Acute Surgical Presentations — MCQs
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A 51-year-old woman with Crohn's disease presents with a 24-hour history of severe right lower quadrant pain and fever. She has had previous terminal ileal resections 5 and 10 years ago. CT demonstrates a 12cm segment of grossly dilated small bowel (diameter 5cm) proximal to the previous anastomosis, with wall thickening, enhancement, and surrounding fat stranding. The bowel distal to this is collapsed. What is the most likely diagnosis?
What is Chilaiditi's sign and what is its clinical significance in the context of acute abdominal presentations?
A 38-year-old man presents with a 10-hour history of severe epigastric pain radiating to the back. He has consumed 8-10 units of alcohol daily for 15 years. Observations show temperature 37.9°C, heart rate 108 bpm, blood pressure 118/75 mmHg. Abdominal examination reveals epigastric tenderness without rigidity or guarding. Serum amylase is 1250 U/L. Erect chest radiograph demonstrates free gas under both hemidiaphragms. What is the most appropriate next step in management?
A 62-year-old woman with metastatic ovarian cancer on chemotherapy presents with a 72-hour history of progressive abdominal distension, vomiting, and colicky central pain. She has not opened her bowels for 5 days despite laxatives. CT demonstrates multiple transition points throughout the small bowel with peritoneal nodularity and ascites. Her performance status is good (ECOG 1). What is the most appropriate management approach?
What is the mechanism by which sigmoid volvulus differs from caecal volvulus in terms of anatomical predisposition and typical patient demographics?
A 41-year-old man with ulcerative colitis undergoes urgent colonoscopy for a severe flare. During the procedure, the endoscopist notes extensive deep ulceration throughout the colon with areas of necrosis. Six hours post-procedure, the patient develops sudden onset severe generalized abdominal pain with rigidity. Erect chest radiograph shows no free gas under the diaphragm. What best explains the absence of pneumoperitoneum?
A 74-year-old man with a history of previous sigmoid colectomy for diverticular disease 8 years ago presents with a 4-day history of progressive abdominal distension, colicky pain, and absolute constipation. Plain abdominal radiograph shows dilated small bowel loops with valvulae conniventes visible, and a 'coffee bean' shaped dilated structure in the left upper quadrant. What is the most likely diagnosis?
A 56-year-old woman with known sigmoid diverticular disease presents with a 48-hour history of left lower quadrant pain and fever. CT abdomen demonstrates a 6cm pericolic fluid collection adjacent to an inflamed sigmoid colon with multiple diverticula. Her observations are: temperature 38.1°C, heart rate 92 bpm, blood pressure 132/78 mmHg. She is tolerating oral fluids and passing flatus. White cell count is 14.2 × 10⁹/L, CRP 145 mg/L. What is the most appropriate initial management according to current guidelines?
What is the pathophysiological mechanism by which paralytic ileus develops following acute peritonitis from bowel perforation?
A 32-year-old man undergoes emergency laparotomy for perforated appendicitis. During surgery, 500ml of purulent fluid is drained from the peritoneal cavity. The appendix is gangrenous and perforated. What is the most appropriate surgical approach according to current evidence-based practice?
Acute Surgical Presentations UK Medical PG Practice Questions and MCQs
Question 121: A 51-year-old woman with Crohn's disease presents with a 24-hour history of severe right lower quadrant pain and fever. She has had previous terminal ileal resections 5 and 10 years ago. CT demonstrates a 12cm segment of grossly dilated small bowel (diameter 5cm) proximal to the previous anastomosis, with wall thickening, enhancement, and surrounding fat stranding. The bowel distal to this is collapsed. What is the most likely diagnosis?
