Colorectal Surgery Practice Questions

Q: A 60-year-old man presents with progressive fatigue. Laboratory results reveal microcytic anemia, and a colonoscopy shows a mass. Which type of colon cancer is most commonly associated with this presentation?

Ascending colon carcinoma. ***Ascending colon carcinoma*** - Carcinomas in the **right (ascending) colon** often present with **occult bleeding** leading to **iron deficiency anemia** (microcytic anemia), and subtle symptoms like fatigue, making them harder to detect until advanced [1]. - The wider lumen and more liquid stool in the ascending colon allow tumors to grow larger before causing obstructive symptoms [1]. *Sigmoid colon carcinoma* - **Sigmoid colon cancers** are distal and typically present with symptoms related to **obstruction**, changes in bowel habits, or more overt rectal bleeding due to the narrower lumen and more formed stool [1]. - While they can cause anemia, it's less commonly the sole or primary presenting symptom compared to right-sided lesions [1]. *Rectal carcinoma* - **Rectal cancers** commonly present with symptoms such as **hematochezia** (bright red blood per rectum), tenesmus, or changes in stool caliber [1]. - While they can also lead to anemia, their proximity to the anus often causes more immediate and noticeable bleeding symptoms [1]. *Descending colon carcinoma* - Similar to sigmoid colon cancers, **descending colon carcinomas** tend to cause symptoms related to **partial obstruction**, such as changes in bowel habits, abdominal pain, or tenesmus. - They are less frequently associated with occult bleeding and microcytic anemia as the primary presentation compared to right-sided lesions.

Q: A 70-year-old male presents with abdominal pain and weight loss. A barium enema shows an 'apple core' lesion. What is the most likely diagnosis?

Colon cancer. ***Colon cancer*** - An **'apple core' lesion** on a barium enema is a classic radiographic sign highly suggestive of an obstructing **colorectal carcinoma** [1]. - The patient's age combined with **abdominal pain** and **weight loss** are common symptoms of advanced colon cancer [1]. *Diverticulosis* - Characterized by the presence of **diverticula** (outpouchings) in the colon, which are not typically associated with an 'apple core' lesion. - While diverticulosis can cause abdominal pain, **weight loss** is not a common associated symptom. *Crohn's disease* - Often presents with **skip lesions**, **transmural inflammation**, and sometimes **strictures**, but not typically an 'apple core' appearance [2]. - While it can cause abdominal pain and weight loss, it is more common in younger patients and has distinct endoscopic and histological features [2]. *Ulcerative colitis* - Involves **continuous inflammation** of the colon, starting from the rectum, and is characterized by mucosal rather than transmural involvement. - It does not present with an 'apple core' lesion and often causes bloody diarrhea, which is not mentioned in this case.

Q: Treatment of choice for low fistula in ano?

Fistulotomy. ***Fistulotomy*** - **Fistulotomy** is the treatment of choice for **low fistula-in-ano** because it offers the highest success rate (>90%) with minimal risk of incontinence. - This procedure involves laying open the fistula tract, allowing it to heal from the inside out. - Low fistulas involve <30% of the external sphincter, making fistulotomy safe and effective. *Seton placement* - **Seton placement** is a technique where a thread or drain is placed through the fistula tract. - It is typically reserved for **high or complex fistulas** that involve a significant portion of the sphincter, where immediate fistulotomy would risk incontinence. - For simple low fistulas, seton placement is unnecessary and delays definitive treatment. *Intravenous antibiotics* - **Antibiotics** are primarily used to treat **acute infections** or abscesses associated with fistulas, but they do not resolve the fistula tract itself. - A fistula-in-ano is a chronic condition that requires **surgical intervention** for definitive cure. *Staged surgical resection* - **Staged procedures** or complex repairs (e.g., advancement flaps, LIFT procedure) are typically reserved for **high fistulas** or recurrent cases involving significant sphincter muscle. - For low fistulas, the simpler **fistulotomy** is usually sufficient and safer.

Q: Which of the following is NOT a contraindication for colostomy planning?

Age > 60 yrs. ***Age > 60 yrs*** - While older patients may have more comorbidities, advanced age alone is generally **not an absolute contraindication** for colostomy planning or ostomy surgery. - The decision is based on the patient's overall health and ability to manage the stoma, not solely their age. *Stoma near skin creases and bony prominences* - Placing a stoma in these areas can **impair the seal of the ostomy appliance**, leading to leaks, skin irritation, and discomfort. - Such locations are therefore considered **contraindicated** to ensure proper stoma function and patient comfort. *Poorly motivated patient for elective stoma* - A patient's motivation and ability to learn stoma care are crucial for managing an ostomy successfully. - Poor motivation can lead to **neglect of stoma care**, resulting in complications like skin breakdown, infection, and social isolation. *Stomas through previous scars* - Positioning a stoma through a previous surgical scar increases the risk of **compromised healing**, **hernia formation**, and **stomal stenosis**. - Scar tissue may also make appliance adherence difficult, leading to leaks and skin issues.

Q: What is the critical diameter of the caecum when perforation is considered imminent in pseudo-obstruction?

