Colorectal Surgery — MCQs

Colorectal Surgery Indian Medical PG Practice Questions and MCQs

Question 111: Carcinoma of the transverse colon is normally treated by which surgical procedure?

A. Right hemicolectomy
B. Extended right hemicolectomy (Correct Answer)
C. Left hemicolectomy
D. Extended left hemicolectomy

Explanation: **Explanation:** The surgical management of colon cancer is dictated by the **vascular supply** and the corresponding **lymphatic drainage** of the tumor site. **Why Extended Right Hemicolectomy is Correct:** The transverse colon has a dual blood supply: the proximal two-thirds is supplied by the **middle colic artery** (branch of the Superior Mesenteric Artery - SMA), while the distal third is supplied by the **left colic artery** (branch of the Inferior Mesenteric Artery - IMA). For tumors located in the transverse colon, an **Extended Right Hemicolectomy** is the procedure of choice. This involves removing the terminal ileum, cecum, ascending colon, hepatic flexure, and the entire transverse colon up to the splenic flexure. This ensures the complete clearance of the middle colic artery lymph nodes and addresses the potential for skip metastases or multi-centricity within the transverse segment. **Analysis of Incorrect Options:** * **Right Hemicolectomy:** This is indicated for tumors of the cecum and ascending colon. It involves ligating the ileocolic and right colic arteries but typically spares the left branch of the middle colic artery, making it inadequate for transverse colon lesions. * **Left Hemicolectomy:** This is used for tumors of the descending colon. It involves ligating the left colic artery and the first sigmoid branch. * **Extended Left Hemicolectomy:** This is indicated for tumors at the splenic flexure. It involves removing the distal transverse colon, splenic flexure, and descending colon, with ligation of the left colic and the left branch of the middle colic artery. **High-Yield Clinical Pearls for NEET-PG:** * **Marginal Artery of Drummond:** The critical anastomosis between the SMA and IMA that maintains collateral circulation. * **Griffith’s Point:** The splenic flexure is a "watershed area" most prone to ischemic colitis. * **Standard of Care:** A minimum of **12 lymph nodes** must be harvested for adequate staging of colorectal carcinoma.

Question 112: An AIDS patient presents with fistula-in-ano. His CD4 count is below 50. What is the treatment of choice?

A. Seton (Correct Answer)
B. Fistulectomy
C. None
D. Both

Explanation: **Explanation:** The management of fistula-in-ano in HIV-positive patients depends heavily on their immune status, specifically the CD4 count. **Why Seton is the correct answer:** In patients with advanced AIDS (CD4 count < 50-100 cells/mm³), wound healing is severely impaired due to poor local inflammatory response and systemic debilitation. Aggressive surgical procedures like fistulectomy or fistulotomy are contraindicated because they often lead to non-healing surgical wounds, chronic pain, and fecal incontinence. A **Seton** (non-cutting/loose) is the treatment of choice because it provides a conservative approach. It maintains drainage, prevents the formation of recurrent anorectal abscesses, and controls symptoms without requiring the extensive tissue healing necessary for more invasive surgeries. **Why other options are incorrect:** * **Fistulectomy:** This involves complete excision of the fistula tract. In an immunocompromised patient with a CD4 < 50, this would result in a large, non-healing wound and a high risk of secondary infection and sphincter damage. * **None:** While conservative management is preferred, "None" is incorrect because active drainage (via Seton) is necessary to prevent sepsis and abscess formation, which can be life-threatening in an AIDS patient. **High-Yield Clinical Pearls for NEET-PG:** 1. **CD4 Count Cut-off:** If CD4 > 200, standard surgical treatments (fistulotomy) can be considered. If CD4 < 100, conservative management with Setons is mandatory. 2. **Most common anorectal lesion in HIV:** Anal fissure (often multiple or in atypical locations). 3. **Healing Rates:** Wound healing in HIV patients is directly proportional to the CD4 count and the use of HAART (Highly Active Antiretroviral Therapy). 4. **Symptom Control:** The primary goal in advanced AIDS is palliation and infection control, not necessarily the anatomical "cure" of the fistula.