- A. Adhesional small bowel obstruction at the site of previous anastomosis
- B. Anastomotic stricture due to recurrent Crohn's disease causing closed-loop obstruction (Correct Answer)
- C. Enteroenteric fistula causing bypass of intestinal contents and proximal dilatation
- D. Intra-abdominal abscess causing mass effect and external compression
- E. Internal hernia through a mesenteric defect from previous surgery
Explanation: ***Anastomotic stricture due to recurrent Crohn's disease causing closed-loop obstruction*** - The patient's history of **Crohn's disease** and previous **terminal ileal resections** makes recurrence at an anastomotic site highly probable, especially with CT findings of **wall thickening**, **enhancement**, and **fat stranding** indicating active inflammation. - The **grossly dilated small bowel** proximal to the obstruction with collapsed bowel distally, combined with inflammation, strongly suggests a **high-grade mechanical obstruction** and potential **closed-loop physiology**, a severe complication requiring urgent management. *Adhesional small bowel obstruction at the site of previous anastomosis* - While common after surgery, **adhesions** typically cause extrinsic compression without significant **bowel wall thickening**, **enhancement**, or **fat stranding** within the bowel wall itself. - These inflammatory imaging features are more indicative of **active intrinsic bowel pathology** (like recurrent Crohn's disease) rather than simple fibrous adhesions. *Enteroenteric fistula causing bypass of intestinal contents and proximal dilatation* - An **enteroenteric fistula** would usually act to **decompress** the proximal bowel by diverting flow, rather than causing gross **proximal dilatation** and complete obstruction as described. - The CT findings of a distinct mechanical obstruction with dilated proximal and collapsed distal bowel are inconsistent with a functioning bypass fistula. *Intra-abdominal abscess causing mass effect and external compression* - An **intra-abdominal abscess** would be characterized by a well-defined **fluid collection** with peripheral enhancement and possibly gas, distinct from the bowel wall. - While an abscess can cause symptoms, the primary CT finding here is **transmural bowel wall thickening** and primary luminal obstruction at the anastomosis, pointing to intrinsic bowel disease. *Internal hernia through a mesenteric defect from previous surgery* - **Internal hernias** typically present with clustered bowel loops in an abnormal location and a characteristic **swirl sign** of mesenteric vessels, indicating anatomical displacement. - The described **bowel wall thickening**, **enhancement**, and **fat stranding** are specific inflammatory changes occurring directly at the anastomotic site, not a general displacement of bowel segments.
Question 122: What is Chilaiditi's sign and what is its clinical significance in the context of acute abdominal presentations?
- A. The presence of gas in the portal venous system indicating bowel ischaemia requiring emergency surgery
- B. Interposition of bowel (usually hepatic flexure of colon) between the liver and right hemidiaphragm, which is usually incidental but may be mistaken for pneumoperitoneum (Correct Answer)
- C. The presence of air in the biliary tree indicating a biliary-enteric fistula requiring urgent intervention
- D. A double-wall sign on abdominal radiograph indicating pneumoperitoneum requiring immediate surgical exploration
- E. The presence of dilated bowel loops arranged in a ladder pattern diagnostic of small bowel obstruction
Explanation: ***Interposition of bowel (usually hepatic flexure of colon) between the liver and right hemidiaphragm, which is usually incidental but may be mistaken for pneumoperitoneum*** - **Chilaiditi's sign** is a benign radiological finding where gas-filled bowel segments, often the **hepatic flexure of the colon**, are located between the liver and the right hemidiaphragm. - Its clinical significance lies in preventing misdiagnosis of **pneumoperitoneum** (free intraperitoneal air), thereby avoiding unnecessary and potentially harmful **surgical interventions**. *The presence of gas in the portal venous system indicating bowel ischaemia requiring emergency surgery* - This describes **portal venous gas**, a serious sign often associated with **bowel ischaemia** or necrosis, appearing as branching radiolucencies within the liver parenchyma. - Unlike Chilaiditi's sign, which is usually benign, portal venous gas signifies a critical intra-abdominal emergency. *The presence of air in the biliary tree indicating a biliary-enteric fistula requiring urgent intervention* - This finding is known as **pneumobilia**, characterized by air within the **biliary ducts**, commonly seen after biliary instrumentation or in cases of **gallstone ileus**. - Pneumobilia's air pattern is central within the liver, distinct from the gas seen superior to the liver in Chilaiditi's sign. *A double-wall sign on abdominal radiograph indicating pneumoperitoneum requiring immediate surgical exploration* - The **double-wall sign**, or **Rigler's sign**, indicates **pneumoperitoneum** (free air in the abdominal cavity) by visualizing both sides of the bowel wall. - This sign confirms true intraperitoneal free air, demanding immediate surgical exploration, unlike the bowel interposition of Chilaiditi's sign. *The presence of dilated bowel loops arranged in a ladder pattern diagnostic of small bowel obstruction* - A **ladder pattern** of dilated bowel loops is a classic radiological sign of **small bowel obstruction** due to proximal accumulation of gas and fluid. - This finding is related to intestinal lumen pathology and does not involve the diaphragm or misidentification of free air, differentiating it from Chilaiditi's sign.
