A 58-year-old woman presents to the emergency department with a 48-hour history of cramping abdominal pain and absolute constipation. She has a history of previous total abdominal hysterectomy for fibroids 5 years ago. On examination, her abdomen is distended with visible peristalsis, tympanic to percussion, and high-pitched bowel sounds are present. She is haemodynamically stable. CT abdomen shows dilated small bowel loops measuring 4.5 cm with a transition point in the pelvis and no free fluid. Initial management includes nil by mouth, intravenous fluids, and nasogastric tube insertion. What is the most appropriate next step in management?
Q32
A 52-year-old man with Crohn's disease presents with a 36-hour history of cramping abdominal pain, distension, and vomiting. He has had three previous laparotomies for Crohn's complications. CT shows transition point in the mid-ileum with proximal dilated loops measuring up to 4.5cm and collapsed distal bowel. There is no bowel wall thickening, no free fluid, and normal enhancement of the bowel wall. Lactate is 1.2 mmol/L. He is started on conservative management with nasogastric decompression and intravenous fluids. After 48 hours, his symptoms persist unchanged. What is the most appropriate next step in management?
Q33
A 75-year-old man undergoes emergency laparotomy for perforated sigmoid diverticulitis with faecal peritonitis. A Hartmann's procedure is performed. Post-operatively he develops progressive abdominal distension and AKI. On day 3 post-surgery, his intra-abdominal pressure measured via bladder catheter is 28 mmHg. He has oliguria despite adequate fluid resuscitation, peak airway pressures are increasing, and he is hypotensive requiring noradrenaline. What is the most appropriate management?
Q34
A 42-year-old woman presents with a 12-hour history of severe right upper quadrant pain. Ultrasound shows multiple gallstones, gallbladder wall thickening to 6mm, pericholecystic fluid, and a positive sonographic Murphy's sign. Her white cell count is 16.2 × 10⁹/L and CRP is 185 mg/L. She is haemodynamically stable and started on intravenous antibiotics. According to current evidence-based guidelines, when should definitive surgical management ideally be performed?
Q35
A 67-year-old man with a background of ischaemic heart disease, COPD, and type 2 diabetes presents with a 4-day history of left lower quadrant pain and fever. CT shows a 5cm pericolic abscess adjacent to the sigmoid colon with sigmoid diverticulitis (Hinchey grade II). He is haemodynamically stable. Which of the following represents the most appropriate initial management?
Q36
A 48-year-old woman presents with a 6-hour history of sudden onset severe epigastric pain radiating to the back. She has a history of recurrent acute pancreatitis. Examination reveals epigastric tenderness with guarding but no rebound. Her amylase is 145 U/L (normal <100). CT abdomen shows a 2cm fluid collection in the lesser sac with a small amount of free intraperitoneal fluid and subtle stranding around the pancreatic tail. There is no free air. What is the most likely diagnosis?
Q37
A 70-year-old man with a history of previous appendicectomy 40 years ago presents with a 72-hour history of colicky central abdominal pain, distension, and vomiting. Plain abdominal radiograph shows multiple dilated loops of small bowel with valvulae conniventes visible. He is haemodynamically stable with normal lactate. Conservative management with intravenous fluids and nasogastric decompression is initiated. After how many hours of conservative management would water-soluble contrast study be most appropriately performed to predict the need for surgery?
Q38
What is the physiological mechanism by which prolonged small bowel obstruction leads to metabolic alkalosis rather than metabolic acidosis in the early stages?
Q39
A 40-year-old man with ulcerative colitis on long-term azathioprine and prednisolone presents with a 24-hour history of severe generalized abdominal pain and fever. Examination reveals a temperature of 38.9°C, heart rate 125 bpm, blood pressure 95/60 mmHg, and a rigid, silent abdomen. Erect chest radiograph shows no free air. CT abdomen demonstrates thickening of the transverse colon with free intraperitoneal fluid but no pneumoperitoneum. Which mechanism best explains the absence of pneumoperitoneum in this clinical scenario?
Q40
A 58-year-old woman with a BMI of 52 kg/m² presents with a 48-hour history of severe epigastric pain, nausea, and bilious vomiting. CT abdomen demonstrates a closed-loop small bowel obstruction with fluid-filled dilated loops, mesenteric oedema, and reduced enhancement of the bowel wall. Laboratory investigations show white cell count 18.5 × 10⁹/L, lactate 4.8 mmol/L, and CRP 245 mg/L. What is the most appropriate immediate management?
