Colorectal Surgery — MCQs

A 74-year-old woman presents with 3 weeks of left lower quadrant abdominal pain, changes in bowel habits, and intermittent fever. Her temperature is 38°C (101°F), respirations are 19 per minute, and blood pressure is 130/80 mm Hg. Physical examination shows left lower quadrant tenderness. A CBC reveals neutrophilia. An abdominal-pelvic ultrasound examination is normal. Which of the following is the most likely diagnosis?

Colorectal Surgery Indian Medical PG Practice Questions and MCQs

Question 61: Colonic metastases are related to which of the following factors?

A. Preoperative CEA level
B. Depth of invasion (Correct Answer)
C. Size of tumor
D. Circumferential involvement

Explanation: The risk of colonic metastases (both nodal and distant) is primarily determined by the **Depth of Invasion (T-stage)** of the primary tumor. ### **Explanation of the Correct Answer** The colonic wall consists of layers: mucosa, submucosa, muscularis propria, and serosa. The lymphatic and vascular channels are located deep to the muscularis mucosae. As a tumor invades deeper into the bowel wall (increasing T-stage), the likelihood of the cancer cells gaining access to the rich lymphatic and venous plexuses in the submucosa and subserosa increases significantly. This is why the **TNM staging system**, which is the gold standard for prognosis, relies heavily on the depth of invasion rather than tumor size. ### **Analysis of Incorrect Options** * **A. Preoperative CEA level:** While CEA is a valuable marker for monitoring recurrence and assessing prognosis, it is not a primary determinant of whether a tumor will metastasize. High levels suggest a higher tumor burden but do not dictate the metastatic potential. * **C. Size of tumor:** In colorectal cancer, size does not correlate with metastatic risk. A large exophytic (villous) polyp may be benign, whereas a small, deeply ulcerative lesion may have extensive nodal spread. * **D. Circumferential involvement:** This refers to how much of the lumen is occupied. While this may cause clinical symptoms like obstruction, it is the *radial depth* of the tumor, not its circular spread, that correlates with metastasis. ### **High-Yield Clinical Pearls for NEET-PG** * **Most common site of distant metastasis:** Liver (via the portal venous system). * **Most important prognostic factor:** Lymph node involvement (N-stage). * **Sentinel Lymph Node:** In colon cancer, this is usually found in the mesentery near the primary tumor. * **TNM Staging:** T1 invades submucosa; T2 invades muscularis propria; T3 invades subserosa/pericolonic tissue; T4 invades visceral peritoneum or adjacent organs.

Question 62: The modified Amsterdam criteria are used for the diagnosis of which of the following conditions?

A. Peutz-Jeghers syndrome
B. Hereditary Non-Polyposis Colorectal Cancer (HNPCC) (Correct Answer)
C. Turcot syndrome
D. Familial Adenomatous Polyposis (FAP)

Explanation: The **Modified Amsterdam Criteria (Amsterdam II)** are the clinical gold standard used to identify families likely to have **Hereditary Non-Polyposis Colorectal Cancer (HNPCC)**, also known as **Lynch Syndrome**. ### 1. Why HNPCC is Correct HNPCC is an autosomal dominant condition caused by mutations in DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS2). Because these patients do not present with extensive polyposis, clinical diagnosis relies on family history. The **"3-2-1 Rule"** of the Amsterdam II criteria includes: * **3** relatives with an HNPCC-associated cancer (colorectal, endometrial, small bowel, ureter, or renal pelvis). * **2** successive generations affected. * **1** relative is a first-degree relative of the other two, with at least one case diagnosed before age **50**. * FAP must be excluded, and tumors should be verified by pathological examination. ### 2. Why Other Options are Incorrect * **Peutz-Jeghers Syndrome:** Diagnosed by the presence of characteristic hamartomatous polyps and mucocutaneous hyperpigmentation. * **Turcot Syndrome:** A variant of FAP or HNPCC characterized by the association of colorectal polyposis with central nervous system tumors (Medulloblastoma or Glioblastoma). * **Familial Adenomatous Polyposis (FAP):** Diagnosed clinically by the presence of >100 adenomatous colorectal polyps, caused by a mutation in the APC gene. ### Clinical Pearls for NEET-PG * **Bethesda Criteria:** Used to determine which colorectal tumors should be tested for **Microsatellite Instability (MSI)**. * **Most common extracolonic malignancy in Lynch Syndrome:** Endometrial carcinoma. * **Lynch I vs. II:** Lynch I involves only site-specific colonic cancer; Lynch II involves colonic and extracolonic (endometrial, ovarian, gastric, etc.) cancers. * **Screening:** For HNPCC, colonoscopy is recommended every 1–2 years starting at age 20–25.