Question 123: A 38-year-old man presents with a 10-hour history of severe epigastric pain radiating to the back. He has consumed 8-10 units of alcohol daily for 15 years. Observations show temperature 37.9°C, heart rate 108 bpm, blood pressure 118/75 mmHg. Abdominal examination reveals epigastric tenderness without rigidity or guarding. Serum amylase is 1250 U/L. Erect chest radiograph demonstrates free gas under both hemidiaphragms. What is the most appropriate next step in management?
- A. Continue with conservative management of acute pancreatitis as the free gas is likely due to pneumomediastinum tracking down from retching
- B. Arrange emergency laparotomy for suspected perforated peptic ulcer
- C. Perform urgent CT abdomen with oral and intravenous contrast to differentiate between acute pancreatitis and perforation (Correct Answer)
- D. Commence broad-spectrum antibiotics and arrange urgent ERCP to exclude biliary obstruction
- E. Perform diagnostic peritoneal lavage to confirm or exclude hollow viscus perforation
Explanation: ***Perform urgent CT abdomen with oral and intravenous contrast to differentiate between acute pancreatitis and perforation*** - The patient presents with features of both severe **acute pancreatitis** (high amylase, alcohol history) and a potential **hollow viscus perforation** (free gas under both hemidiaphragms), necessitating immediate and precise diagnostic clarification. - An **urgent CT scan** with contrast is the most appropriate next step as it can accurately assess pancreatic inflammation and complications, identify the source of **pneumoperitoneum**, and guide definitive management, avoiding unnecessary exploratory surgery for pancreatitis alone. *Continue with conservative management of acute pancreatitis as the free gas is likely due to pneumomediastinum tracking down from retching* - Assuming the **free gas under the diaphragm** is benign, such as from **pneumomediastinum**, without further investigation is extremely dangerous as a missed **hollow viscus perforation** carries a very high mortality rate. - While retching can cause pneumomediastinum, the presence of free gas under *both hemidiaphragms* warrants a more definitive investigation to rule out a surgical emergency. *Arrange emergency laparotomy for suspected perforated peptic ulcer* - Although **free gas** strongly suggests a perforation, the markedly elevated serum amylase (1250 U/L) is highly indicative of **acute pancreatitis**. - Proceeding directly to **emergency laparotomy** for suspected perforation in a patient with severe pancreatitis without clear evidence of perforation on imaging could worsen the patient's condition and outcomes due to the systemic inflammatory response of pancreatitis. *Commence broad-spectrum antibiotics and arrange urgent ERCP to exclude biliary obstruction* - The patient's significant **alcohol history** makes **alcohol-induced pancreatitis** the more likely etiology than biliary obstruction, thus urgent **ERCP** is not the primary indication. - **Broad-spectrum antibiotics** are not routinely indicated in the initial management of acute pancreatitis unless there is clear evidence of infection, and they do not address the critical finding of **free intraperitoneal gas**. *Perform diagnostic peritoneal lavage to confirm or exclude hollow viscus perforation* - **Diagnostic peritoneal lavage (DPL)** is an invasive procedure that has largely been superseded by more advanced and less invasive imaging modalities like **CT scanning**. - DPL may not reliably differentiate between the enzyme-rich fluid of severe pancreatitis and the contents of a true **hollow viscus perforation**, potentially leading to inconclusive or misleading results in this complex clinical scenario.