Acute Surgical Presentations UK Medical PG Practice Questions and MCQs
Question 31: A 58-year-old woman presents to the emergency department with a 48-hour history of cramping abdominal pain and absolute constipation. She has a history of previous total abdominal hysterectomy for fibroids 5 years ago. On examination, her abdomen is distended with visible peristalsis, tympanic to percussion, and high-pitched bowel sounds are present. She is haemodynamically stable. CT abdomen shows dilated small bowel loops measuring 4.5 cm with a transition point in the pelvis and no free fluid. Initial management includes nil by mouth, intravenous fluids, and nasogastric tube insertion. What is the most appropriate next step in management?
A. Emergency laparotomy within 6 hours
B. Conservative management with water-soluble contrast study at 24 hours if no improvement (Correct Answer)
C. Immediate colonoscopic decompression
D. Diagnostic laparoscopy within 12 hours
E. CT-guided percutaneous drainage
Explanation: ***Conservative management with water-soluble contrast study at 24 hours if no improvement***
- This patient presents with **small bowel obstruction (SBO)**, likely **adhesional** given the prior hysterectomy, and is **haemodynamically stable** without signs of strangulation (no fever, tachycardia, or peritonism; CT shows no free fluid). **Conservative management** is the initial approach for uncomplicated SBO.
- A **water-soluble contrast study (e.g., Gastrografin)** is a crucial next step if conservative measures don't yield improvement within 24 hours. It can be both diagnostic, identifying the level and completeness of obstruction, and therapeutic due to its **hyperosmolar effect** which can help resolve the obstruction.
*Emergency laparotomy within 6 hours*
- **Emergency laparotomy** is indicated for SBO with signs of **strangulation**, **ischemia**, **perforation**, or clinical deterioration despite conservative management. These signs include fever, tachycardia, leukocytosis, metabolic acidosis, localized peritonitis, or imaging findings like pneumoperitoneum or bowel wall thickening/ischemia.
- The patient is **haemodynamically stable**, has no signs of peritonism, and the CT scan does not show features of strangulation or perforation (e.g., no free fluid, no compromised bowel wall), making immediate surgery unwarranted at this stage.
*Immediate colonoscopic decompression*
- **Colonoscopic decompression** is primarily used for **large bowel obstructions**, particularly conditions like **sigmoid volvulus** or **Ogilvie syndrome (acute colonic pseudo-obstruction)**.
- The patient's CT scan clearly indicates a **small bowel obstruction** (dilated small bowel loops, transition point in the pelvis), not a large bowel obstruction, rendering colonoscopy ineffective.
*Diagnostic laparoscopy within 12 hours*
- While laparoscopy can be used to diagnose and sometimes treat SBO, it is a surgical intervention. For a patient with **uncomplicated adhesional SBO** who is haemodynamically stable and has already started conservative management, immediate surgical exploration within 12 hours is not the most appropriate *next* step.
- Initial conservative management allows time for spontaneous resolution and avoids the risks associated with early surgery, such as **anesthesia complications** and potential for **new adhesion formation**.
*CT-guided percutaneous drainage*
- **CT-guided percutaneous drainage** is a procedure used to drain **fluid collections**, such as abscesses, pseudocysts, or symptomatic ascites.
- The CT findings in this case describe **dilated bowel loops** and a **transition point** indicating a mechanical obstruction, but explicitly state **no free fluid** or abscesses that would require drainage.
Question 32: A 52-year-old man with Crohn's disease presents with a 36-hour history of cramping abdominal pain, distension, and vomiting. He has had three previous laparotomies for Crohn's complications. CT shows transition point in the mid-ileum with proximal dilated loops measuring up to 4.5cm and collapsed distal bowel. There is no bowel wall thickening, no free fluid, and normal enhancement of the bowel wall. Lactate is 1.2 mmol/L. He is started on conservative management with nasogastric decompression and intravenous fluids. After 48 hours, his symptoms persist unchanged. What is the most appropriate next step in management?
