Colorectal Surgery Practice Questions

Q: A 65-year-old man with chronic constipation and a history of psychiatric illness presents to the emergency department with sudden-onset abdominal distension, absolute constipation for 48 hours, and colicky central abdominal pain. His abdomen is tympanitic on percussion. Vital signs are stable. The plain erect abdominal X-ray is shown in Image 2. There is no peritonism on examination. What is the most appropriate initial management?

A. Rigid sigmoidoscopy and flatus tube decompression. ***A. Rigid sigmoidoscopy and flatus tube decompression*** - This patient presents with signs of **sigmoid volvulus**, characterized by the **"coffee-bean" sign** on X-ray, chronic constipation, and a history of psychiatric illness (possibly related to neuroleptic use). - In a **hemodynamically stable** patient without signs of **peritonitis** or intestinal ischemia, the first-line management is **non-operative decompression** using rigid sigmoidoscopy and insertion of a flatus tube. *B. Emergency Hartmann's procedure* - This is an invasive surgical procedure reserved for cases with evidence of **bowel gangrene**, **perforation**, or when endoscopic decompression is unsuccessful. - Performing an **emergency resection** as the first step in a stable patient increases morbidity unnecessarily compared to initial decompression. *C. Gastrografin enema to confirm and treat the obstruction* - While **Gastrografin enemas** are useful in diagnosing and treating **distal large bowel obstruction** or pseudo-obstruction, they are not the gold standard for managing volvulus. - Decompression via a **rectal tube** is more direct and effective for relieving the high-pressure gas accumulation in a sigmoid loop. *D. Colonoscopic decompression under general anaesthesia* - Flexible **colonoscopic decompression** is a secondary option if rigid sigmoidoscopy fails, but it does not typically require **general anesthesia**. - Starting with a complex procedure under anesthesia is inappropriate when **bedside rigid sigmoidoscopy** is less invasive and highly successful.

Q: A 62-year-old woman presents with a 4-month history of altered bowel habit, passage of blood mixed with stool, and a 6 kg unintentional weight loss. Colonoscopy was attempted but could not be completed due to a near-obstructing lesion in the descending colon. Her haemoglobin is 9.2 g/dL with a microcytic picture. She is clinically stable with no abdominal distension, peritonitis, or complete bowel obstruction. The barium enema is shown in Image 1. Staging CT confirms the lesion is confined to the bowel wall with no nodal or distant metastases (T2N0M0). Which of the following is the most appropriate surgical procedure?

A. Left hemicolectomy with primary anastomosis. ***A. Left hemicolectomy with primary anastomosis*** - This is the procedure of choice for a **localized tumor (T2N0M0)** of the **descending colon** in a stable, elective setting, allowing for curative resection and immediate restoration of bowel continuity. - The patient's lack of **peritonitis** or **acute complete obstruction** makes a primary anastomosis safe and appropriate for re-establishing the GI tract. *B. Hartmann's procedure with end colostomy* - This approach is typically reserved for **emergency settings**, such as **perforated diverticulitis** or fecal peritonitis, where a primary anastomosis would be unsafe. - Since the patient is clinically stable and undergoing a semi-elective procedure, a **permanent or temporary stoma** is not necessary as the first-line surgical option. *C. Abdominoperineal resection with permanent colostomy* - This procedure is specifically indicated for **low rectal cancers** that involve or are very close to the **anal sphincter** mechanism. - It is not anatomically relevant for a lesion located in the **descending colon**, which is significantly more proximal. *D. Transverse loop colostomy as definitive palliation* - This is a **palliative procedure** used to bypass an unresectable or obstructing lesion in patients who are not candidates for curative surgery. - The CT staging (T2N0M0) indicates the lesion is **resectable and localized**, making curative surgery with a **left hemicolectomy** the standard of care over simple diversion.

Q: Why should acute mechanical large bowel obstruction be operated on early?