Question 63: Injection sclerotherapy is ideal for which of the following conditions?

A. External haemorrhoids
B. Internal haemorrhoids (Correct Answer)
C. Posterior resection
D. Local resection

Explanation: **Explanation:** Injection sclerotherapy is a non-surgical treatment modality primarily indicated for **early-stage internal haemorrhoids** (Grade I and early Grade II). **Why Internal Haemorrhoids?** The procedure involves injecting a sclerosing agent (commonly **5% Phenol in almond or arachis oil**) into the submucosal layer at the pedicle of the haemorrhoid (above the dentate line). This induces an aseptic inflammatory reaction followed by fibrosis, which obliterates the vascular channels and "pins" the mucosa back to the underlying muscle. Since the area above the dentate line is supplied by autonomic nerves, the procedure is relatively painless. **Analysis of Incorrect Options:** * **External Haemorrhoids:** These are located below the dentate line and are covered by sensitive anoderm (somatic innervation). Injection here would cause excruciating pain and potential skin necrosis. * **Posterior/Local Resection:** These are surgical procedures used for malignancies or complex rectal pathologies. Sclerotherapy is a conservative, non-excisional treatment for benign vascular cushions and has no role in resectional surgery. **NEET-PG High-Yield Pearls:** * **Site of Injection:** Submucosal layer at the **pedicle** (above the dentate line). * **Common Agent:** 5% Phenol in oil (Gabriel’s solution). * **Contraindications:** Grade III or IV haemorrhoids (require surgery), acutely thrombosed piles, or inflammatory bowel disease. * **Complications:** Prostatic abscess or hematuria (if injected too deeply/anteriorly), and localized pain or sloughing. * **Best for:** Grade I haemorrhoids presenting with bleeding.

Question 64: A patient with external hemorrhoids develops pain while passing stools and was advised a Sitz Bath. Which of the following statements about Sitz Baths is false?

A. Relieves congestion and edema.
B. Reduces pain.
C. Sitz baths can be advised for patients with fissure-in-ano.
D. A Sitz bath involves sitting in a basin containing warm water. (Correct Answer)

Explanation: ### Explanation The correct answer is **D**, because the statement is technically incomplete/incorrect in the context of standard surgical practice. While a Sitz bath involves sitting in warm water, the therapeutic efficacy depends on the **temperature** and the **duration** (usually 10–15 minutes). In many clinical definitions, a Sitz bath is specifically defined as sitting in warm water *up to the hips* or *pelvic region*, often using a specialized basin that fits over a toilet seat, but the "false" nature of this option in competitive exams often hinges on it being a purely symptomatic treatment rather than a curative procedure, or more commonly, that the water should be "warm" (37-40°C) and not "hot" to avoid burns and reflex vasodilation. **Analysis of Options:** * **A & B (Relieves congestion, edema, and pain):** These are **true**. The warm water promotes vasodilation, which improves local blood circulation, reduces tissue edema, and relaxes the internal anal sphincter. This relaxation significantly alleviates the "spasm-pain-spasm" cycle associated with anal pathologies. * **C (Advised for fissure-in-ano):** This is **true**. Sitz baths are a cornerstone of conservative management for acute anal fissures as they help relax the hypertonic internal sphincter, promoting healing. * **D (The "False" Statement):** In the context of NEET-PG, this is often marked as the answer because a Sitz bath is not merely "sitting in a basin"; it is a specific therapeutic procedure. Some texts also emphasize that it should be "plain" warm water without additives (like povidone-iodine), which can cause dermatitis. **Clinical Pearls for NEET-PG:** * **Temperature:** Ideal temperature is **37°C to 40°C**. * **Mechanism:** The primary benefit in fissures is the **reduction of resting anal pressure** (sphincter relaxation). * **Indications:** Post-hemorrhoidectomy, anal fissures, perianal abscess (post-drainage), and painful external hemorrhoids. * **Contraindication:** Acute inflammation where heat might aggravate the condition, though this is rare in perianal cases.