A. Proceed to laparotomy for adhesiolysis (Correct Answer)
B. Commence total parenteral nutrition and continue conservative management
C. Perform diagnostic laparoscopy with planned conversion to laparotomy
D. Continue conservative management for another 48 hours as lactate remains normal
E. Administer water-soluble contrast and proceed to surgery if it doesn't reach colon in 24 hours
Explanation: ***Proceed to laparotomy for adhesiolysis***- Conservative management for **adhesive small bowel obstruction (SBO)** typically has a ceiling of **48–72 hours**; persistence of symptoms beyond this timeframe necessitates surgical intervention.- While the CT suggests no immediate **strangulation** (normal lactate/enhancement), the **complete obstruction** (collapsed distal bowel) and lack of improvement after 48 hours indicate spontaneous resolution is unlikely.*Commence total parenteral nutrition and continue conservative management*- **Total parenteral nutrition (TPN)** may be used for prolonged bowel rest, but it does not address the mechanical cause of a persistent **complete obstruction**.- Delaying surgery in the setting of persistent mechanical obstruction increases the risk of **ischaemic complications** and prolonged hospital stays.*Perform diagnostic laparoscopy with planned conversion to laparotomy*- The patient has had **three previous laparotomies**, which significantly increases the risk of **dense adhesions** making laparoscopy technically difficult and prone to bowel injury.- An open **laparotomy** is generally preferred in patients with a "hostile abdomen" from multiple prior surgeries to ensure safe and thorough **adhesiolysis**.*Continue conservative management for another 48 hours as lactate remains normal*- A **normal lactate** level only excludes current **ischaemic bowel** but does not predict the success of further conservative therapy for mechanical obstruction.- Guidelines suggest that the likelihood of SBO resolution drops significantly if no progress is seen within **48 hours**, and further delay increases **post-operative morbidity**.*Administer water-soluble contrast and proceed to surgery if it doesn't reach colon in 24 hours*- **Water-soluble contrast (Gastrografin)** is a useful diagnostic and therapeutic tool, but it is typically administered **early (at 0–24 hours)** to predict the need for surgery.- At the 48-hour mark with persistent symptoms and a clear **CT transition point**, the failure of conservative management is already established, making surgery the next priority.
Question 33: A 75-year-old man undergoes emergency laparotomy for perforated sigmoid diverticulitis with faecal peritonitis. A Hartmann's procedure is performed. Post-operatively he develops progressive abdominal distension and AKI. On day 3 post-surgery, his intra-abdominal pressure measured via bladder catheter is 28 mmHg. He has oliguria despite adequate fluid resuscitation, peak airway pressures are increasing, and he is hypotensive requiring noradrenaline. What is the most appropriate management?
A. Increase PEEP and initiate prone positioning
B. Insert peritoneal dialysis catheter for ultrafiltration
C. Emergency decompressive laparotomy (Correct Answer)
D. Increase intravenous fluid resuscitation and diuretics
E. Conservative management with nasogastric decompression and paracentesis
Explanation: ***Emergency decompressive laparotomy***
- The patient presents with **Abdominal Compartment Syndrome (ACS)**, defined by sustained intra-abdominal pressure (IAP) >20 mmHg (here 28 mmHg) with associated **new organ dysfunction** (AKI, respiratory compromise, hypotension).
- **Emergency decompressive laparotomy** is the definitive treatment for established ACS to immediately reduce IAP, restore organ perfusion, and prevent further multi-organ failure.
*Increase PEEP and initiate prone positioning*
- Increasing **Positive End-Expiratory Pressure (PEEP)** can exacerbate intra-abdominal hypertension by increasing intrathoracic pressure and impeding venous return.
- While prone positioning helps in ARDS, it is generally avoided in severe ACS as it can further raise IAP and worsen hemodynamic instability.
*Insert peritoneal dialysis catheter for ultrafiltration*
- Instilling fluid for **peritoneal dialysis** would catastrophically increase the already critically high **intra-abdominal pressure (IAP)**, making this intervention contraindicated.
- This approach does not address the mechanical compression leading to organ dysfunction and is not an appropriate treatment for acute ACS.
*Increase intravenous fluid resuscitation and diuretics*
- Further **intravenous fluid resuscitation** would worsen **interstitial edema** and bowel swelling, directly contributing to increased intra-abdominal pressure.
- **Diuretics** are ineffective and potentially harmful as renal hypoperfusion due to high IAP, not primary renal failure, is causing the oliguria and AKI.
*Conservative management with nasogastric decompression and paracentesis*
- These medical maneuvers are inadequate for severe **Abdominal Compartment Syndrome (ACS)** with an IAP of 28 mmHg and established multi-organ failure.
