5.3 Acute Surgical Conditions (Appendicitis, Cholecystitis, Bowel Obstruction)
Key Takeaways
- Acute appendicitis presents with dull periumbilical pain migrating to the right lower quadrant (McBurney's point) accompanied by anorexia, nausea, and localized peritoneal signs.
- Acute cholecystitis is diagnosed by right upper quadrant tenderness, positive sonographic Murphy's sign, gallbladder wall thickening (>3 mm), and pericholecystic fluid on ultrasound.
- Ascending cholangitis presents with Charcot's triad (fever, jaundice, RUQ pain) or Reynolds' pentad (+ shock and altered mental status) and requires emergent ERCP biliary decompression.
- Small bowel obstruction (SBO) is most commonly caused by postoperative adhesions, presenting with crampy abdominal pain, obstipation, vomiting, and dilated bowel loops with air-fluid levels on X-ray/CT.
- Strangulated bowel obstruction or perforated viscus requires emergent fluid resuscitation, broad-spectrum IV antibiotics, and urgent exploratory laparotomy.
Acute Surgical Abdominal Conditions
Evaluating the acute abdomen requires distinguishing non-operative medical conditions from surgical emergencies requiring urgent source control. Clinical evaluation focuses on anatomical localization, peritoneal signs (rebound, involuntary guarding, rigidity), and hemodynamic stability.
Acute Appendicitis
Pathophysiology & Clinical Presentation
Acute appendicitis is caused by luminal obstruction of the appendix by a fecolith (adults) or lymphoid hyperplasia (children/young adults). Obstruction leads to mucus accumulation, bacterial overgrowth, ischemic necrosis, and perforation.
- Classic Symptom Progression: Visceral periumbilical pain (T10 dermatome) $\rightarrow$ Anorexia ('hamburger sign') and nausea $\rightarrow$ Migration to Right Lower Quadrant (RLQ) somatic pain at McBurney's point (2/3 from umbilicus to anterior superior iliac spine).
- Physical Signs:
- Rovsing Sign: RLQ pain elicited by deep palpation of the left lower quadrant.
- Psoas Sign: RLQ pain on passive extension of the right hip (indicates retrocecal appendix).
- Obturator Sign: RLQ pain on passive internal rotation of the flexed right hip (indicates pelvic appendix).
Diagnostic Strategy & Management
- Laboratory Findings: Mild leukocytosis ($11,000\text{--}16,000/\mu\text{L}$) with left shift; elevated C-reactive protein (CRP).
- Imaging Modality Choice:
- Children & Pregnant Women: Ultrasound is initial choice (target: non-compressible blind-ending tubular structure $> 6\text{ mm}$ outer diameter). MRI if US inconclusive in pregnancy.
- Non-pregnant Adults: Abdominal/pelvic CT scan with IV contrast is definitive ($> 95%$ sensitivity/specificity; shows appendiceal enlargement $> 6\text{ mm}$, wall thickening, fat stranding, appendicolith).
- Management:
- Uncomplicated Appendicitis: Preoperative single-dose IV antibiotics (cefazolin + metronidazole OR piperacillin-tazobactam) followed by laparoscopic appendectomy within 24 hours.
- Perforated Appendicitis with Abscess: If patient is hemodynamically stable without generalized peritonitis, manage non-operatively with IV antibiotics and percutaneous image-guided drainage, followed by interval appendectomy in 6–8 weeks.
Biliary Tract Emergencies
Biliary pathology exists along a clinical spectrum dictated by the location of stone impaction and presence of infection.
| Condition | Anatomical Site of Obstruction | Key Clinical & Lab Features | Ultrasound Findings | Definitive Management |
|---|---|---|---|---|
| Biliary Colic | Transient cystic duct obstruction | Episodic RUQ postprandial pain ($< 6\text{ hours}$); normal LFTs and WBC | Gallstones present; normal wall, no pericholecystic fluid | Elective outpatient laparoscopic cholecystectomy |
| Acute Cholecystitis | Persistent cystic duct impaction | Continuous RUQ pain ($> 6\text{ hours}$), fever, leukocytosis, Murphy's sign | Wall thickening $> 3\text{ mm}$, pericholecystic fluid, sonographic Murphy sign | IV fluids, IV antibiotics, Early laparoscopic cholecystectomy ($< 72\text{ hours}$) |
| Choledocholithiasis | Common bile duct (CBD) stone | RUQ/epigastric pain, jaundice, elevated ALP and conjugated bilirubin | Dilated CBD ($> 6\text{ mm}$), +/- visualized stone in CBD | ERCP with sphincterotomy and stone extraction $\rightarrow$ Cholecystectomy |
| Ascending Cholangitis | Infected CBD obstruction | Charcot's Triad: Fever, Jaundice, RUQ pain.<br/>Reynolds' Pentad: + Shock & altered mental status | Dilated CBD, biliary ductal gas / sludge | EMERGENT ERCP biliary decompression + broad-spectrum IV antibiotics |
| Gallstone Ileus | Cholecystenteric fistula (duodenum) | Mechanical small bowel obstruction in elderly female | Rigler's Triad: Pneumobilia, SBO, ectopic gallstone in RLQ | Enterolithotomy (stone extraction) +/- repair of fistula |
⚠️ Exam Trap: Do NOT confuse acute cholecystitis with ascending cholangitis. Acute cholecystitis causes normal or slightly elevated bilirubin because the CBD remains open; ascending cholangitis involves common bile duct obstruction and causes severe conjugated hyperbilirubinemia, jaundice, and potential septic shock.