Question 65: What is the commonest cause of significant lower gastrointestinal bleeding in a middle-aged person without any known precipitating factor?

A. Ulcerative colitis
B. Ischemic colitis
C. Angiodysplasia
D. Diverticulum of the sigmoid colon (Correct Answer)

Explanation: **Explanation:** **Diverticulosis (Diverticulum of the sigmoid colon)** is the most common cause of significant (painless, brisk) lower gastrointestinal (LGI) bleeding in adults, particularly in middle-aged and elderly populations. The bleeding occurs because the diverticulum forms at the site where the *vasa recta* (nutrient arteries) penetrate the muscularis layer. Over time, these vessels become draped over the dome of the diverticulum, separated from the lumen only by a thin layer of mucosa. Chronic stress leads to eccentric thickening of the vessel and eventual rupture into the colonic lumen. **Analysis of Incorrect Options:** * **Ulcerative Colitis:** Typically presents with bloody diarrhea, mucus, and tenesmus rather than sudden, massive, painless hematochezia. * **Ischemic Colitis:** Usually presents with sudden onset abdominal pain followed by bloody diarrhea in patients with cardiovascular risk factors. The bleeding is rarely "significant" or massive. * **Angiodysplasia:** These are ectatic vascular lesions. While a common cause of LGI bleeding in the elderly (usually >65 years), it is statistically less common than diverticulosis and often presents as occult blood loss or chronic anemia. **Clinical Pearls for NEET-PG:** * **Most common site for Diverticula:** Sigmoid colon (due to high intraluminal pressure). * **Most common site for Diverticular Bleeding:** Right colon (Diverticula are more common on the left, but those on the right are wider and have more exposed vasa recta, making them more prone to bleed). * **Management:** 70–80% of diverticular bleeds stop spontaneously with conservative management. * **Gold Standard Investigation (Acute Bleed):** Colonoscopy (diagnostic and potentially therapeutic). If bleeding is too rapid, CT Angiography is preferred.

Question 66: Saw-tooth appearance on barium enema is characteristic of which condition?

A. Carcinoma of the colon
B. Ulcerative colitis
C. Crohn's disease
D. Diverticular disease (Correct Answer)

Explanation: **Explanation:** The **"Saw-tooth appearance"** on a barium enema is a classic radiological sign of **Diverticular disease** (specifically diverticulosis/diverticulitis). This appearance is caused by two main factors: 1. **Circular Muscle Hypertrophy:** Chronic high intraluminal pressure leads to thickening and shortening of the circular muscle fibers (myochosis). 2. **Mucosal Redundancy:** The thickened muscle causes the overlying mucosa to bunch up into folds, while the multiple diverticular outpouchings create irregular indentations along the bowel wall, mimicking the teeth of a saw. **Analysis of Incorrect Options:** * **Carcinoma of the colon:** Typically presents with an **"Apple-core deformity"** (napkin-ring sign) due to annular constriction of the lumen by a malignant mass. * **Ulcerative colitis:** In chronic cases, the loss of haustrations and bowel shortening leads to a **"Lead-pipe"** or **"Stove-pipe"** appearance. * **Crohn’s disease:** Characterized by a **"String sign of Kantor"** (terminal ileal narrowing), **"Cobblestone appearance"** (deep longitudinal ulcers), and "Rose-thorn ulcers." **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Sigmoid colon (due to the narrowest diameter and highest intraluminal pressure). * **Investigation of Choice (Acute Diverticulitis):** Contrast-Enhanced CT (CECT). Barium enema and colonoscopy are **contraindicated** in the acute phase due to the risk of perforation. * **Hinchey Classification:** Used to grade the severity of diverticulitis based on CT findings (Stage I: Pericolic abscess; Stage IV: Fecal peritonitis).

Question 67: Which of the following statements is true regarding Familial adenomatous polyposis (FAP)?

A. It is an autosomal recessive trait.
B. It is less common than Hereditary nonpolyposis colorectal cancer (HNPCC). (Correct Answer)
C. Colorectal cancer develops in all patients before age 20.
D. The genetic mutation is typically found on chromosome 12.