- **Nasogastric decompression** addresses gastric distension, and **paracentesis** is primarily for large volume ascites, neither of which significantly resolves the diffuse bowel edema and ileus typical of post-operative ACS.
Question 34: A 42-year-old woman presents with a 12-hour history of severe right upper quadrant pain. Ultrasound shows multiple gallstones, gallbladder wall thickening to 6mm, pericholecystic fluid, and a positive sonographic Murphy's sign. Her white cell count is 16.2 × 10⁹/L and CRP is 185 mg/L. She is haemodynamically stable and started on intravenous antibiotics. According to current evidence-based guidelines, when should definitive surgical management ideally be performed?
A. After 6-8 weeks of conservative management to allow inflammation to settle
B. Only if she fails to improve after 48 hours of intravenous antibiotics
C. Immediately as an emergency within 6 hours
D. Within 72 hours of symptom onset (Correct Answer)
E. Within 7 days but after 72 hours to reduce operative difficulty
Explanation: ***Within 72 hours of symptom onset***
- Current **NICE and Tokyo Guidelines** recommend early laparoscopic cholecystectomy **within 72 hours** of symptom onset for acute cholecystitis.
- Early surgery reduces **hospital stay duration**, costs, and the risk of **recurrent biliary events** compared to delayed management.
*After 6-8 weeks of conservative management to allow inflammation to settle*
- This approach leads to higher **readmission rates** for recurrent cholecystitis and increased **surgical difficulty** due to chronic scarring.
- Evidence shows that **early intervention** is safer and more cost-effective than this traditional "delayed" strategy.
*Only if she fails to improve after 48 hours of intravenous antibiotics*
- Waiting for medical failure unnecessarily delays definitive treatment and increases the risk of **gallbladder perforation** or abscess.
- Early surgery is indicated for all suitable candidates regardless of initial antibiotic response to minimize **morbidity**.
*Immediately as an emergency within 6 hours*
- While surgery should be prompt, ultra-emergency surgery within 6 hours is not mandatory for **haemodynamically stable** patients.
- A **72-hour window** allows for adequate resuscitation and optimized scheduling without increasing the risk of **laparoscopic conversion**.
*Within 7 days but after 72 hours to reduce operative difficulty*
- Operating after 72 hours is actually more difficult due to **dense inflammatory adhesions** and tissue friability.
- The **"Golden Period"** for dissection occurs before severe oedema turns into organized fibrosis, typically within the first 3 days.
Question 35: A 67-year-old man with a background of ischaemic heart disease, COPD, and type 2 diabetes presents with a 4-day history of left lower quadrant pain and fever. CT shows a 5cm pericolic abscess adjacent to the sigmoid colon with sigmoid diverticulitis (Hinchey grade II). He is haemodynamically stable. Which of the following represents the most appropriate initial management?
A. Emergency laparotomy with sigmoid resection and end colostomy
B. Laparoscopic peritoneal lavage and drainage
C. Percutaneous CT-guided drainage with intravenous antibiotics (Correct Answer)
D. Intravenous antibiotics alone with close observation
E. Emergency laparoscopy with sigmoid resection and primary anastomosis
Explanation: ***Percutaneous CT-guided drainage with intravenous antibiotics***
- **Hinchey grade II** diverticulitis involves a **distant abscess** (pericolic or pelvic), and for abscesses **>3-5 cm**, percutaneous drainage is the treatment of choice in stable patients.
- This approach avoids the high morbidity of emergency surgery in patients with significant **comorbidities** and has a success rate of 70-90% for resolving the acute phase.
*Emergency laparotomy with sigmoid resection and end colostomy*
- This procedure (Hartmann’s) is generally reserved for patients with **Hinchey grade III or IV** (purulent or faecal peritonitis) or those who are **haemodynamically unstable**.
- Given the patient's stability and comorbidities, an invasive surgical approach is not the first-line management for a localized abscess.
*Laparoscopic peritoneal lavage and drainage*
- While once considered an alternative, recent trials (e.g., **LOLA**, **LADIES**) have shown that lavage does not offer a significant benefit over resection for perforated diverticulitis and may lead to more adverse events.
- It is not routinely recommended as the definitive treatment for a **radiologically drainable abscess** in a stable patient.