Question 124: A 62-year-old woman with metastatic ovarian cancer on chemotherapy presents with a 72-hour history of progressive abdominal distension, vomiting, and colicky central pain. She has not opened her bowels for 5 days despite laxatives. CT demonstrates multiple transition points throughout the small bowel with peritoneal nodularity and ascites. Her performance status is good (ECOG 1). What is the most appropriate management approach?
- A. Emergency laparotomy with extensive adhesiolysis and resection of obstructed segments
- B. Conservative management with nasogastric decompression, intravenous fluids, and pharmacological bowel management including corticosteroids and octreotide (Correct Answer)
- C. Palliative care referral with symptom control using antiemetics and opioids only, avoiding surgical intervention
- D. Insertion of percutaneous venting gastrostomy for long-term decompression
- E. Trial of total parenteral nutrition with surgical intervention if no improvement after 2 weeks
Explanation: ***Conservative management with nasogastric decompression, intravenous fluids, and pharmacological bowel management including corticosteroids and octreotide*** - Initial management for **malignant bowel obstruction (MBO)** in patients with **peritoneal carcinomatosis** focuses on medical stabilization; **corticosteroids** reduce peritumoral edema, while **octreotide** decreases gastrointestinal secretions. - Approximately 30-40% of cases respond to this approach, which is preferred when CT shows **multiple transition points**, making successful surgical intervention less likely. *Emergency laparotomy with extensive adhesiolysis and resection of obstructed segments* - Surgery for **multiple levels of obstruction** due to carcinomatosis carries high **morbidity (30-40%)** and **mortality (6-32%)** with poor long-term outcomes. - Surgical intervention is generally reserved for patients with a **single-level obstruction** and a predicted survival of more than three months who fail medical management. *Palliative care referral with symptom control using antiemetics and opioids only, avoiding surgical intervention* - While palliative care is essential, purely symptomatic relief without a trial of **active medical management** is premature for a patient with a **good performance status (ECOG 1)**. - This approach ignores the potential to resolve the obstruction medically and proceed with further **oncological treatments** or palliative chemotherapy. *Insertion of percutaneous venting gastrostomy for long-term decompression* - **Venting gastrostomy** is an excellent palliative tool but is typically indicated for **refractory cases** that have failed conservative pharmacological measures. - It is not the first-line management for a patient presenting acutely who may still respond to **nasogastric decompression** and medication. *Trial of total parenteral nutrition with surgical intervention if no improvement after 2 weeks* - **Total parenteral nutrition (TPN)** for two weeks prior to surgery causes unnecessary delay and does not address the underlying **mechanical obstruction**. - Nutrition alone is not a primary treatment for MBO, and decisions regarding surgery should be based on clinical response to decompression and the **extent of carcinomatosis**.
Question 125: What is the mechanism by which sigmoid volvulus differs from caecal volvulus in terms of anatomical predisposition and typical patient demographics?
