Colorectal Surgery Practice Questions

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

Apple core deformity on imaging. **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).

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

Colovesical. **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.

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

Concurrent chemoradiation. **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.

Q: What is the most common site for colon cancer?

Rectosigmoid. **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).

Q: 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?

Use of an inferior vena cava (IVC) filter. ### **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.

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

Seton's procedure. **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).

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

Closure and lavage. **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].

Question 1

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

Accepted Answer

Apple core deformity on imaging

Answer

Bleeding is the usual presentation

Answer

A palpable mass is usually present

Answer

The stools are typically liquid

Question 2

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

Accepted Answer

Ascending colon, cecum, terminal ileum, a portion of the transverse colon, the spleen, and the gallbladder

Answer

Ascending colon, cecum, terminal ileum, and a portion of the transverse colon

Answer

Ascending colon, cecum, terminal ileum, a portion of the transverse colon, and the spleen

Answer

Ascending colon, cecum, terminal ileum, a portion of the transverse colon, the spleen, the gallbladder, and the pancreas

Question 3

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

Accepted Answer

Colovesical

Answer

Coloenteric

Answer

Colocolonic

Answer

Colovaginal

Question 4

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

Accepted Answer

Concurrent chemoradiation

Answer

Abdominoperineal resection (APR)

Answer

APR followed by chemoradiation

Answer

Neoadjuvant chemotherapy followed by surgery

Question 5

What is the most common site for colon cancer?

Accepted Answer

Rectosigmoid

Answer

Cecum

Answer

Transverse colon

Answer

Ascending colon

Question 6

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?

Accepted Answer

Use of an inferior vena cava (IVC) filter

Answer

Increasing the dose of anticoagulants

Answer

Discontinuing anticoagulants

Answer

CT scan of the leg and abdomen

Question 7

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?

Accepted Answer

Hemorrhoids

Answer

Anal cancer

Answer

Anal fissure

Answer

Ischiorectal abscess

Question 8

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

Accepted Answer

Seton's procedure

Answer

Sitz bath

Answer

Botox injection

Answer

Diltiazem gel

Question 9

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

Accepted Answer

Villous

Answer

Stenosing

Answer

Ulcerative

Answer

Tubular

Question 10

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

Accepted Answer

Closure and lavage

Answer

Temporary colostomy

Answer

Permanent colostomy

Answer

Symptomatic treatment

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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