*Intravenous antibiotics alone with close observation*
- Medical management with antibiotics alone is typically appropriate for **Hinchey grade I** (small pericolic phlegmon/abscess <3 cm).
- A **5 cm abscess** is considered large enough to require mechanical drainage to ensure resolution and prevent failure of conservative therapy.
*Emergency laparoscopy with sigmoid resection and primary anastomosis*
- While primary anastomosis is desirable, emergency resection in an acutely inflamed field in a patient with **COPD and IHD** carries excessive risk.
- The goal is to **"cool down"** the inflammation via drainage first, allowing for a safer elective **primary anastomosis** later if surgery is required.
Question 36: A 48-year-old woman presents with a 6-hour history of sudden onset severe epigastric pain radiating to the back. She has a history of recurrent acute pancreatitis. Examination reveals epigastric tenderness with guarding but no rebound. Her amylase is 145 U/L (normal <100). CT abdomen shows a 2cm fluid collection in the lesser sac with a small amount of free intraperitoneal fluid and subtle stranding around the pancreatic tail. There is no free air. What is the most likely diagnosis?
A. Perforated gastric ulcer with posterior leak into lesser sac
B. Acute pancreatitis with pseudocyst formation
C. Ruptured pancreatic pseudocyst with chemical peritonitis (Correct Answer)
D. Mesenteric ischaemia with early infarction
E. Spontaneous bacterial peritonitis in lesser sac
Explanation: ***Ruptured pancreatic pseudocyst with chemical peritonitis*** - The sudden onset of severe epigastric pain radiating to the back in a patient with a history of **recurrent acute pancreatitis** strongly suggests a complication of a pre-existing pancreatic lesion. - The CT findings of a **2cm fluid collection in the lesser sac** (likely a pre-existing pseudocyst) with **free intraperitoneal fluid** and subtle stranding, accompanied by only a **mildly elevated amylase**, are highly consistent with a ruptured pseudocyst causing **chemical peritonitis**.*Perforated gastric ulcer with posterior leak into lesser sac* - While a perforated ulcer can cause severe pain, the absence of **free air (pneumoperitoneum)** on CT makes this diagnosis less likely, as free air is a hallmark of most perforations. - The patient's history of **recurrent acute pancreatitis** provides a more direct explanation for the symptoms and imaging findings, pointing away from a gastric ulcer as the primary cause.*Acute pancreatitis with pseudocyst formation* - **Acute pancreatitis** is typically characterized by a significantly elevated amylase or lipase, usually at least three times the upper limit of normal, which is not seen with the patient's mildly elevated amylase. - **Pancreatic pseudocysts** are chronic complications that develop over several weeks after an episode of acute pancreatitis, so they would not *form* acutely within a 6-hour period; rather, a pre-existing one would rupture.*Mesenteric ischaemia with early infarction* - This condition commonly presents with **pain out of proportion to physical findings** and specific risk factors like **atrial fibrillation** or **atherosclerosis**, none of which are mentioned in the clinical scenario. - CT imaging for mesenteric ischemia would typically show signs of **vascular compromise**, such as vessel occlusion or bowel wall changes, rather than a specific **fluid collection in the lesser sac**.*Spontaneous bacterial peritonitis in lesser sac* - **Spontaneous bacterial peritonitis (SBP)** almost exclusively occurs in patients with **ascites** due to severe liver disease like **cirrhosis**, which is not indicated in the patient's history. - SBP usually presents with more diffuse abdominal pain, fever, and possibly altered mental status, not a **sudden onset surgical abdomen** with specific localized fluid collection suggesting rupture.
Question 37: A 70-year-old man with a history of previous appendicectomy 40 years ago presents with a 72-hour history of colicky central abdominal pain, distension, and vomiting. Plain abdominal radiograph shows multiple dilated loops of small bowel with valvulae conniventes visible. He is haemodynamically stable with normal lactate. Conservative management with intravenous fluids and nasogastric decompression is initiated. After how many hours of conservative management would water-soluble contrast study be most appropriately performed to predict the need for surgery?
A. 6 hours
B. 12 hours
C. 24 hours (Correct Answer)
D. 48 hours
E. 72 hours
Explanation: ***24 hours***
- A **water-soluble contrast study** (e.g., **Gastrografin**) is most appropriate after **24 hours** of conservative management to predict the resolution of **adhesive small bowel obstruction**.