- A. Sigmoid volvulus occurs in elderly patients with chronic constipation and elongated sigmoid mesentery; caecal volvulus occurs in younger patients with congenital incomplete peritoneal fixation of the right colon (Correct Answer)
- B. Sigmoid volvulus results from excessive peristalsis in young athletic individuals; caecal volvulus occurs in obese patients with increased intra-abdominal pressure
- C. Sigmoid volvulus is associated with pregnancy-related hormonal changes affecting colonic motility; caecal volvulus results from post-surgical adhesions
- D. Sigmoid volvulus predominantly affects patients with inflammatory bowel disease; caecal volvulus affects patients with previous abdominal radiotherapy
- E. Both conditions have identical risk factors and demographics, differing only in anatomical location
Explanation: ***Sigmoid volvulus occurs in elderly patients with chronic constipation and elongated sigmoid mesentery; caecal volvulus occurs in younger patients with congenital incomplete peritoneal fixation of the right colon***- **Sigmoid volvulus** typically affects **elderly patients** and those with **chronic constipation**, where a redundant sigmoid colon on a long, narrow mesentery twists.- **Caecal volvulus** occurs in a **younger demographic** (often 30-60 years old) due to **congenital incomplete fixation** of the caecum to the posterior abdominal wall, allowing for abnormal mobility.*Sigmoid volvulus results from excessive peristalsis in young athletic individuals; caecal volvulus occurs in obese patients with increased intra-abdominal pressure*- **Sigmoid volvulus** is not primarily associated with young athletic individuals or excessive peristalsis; its main risk factors are **age** and **chronic constipation**.- **Obesity** and increased intra-abdominal pressure are not the primary mechanisms or risk factors for **caecal volvulus**, which is fundamentally a defect in **peritoneal fixation**.*Sigmoid volvulus is associated with pregnancy-related hormonal changes affecting colonic motility; caecal volvulus results from post-surgical adhesions*- While **pregnancy** can be a risk factor for volvulus due to mass effect and hormonal changes, it's not the most common demographic for **sigmoid volvulus**.- **Caecal volvulus** is caused by congenital hypermobility of the caecum, not typically by **post-surgical adhesions**, which more commonly cause small bowel obstruction.*Sigmoid volvulus predominantly affects patients with inflammatory bowel disease; caecal volvulus affects patients with previous abdominal radiotherapy*- **Inflammatory bowel disease** is not a primary risk factor for **sigmoid volvulus**; conditions like toxic megacolon or strictures are more common.- **Abdominal radiotherapy** typically causes fibrosis and fixation, which would **reduce** the mobility necessary for a **volvulus** to occur.*Both conditions have identical risk factors and demographics, differing only in anatomical location*- This statement is incorrect as **sigmoid and caecal volvulus** have distinct anatomical predispositions and patient demographics.- **Sigmoid volvulus** is often acquired in the **elderly** due to redundancy, while **caecal volvulus** is typically congenital due to malrotation in **younger adults**.
Question 126: A 41-year-old man with ulcerative colitis undergoes urgent colonoscopy for a severe flare. During the procedure, the endoscopist notes extensive deep ulceration throughout the colon with areas of necrosis. Six hours post-procedure, the patient develops sudden onset severe generalized abdominal pain with rigidity. Erect chest radiograph shows no free gas under the diaphragm. What best explains the absence of pneumoperitoneum?
- A. The perforation is contained by omentum forming a localized abscess without free communication to the peritoneal cavity
- B. Colonic perforations frequently seal immediately due to high intraluminal bacterial load causing rapid fibrin deposition
- C. Retroperitoneal perforation has occurred, allowing gas to track into the retroperitoneum rather than free peritoneal cavity (Correct Answer)
- D. The volume of gas escaping is too small to be detected on plain radiography and CT would be required
- E. The patient's position during radiography was not maintained for sufficient duration to allow gas to rise to the diaphragm