Question 113: What is the surgical procedure to create an external opening for the discharge of colonic contents?

A. Colostomy (Correct Answer)
B. Ileostomy
C. Colpocystocele
D. Colorrhaphy

Explanation: **Explanation:** The correct answer is **Colostomy**. This surgical procedure involves bringing a portion of the **large intestine (colon)** through the abdominal wall to create a stoma. This allows fecal matter to bypass a diseased or obstructed distal segment of the bowel and exit into an external collection bag. **Analysis of Options:** * **Colostomy (Correct):** Derived from "Colon" + "Stoma" (opening). It is indicated in cases of colorectal cancer, diverticulitis, or as a protective measure for distal anastomoses. * **Ileostomy:** This involves creating an opening from the **ileum** (small intestine). The discharge is typically liquid and enzyme-rich, unlike the more formed stool of a colostomy. * **Colpocystocele:** This is a medical condition (not a procedure), specifically a prolapse where the urinary bladder protrudes into the vaginal wall. * **Colorrhaphy:** This refers to the surgical **suturing or repair** of a defect in the colon wall, rather than the creation of an external opening. **NEET-PG High-Yield Pearls:** 1. **Types of Colostomy:** * **Loop Colostomy:** Usually temporary; used for fecal diversion. * **End Colostomy (Hartmann’s Procedure):** The proximal bowel is brought out as a stoma, and the distal stump is closed; commonly used in emergency sigmoid surgery. 2. **Stoma Site:** A colostomy is typically placed in the **Left Iliac Fossa (LIF)**, whereas an ileostomy is usually placed in the **Right Iliac Fossa (RIF)**. 3. **Complications:** Parastomal hernia is the most common late complication of a permanent colostomy.

Question 114: Which of the following statements about Familial Adenomatous Polyposis (FAP) is FALSE?

A. It is the most common genetic polyposis syndrome.
B. More than 100 polyps may be seen in the colon.
C. Colon cancer usually develops around 20 years of age. (Correct Answer)
D. It is caused by a mutation in the APC gene.

Explanation: **Explanation:** Familial Adenomatous Polyposis (FAP) is an autosomal dominant condition caused by a germline mutation in the **APC (Adenomatous Polyposis Coli) gene** on chromosome 5q21. It is characterized by the development of hundreds to thousands of adenomatous polyps throughout the colon. **Why Option C is False:** While polyps begin to appear in the second decade of life (puberty), colorectal cancer (CRC) typically develops about 10–15 years later. The average age for the onset of **colon cancer in untreated FAP patients is 39–40 years**. By age 20, most patients have polyps, but frank malignancy at this age is uncommon. Without a prophylactic total proctocolectomy, the risk of developing CRC is nearly 100% by age 45–50. **Analysis of Other Options:** * **Option A:** FAP is indeed the **most common** hereditary polyposis syndrome (though HNPCC/Lynch Syndrome is the most common non-polyposis syndrome). * **Option B:** The clinical diagnosis of classic FAP requires the presence of **>100 colorectal adenomas**. * **Option D:** The molecular basis is a mutation in the **APC gene**, a tumor suppressor gene. **High-Yield Clinical Pearls for NEET-PG:** * **Extracolonic Manifestations:** Duodenal adenomas (most common cause of death after colectomy), desmoid tumors, and osteomas. * **Gardner Syndrome:** FAP + Osteomas + Soft tissue tumors (epidermoid cysts, desmoids). * **Turcot Syndrome:** FAP + CNS tumors (Medulloblastoma). * **Screening:** Annual sigmoidoscopy starting at age 10–12 years for at-risk relatives. * **Surgery:** Prophylactic surgery is usually recommended in the late teens or early twenties.