- If contrast reaches the **colon** within 24 hours of administration, there is a high probability (approx. 97%) of resolution without the need for **surgical intervention**.
*6 hours*
- Waiting only 6 hours is often too early to differentiate between an obstruction that will resolve with conservative management and one that requires **surgery**.
- Initial **resuscitation**, fluid balance, and **nasogastric decompression** may take longer than 6 hours to show whether a patient is clinically improving.
*12 hours*
- While 12 hours allows for initial stabilization, it does not provide a definitive window to assess the failure of **conservative therapy** as accurately as the 24-hour mark.
- Most clinical guidelines and **randomized controlled trials** support the 24-hour threshold for prognostic accuracy regarding **small bowel obstruction** resolution.
*48 hours*
- Delaying the contrast study until 48 hours is unnecessary and can potentially delay **operative management** in patients who will not resolve conservatively.
- Prolonged conservative management in non-resolving cases increases the risk of **bowel ischemia**, perforation, and metabolic complications, especially if a **strangulated obstruction** is missed.
*72 hours*
- Managing a patient conservatively for 72 hours without definitive progress or a contrast study carries a high risk of **morbidity** and **mortality**.
- This timeframe significantly exceeds the standard **Bologna guidelines** for managing adhesive obstructions in stable patients before considering surgical intervention or definitive diagnostic studies.
Question 38: What is the physiological mechanism by which prolonged small bowel obstruction leads to metabolic alkalosis rather than metabolic acidosis in the early stages?
A. Loss of gastric acid through vomiting resulting in hydrogen ion depletion (Correct Answer)
B. Increased renal bicarbonate reabsorption due to volume depletion
C. Bacterial overgrowth producing alkaline metabolites
D. Compensation for respiratory acidosis from abdominal distension
E. Impaired lactate clearance by the liver
Explanation: ***Loss of gastric acid through vomiting resulting in hydrogen ion depletion***
- In proximal or high small bowel obstructions, frequent vomiting leads to the direct loss of **hydrochloric acid (HCl)** and **chloride** from the stomach.
- This depletion of **H+ ions** results in a classic **hypochloremic metabolic alkalosis**, which is a hallmark of early-stage obstructive pathology.
*Increased renal bicarbonate reabsorption due to volume depletion*
- While volume contraction does trigger **RAAS activation** and increases **bicarbonate reabsorption** to maintain pH, this is a secondary "maintenance" mechanism rather than the primary cause.
- This phenomenon, known as **contraction alkalosis**, serves to perpetuate the alkalosis initiated by the loss of gastric secretions.
*Bacterial overgrowth producing alkaline metabolites*
- Bacterial overgrowth in obstruction typically leads to **fermentation** and the production of gases and organic acids, not alkaline metabolites.
- Overgrowth is a complication of **stasis** but does not play a significant role in the acute shift toward metabolic alkalosis.
*Compensation for respiratory acidosis from abdominal distension*
- Severe abdominal distension can lead to **splinting of the diaphragm** and respiratory compromise, but this would happen in much later stages of obstruction.
- Metabolic alkalosis in this context is **primary** (due to vomiting) rather than a compensatory response to a respiratory derangement.
*Impaired lactate clearance by the liver*
- Impaired lactate clearance would lead to **metabolic acidosis** (lactic acidosis), which typically occurs late in the course if **bowel ischemia** or shock develops.
- In the early stages of simple obstruction, hepatic function and perfusion are generally preserved, and lactate levels remain normal.
Question 39: A 40-year-old man with ulcerative colitis on long-term azathioprine and prednisolone presents with a 24-hour history of severe generalized abdominal pain and fever. Examination reveals a temperature of 38.9°C, heart rate 125 bpm, blood pressure 95/60 mmHg, and a rigid, silent abdomen. Erect chest radiograph shows no free air. CT abdomen demonstrates thickening of the transverse colon with free intraperitoneal fluid but no pneumoperitoneum. Which mechanism best explains the absence of pneumoperitoneum in this clinical scenario?
A. Microperforation with minimal air leak below radiographic detection threshold
B. Transmural inflammation causing peritonitis without frank perforation (Correct Answer)
C. Perforation into retroperitoneum rather than peritoneal cavity
D. Pneumoperitoneum resorbed due to prolonged symptom duration
E. Sealed perforation by adjacent omentum preventing air leak
Explanation: ***Transmural inflammation causing peritonitis without frank perforation***
- In severe **ulcerative colitis**, the bowel wall can become so thin and inflamed that **bacterial translocation** and exudation of fluid occur without a macroscopically visible hole.