Explanation: ***Retroperitoneal perforation has occurred, allowing gas to track into the retroperitoneum rather than free peritoneal cavity*** - Parts of the **ascending and descending colon** are retroperitoneal; a perforation in these segments can lead to gas and contents leaking into the **retroperitoneal space**, explaining the absence of **free intraperitoneal gas** on an erect chest radiograph. - Despite no free gas on imaging, the **severe generalized abdominal pain** with **rigidity** indicates peritonitis, which can still occur with retroperitoneal perforation as inflammation spreads. *The perforation is contained by omentum forming a localized abscess without free communication to the peritoneal cavity* - While the **omentum** can sometimes contain perforations, the patient's presentation of **sudden onset severe generalized abdominal pain** and **rigidity** strongly suggests diffuse peritonitis, not a localized process. - A localized abscess would typically cause more focal pain and potentially a less acute onset of such severe generalized symptoms. *Colonic perforations frequently seal immediately due to high intraluminal bacterial load causing rapid fibrin deposition* - High bacterial load in the colon typically exacerbates inflammation and infection in a perforation, rather than promoting rapid and effective sealing via **fibrin deposition**. - The severe inflammation and **necrosis** noted during colonoscopy in **ulcerative colitis** make spontaneous sealing of a perforation highly unlikely and structurally difficult. *The volume of gas escaping is too small to be detected on plain radiography and CT would be required* - An erect chest radiograph is quite sensitive for detecting **free intraperitoneal gas**, often able to visualize as little as **1-2 mL** of air beneath the diaphragm. - Given the significant clinical signs of **peritonitis** (severe pain, rigidity), a perforation large enough to cause this would typically release enough gas to be detectable if it were truly intraperitoneal. *The patient's position during radiography was not maintained for sufficient duration to allow gas to rise to the diaphragm* - Standard radiographic practice for detecting pneumoperitoneum involves an erect position for at least **10-20 minutes** to allow gas to rise, which is generally assumed to be followed in a clinical setting for a critical patient. - Assuming correct technique, the absence of free gas points to an anatomical reason (like retroperitoneal perforation) rather than a technical oversight as the primary explanation for severe, symptomatic perforation without pneumoperitoneum.
Question 127: A 74-year-old man with a history of previous sigmoid colectomy for diverticular disease 8 years ago presents with a 4-day history of progressive abdominal distension, colicky pain, and absolute constipation. Plain abdominal radiograph shows dilated small bowel loops with valvulae conniventes visible, and a 'coffee bean' shaped dilated structure in the left upper quadrant. What is the most likely diagnosis?
- A. Adhesional small bowel obstruction with a single transition point
- B. Sigmoid volvulus with clockwise rotation around the mesenteric axis
- C. Caecal volvulus with axial rotation and ileocaecal valve incompetence
- D. Small bowel volvulus secondary to adhesions from previous surgery (Correct Answer)
- E. Large bowel obstruction due to anastomotic stricture
Explanation: ***Small bowel volvulus secondary to adhesions from previous surgery***- The presence of **valvulae conniventes** (which cross the full width of the bowel) and a **'coffee bean'** sign in the **left upper quadrant** points toward a small bowel volvulus, often involving a **closed-loop obstruction**.- Previous **sigmoid colectomy** leads to **adhesion formation**, providing a fixed point for the bowel to twist around its mesenteric axis, causing this presentation.*Adhesional small bowel obstruction with a single transition point*- Simple **adhesional obstruction** typically shows generalized dilated loops but lacks the specific **'coffee bean' shaped** closed-loop appearance.- While adhesions are the most common cause of obstruction, the presence of the sign in the **LUQ** suggests a rotation/volvulus rather than a simple band restriction.*Sigmoid volvulus with clockwise rotation around the mesenteric axis*- **Sigmoid volvulus** is impossible in this patient because he has already undergone a **sigmoid colectomy**, meaning the sigmoid colon is no longer present.- Classically, sigmoid volvulus originates in the pelvis and points toward the **right upper quadrant**, whereas this is in the left.*Caecal volvulus with axial rotation and ileocaecal valve incompetence*- **Caecal volvulus** usually presents with a dilated loop containing **haustra** (incomplete segments) rather than the **valvulae conniventes** seen in the small bowel.- The dilated segment in caecal volvulus typically moves from the right lower quadrant toward the **epigastrium or left upper quadrant**, but wouldn't explain the generalized small bowel pattern as specifically as small bowel volvulus.*Large bowel obstruction due to anastomotic stricture*- A **stricture** would cause progressive **proximal colonic dilation**; however, it does not produce the characteristic **coffee bean sign** seen on the radiograph.- The radiographic evidence of **valvulae conniventes** and the specific LUQ loop shape are more indicative of a **small bowel pathology** than a chronic large bowel narrowing.