Question 115: Jeep disease is also known as:

A. Anal incontinence
B. Hemorrhoids
C. Pilonidal sinus (Correct Answer)
D. Anal fissure

Explanation: **Explanation:** **Pilonidal Sinus (Option C)** is the correct answer. The term **"Jeep Disease"** became widely used during World War II when more than 80,000 soldiers were hospitalized with pilonidal disease. It was attributed to the prolonged sitting and constant "jolting" or repetitive friction experienced while driving Jeeps over rough terrain. This mechanical irritation causes hair to be forced into the subcutaneous tissue of the natal cleft, leading to a foreign body granuloma and sinus formation. **Why other options are incorrect:** * **Anal Incontinence (Option A):** Refers to the involuntary loss of flatus or stool, usually due to sphincter injury or neurological deficits; it has no historical association with Jeep transport. * **Hemorrhoids (Option B):** These are vascular cushions in the anal canal. While sitting for long periods can exacerbate them, they are not termed Jeep disease. * **Anal Fissure (Option C):** This is a linear tear in the anoderm, typically caused by trauma from hard stools, not external vehicular friction. **Clinical Pearls for NEET-PG:** * **Etiology:** It is an **acquired** condition (not congenital), primarily affecting young, hirsute (hairy) males. * **Common Site:** The sacrococcygeal region (natal cleft). * **Risk Factors:** Obesity, sedentary occupation, local hirsutism, and poor hygiene. * **Treatment of Choice:** For an acute abscess, incision and drainage. For chronic sinus, options include **Bascom’s procedure**, **Limberg flap** (transposition flap), or wide local excision. * **Histology:** The sinus is usually lined by **granulation tissue**, not epithelium.

Question 116: A 40-year-old male patient presented with a history of serous discharge from an external opening in the perianal region (posterior openings). On examination, the external opening was located at the 4 o'clock position. What is the location of the internal opening?

A. 3 o'clock
B. 4 o'clock
C. 5 o'clock
D. 6 o'clock (Correct Answer)

Explanation: ### Explanation The correct answer is **6 o’clock (Option D)**. This question tests the application of **Goodsall’s Rule**, a fundamental clinical principle used to predict the trajectory of an anal fistula based on the location of its external opening. #### 1. Why 6 o’clock is correct According to **Goodsall’s Rule**: * **Posterior Openings:** Any external opening located **posterior** to a transverse line drawn through the center of the anus (the coronal plane) will have a track that curves toward the midline to enter the anal canal at the **6 o'clock position** (posterior midline). * In this case, the external opening is at the **4 o'clock position**. Since the patient is in the lithotomy position, 4 o'clock is posterior to the transverse line. Therefore, the track will follow a curved path and open internally at the 6 o'clock position. #### 2. Why other options are incorrect * **Options A (3 o'clock) & B (4 o'clock):** These would imply a straight radial track. According to Goodsall's Rule, only **anterior** openings (within 3 cm of the anus) follow a straight radial path to the internal opening. * **Option C (5 o'clock):** This is neither the midline nor the radial point of origin. Internal openings for posterior fistulae almost invariably converge at the posterior midline crypt (6 o'clock). #### 3. High-Yield Clinical Pearls for NEET-PG * **Goodsall’s Rule Exception:** An anterior external opening that is **>3 cm** from the anal verge does not follow a straight track; instead, it curves posteriorly to open at the **6 o'clock position** (behaving like a posterior fistula). * **Park’s Classification:** The most common type of fistula-in-ano is **Intersphincteric** (approx. 45-70%). * **Investigation of Choice:** **MRI Proctogram** (Pelvic MRI) is the gold standard for complex or recurrent fistulae. * **Management:** Simple low-lying fistulae are treated with **Fistulotomy**, while complex/high-lying fistulae may require a **Seton** or **LIFT** (Ligation of Intersphincteric Fistula Tract) procedure to preserve continence.

Question 117: Which of the following is true about carcinoma of the colon?

