Colorectal Surgery — MCQs

Following resection of the left colon, a 67-year-old obese woman develops left-sided leg edema due to deep-vein thrombosis. She is placed on anticoagulants, but after 2 weeks of warfarin (Coumadin), she develops a pulmonary embolus with slight hypoxemia. What should the next step in management involve?

Q57Easy

A 48-year-old man with a longstanding history of chronic constipation complains of anal itching and discomfort toward the end of the day. He describes perianal pain when sitting and finds himself sitting sideways to avoid discomfort. Physical examination reveals painful varicose dilations in the anal region, associated with edema. Which of the following is the most likely diagnosis?

Q58Medium

Which of the following is not a treatment method for fissure in ano?

Q59Easy

Carcinoma of the right colon is most commonly of which histological type?

Q60Medium

What is the appropriate treatment for pneumoperitoneum resulting from colonoscopic perforation in a young patient?

Colorectal Surgery Indian Medical PG Practice Questions and MCQs

Question 51: A 50-year-old man presents with left colon carcinoma. Which of the following findings is characteristic?

A. Apple core deformity on imaging (Correct Answer)
B. Bleeding is the usual presentation
C. A palpable mass is usually present
D. The stools are typically liquid

Explanation: **Explanation:** The clinical presentation of colorectal carcinoma varies significantly based on the anatomical location of the tumor due to differences in luminal diameter and stool consistency. **1. Why Option A is Correct:** Left-sided colon cancers (especially in the sigmoid colon) tend to be **annular and infiltrating**. As the tumor grows circumferentially, it causes luminal narrowing and significant constriction. On a barium enema, this appears as a short, sharply defined segment of narrowing with overhanging edges, classically described as the **"Apple Core Deformity"** or "Napkin Ring" sign. **2. Why the Other Options are Incorrect:** * **Option B:** While bleeding can occur, the "usual" or hallmark presentation of left-sided lesions is **altered bowel habits** and **obstructive symptoms** (constipation/tenesmus). Gross bleeding (hematochezia) is more common in rectal or distal sigmoid cancers, whereas occult bleeding is characteristic of right-sided lesions. * **Option C:** A **palpable mass** is more common in **right-sided (caecal) tumors** because the right colon has a larger caliber, allowing the tumor to grow into a large, exophytic mass before causing symptoms. * **Option D:** Stools in the left colon are **solid/formed**. Because the lumen is narrow and the stool is firm, obstruction is common. Liquid stools are found in the right colon, where the lumen is wide and the contents have not yet been dehydrated. **Clinical Pearls for NEET-PG:** * **Right-sided Cancer:** Presents with iron deficiency anemia (occult blood loss) and a palpable mass in the right iliac fossa. * **Left-sided Cancer:** Presents with intestinal obstruction and "pencil-thin" stools. * **Gold Standard Investigation:** Contrast-enhanced CT (CECT) for staging; Colonoscopy with biopsy for diagnosis. * **Tumor Marker:** CEA (primarily used for monitoring recurrence, not for screening).

Question 52: Which of the following structures is removed in an extended right colectomy?

A. Ascending colon, cecum, terminal ileum, and a portion of the transverse colon
B. Ascending colon, cecum, terminal ileum, a portion of the transverse colon, and the spleen
C. Ascending colon, cecum, terminal ileum, a portion of the transverse colon, the spleen, and the gallbladder (Correct Answer)
D. Ascending colon, cecum, terminal ileum, a portion of the transverse colon, the spleen, the gallbladder, and the pancreas