Intestinal Obstruction & Volvulus
Small Bowel Obstruction (SBO)
- Etiology: Postoperative adhesions (60–70% of cases), incarcerated hernias (20%), and primary/metastatic malignancy (10%).
- Clinical Presentation: High-pitched hyperactive bowel sounds early ('tinkling'), progressing to absent sounds; crampy abdominal pain, bilious vomiting, abdominal distension, and obstipation (inability to pass flatus or stool).
- Imaging Findings: Abdominal X-ray shows dilated loops of small bowel ($> 3\text{ cm}$), central distribution, multiple air-fluid levels in a step-ladder configuration, and absence of colonic gas. CT with IV contrast is definitive to identify transition point and ischemia.
- Management:
- Uncomplicated / Partial SBO: Initial conservative trial with NPO, nasogastric (NG) tube suction decompression, IV fluid resuscitation, and correction of hypokalemia/hypochloremia. Water-soluble contrast (Gastrografin) challenge accelerates resolution.
- Complicated / Strangulated SBO: Signs of ischemia (fever, leukocytosis, localized peritonitis, elevated serum lactate, loss of bowel wall enhancement on CT) require emergency exploratory laparotomy and resection of necrotic bowel.
Large Bowel Obstruction (LBO) & Volvulus
- Etiology: Colorectal adenocarcinoma (most common cause of LBO), followed by diverticular strictures and volvulus.
- Sigmoid Volvulus: Torsion of sigmoid colon on its mesentery, common in elderly, institutionalized patients with chronic constipation. Abdominal X-ray shows classic 'coffee bean sign' pointing to RUQ. Initial management: Endoscopic sigmoidoscopic decompression and rectal tube placement, followed by elective resection.
- Cecal Volvulus: Torsion of cecum in younger patients with mobile cecum. X-ray shows embryonic 'comma-shaped' cecum in LUQ. Treatment is emergent surgical resection (right hemicolectomy); endoscopic reduction is contraindicated due to high failure and ischemia rates.
Perforated Viscus & Peritonitis
Perforation of any hollow viscus (duodenal ulcer, perforated diverticulitis, appendiceal rupture) releases gastric/intestinal contents into the peritoneal cavity.
- Physical Exam: Board-like abdominal rigidity, severe involuntary guarding, rebound tenderness, and absent bowel sounds.
- Diagnostic Key: Upright chest radiograph or CT scan showing pneumoperitoneum (free air under the diaphragmatic domes).
- Immediate Therapy: Aggressive IV fluid resuscitation, immediate IV broad-spectrum antibiotics (covering enteric Gram-negative rods and anaerobes), and emergent exploratory laparotomy for definitive source control.
A 67-year-old female presents to the emergency department with a 12-hour history of severe RUQ pain, shaking chills, and yellowing of her eyes. Vital signs: T 39.2°C, BP 82/48 mmHg, HR 128 bpm, RR 24/min. She is lethargic and confused. Physical exam reveals marked scleral icterus and severe RUQ tenderness. Lab results show WBC 22,000/uL, total bilirubin 145 umol/L, ALP 480 U/L. Ultrasound demonstrates multiple gallstones and a common bile duct diameter of 11 mm. What is the most appropriate definitive management?
A 45-year-old male with a history of open appendectomy 10 years ago presents with 2 days of crampy abdominal pain, bilious vomiting, and abdominal distension. He has not passed flatus for 24 hours. On exam, his abdomen is distended with high-pitched bowel sounds. T 37.1°C, BP 124/78 mmHg, HR 88 bpm. WBC is 8,500/uL, lactate is 1.1 mmol/L. Abdominal radiograph confirms small bowel obstruction with dilated loops and air-fluid levels. What is the most appropriate next step in management?
A 22-year-old male presents with a 14-hour history of abdominal pain. The pain started around his belly button and has moved to his right lower abdomen. He reports total loss of appetite and nausea. T 38.1°C, HR 96 bpm. Palpation reveals maximal tenderness at McBurney's point with rebound tenderness and a positive Rovsing sign. What is the most appropriate diagnostic or management step?