Colorectal Surgery — MCQs

Colorectal Surgery Indian Medical PG Practice Questions and MCQs

Question 231: Familial adenomatous polyposis is characterized by all of the following except:

A. Autosomal recessive transmission (Correct Answer)
B. More than 100 polyps in the colorectal area
C. Polyps seen in the duodenum
D. Extra-intestinal manifestations are present

Explanation: **Explanation:** **Familial Adenomatous Polyposis (FAP)** is a hereditary colorectal cancer syndrome caused by a germline mutation in the **APC (Adenomatous Polyposis Coli) gene** located on chromosome **5q21**. 1. **Why Option A is the correct answer:** FAP follows an **Autosomal Dominant** pattern of inheritance, not recessive. A child of an affected parent has a 50% chance of inheriting the mutation. Approximately 25% of cases arise from *de novo* mutations without a family history. 2. **Analysis of other options:** * **Option B:** By definition, classic FAP is characterized by the development of **hundreds to thousands** of adenomatous polyps throughout the colon and rectum, typically appearing in the second decade of life. * **Option C:** FAP is a systemic predisposition to polyps. **Duodenal adenomas** (especially in the periampullary region) occur in up to 90% of patients and are the second leading cause of cancer death in FAP after colorectal cancer. * **Option D:** FAP often presents with **extra-intestinal manifestations**. When associated with osteomas, soft tissue tumors (desmoids), and dental abnormalities, it is known as **Gardner’s Syndrome**. Association with CNS tumors (medulloblastoma) is known as **Turcot’s Syndrome**. **High-Yield Clinical Pearls for NEET-PG:** * **CHRPE:** Congenital Hypertrophy of Retinal Pigment Epithelium is the earliest detectable clinical sign of FAP. * **Management:** Prophylactic **Proctocolectomy** is the treatment of choice, usually performed in late teens or early 20s, as the risk of progression to colorectal carcinoma is **100%** by age 40-50. * **Screening:** Annual flexible sigmoidoscopy starting at age 10-12 for at-risk relatives.

Question 232: What is the most common site of perforation during colonoscopy?

A. Cecum
B. Hepatic flexure
C. Splenic flexure
D. Sigmoid colon (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Sigmoid Colon** The **sigmoid colon** is the most common site of perforation during both diagnostic and therapeutic colonoscopies. This is primarily due to its unique anatomical and physiological characteristics: 1. **Redundancy and Mobility:** The sigmoid is an intraperitoneal segment with a long mesentery, making it prone to looping (alpha loops) during scope insertion. 2. **Acute Angulations:** It has sharp bends that increase the risk of mechanical trauma from the tip of the colonoscope. 3. **Diverticular Disease:** The sigmoid is the most common site for diverticula. The weakened wall in diverticulosis and the narrowed lumen from chronic inflammation make it highly susceptible to barotrauma (over-insufflation) and mechanical rupture. **Analysis of Incorrect Options:** * **A. Cecum:** While the cecum is the most common site for perforation due to **distension** (Law of Laplace, e.g., in Ogilvie’s syndrome or distal obstruction), it is not the most common site for iatrogenic colonoscopic injury. * **B & C. Hepatic and Splenic Flexures:** These are "fixed" points of the colon. While they represent areas of technical difficulty where the scope may encounter resistance, they are less frequently perforated compared to the highly mobile and diseased sigmoid. **Clinical Pearls for NEET-PG:** * **Incidence:** Perforation occurs in ~0.1% of diagnostic and up to 1% of therapeutic colonoscopies. * **Mechanism:** Most perforations are **mechanical** (direct tip trauma or bowing of a loop), followed by **barotrauma** and **thermal injury** (during polypectomy). * **Management:** Small, "clean" perforations recognized immediately in a prepped bowel can sometimes be managed conservatively or with endoscopic clips. Large perforations or those with peritonitis require urgent laparotomy and repair/resection. * **Signs:** The earliest sign of perforation during the procedure is often the loss of luminal visualization or the sight of extra-luminal fat/peritoneal structures.