Explanation: **Explanation:** **Familial Adenomatous Polyposis (FAP)** is a high-penetrance syndrome characterized by the development of hundreds to thousands of adenomatous polyps in the colon and rectum. 1. **Why Option B is correct:** HNPCC (Lynch Syndrome) is the most common form of hereditary colorectal cancer, accounting for approximately **3–5%** of all colorectal cancers. In contrast, FAP is much rarer, accounting for less than **1%** of cases. 2. **Why other options are incorrect:** * **Option A:** FAP is an **autosomal dominant** trait, not recessive. Offspring of an affected parent have a 50% chance of inheriting the mutation. * **Option C:** While polyps begin to appear in the second decade of life, the risk of malignancy reaches 100% by age **40–50** if left untreated. It is rare for cancer to develop in *all* patients before age 20, though screening starts early (age 10–12). * **Option D:** The genetic defect in FAP is a mutation in the **APC (Adenomatous Polyposis Coli) gene**, which is located on the long arm of **chromosome 5 (5q21)**. Chromosome 12 is associated with KRAS mutations. **High-Yield Clinical Pearls for NEET-PG:** * **Gardner Syndrome:** FAP + Extra-colonic manifestations (Osteomas of the mandible/skull, epidermoid cysts, and desmoid tumors). * **Turcot Syndrome:** FAP + CNS tumors (specifically Medulloblastoma). * **Management:** The gold standard treatment is **Proctocolectomy with Ileal Pouch-Anal Anastomosis (IPAA)**, typically performed in the late teens or early twenties. * **CHRPE:** Congenital Hypertrophy of Retinal Pigment Epithelium is a specific extra-colonic sign seen on fundoscopy in FAP patients.

Question 68: Which of the following is NOT true about solitary rectal ulcer syndrome?

A. Increased muscle layer proliferation
B. Crypt distortion
C. Lamina propria infiltration with lymphocytes (Correct Answer)
D. Subepithelial fibrosis

Explanation: **Explanation:** Solitary Rectal Ulcer Syndrome (SRUS) is a chronic, benign disorder often associated with pelvic floor dyssynergia and rectal prolapse. The hallmark histological feature of SRUS is **fibromuscular obliterans**, which distinguishes it from inflammatory conditions. **Why Option C is correct:** In SRUS, the lamina propria is characterized by **fibroblast proliferation and collagen deposition** (fibrosis) rather than an acute or chronic inflammatory infiltrate. Therefore, **lamina propria infiltration with lymphocytes** is NOT a feature of SRUS; instead, it is characteristic of Inflammatory Bowel Disease (IBD) or infectious colitis. **Analysis of Incorrect Options:** * **Option A (Increased muscle layer proliferation):** This is a classic feature. Hypertrophy and extension of the muscularis mucosae fibers upward into the lamina propria (fibromuscular hyperplasia) are diagnostic. * **Option B (Crypt distortion):** Chronic mucosal injury and repeated cycles of prolapse lead to architectural changes, including crypt distortion, branching, and shortening. * **Option C (Subepithelial fibrosis):** As part of fibromuscular obliterans, the replacement of the normal lamina propria with collagen and fibroblasts (fibrosis) is a defining pathological finding. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** Most common in young adults; symptoms include straining, rectal bleeding, mucoid discharge, and a feeling of incomplete evacuation. * **Location:** Despite the name, ulcers are not always "solitary" (can be multiple) or "ulcerated" (can appear as polypoid or erythematous lesions). They are typically located on the **anterior rectal wall**, 5–10 cm from the anal verge. * **Pathogenesis:** Primarily due to **ischemia** caused by mucosal prolapse and direct trauma from digital evacuation. * **Diagnosis:** Histopathology is the gold standard to rule out malignancy and IBD. Look for the keyword **"Fibromuscular Obliterans."**

Question 69: Which of the following are associated with an increased risk of colorectal cancer?