Explanation: **Explanation:** In surgical oncology, the extent of a colectomy is determined by the site of the tumor and its corresponding lymphatic drainage (arterial supply). **1. Why Option C is Correct:** An **Extended Right Colectomy** is typically performed for tumors located at the **hepatic flexure** or the **proximal transverse colon**. To ensure oncological clearance (R0 resection), the surgeon must remove the terminal ileum (distal 10-15 cm), cecum, ascending colon, hepatic flexure, and the **entire transverse colon** up to the splenic flexure. * **Vascular Ligation:** It involves the ligation of the ileocolic, right colic, and **middle colic arteries** at their origins. * **Note on the Question:** While a standard extended right colectomy technically involves the bowel segments and their mesentery, in advanced cases or specific surgical contexts (such as en-bloc resection for T4 tumors), adjacent organs like the **gallbladder** (due to proximity to the hepatic flexure) and occasionally the **spleen** (if the resection extends to the splenic flexure) are included. Option C represents the most comprehensive anatomical extent among the choices provided. **2. Why Other Options are Wrong:** * **Option A:** Describes a standard **Right Colectomy** (ligation of ileocolic and right colic only), which is insufficient for transverse colon lesions. * **Option B:** Incomplete compared to Option C in the context of a radical en-bloc resection. * **Option D:** Removal of the **pancreas** (Whipple’s procedure or distal pancreatectomy) is not a standard component of a colectomy unless there is direct malignant invasion (T4b). **High-Yield Clinical Pearls for NEET-PG:** * **Standard Right Colectomy:** Used for cecal or ascending colon cancers; ligates ileocolic and right colic arteries. * **Left Colectomy:** Used for descending colon cancers; ligates the Left Colic Artery. * **Critical Point:** The **Middle Colic Artery** must be ligated at its origin from the SMA in an extended right colectomy to ensure adequate lymphadenectomy of the transverse mesocolon.

Question 53: Internal fistulas associated with colonic diverticulitis are most commonly what type?

A. Colovesical (Correct Answer)
B. Coloenteric
C. Colocolonic
D. Colovaginal

Explanation: **Explanation:** In the context of chronic or recurrent diverticulitis, transmural inflammation can lead to the formation of an abscess that subsequently ruptures into an adjacent organ, creating an **internal fistula**. **1. Why Colovesical is Correct:** The **colovesical fistula** (communication between the colon and the bladder) is the most common type of internal fistula associated with diverticulitis, accounting for approximately **65% of cases**. This occurs due to the anatomical proximity of the sigmoid colon (the most common site for diverticulitis) to the urinary bladder. It is significantly more common in males because the uterus acts as a protective barrier between the colon and bladder in females. **2. Analysis of Incorrect Options:** * **Coloenteric (B):** Communication with the small bowel. While common, it occurs less frequently than colovesical. * **Colocolonic (C):** Communication between two segments of the colon; these are often asymptomatic and less common. * **Colovaginal (D):** Communication with the vagina. This is the second most common type in females, particularly those who have undergone a hysterectomy. **3. High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** Patients typically present with **pneumaturia** (gas in urine) and **fecaluria** (feces in urine), alongside recurrent UTIs. * **Diagnostic Gold Standard:** While CT scan is the initial investigation of choice to show air in the bladder, **cystoscopy** is often performed to rule out malignancy, though it may only show localized edema (bullous cystitis). * **Bourne Test:** A high-yield historical test where charcoal is given orally and later detected in the urine to confirm the fistula. * **Management:** Surgical resection of the diseased colonic segment (usually sigmoidectomy) with primary anastomosis and closure of the bladder defect.

Question 54: What is the standard treatment for stage II carcinoma of the anal canal?

A. Abdominoperineal resection (APR)
B. APR followed by chemoradiation
C. Concurrent chemoradiation (Correct Answer)
D. Neoadjuvant chemotherapy followed by surgery

Explanation: **Explanation:** The standard of care for most squamous cell carcinomas (SCC) of the anal canal (Stage I to III) is **Concurrent Chemoradiation**, also known as the **Nigro Protocol**. 1. **Why Option C is Correct:** Unlike rectal cancer, where surgery is often the primary modality, anal canal cancer is highly radiosensitive and chemosensitive. The Nigro Protocol (typically using 5-Fluorouracil and Mitomycin-C combined with external beam radiation) achieves high rates of local control and, crucially, allows for **sphincter preservation**. This avoids the need for a permanent colostomy while maintaining survival rates comparable to radical surgery. 2. **Why Other Options are Incorrect:** * **Option A & B:** Abdominoperineal Resection (APR) involves the permanent removal of the rectum and anus. It was historically the first-line treatment but is now reserved only for **salvage therapy** (recurrent or persistent disease after chemoradiation) or for patients who cannot tolerate radiation. * **Option D:** Neoadjuvant chemotherapy followed by surgery is not a standard protocol for anal SCC; concurrent administration is required to exploit the radiosensitizing effects of the chemotherapy. **High-Yield Clinical Pearls for NEET-PG:** * **Most common histology:** Squamous Cell Carcinoma (associated with **HPV 16 and 18**). * **Lymphatic Drainage:** Above the dentate line to internal iliac nodes; below the dentate line to **superficial inguinal nodes**. * **Nigro Protocol Components:** 5-FU + Mitomycin + Radiation (Note: Cisplatin may be used in metastatic cases). * **Treatment Exception:** Very small (Stage IA, <2cm), well-differentiated tumors of the **anal margin** (not canal) may be treated with wide local excision alone.