Question 128: A 56-year-old woman with known sigmoid diverticular disease presents with a 48-hour history of left lower quadrant pain and fever. CT abdomen demonstrates a 6cm pericolic fluid collection adjacent to an inflamed sigmoid colon with multiple diverticula. Her observations are: temperature 38.1°C, heart rate 92 bpm, blood pressure 132/78 mmHg. She is tolerating oral fluids and passing flatus. White cell count is 14.2 × 10⁹/L, CRP 145 mg/L. What is the most appropriate initial management according to current guidelines?
- A. Immediate laparotomy with Hartmann's procedure
- B. Intravenous antibiotics and CT-guided percutaneous drainage of the collection (Correct Answer)
- C. Intravenous antibiotics alone with serial clinical assessment
- D. Emergency flexible sigmoidoscopy to exclude perforation
- E. Conservative management with oral antibiotics and outpatient follow-up
Explanation: ***Intravenous antibiotics and CT-guided percutaneous drainage of the collection*** - This patient has **complicated diverticulitis** with a significant **6cm pericolic abscess**, which is classified as Hinchey Stage II. - Current guidelines recommend **CT-guided percutaneous drainage** for abscesses **>3-4 cm** in stable patients, combined with **intravenous antibiotics**, to achieve source control and avoid emergency surgery. *Immediate laparotomy with Hartmann's procedure* - This invasive surgical intervention is reserved for **Hinchey Stage III or IV diverticulitis** (purulent or fecal peritonitis), free perforation, or **hemodynamically unstable** patients. - The patient is stable, tolerating oral fluids, and passing flatus, without signs of **generalized peritonitis**, making immediate major surgery inappropriate. *Intravenous antibiotics alone with serial clinical assessment* - While suitable for uncomplicated diverticulitis or very small abscesses (<3-4 cm), antibiotics alone are insufficient for a **6cm collection**. - Delaying definitive source control via drainage for a large abscess significantly increases the risk of treatment failure, persistence, or progression to **perforated diverticulitis**. *Emergency flexible sigmoidoscopy to exclude perforation* - **Endoscopy is contraindicated** in acute diverticulitis due to the high risk of **bowel perforation** caused by air insufflation into an inflamed, friable colon. - The presence of a pericolic fluid collection and inflamed sigmoid is already clearly diagnosed by the **CT abdomen**, rendering endoscopy unnecessary and unsafe. *Conservative management with oral antibiotics and outpatient follow-up* - This approach is only appropriate for **uncomplicated diverticulitis** in patients who are clinically well, afebrile, and have no evidence of an abscess or systemic inflammation. - The patient's **fever**, elevated **WBC** and **CRP**, and the presence of a **large abscess** on CT, indicate complicated disease requiring inpatient management with intravenous therapy and an invasive procedure.
Question 129: What is the pathophysiological mechanism by which paralytic ileus develops following acute peritonitis from bowel perforation?
- A. Direct mechanical compression of the bowel by inflammatory exudate preventing peristalsis
- B. Bacterial endotoxins causing direct smooth muscle paralysis through inhibition of actin-myosin interaction
- C. Inflammatory mediators disrupting the normal neural coordination of intestinal motility through effects on the enteric nervous system (Correct Answer)
- D. Systemic hypotension leading to intestinal hypoperfusion and loss of smooth muscle contractility
- E. Electrolyte disturbances, particularly hypokalaemia, preventing normal smooth muscle depolarization
Explanation: ***Inflammatory mediators disrupting the normal neural coordination of intestinal motility through effects on the enteric nervous system*** - Peritonitis triggers the release of **pro-inflammatory cytokines** (e.g., IL-1β, TNF-α) and **prostaglandins**, which activate immune cells and directly affect neuronal function within the gut wall. - These mediators interfere with **cholinergic neurotransmission** and modulate the activity of the **enteric nervous system**, leading to a functional shutdown of peristalsis. *Direct mechanical compression of the bowel by inflammatory exudate preventing peristalsis* - Paralytic ileus is a **functional obstruction**, not a mechanical one; while inflammatory exudate is present, it does not physically block the bowel lumen. - **Mechanical obstruction** would typically involve increased, then absent, bowel sounds, whereas ileus presents with **diminished or absent bowel