Question 233: A 33-year-old male presents with sudden onset acute abdominal pain, constipation for 1 day, persistent hiccups, and occasional vomiting. An abdominal X-ray was performed. Identify the pathology.

A. Sigmoid volvulus (Correct Answer)
B. Intussusception
C. Caecal volvulus
D. Mechanical obstruction

Explanation: ***Sigmoid volvulus*** - The abdominal X-ray demonstrates the classic **"coffee bean" sign**, which is a pathognomonic finding for sigmoid volvulus, representing a massively dilated loop of the sigmoid colon. - The clinical presentation of acute abdominal pain, distension, and constipation is consistent with a **large bowel obstruction**, which is caused by the twisting of the sigmoid colon on its mesentery. *Caecal volvulus* - Radiographically, a caecal volvulus typically appears as a kidney-shaped or comma-shaped dilated loop of bowel displaced towards the **left upper quadrant**, which is not seen in this image. - It is less common than sigmoid volvulus and is often associated with a mobile cecum and the absence of prior abdominal surgery. *Intussusception* - Intussusception, the telescoping of one bowel segment into another, is more common in children and classically presents with a **"target sign"** on ultrasound or CT. - While it can cause obstruction in adults, the radiographic finding of a massive, single, air-filled loop is not characteristic of intussusception. *Mechanical obstruction* - This is a general term for physical blockage of the bowel lumen. While sigmoid volvulus is a specific cause of mechanical obstruction, the X-ray provides specific findings that point to a more precise diagnosis. - Non-specific signs of mechanical obstruction, such as multiple dilated bowel loops with **air-fluid levels**, are different from the characteristic single-loop dilation seen here.

Question 234: A 70-year-old patient presents with absolute constipation and abdominal distension. The X-ray abdomen is given below. What is the most likely diagnosis?

A. Caecal Volvulus
B. Sigmoid Volvulus (Correct Answer)
C. Intestinal Obstruction
D. Small Bowel Volvulus

Explanation: ***Sigmoid Volvulus*** - The abdominal X-ray demonstrates the classic **"coffee bean" sign**, which is a massively dilated, haustra-less loop of the sigmoid colon that appears bent upon itself, originating from the pelvis. - This diagnosis aligns with the clinical presentation of an elderly patient with **absolute constipation** and significant **abdominal distension**, which are hallmark features of a closed-loop large bowel obstruction caused by sigmoid volvulus. *Caecal Volvulus* - A caecal volvulus typically presents as a **kidney-bean** or **comma-shaped** dilated structure that is displaced from the right lower quadrant towards the left upper quadrant, which is morphologically distinct from the inverted U-shape seen in the image. - The dilated cecum in a caecal volvulus often retains some **haustral markings**, unlike the smooth, featureless appearance of the dilated sigmoid colon seen here. *Intestinal Obstruction* - While sigmoid volvulus is a cause of intestinal obstruction, this is a non-specific diagnosis. The radiological findings are specific enough to identify the underlying cause. - A general diagnosis of intestinal obstruction doesn't account for the pathognomonic **"coffee bean" sign**, which specifically points to sigmoid volvulus as the etiology. *Small Bowel Volvulus* - The dilated loop in the X-ray lacks **valvulae conniventes** (also known as plicae circulares), which are characteristic transverse folds of the small bowel. The loop's appearance is consistent with the large bowel. - The caliber of the distended loop is exceptionally large, which is more typical for a colonic obstruction rather than a small bowel obstruction, which usually involves multiple, smaller-caliber loops.

Question 235: A patient with grade 2 hemorrhoids underwent surgery, identify the instrument.