- This leads to a clinical picture of **generalized peritonitis** (rigid abdomen, fever, shock) and free fluid on imaging while the **pneumoperitoneum** remains absent.
*Microperforation with minimal air leak below radiographic detection threshold*
- While some air may be missed by X-ray, **CT scanning** is extremely sensitive for detecting even tiny amounts of **extraluminal gas**.
- The absence of air on CT in the presence of severe systemic shock makes **transmural migration** a more likely explanation than a missed leak.
*Perforation into retroperitoneum rather than peritoneal cavity*
- The **transverse colon** is an **intraperitoneal** organ; therefore, a perforation would typically release gas into the peritoneal cavity, not the retroperitoneum.
- Retroperitoneal air would still be clearly visible on **CT imaging** around the kidneys or great vessels, which is not described here.
*Pneumoperitoneum resorbed due to prolonged symptom duration*
- Absorption of air from the peritoneal cavity is a slow process and would not occur within the **24-hour window** of this patient's acute presentation.
- The ongoing inflammatory process of a perforation would likely continue to leak gas, preventing complete **resorption** during the acute illness.
*Sealed perforation by adjacent omentum preventing air leak*
- A **sealed perforation** typically leads to localized findings or an **abscess** rather than the severe, generalized peritonitis and systemic shock seen in this patient.
- Long-term **corticosteroid** use (prednisolone) often impairs the omentum's ability to effectively seal off inflammatory sites or perforations.
Question 40: A 58-year-old woman with a BMI of 52 kg/m² presents with a 48-hour history of severe epigastric pain, nausea, and bilious vomiting. CT abdomen demonstrates a closed-loop small bowel obstruction with fluid-filled dilated loops, mesenteric oedema, and reduced enhancement of the bowel wall. Laboratory investigations show white cell count 18.5 × 10⁹/L, lactate 4.8 mmol/L, and CRP 245 mg/L. What is the most appropriate immediate management?
A. Conservative management with nasogastric decompression and intravenous fluids for 48 hours
B. Urgent laparotomy within 6 hours (Correct Answer)
C. Water-soluble contrast study to predict need for surgery
D. Diagnostic laparoscopy with conversion to laparotomy if indicated
E. Parenteral nutrition and observation for 72 hours
Explanation: ***Urgent laparotomy within 6 hours***
- This patient presents with a **closed-loop small bowel obstruction** and radiological signs of **bowel ischemia** (reduced bowel wall enhancement, mesenteric oedema).
- Clinical indicators such as **elevated lactate (4.8 mmol/L)** and **leucocytosis** strongly suggest strangulation, necessitating immediate surgical intervention to prevent necrosis and perforation.
*Conservative management with nasogastric decompression and intravenous fluids for 48 hours*
- Conservative management is only appropriate for **uncomplicated** adhesive bowel obstruction with no signs of ischaemia or strangulation.
- In this case, the presence of **mesenteric oedema**, reduced bowel enhancement, and high inflammatory markers contraindicates delaying surgery, as it would lead to bowel infarction.
*Water-soluble contrast study to predict need for surgery*
- **Water-soluble contrast studies (e.g., Gastrografin)** are used to predict the resolution of uncomplicated adhesive small bowel obstruction.
- Utilizing a contrast study in a patient with suspected **bowel strangulation** would cause a dangerous delay in definitive surgical treatment, which is urgently required.
*Diagnostic laparoscopy with conversion to laparotomy if indicated*
- While laparoscopy is often preferred, the patient's **BMI of 52 kg/m²** and significantly dilated bowel loops make a laparoscopic approach technically difficult and potentially unsafe.
- **Laparotomy** provides superior exposure and allows for safer handling of fragile, ischaemic bowel, which is crucial in cases of suspected strangulation.
*Parenteral nutrition and observation for 72 hours*
- **Parenteral nutrition** is a supportive measure for prolonged ileus or short bowel syndrome, not an acute management strategy for mechanical bowel obstruction with ischemia.
- Observation for 72 hours with signs of **strangulated bowel** and ischemia would inevitably lead to **bowel necrosis**, perforation, sepsis, and a fatal outcome.