sounds** from the outset due to lack of peristalsis. *Bacterial endotoxins causing direct smooth muscle paralysis through inhibition of actin-myosin interaction* - While bacterial **endotoxins** initiate the inflammatory cascade, they do not directly inhibit the **actin-myosin cross-bridge cycle** in smooth muscle to cause paralysis. - The primary mechanism involves the **inflammatory response** affecting the neural control of the gut, rather than direct myotoxicity. *Systemic hypotension leading to intestinal hypoperfusion and loss of smooth muscle contractility* - Although **systemic hypotension** can worsen ileus or cause bowel ischemia, the primary mechanism for ileus in acute peritonitis is the **local inflammatory response** affecting the enteric nervous system. - Ileus can develop even before significant **systemic shock** or profound hypotension is present, highlighting the local nature of the initial insult. *Electrolyte disturbances, particularly hypokalaemia, preventing normal smooth muscle depolarization* - **Hypokalemia** is a known cause of ileus, but in acute peritonitis, it is usually a **secondary factor** or a complication, rather than the primary initiating mechanism. - The immediate cause of ileus following bowel perforation is the **acute inflammatory response** affecting the neural regulation of gut motility.
Question 130: A 32-year-old man undergoes emergency laparotomy for perforated appendicitis. During surgery, 500ml of purulent fluid is drained from the peritoneal cavity. The appendix is gangrenous and perforated. What is the most appropriate surgical approach according to current evidence-based practice?
- A. Appendicectomy with primary closure of all layers and insertion of peritoneal drain
- B. Appendicectomy with peritoneal lavage and closure without drains (Correct Answer)
- C. Appendicectomy with delayed primary closure of the skin after 3-5 days
- D. Appendicectomy with closure of peritoneum and fascia but leaving skin open for secondary intention healing
- E. Appendicectomy with mass closure using interrupted sutures and prophylactic mesh placement
Explanation: ***Appendicectomy with peritoneal lavage and closure without drains*** - Evidence-based guidelines indicate that **routine drainage** in complicated appendicitis does not prevent **intra-abdominal abscesses** and may increase the risk of surgical site infections (SSI). - Thorough **peritoneal lavage** (washing) and **primary closure** of the incision are currently favored to reduce hospital stay and complications, even in the presence of **purulent fluid**. *Appendicectomy with primary closure of all layers and insertion of peritoneal drain* - Prophylactic **peritoneal drains** are generally discouraged in contaminated fields due to their potential to serve as a **conduit for bacteria**, increasing the risk of wound and intra-abdominal infections. - Studies show that routine drainage in perforated appendicitis does not improve outcomes and may actually lead to **prolonged hospital stay** and drain-related complications. *Appendicectomy with delayed primary closure of the skin after 3-5 days* - **Delayed primary closure (DPC)** was historically used for contaminated wounds, but current evidence suggests it offers no significant advantage over **primary closure** in reducing infection rates for perforated appendicitis. - This approach results in **increased costs**, longer nursing care requirements, and prolonged patient discomfort without a clear benefit in preventing **surgical site infections**. *Appendicectomy with closure of peritoneum and fascia but leaving skin open for secondary intention healing* - Leaving the skin open for **secondary intention healing** results in significantly **prolonged wound care**, increased patient discomfort, and less favorable cosmetic outcomes. - This method is generally reserved for grossly **contaminated wounds** or those with established infection that cannot be primarily closed, which is not the standard approach for a well-lavaged peritoneal cavity. *Appendicectomy with mass closure using interrupted sutures and prophylactic mesh placement* - **Prophylactic mesh placement** is absolutely contraindicated in the setting of an **acute, contaminated abdominal infection** like perforated appendicitis due to the extremely high risk of **mesh infection**, erosion, and fistula formation. - While **mass closure** is a technique for abdominal wall closure, the addition of mesh in an infected field is inappropriate and would lead to severe, potentially life-threatening complications.
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