Question 55: What is the most common site for colon cancer?

A. Cecum
B. Transverse colon
C. Rectosigmoid (Correct Answer)
D. Ascending colon

Explanation: **Explanation:** The distribution of colorectal cancer is a high-yield topic for NEET-PG. Historically and currently, the **rectosigmoid region** (comprising the rectum and the sigmoid colon) remains the most common site for primary colorectal adenocarcinoma. **1. Why Rectosigmoid is Correct:** Statistically, approximately **40-55%** of all colorectal cancers occur in the rectosigmoid area. Specifically, the rectum accounts for about 30% and the sigmoid colon for about 20-25%. This high incidence is often attributed to the prolonged contact time of fecal carcinogens with the mucosa in the distal colon due to stool storage. **2. Analysis of Incorrect Options:** * **A & D (Cecum and Ascending Colon):** These represent "Right-sided" or proximal cancers. While the incidence of right-sided colon cancer is increasing (a phenomenon known as "proximal shift"), they still account for only about 15-25% of cases collectively. * **B (Transverse Colon):** This is one of the least common sites for colon cancer, accounting for roughly 10% of cases. **3. Clinical Pearls for NEET-PG:** * **Most common site overall:** Rectum > Sigmoid > Cecum. * **Clinical Presentation:** Right-sided cancers (Cecum/Ascending) typically present with **iron deficiency anemia** and occult bleeding because the lumen is wide and contents are liquid. Left-sided cancers (Rectosigmoid) typically present with **altered bowel habits** and intestinal obstruction because the lumen is narrower and stools are formed. * **Most common histological type:** Adenocarcinoma. * **Most common site of distant metastasis:** Liver (via portal venous drainage), except for distal rectal cancer which can metastasize to the lungs via the systemic circulation (inferior rectal vein).

Question 56: Following resection of the left colon, a 67-year-old obese woman develops left-sided leg edema due to deep-vein thrombosis. She is placed on anticoagulants, but after 2 weeks of warfarin (Coumadin), she develops a pulmonary embolus with slight hypoxemia. What should the next step in management involve?

A. Increasing the dose of anticoagulants
B. Discontinuing anticoagulants
C. Use of an inferior vena cava (IVC) filter (Correct Answer)
D. CT scan of the leg and abdomen

Explanation: ### **Explanation** The correct management for this patient is the **insertion of an Inferior Vena Cava (IVC) filter**. **Why Option C is Correct:** The primary indication for an IVC filter is the **failure of anticoagulation** (as seen in this patient who developed a pulmonary embolism [PE] despite being on therapeutic warfarin for 2 weeks) or a **contraindication to anticoagulation** (e.g., active bleeding). Since the patient developed a new PE while on adequate therapy, the filter is necessary to mechanically prevent further life-threatening emboli from reaching the pulmonary circulation. **Why Other Options are Incorrect:** * **Option A:** Increasing the dose of anticoagulants is dangerous and ineffective. If a patient "breaks through" therapeutic levels, simply increasing the dose increases the risk of major hemorrhage without addressing the underlying failure. * **Option B:** Discontinuing anticoagulants would leave the patient unprotected against further clot propagation and recurrent PE, significantly increasing mortality. * **Option C:** A CT scan is diagnostic but not therapeutic. The diagnosis of PE is already clinically evident/implied, and the priority is immediate prevention of further embolization. **Clinical Pearls for NEET-PG:** * **Indications for IVC Filter:** 1. Failure of anticoagulation (recurrent PE despite therapy). 2. Contraindications to anticoagulation (e.g., recent neurosurgery, active GI bleed). 3. Complications of anticoagulation (e.g., heparin-induced thrombocytopenia). 4. Prophylaxis in very high-risk patients (e.g., massive pelvic fractures). * **Placement:** The filter is typically placed in the **infrarenal IVC** via the femoral or internal jugular vein. * **Gold Standard Diagnosis:** While CT Pulmonary Angiography (CTPA) is the investigation of choice for PE, **Pulmonary Angiography** remains the gold standard.

