Colorectal Surgery Practice Questions

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

Familial Adenomatous Polyposis. **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.

Q: What is the most common site for colonic diverticula?

Sigmoid colon. **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.

Q: What is the etiology for this condition?

Sigmoid volvulus. ***Sigmoid volvulus*** - The **coffee bean sign** or **omega loop** on plain abdominal X-ray is pathognomonic for sigmoid volvulus, showing the twisted sigmoid colon. - Typically occurs in elderly patients with chronic constipation and presents with **acute large bowel obstruction** and abdominal distension. *Adhesive obstruction* - Usually causes **small bowel obstruction** with dilated small bowel loops and air-fluid levels on X-ray. - Associated with **previous abdominal surgery** and presents with colicky abdominal pain and vomiting. *Meckel's diverticulum* - A **true diverticulum** of the small bowel that rarely causes obstruction in adults. - More commonly presents with **GI bleeding** or **intussusception** in children, not the classic radiological sign described. *Gastric volvulus* - Involves twisting of the **stomach** rather than the sigmoid colon. - Presents with **Borchardt's triad** (severe epigastric pain, retching without vomiting, inability to pass NGT) and different radiological appearance.

Q: A 50-year-old male, working as a hotel cook and having four dependent family members, has been diagnosed with early-stage squamous cell carcinoma of the anal canal. He has more than a 60% chance of cure. What is the best treatment option?

Combined chemotherapy and radiotherapy. **Explanation:** The primary goal in treating squamous cell carcinoma (SCC) of the anal canal is **organ preservation** without compromising survival. The standard of care for most stages of anal SCC is the **Nigro Protocol**, which consists of **concurrent Chemoradiotherapy (CRT)**. 1. **Why Option C is correct:** Unlike most gastrointestinal cancers where surgery is the mainstay, anal SCC is highly radiosensitive and chemosensitive. Combined CRT (typically using 5-Fluorouracil and Mitomycin-C) achieves high cure rates (60–90%) while preserving the anal sphincter. This is particularly crucial for this patient, a hotel cook and breadwinner, as it avoids a permanent colostomy and maintains his quality of life and functional status. 2. **Why other options are incorrect:** * **Option A (APR):** Abdomino-perineal resection involves removing the rectum and anus, resulting in a permanent colostomy. It is now reserved only for "salvage surgery" (persistent or recurrent disease after CRT). * **Option B:** Surgery is not typically combined with radiotherapy as a primary approach because CRT alone is usually curative. * **Option D:** Chemotherapy alone is palliative and insufficient for a cure in localized anal SCC. **Clinical Pearls for NEET-PG:** * **Nigro Protocol:** 5-FU + Mitomycin-C + Radiation (45–60 Gy). * **Most common histology:** Squamous Cell Carcinoma (associated with HPV 16 and 18). * **Follow-up:** Digital Rectal Examination (DRE) is the most important tool to assess response, usually 12–26 weeks post-treatment. * **Indication for Surgery (APR):** Only for residual disease, recurrence, or incontinence.

Question 1

Which of the following are predisposing factors for colon cancer?

Accepted Answer

Animal fat consumption, Familial adenomatous polyposis, Ulcerative colitis, Crohn's disease

Answer

Animal fat consumption, Familial adenomatous polyposis, Ulcerative colitis

Answer

Animal fat consumption, Ulcerative colitis, Crohn's disease, TB

Answer

Animal fat consumption, Familial adenomatous polyposis, Crohn's disease, TB

Question 2

What is the treatment for solitary rectal ulcer?

Accepted Answer

Banding

Answer

Laxatives

Answer

Rectopexy

Answer

All of the above

Question 3

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

Accepted Answer

Familial Adenomatous Polyposis

Answer

Peutz-Jeghers syndrome

Answer

Juvenile familial polyposis

Answer

Lynch syndrome

Question 4

What is the most common site for colonic diverticula?

Accepted Answer

Sigmoid colon

Answer

Ascending colon

Answer

Transverse colon

Answer

Descending colon

Question 5

What is the etiology for this condition?

Accepted Answer

Sigmoid volvulus

Answer

Adhesive obstruction

Answer

Meckel's diverticulum

Answer

Gastric volvulus

Question 6

A 20-year-old woman in her ninth month of pregnancy presents with increasing pain on defecation and bright red blood on toilet paper. She had no prior gastrointestinal issues. Following childbirth, her rectal pain resolved and bleeding ceased. What is the most likely diagnosis?

Accepted Answer

Hemorrhoids

Answer

Angiodysplasia

Answer

Intussusception

Answer

Ischemic colitis

Question 7

A 50-year-old male, working as a hotel cook and having four dependent family members, has been diagnosed with early-stage squamous cell carcinoma of the anal canal. He has more than a 60% chance of cure. What is the best treatment option?

Accepted Answer

Combined chemotherapy and radiotherapy

Answer

Abdomino-perineal resection

Answer

Combined surgery and radiotherapy

Answer

Chemotherapy alone

Question 8

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

Accepted Answer

The ulcer primarily involves the anterior rectal wall.

Answer

Approximately 20% of ulcers are multiple.

Answer

Recurrent rectal prolapse is a common predisposing factor.

Answer

Management may include digital repositioning of the rectum.

Question 9

Which of the following is NOT true regarding malignancy arising from Ulcerative colitis?

Accepted Answer

Left-sided disease is more common

Answer

Takes at least 10 years to develop

Answer

Associated with dysplasia in the rest of the colon

Answer

Younger age of onset is associated with an increased chance of carcinoma

Question 10

What is the best investigation to diagnose hemorrhoids?

Accepted Answer

Proctoscopy

Answer

Digital Rectal Examination (DRE)

Answer

Barium enema

Answer

Ultrasound (USG)

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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