9 cm. ***9 cm*** - A cecal diameter of **9-12 cm** is the critical threshold beyond which the risk of **perforation** in pseudo-obstruction becomes imminent. - This is based on **Laplace's Law**: wall tension is proportional to radius, making larger diameter bowel more susceptible to perforation. - At 9 cm, aggressive management including decompression should be strongly considered to prevent perforation. *7 cm* - While representing colonic dilatation, **7 cm** is below the critical threshold for imminent perforation. - This diameter typically warrants monitoring but does not necessitate immediate aggressive intervention. *8 cm* - A cecal diameter of **8 cm** indicates significant dilatation with increased risk. - Usually managed with close observation and conservative measures before considering urgent decompression. - Perforation risk rises sharply as diameter approaches 9 cm. *10 cm* - A diameter of **10 cm** definitely signifies imminent perforation risk requiring immediate intervention. - However, **9 cm** is recognized as the lower end of the critical range where aggressive management should be initiated to prevent perforation. - The critical range is generally considered **9-12 cm**.

Q: According to Goodsall's rule, what is the distance from the anal margin that indicates an exception to the rule?

3 cm. ***3 cm*** - Goodsall's rule states that fistulas with external openings located **more than 3 cm** from the anal margin are **exceptions to the rule**. - This is the **classical teaching** described in standard surgical textbooks (Bailey & Love's, Schwartz's Principles of Surgery). - At distances **>3 cm**, the fistula tract tends to take a **radial (direct) course** to the nearest crypt at the dentate line, regardless of whether it is anterior or posterior. - These distant fistulas do not follow the typical anterior-radial/posterior-curved pattern of Goodsall's rule. *1 cm* - This distance is very close to the anal margin and falls well within the range where Goodsall's rule applies accurately. - Fistulas at 1 cm follow the standard rule: anterior openings → radial tract; posterior openings → curved tract to posterior midline. *4 cm* - While 4 cm is beyond the 3 cm exception threshold, it is not the specific distance that defines the classical exception to Goodsall's rule. - The standard teaching specifically identifies **3 cm** as the cutoff distance. *5 cm* - Although fistulas at 5 cm would certainly not follow Goodsall's rule, this is not the classical cutoff distance taught in surgical literature. - The exception threshold is **3 cm**, not 5 cm.

Q: Colonoscopy is not indicated in which of the following conditions?

Multiple Endocrine Neoplasia type 2B. ***Multiple Endocrine Neoplasia type 2B*** - **MEN 2B** is characterized by **medullary thyroid carcinoma**, **pheochromocytoma**, and specific features such as **mucosal neuromas** and a marfanoid habitus, but it does **not involve colonic polyps or an increased risk of colorectal cancer** that would necessitate colonoscopy. - While gastrointestinal manifestations like ganglioneuromatosis may be present, **routine colonoscopy screening** is not indicated in this syndrome as there is no increased colorectal cancer risk. *Familial Adenomatous Polyposis* - **FAP** is an autosomal dominant disorder characterized by the development of hundreds to thousands of **colorectal adenomatous polyps**, which have an almost 100% risk of progressing to **colorectal cancer** if untreated. - **Regular colonoscopic surveillance** and eventual colectomy are essential for managing this condition due to the high malignancy risk. *Hereditary Nonpolyposis Colorectal Cancer* - Also known as **Lynch syndrome**, HNPCC is characterized by an increased risk of **colorectal cancer** and other extra-colonic cancers (e.g., endometrial, ovarian) due to germline mutations in **mismatch repair genes**. - **Colonoscopy is crucial** for early detection and prevention of colorectal cancer in affected individuals, typically starting at age 20-25 years or 2-5 years before the youngest family member was diagnosed. *Peutz-Jeghers Syndrome* - **Peutz-Jeghers Syndrome** is an autosomal dominant condition characterized by **hamartomatous polyps** throughout the gastrointestinal tract and mucocutaneous pigmentation (melanotic macules on lips, oral mucosa, and digits). - These polyps have **malignant potential** with increased risk of gastrointestinal and extra-intestinal cancers (breast, ovarian, pancreatic). - **Regular colonoscopic surveillance** is recommended starting from late teens or early 20s for polyp detection and removal.

Q: How is an anal fissure typically diagnosed?

Clinical examination. ***Clinical examination*** - An anal fissure is typically diagnosed by visual inspection during a **physical examination** of the perianal area. - The fissure appears as a **linear tear or crack** in the anoderm, often at the posterior midline. *Transrectal ultrasound (TRUS)* - TRUS is primarily used for assessing conditions like **prostate cancer** or abnormalities of the rectal wall and sphincter complex. - It is not the initial or routine diagnostic tool for a basic anal fissure. *Colonoscopy examination* - Colonoscopy is an invasive procedure used to visualize the entire colon and is indicated for conditions like **colorectal cancer screening**, inflammatory bowel disease, or unexplained bleeding from higher up in the colon. - It is not necessary for the diagnosis of a visible anal fissure. *Barium enema* - A barium enema is a radiographic study used to visualize the **large intestine** for polyps, tumors, or structural changes. - It is not suitable for directly visualizing or diagnosing a superficial anal tear.