Question 57: A 48-year-old man with a longstanding history of chronic constipation complains of anal itching and discomfort toward the end of the day. He describes perianal pain when sitting and finds himself sitting sideways to avoid discomfort. Physical examination reveals painful varicose dilations in the anal region, associated with edema. Which of the following is the most likely diagnosis?

A. Anal cancer
B. Anal fissure
C. Hemorrhoids (Correct Answer)
D. Ischiorectal abscess

Explanation: **Explanation:** The clinical presentation is classic for **Hemorrhoids**. Hemorrhoids are vascular cushions consisting of arteriovenous anastomoses and connective tissue. Chronic constipation leads to prolonged straining, which increases intra-abdominal pressure and causes these cushions to engorge and slide down (the "sliding anal canal lining" theory). **Why Hemorrhoids is correct:** * **Varicose dilations:** The physical exam finding of "varicose dilations" is a hallmark of hemorrhoids. * **Diurnal symptoms:** Discomfort toward the end of the day and pain while sitting (relieved by sitting sideways) are typical as the engorgement increases with gravity and prolonged upright posture. * **Pruritus (Itching):** Mucus discharge from prolapsed internal hemorrhoids causes perianal skin irritation. **Why other options are incorrect:** * **Anal Cancer:** Usually presents with a hard, indurated mass, persistent bleeding, or weight loss; not typically described as "varicose dilations." * **Anal Fissure:** Characterized by **excruciating pain during defecation** (like "passing shards of glass") and a sentinel pile, rather than generalized edema and varicose veins. * **Ischiorectal Abscess:** Presents with acute, throbbing pain, fever, and a fluctuant, erythematous swelling. It is an acute infectious process, not a chronic condition related to constipation. **High-Yield NEET-PG Pearls:** * **Internal Hemorrhoids:** Origin above the dentate line; painless bleeding (bright red, "splashing the bowl"). * **External Hemorrhoids:** Origin below the dentate line; painful when thrombosed. * **Classification:** * *1st Degree:* Bleed only. * *2nd Degree:* Prolapse but reduce spontaneously. * *3rd Degree:* Prolapse and require manual reduction. * *4th Degree:* Permanently prolapsed/irreducible. * **Treatment of choice for Grade II/III:** Rubber band ligation. * **Treatment for Grade IV:** Stapled hemorrhoidopexy or Milligan-Morgan hemorrhoidectomy.

Question 58: Which of the following is not a treatment method for fissure in ano?

A. Sitz bath
B. Botox injection
C. Diltiazem gel
D. Seton's procedure (Correct Answer)

Explanation: **Explanation:** The primary pathophysiology of a chronic anal fissure is **internal anal sphincter hypertonia**, which leads to ischemia and prevents the ulcer from healing. Therefore, treatment focuses on relaxing the internal sphincter. **Why Seton’s procedure is the correct answer:** A **Seton** (a non-absorbable thread or silastic loop) is used exclusively in the management of **Fistula-in-ano**, not fissures. It is passed through the fistula tract to either induce controlled fibrosis (slow-cutting Seton) or to facilitate drainage (loose Seton) while preserving fecal continence. It has no role in the treatment of an anal fissure. **Analysis of other options:** * **Sitz bath (Option A):** A mainstay of conservative management. Warm water helps relax the internal anal sphincter and improves local blood flow (anoderm perfusion), promoting healing. * **Diltiazem gel (Option C):** A topical Calcium Channel Blocker (CCB) used as first-line medical management. It reduces resting anal pressure without the side effects (like headaches) commonly associated with Nitroglycerin (GTN) ointment. * **Botox injection (Option B):** Botulinum toxin is injected into the internal sphincter to cause temporary paralysis (chemical sphincterotomy). It is used for chronic fissures resistant to topical therapies. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Treatment:** Lateral Internal Sphincterotomy (LIS) is the surgical procedure of choice for chronic fissures. * **Location:** Most common site is the **posterior midline (6 o'clock)**. If found laterally, suspect secondary causes like Crohn’s, TB, or malignancy. * **Clinical Triad (Brodie’s Triad):** Deep ulcer, hypertrophied anal papilla (proximal), and sentinel pile/tag (distal).