A. Stapler kit
B. CO2 laser
C. Haemorrhoids resection kit
D. Haemorrhoids band kit (Correct Answer)

Explanation: ***Haemorrhoids band kit*** - The image shows a **band ligator** applying a small elastic band to the base of an internal hemorrhoid, which is the procedure known as **rubber band ligation**. - This technique is a common office-based procedure for **grade I, II, and selected grade III** internal hemorrhoids, causing them to necrose and slough off by cutting off their blood supply. *Haemorrhoids resection kit* - This kit contains instruments for a formal **hemorrhoidectomy**, a surgical procedure that involves excising the hemorrhoidal tissue, typically reserved for severe **grade III and IV hemorrhoids**. - A resection is a more invasive procedure involving cutting and suturing, which is different from the banding method shown. *Stapler kit* - A stapler kit is used for a **stapled hemorrhoidopexy** (PPH procedure), which involves a circular stapler to resect a ring of mucosa above the hemorrhoids and lift them back into a normal position. - The instrument and the principle of action (resection and fixation) are distinct from the ligation shown in the image. *CO2 laser* - **Laser hemorrhoidoplasty** uses a laser probe to deliver energy to shrink the hemorrhoidal plexus; it does not involve the application of a mechanical band. - The instrument is a thin laser fiber, which looks different from the ligator depicted in the illustration.

Question 236: A homosexual man complains of painful defecation and mass protruding from the anal canal. Biopsy reveals squamous cell carcinoma of anus. Correct management for this patient is

A. Wide local excision
B. Combined chemoradiation (Correct Answer)
C. Chemotherapy
D. Abdominoperineal repair

Explanation: ***Combined chemoradiation***- **Combined chemoradiation (Nigro protocol)** is the standard of care and preferred, organ-preserving primary treatment for most stages of squamous cell carcinoma of the anus.- This curative regimen typically involves sequential or concurrent use of **5-Fluorouracil**, **Mitomycin C** (or Cisplatin), and focused external beam radiation therapy, resulting in high rates of complete remission.*Chemotherapy*- Chemotherapy alone is insufficient as a curative primary modality for localized anal carcinoma and is inferior to combined treatment.- Systemic chemotherapy is primarily reserved for the management of **metastatic** disease or palliation in advanced, unresectable cases.*Abdominoperineal repair*- **Abdominoperineal resection (APR)**, which creates a permanent colostomy, is primarily reserved as a highly morbid **salvage operation** for locoregional failure following initial chemoradiation.- Primary APR is rarely performed because combined chemoradiation offers similar long-term survival rates with sphincter preservation.*Wide local excision*- **Wide local excision (WLE)** is only appropriate for very small (T1, <2cm), well-differentiated tumors located at the anal margin (perianal skin), which are much less common.- A bulky, protruding mass usually indicates a deeper primary tumor or involvement of the anal canal, requiring definitive **chemoradiation** rather than surgery.

Question 237: A man came with complaints of recurrent discharge and pain due to lesions around the anus for 3 years. A diagnosis of fistula-in-ano is made. What is the gold standard investigation for this condition?

A. Fistulogram
B. USG
C. CECT
D. MRI (Correct Answer)

Explanation: ***MRI*** - **Gold standard investigation** for fistula-in-ano for preoperative assessment - Provides **superior soft tissue contrast** and multiplanar imaging capabilities - Accurately delineates the **fistula tract, internal and external openings** - Detects **secondary tracts, horseshoe extensions, and abscesses** - Helps in **Parks classification** (intersphincteric, trans-sphincteric, suprasphincteric, extrasphincteric) - Essential for **surgical planning** and predicting recurrence risk - MRI with fat suppression sequences (T2-weighted) provides best visualization *Fistulogram* - Outdated investigation with **limited accuracy** (40-50%) - Cannot adequately assess sphincter involvement or secondary tracts - Invasive and uncomfortable for the patient - Risk of extravasation and infection *USG (Endoanal/Transperineal Ultrasound)* - Useful adjunct but **not gold standard** - Operator-dependent with limited field of view - Difficulty visualizing high or complex fistulas - Less accurate for secondary extensions *CECT* - Not routinely used for fistula-in-ano assessment - **Inferior soft tissue resolution** compared to MRI - Radiation exposure - Limited differentiation of sphincter anatomy

Question 238: A 65-year-old patient undergoes colonoscopy for altered bowel habits. A 6 cm colonic mass is biopsied and histopathology shows adenocarcinoma confined to the mucosa with no lymph node or distant metastasis. What is the most appropriate TNM stage of this tumor?