A. More intake of animal fat, Aspirin, and Amoebic colitis
B. Aspirin, Ulcerative colitis, and Amoebic colitis
C. Ulcerative colitis, Amoebic colitis, and Polyps
D. More intake of animal fat, Ulcerative colitis, and Polyps (Correct Answer)

Explanation: ### Explanation Colorectal cancer (CRC) is a multifactorial disease influenced by dietary habits, chronic inflammatory states, and precursor neoplastic lesions. **1. Why Option D is Correct:** * **Animal Fat:** High intake of red meat and animal fats increases bile acid secretion. These are converted by gut bacteria into secondary bile acids (like lithocholic acid), which are co-carcinogenic. Furthermore, high-fat diets are often low in protective fiber. * **Ulcerative Colitis (UC):** Chronic inflammation leads to increased cell turnover and oxidative stress, promoting the "dysplasia-carcinoma sequence." The risk increases significantly 8–10 years after diagnosis and with greater colonic involvement (pancolitis). * **Polyps:** Specifically adenomatous polyps (villous > tubulovillous > tubular) and sessile serrated lesions are direct precursors to CRC. **2. Why Other Options are Incorrect:** * **Aspirin:** Contrary to being a risk factor, **Aspirin and NSAIDs are protective**. They inhibit the COX-2 enzyme, which is overexpressed in many colorectal adenomas and cancers, thereby reducing cell proliferation. * **Amoebic Colitis:** This is an infectious etiology caused by *Entamoeba histolytica*. Unlike Ulcerative Colitis or Crohn’s disease, it does not cause chronic dysplastic changes and is **not** associated with an increased risk of malignancy. **3. NEET-PG High-Yield Pearls:** * **Dietary Protective Factors:** High fiber, Calcium, Vitamin D, and Selenium. * **Most Common Site:** Historically the rectum; however, there is a rising trend in right-sided (proximal) colon cancers. * **Genetic Syndromes:** Lynch Syndrome (HNPCC) is the most common inherited CRC syndrome (DNA mismatch repair gene mutation). * **Pre-malignant Polyps:** Villous adenomas have the highest malignant potential (up to 40%).

Question 70: A 74-year-old woman presents with 3 weeks of left lower quadrant abdominal pain, changes in bowel habits, and intermittent fever. Her temperature is 38°C (101°F), respirations are 19 per minute, and blood pressure is 130/80 mm Hg. Physical examination shows left lower quadrant tenderness. A CBC reveals neutrophilia. An abdominal-pelvic ultrasound examination is normal. Which of the following is the most likely diagnosis?

A. Appendicitis
B. Diverticulitis (Correct Answer)
C. Ovarian carcinoma
D. Renal colic

Explanation: **Explanation:** The clinical presentation of **left lower quadrant (LLQ) pain**, fever, and altered bowel habits in an elderly patient is the classic triad for **Acute Diverticulitis**, often referred to as "Left-sided Appendicitis." **Why Diverticulitis is Correct:** Diverticulitis occurs when a diverticulum (herniation of mucosa through the muscularis layer) becomes obstructed or perforated, leading to inflammation. The patient’s age (74), localized LLQ tenderness, fever, and neutrophilia (leukocytosis) are hallmark signs. While ultrasound is often the first-line investigation in some settings, **Contrast-Enhanced CT (CECT)** is the gold standard for diagnosis and staging (Hinchey Classification). **Why Other Options are Incorrect:** * **Appendicitis:** Typically presents with periumbilical pain migrating to the **Right Lower Quadrant (RLQ)**. While "situs inversus" or a long pelvic appendix can cause left-sided pain, it is far less common in this age group than diverticulitis. * **Ovarian Carcinoma:** Usually presents subacutely with bloating, weight loss, or an adnexal mass. It does not typically cause acute fever and neutrophilia unless there is torsion or rupture. * **Renal Colic:** Characterized by sudden, excruciating "loin to groin" paroxysmal pain and hematuria. It generally does not present with fever or neutrophilia unless complicated by an infection (pyelonephritis). **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** CECT of the Abdomen/Pelvis. * **Contraindication:** Colonoscopy and Barium Enema are **strictly contraindicated** in the acute phase due to the high risk of perforation. * **Most Common Site:** Sigmoid Colon (due to high intraluminal pressure). * **Management:** Uncomplicated cases are managed with bowel rest and antibiotics; complicated cases (abscess, perforation) may require drainage or a **Hartmann’s Procedure**.

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

Practice Questions

Rectal Prolapse

Practice Questions

Fecal Incontinence

Practice Questions

Intestinal Stomas Creation and Management

Practice Questions

Pelvic Floor Disorders

Practice Questions

Enhanced Recovery After Colorectal Surgery

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