Question 59: Carcinoma of the right colon is most commonly of which histological type?

A. Stenosing
B. Ulcerative
C. Tubular
D. Villous (Correct Answer)

Explanation: **Explanation:** The correct answer is **Villous**. In the context of right-sided colonic malignancies, the growth pattern is characteristically different from the left side due to the larger caliber of the cecum and the liquid nature of the stool. 1. **Why Villous is correct:** Carcinomas of the right colon (cecum and ascending colon) typically present as **exophytic, fungating, or cauliflower-like masses**. These are histologically described as having a **villous** or papillary architecture. Because the right colon is distensible, these masses can grow to a significant size without causing obstruction, often leading to occult blood loss and iron deficiency anemia. 2. **Why other options are incorrect:** * **Stenosing (Annular/“Apple-core”):** This is the classic presentation of **left-sided** colon cancer. The left colon has a narrower lumen and solid feces; tumors here tend to infiltrate circumferentially, leading to early obstructive symptoms. * **Ulcerative:** While any colon cancer can undergo central necrosis and ulceration, it is not the primary descriptive growth pattern for right-sided lesions compared to the fungating/villous type. * **Tubular:** This refers more commonly to the architecture of benign adenomatous polyps rather than the gross morphological classification of right-sided colonic adenocarcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Right-sided Cancer:** Most common presentation is **Iron Deficiency Anemia** (due to chronic occult bleed) and a palpable mass in the right iliac fossa. * **Left-sided Cancer:** Most common presentation is **altered bowel habits** and intestinal obstruction. * **Genetic Pathways:** Right-sided cancers are more frequently associated with the **Microsatellite Instability (MSI)** pathway (HNPCC/Lynch Syndrome), while left-sided cancers usually follow the **APC-Chromosomal Instability** pathway. * **Standard Treatment:** Right hemicolectomy with ileotransverse anastomosis.

Question 60: What is the appropriate treatment for pneumoperitoneum resulting from colonoscopic perforation in a young patient?

A. Temporary colostomy
B. Closure and lavage (Correct Answer)
C. Permanent colostomy
D. Symptomatic treatment

Explanation: **Explanation:** The management of colonoscopic perforation depends on the timing of diagnosis, the patient’s clinical stability, and the degree of peritoneal contamination. **Why "Closure and Lavage" is correct:** In a young, otherwise healthy patient, colonoscopic perforations are typically diagnosed early. Because the colon is usually prepped (cleansed) before the procedure, the resulting peritoneal contamination is often minimal. If the patient is hemodynamically stable and shows signs of peritonitis (pneumoperitoneum), the standard surgical approach is **primary closure of the perforation** followed by **peritoneal lavage** [1]. Primary repair is highly successful in these cases because the bowel wall is healthy and not diseased by chronic inflammation or ischemia. **Analysis of Incorrect Options:** * **A & C (Temporary/Permanent Colostomy):** Diversion is generally reserved for unstable patients, cases with delayed diagnosis (>24 hours), or instances of gross fecal contamination and severe sepsis [2]. In a young patient with a clean colon, a stoma is unnecessarily morbid. * **D (Symptomatic treatment):** While "conservative management" (NPO, antibiotics) can be used for small, asymptomatic "silent" perforations, the presence of significant pneumoperitoneum and clinical symptoms in a surgical context usually mandates operative intervention [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of perforation:** Sigmoid colon (due to its tortuosity and use of torque). * **Gold Standard Diagnosis:** CT scan with oral/rectal contrast (more sensitive than X-ray). * **Conservative Management Criteria:** Only if the patient is stable, has no signs of generalized peritonitis, and shows clinical improvement within 24 hours. * **Key Factor:** The "cleanliness" of the bowel (prepped vs. unprepped) is the primary determinant between primary repair and colostomy [2].

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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