A. Stage 0 (Correct Answer)
B. Stage II
C. Stage III
D. Stage I

Explanation: ***Stage 0*** - In the TNM staging system for colorectal cancer, a tumor that is **confined to the mucosa** (Carcinoma in situ) is classified as **Tis**. - Stage 0 is specifically defined by the staging combination **Tis, N0, M0**, indicating tumor confined to the mucosa with no nodal involvement (N0) or distant metastasis (M0). *Incorrect: Stage I* - Stage I encompasses tumors that invade the **submucosa (T1)** or the **muscularis propria (T2)**, provided there is no lymph node or distant spread (N0, M0). - Since this tumor is confined only to the mucosa (Tis), it has not met the criteria for T1 or T2 required for Stage I. *Incorrect: Stage II* - Stage II refers to tumors with deeper wall penetration, classified as **T3** (invasion through muscularis propria into subserosa) or **T4** (invasion into adjacent structures or peritoneum). - Although Stage II also requires N0 and M0, the depth of invasion (T3 or T4) far exceeds the mucosal confinement (Tis) seen in this patient. *Incorrect: Stage III* - Stage III is defined by the presence of **regional lymph node metastasis** (N1 or N2), regardless of the depth of the primary tumor (Any T). - The case description explicitly states **no lymph node or distant metastasis**, ruling out any N staging higher than N0.

Question 239: Identify the fistula according to Park's classification?

A. Extra-sphincteric
B. Trans-sphincteric high
C. Supra-sphincteric
D. Intersphincteric (Correct Answer)

Explanation: ***Intersphincteric*** - This type of fistula tract is confined entirely to the space **between the internal and external anal sphincters**, as clearly depicted in the image. - It represents the **most common** variety of anal fistula, accounting for about 70% of cases in Park's classification. *Supra-sphincteric* - A supra-sphincteric fistula passes through the intersphincteric space, hooks **above the puborectalis muscle**, and then descends through the ischiorectal fossa. - The illustrated tract does not traverse cephalad to the **external anal sphincter** or the puborectalis muscle. *Extra-sphincteric* - This rare type runs **outside both the internal and external anal sphincters** and often penetrates the levator ani muscle to connect the rectum to the perianal skin. - The tract shown is contained **within the muscle planes** of the anal canal, ruling out an extra-sphincteric course. *Trans-sphincteric high* - Trans-sphincteric fistulas pass **through the external anal sphincter** (usually involving the lower or middle third) to reach the ischiorectal fossa. - The depicted track runs strictly **between** the internal and external layers without crossing the external sphincter.

Question 240: Identify the instrument in the image:

A. St Mark's perineal retractor (Correct Answer)
B. Joll retractor
C. Deaver retractor
D. Goligher retractor

Explanation: ***St Mark's perineal retractor*** - This image displays the classic configuration of a **St. Mark's perineal retractor**, which is a self-retaining retractor used to expose the perineal area. - It features two articulating blades with multiple prongs, often shaped distinctly (as seen with the upper blade resembling an elephant's head with teeth), and a **ratchet mechanism** to hold the blades open. *Joll retractor* - A **Joll retractor** is typically used in thyroid surgery and consists of a single blade or a pair of blades, which are more delicate and shaped differently, not self-retaining like the one shown. - It is designed to provide retraction in a more confined area and does not have the complex self-retaining mechanism or multiple broad prongs. *Deaver retractor* - A **Deaver retractor** is a handheld retractor with a distinct S-shaped blade, used primarily for deep abdominal or thoracic retraction. - It does not have a self-retaining mechanism or the multiple prongs characteristic of the instrument in the image. *Goligher retractor* - A **Goligher retractor** is a specific type of self-retaining retractor, but its design differs significantly from the one pictured; it typically has multiple interchangeable blades and a different frame structure. - While it is also self-retaining, it is mainly used for deep abdominal or pelvic surgery and has a more robust frame compared to the depicted perineal retractor.

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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