A. One-third of cases show liver metastasis.
B. Obstruction is common in sigmoid colon carcinoma.
C. Carcinoembryonic antigen (CEA) is useful for prognostic importance.
D. All of the above. (Correct Answer)

Explanation: **Explanation:** Carcinoma of the colon is a high-yield topic for NEET-PG, and understanding its clinical presentation and markers is crucial. * **Option A (Liver Metastasis):** The liver is the most common site of distant metastasis for colorectal cancer because the venous drainage of the colon occurs via the portal system. Approximately **25–35% (one-third)** of patients present with synchronous liver metastases at the time of diagnosis. * **Option B (Obstruction in Sigmoid Colon):** The sigmoid colon is the most common site for **obstructive symptoms**. This is due to the narrower lumen of the left colon compared to the right, and the fact that stool in the distal colon is more solid/formed. In contrast, right-sided (caecal) cancers typically present with occult bleeding and iron deficiency anemia. * **Option C (CEA and Prognosis):** Carcinoembryonic Antigen (CEA) is **not** used for screening due to low sensitivity and specificity. However, it is highly valuable for **prognosis and monitoring**. Pre-operative CEA levels correlate with the stage of the disease, and a failure of CEA levels to fall post-operatively suggests residual disease or metastasis. It is the gold standard for monitoring recurrence. Since all three statements are clinically accurate, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Historically the rectum, but there is a shifting trend toward the proximal colon. * **Investigation of choice:** Colonoscopy with biopsy. * **Apple-core appearance:** Classic radiological sign seen on Barium Enema in stenosing (usually left-sided) lesions. * **Staging:** TNM staging is the most important prognostic factor.

Question 118: Which of the following are predisposing factors for colon cancer?

A. Animal fat consumption, Familial adenomatous polyposis, Ulcerative colitis
B. Animal fat consumption, Familial adenomatous polyposis, Ulcerative colitis, Crohn's disease (Correct Answer)
C. Animal fat consumption, Ulcerative colitis, Crohn's disease, TB
D. Animal fat consumption, Familial adenomatous polyposis, Crohn's disease, TB

Explanation: ### Explanation Colorectal cancer (CRC) is a multifactorial disease influenced by dietary habits, genetic syndromes, and chronic inflammatory states. **1. Why Option B is Correct:** * **Dietary Factors:** High intake of **animal fat** and red meat increases bile acid production, which gut bacteria convert into carcinogenic secondary bile acids. Conversely, high fiber is protective. * **Genetic Syndromes:** **Familial Adenomatous Polyposis (FAP)** is an autosomal dominant condition (APC gene mutation) with a near 100% risk of CRC by age 40 if left untreated. * **Inflammatory Bowel Disease (IBD):** Both **Ulcerative Colitis (UC)** and **Crohn’s Disease** involve chronic mucosal inflammation that triggers the dysplasia-carcinoma sequence. While the risk is traditionally higher in UC, long-standing Crohn’s colitis also significantly increases malignancy risk. **2. Why Other Options are Incorrect:** * **Options C and D:** These include **Tuberculosis (TB)**. Intestinal TB is a chronic granulomatous infection common in developing countries, but it is **not** a recognized predisposing factor for colorectal malignancy. * **Option A:** While the factors listed are correct, it is less comprehensive than Option B, as it omits Crohn’s disease, which is a proven risk factor. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common site of CRC:** Sigmoid colon (historically), though right-sided (proximal) cancers are increasing in incidence. * **IBD Risk:** The risk of cancer in UC increases significantly after **8–10 years** of pancolitis. * **Protective Factors:** NSAIDs (Aspirin), high-fiber diet, and calcium. * **Lynch Syndrome (HNPCC):** The most common form of hereditary CRC; involves DNA mismatch repair (MMR) gene mutations (MSH2, MLH1). * **Streptococcus bovis:** Bacteremia/endocarditis caused by this organism is highly associated with underlying colonic lesions.

Question 119: Which of the following is most commonly associated with a high risk for carcinoma of the colon?

