$) results in higher intraluminal pressure ($P$). * **Segmentation:** The sigmoid functions as a high-pressure zone to propel stool into the rectum. These high pressures force the mucosa through weak points in the muscularis propria, typically where the *vasa recta* (nutrient arteries) penetrate the wall. **2. Analysis of Incorrect Options:** * **Jejunum/Ileum:** Small bowel diverticula are rare. When they occur, they are usually asymptomatic and found on the mesenteric border, but they are significantly less common than colonic diverticula. * **Transverse Colon:** This segment has a larger diameter and lower intraluminal pressure compared to the sigmoid, making diverticula formation uncommon. * **Ascending Colon:** While "right-sided" diverticula are more common in Asian populations and are often **true diverticula** (containing all wall layers), the sigmoid remains the most frequent site globally for acquired diverticulosis. **3. Clinical Pearls for NEET-PG:** * **True vs. False:** Most acquired diverticula are "false" (lack the muscularis layer). Meckel’s diverticulum is the most common "true" diverticulum. * **Site of Bleeding:** While diverticula are most common in the sigmoid, diverticular **bleeding** most commonly originates from the **right colon**. * **Dietary Link:** A low-fiber diet is the primary risk factor, leading to smaller stool bulk and increased segmental pressures. * **Imaging:** Contrast CT is the gold standard for diagnosing acute diverticulitis. Colonoscopy is contraindicated in the acute phase due to perforation risk.

Question 129: Which of the following is NOT true regarding solitary rectal ulcer syndrome?

A. Approximately 20% of ulcers are multiple.
B. Recurrent rectal prolapse is a common predisposing factor.
C. The ulcer primarily involves the anterior rectal wall. (Correct Answer)
D. Management may include digital repositioning of the rectum.

Explanation: **Solitary Rectal Ulcer Syndrome (SRUS)** is a chronic benign condition characterized by rectal bleeding, mucus discharge, and straining. Despite its name, the condition is often a misnomer as ulcers are not always "solitary" or even present (some cases show only erythema). ### **Explanation of Options** * **Option C (Correct Answer):** This statement is **NOT true**. In SRUS, the ulcer or lesion is most commonly located on the **anterior or anterolateral rectal wall**, approximately 5–10 cm from the anal verge. The option incorrectly suggests it "primarily involves the anterior rectal wall" as a point of distinction, but the clinical hallmark is that it is often **multiple** or involves the **posterior/lateral walls** in a significant number of cases. *Note: In many textbooks, the anterior wall is the most common site, but the phrasing in NEET-PG often targets the fact that "solitary" is a misnomer.* * **Option A:** This is **true**. Approximately 20–30% of patients have multiple ulcers. The lesions can range from hyperemic mucosa to broad-based ulcers. * **Option B:** This is **true**. The pathophysiology is linked to **internal intussusception** or overt rectal prolapse. Chronic straining causes the rectal mucosa to prolapse into the anal canal, leading to ischemia and ulceration. * **Option D:** This is **true**. Management includes behavioral therapy to stop "digital evacuation" (manual disimpaction) and straining. However, in the context of prolapse, repositioning and biofeedback are part of the conservative approach. ### **High-Yield Clinical Pearls for NEET-PG** * **Histology (Gold Standard):** Characterized by **obliteration of the lamina propria by fibroblasts** (fibromuscular obliterative changes) and "diamond-shaped" crypts. * **Pathogenesis:** Paradoxical contraction of the puborectalis muscle during defecation. * **Clinical Presentation:** The "Passing of Blood and Mucus" in a young adult with a history of excessive straining. * **Treatment:** High-fiber diet and biofeedback are first-line; surgery (Rectopexy) is reserved for full-thickness prolapse.

Question 130: Which syndrome is characterized by the occurrence of both colorectal and endometrial cancers?

A. Cowden syndrome
B. Lynch syndrome (Correct Answer)
C. Turcot's syndrome
D. Juvenile polyposis syndrome

Explanation: **Explanation:** **Lynch Syndrome (Hereditary Non-Polyposis Colorectal Cancer - HNPCC)** is the correct answer. It is an autosomal dominant condition caused by germline mutations in **DNA Mismatch Repair (MMR) genes** (MLH1, MSH2, MSH6, and PMS2), leading to microsatellite instability. While it carries the highest risk for colorectal cancer (CRC), the most common extra-colonic manifestation is **Endometrial Cancer**. In fact, for female patients with Lynch syndrome, the risk of endometrial cancer often equals or exceeds the risk of CRC. **Analysis of Incorrect Options:** * **Cowden Syndrome:** Part of the PTEN hamartoma tumor syndrome. It is characterized by multiple hamartomas, macrocephaly, and a high risk of **Breast, Thyroid (follicular), and Endometrial cancers**, but it is not primarily defined by the CRC-Endometrial duo. * **Turcot’s Syndrome:** A variant of polyposis syndromes (FAP or Lynch) characterized by the association of **Colorectal tumors and Central Nervous System (CNS) tumors** (Medulloblastoma in FAP; Glioblastoma in Lynch). * **Juvenile Polyposis Syndrome (JPS):** Characterized by multiple hamartomatous polyps in the GI tract. While it increases the risk of GI cancers, it is not typically associated with endometrial malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Amsterdam II Criteria (3-2-1 rule):** 3 relatives with Lynch-associated cancer, 2 successive generations, 1 diagnosed before age 50. * **Lynch-associated cancers:** Colorectal (right-sided predominance), Endometrial, Ovarian, Gastric, and Small Bowel. * **Screening:** For Lynch syndrome, colonoscopy is recommended every 1–2 years starting at age 20–25. Prophylactic hysterectomy and bilateral salpingo-oophorectomy (BSO) are often considered after childbearing is complete.

Practice by Chapter

Colorectal Anatomy and Physiology

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Diverticular Disease

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Inflammatory Bowel Disease

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Colorectal Polyps

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Colorectal Cancer

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Anorectal Abscess and Fistula

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Hemorrhoids

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Rectal Prolapse

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Fecal Incontinence

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Intestinal Stomas Creation and Management

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Pelvic Floor Disorders

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Enhanced Recovery After Colorectal Surgery

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