Q: Recurrent anal fistula, what is the most appropriate investigation?

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** provides excellent soft tissue contrast, allowing for precise visualization of the entire fistula tract, its relationship to the sphincter muscles, and any secondary extensions or abscesses. - For **recurrent anal fistulas**, MRI is particularly valuable in identifying complex anatomy, missed tracts, or undrained collections that can lead to recurrence. *Endorectal Ultrasound* - While useful for initial assessment of **simple anal fistulas**, endorectal ultrasound may have limitations in fully mapping **complex or recurrent tracts**, especially those extending cranially or involving high transsphincteric components. - Its accuracy can be operator-dependent and may not provide the detailed global view of the anatomical planes that MRI offers. *Flexible Sigmoidoscopy* - **Flexible sigmoidoscopy** is primarily used to examine the **mucosa of the sigmoid colon and rectum** for inflammatory bowel disease or other mucosal abnormalities, which might be associated with fistula formation. - It does not directly visualize the **extramural fistula tract** or its relation to the sphincter complex. *Rigid Proctoscopy* - **Rigid proctoscopy** provides a macroscopic view of the **anal canal and lower rectum** to identify the internal opening of a fistula, if visible. - It cannot adequately assess the **depth and complexity of the fistula tract** within the sphincter muscles or beyond, making it less suitable for recurrent cases where thorough mapping is crucial.

Q: Which of the following statements is least common regarding angiodysplasia of the colon?

Involvement of rectum in 50% of cases. ***Involvement of rectum in 50% of cases*** - Angiodysplasia typically does not involve the **rectum** as frequently, with most cases occurring in the colon [1]. - This statement does not reflect the true distribution pattern of angiodysplasia, which is more common in the **right colon** [1]. *Affecting age group > 40 yrs.* - Angiodysplasia is commonly seen in patients **over 40 years** of age, usually presenting after the sixth decade of life [1]. - This is due to **vascular degeneration** processes that occur with aging, making it a frequent finding in this demographic. *Involvement of cecum* - The **cecum** is actually one of the most common sites for angiodysplasia in the colon [1]. - This contributes significantly to the overall occurrence of angiodysplastic lesions in patients. *Cause of troublesome lower G.I. hemorrhage* - Angiodysplasia is indeed a significant cause of **lower gastrointestinal bleeding**, accounting for 20% of major episodes of lower intestinal bleeding [1]. - It can cause **intermittent bleeding** or acute and massive hemorrhage, contributing to anemia and requiring medical intervention [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 787-789.

Question 1

A 60-year-old man presents with progressive fatigue. Laboratory results reveal microcytic anemia, and a colonoscopy shows a mass. Which type of colon cancer is most commonly associated with this presentation?

Accepted Answer

Ascending colon carcinoma

Answer

Sigmoid colon carcinoma

Answer

Rectal carcinoma

Answer

Descending colon carcinoma

Question 2

A 70-year-old male presents with abdominal pain and weight loss. A barium enema shows an 'apple core' lesion. What is the most likely diagnosis?

Accepted Answer

Colon cancer

Answer

Diverticulosis

Answer

Crohn's disease

Answer

Ulcerative colitis

Question 3

Treatment of choice for low fistula in ano?

Accepted Answer

Fistulotomy

Answer

Seton placement

Answer

Intravenous antibiotics

Answer

Staged surgical resection

Question 4

Which of the following is NOT a contraindication for colostomy planning?

Accepted Answer

Age > 60 yrs

Answer

Stoma near skin creases and bony prominences

Answer

Stomas through previous scars

Answer

Poorly motivated patient for elective stoma

Question 5

What is the critical diameter of the caecum when perforation is considered imminent in pseudo-obstruction?

Accepted Answer

9 cm

Answer

7 cm

Answer

8 cm

Answer

10 cm

Question 6

According to Goodsall's rule, what is the distance from the anal margin that indicates an exception to the rule?

Accepted Answer

3 cm

Answer

1 cm

Answer

5 cm

Answer

4 cm

Question 7

Colonoscopy is not indicated in which of the following conditions?

Accepted Answer

Multiple Endocrine Neoplasia type 2B

Answer

Familial Adenomatous Polyposis

Answer

Hereditary Nonpolyposis Colorectal Cancer

Answer

Peutz-Jeghers Syndrome

Question 8

How is an anal fissure typically diagnosed?

Accepted Answer

Clinical examination

Answer

Transrectal ultrasound (TRUS)

Answer

Colonoscopy examination

Answer

Barium enema

Question 9

Recurrent anal fistula, what is the most appropriate investigation?

Accepted Answer

MRI

Answer

Endorectal Ultrasound

Answer

Flexible Sigmoidoscopy

Answer

Rigid Proctoscopy

Question 10

Which of the following statements is least common regarding angiodysplasia of the colon?

Accepted Answer

Involvement of rectum in 50% of cases

Answer

Involvement of cecum

Answer

Cause of troublesome lower G.I. hemorrhage

Answer

Affecting age group > 60 yrs.

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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