Early gangrene and perforation. ### Explanation The primary reason for early surgical intervention in acute mechanical large bowel obstruction (LBO) is to prevent **early gangrene and perforation**, specifically at the **cecum**. #### 1. Why the Correct Answer is Right: The large bowel acts as a "closed loop" if the ileocecal valve is competent (found in 50-60% of cases). According to **Laplace’s Law** ($Pressure = Tension / Radius$), the tension is highest where the diameter is greatest. Since the cecum has the largest diameter in the colon, it is the most common site for ischemic necrosis and perforation. A cecal diameter **>10–12 cm** is a critical warning sign of impending perforation, necessitating urgent surgery to prevent fecal peritonitis, which carries a high mortality rate. #### 2. Why Other Options are Incorrect: * **A & B:** While electrolyte imbalances and septicemia occur, they are usually **late manifestations** or consequences of ischemia/perforation. In LBO, the colon's primary function is water absorption; thus, massive third-space loss is slower compared to small bowel obstruction. * **D:** Respiratory embarrassment due to diaphragmatic splinting occurs in massive distension (e.g., sigmoid volvulus), but it is rarely the primary indication for emergency surgery compared to the risk of bowel death. #### 3. Clinical Pearls for NEET-PG: * **Most common cause of LBO:** Colorectal Carcinoma (followed by Diverticulitis and Volvulus). * **Ogilvie’s Syndrome:** Pseudo-obstruction (no mechanical cause) that can also lead to cecal perforation; treated initially with Neostigmine. * **Bird’s Beak Sign:** Classic radiological finding in Sigmoid Volvulus. * **Management Priority:** If the cecum is distended and tender, it is a surgical emergency.

Question 1

A 65-year-old male with chronic constipation and a history of psychiatric institutionalisation presents with sudden-onset abdominal distension and absolute constipation for 48 hours. He has mild diffuse tenderness without peritoneal signs. HR 102 bpm, BP 118/74 mmHg, afebrile. His plain abdominal X-ray is shown (Image 1). What is the most appropriate next step in management?

Accepted Answer

B. Flexible sigmoidoscopic decompression followed by elective sigmoid resection

Answer

A. Emergency laparotomy and sigmoid resection with end colostomy

Answer

C. Urgent contrast enema to confirm the level of obstruction before any intervention

Answer

D. Nasogastric decompression and intravenous neostigmine infusion

Question 2

A 65-year-old man with chronic constipation and a history of psychiatric illness presents to the emergency department with sudden-onset abdominal distension, absolute constipation for 48 hours, and colicky central abdominal pain. His abdomen is tympanitic on percussion. Vital signs are stable. The plain erect abdominal X-ray is shown in Image 2. There is no peritonism on examination. What is the most appropriate initial management?

Accepted Answer

A. Rigid sigmoidoscopy and flatus tube decompression

Answer

B. Emergency Hartmann's procedure

Answer

C. Gastrografin enema to confirm and treat the obstruction

Answer

D. Colonoscopic decompression under general anaesthesia

Question 3

A 62-year-old woman presents with a 4-month history of altered bowel habit, passage of blood mixed with stool, and a 6 kg unintentional weight loss. Colonoscopy was attempted but could not be completed due to a near-obstructing lesion in the descending colon. Her haemoglobin is 9.2 g/dL with a microcytic picture. She is clinically stable with no abdominal distension, peritonitis, or complete bowel obstruction. The barium enema is shown in Image 1. Staging CT confirms the lesion is confined to the bowel wall with no nodal or distant metastases (T2N0M0). Which of the following is the most appropriate surgical procedure?

Accepted Answer

A. Left hemicolectomy with primary anastomosis

Answer

B. Hartmann's procedure with end colostomy

Answer

C. Abdominoperineal resection with permanent colostomy

Answer

D. Transverse loop colostomy as definitive palliation

Question 4

A 60-year-old male presented with bleeding per rectum. On digital rectal examination, a growth was palpable at the tip of the index finger. Sigmoidoscopy revealed an ulcero-proliferative growth located 6 cm from the anal verge. CECT showed no involvement of the liver or lungs. Following chemoradiation, what is the next best step in management?

Accepted Answer

Low anterior resection

Answer

Observation and follow-up

Answer

Abdominoperineal resection

Answer

Haman's procedure

Question 5

Why should acute mechanical large bowel obstruction be operated on early?

Accepted Answer

Early gangrene and perforation

Answer

Electrolyte imbalance due to third space loss

Answer

Septicemia from absorption of bowel contents

Answer

Respiratory embarrassment from massive abdominal distension

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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