A. Peutz-Jeghers syndrome
B. Juvenile familial polyposis
C. Familial Adenomatous Polyposis (Correct Answer)
D. Lynch syndrome

Explanation: **Explanation:** The correct answer is **Familial Adenomatous Polyposis (FAP)**. FAP is an autosomal dominant condition caused by a germline mutation in the **APC gene** on chromosome 5q21. It is characterized by the development of hundreds to thousands of adenomatous polyps throughout the colon. The risk of progression to colorectal cancer (CRC) is virtually **100% by the age of 40** if a prophylactic total proctocolectomy is not performed. This absolute certainty of malignancy makes it the condition with the highest risk among the options. **Analysis of Incorrect Options:** * **Lynch Syndrome (HNPCC):** While it is the most common *hereditary* cause of CRC, the lifetime risk of developing colon cancer is approximately **70-80%**, which is lower than the 100% risk seen in FAP. * **Juvenile Familial Polyposis:** This is a hamartomatous polyp syndrome. While it carries an increased risk of malignancy (approx. 40-50% lifetime risk), the polyps themselves are initially non-neoplastic. * **Peutz-Jeghers Syndrome:** Characterized by mucocutaneous pigmentation and hamartomatous polyps. While it increases the risk of various cancers (breast, pancreas, colon), the specific risk for colon cancer (approx. 39%) is significantly lower than in FAP. **High-Yield Clinical Pearls for NEET-PG:** * **FAP Screening:** Starts at age 10–12 years with annual flexible sigmoidoscopy. * **Gardner Syndrome:** FAP + Osteomas (mandible) + Soft tissue tumors (Desmoids). * **Turcot Syndrome:** FAP + CNS tumors (Medulloblastoma). * **CHRPE:** Congenital Hypertrophy of Retinal Pigment Epithelium is a specific extra-colonic marker for FAP.

Question 120: Dukes classification is used for which of the following carcinomas?

A. Pancreas carcinoma
B. Gastric carcinoma
C. Urinary bladder carcinoma
D. Colo-rectal carcinoma (Correct Answer)

Explanation: **Explanation:** The **Dukes classification** is a historical yet foundational staging system specifically developed for **Colorectal Carcinoma**. Proposed by Cuthbert Dukes in 1932, it stages the disease based on the depth of local invasion and the presence of lymph node metastasis. * **Dukes A:** Tumor limited to the wall (mucosa/submucosa/muscularis propria); no nodal involvement. * **Dukes B:** Tumor extends through the muscularis propria into the serosa or pericolic fat; no nodal involvement. * **Dukes C:** Any depth of wall involvement with regional lymph node metastasis. * **Dukes D:** (Added later by Astler-Coller) Distant metastasis. **Why other options are incorrect:** * **Pancreas carcinoma:** Staged using the **TNM system** (AJCC). * **Gastric carcinoma:** Staged using the **TNM system** and often classified morphologically by the **Lauren Classification** (Intestinal vs. Diffuse types). * **Urinary bladder carcinoma:** Staged using the **TNM system** and the **Jewett-Strong-Marshall** system. **High-Yield Clinical Pearls for NEET-PG:** 1. While Dukes is historically significant, the **TNM (Tumor, Node, Metastasis) system** is currently the gold standard for staging colorectal cancer. 2. The **Astler-Coller modification** is a common variation of Dukes that further subdivides stages based on the exact depth of penetration (e.g., B1, B2, C1, C2). 3. The most important prognostic factor in colorectal cancer is the **presence of lymph node involvement** (Stage C). 4. **Carcinoembryonic Antigen (CEA)** is the tumor marker used for monitoring recurrence, not for primary diagnosis.

Practice by Chapter

Colorectal Anatomy and Physiology

Practice Questions

Diverticular Disease

Practice Questions

Inflammatory Bowel Disease

Practice Questions

Colorectal Polyps

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Colorectal Cancer

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Anorectal Abscess and Fistula

Practice Questions

Hemorrhoids

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Rectal Prolapse

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Fecal Incontinence

Practice Questions

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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