Management of Abdominal Rigidity in Acute Peritonitis

Pathophysiology and Clinical Significance

• A board‑like rigid abdomen signals peritonitis caused by hollow‑viscus perforation, bowel ischemia, or severe intra‑abdominal infection and mandates immediate surgical intervention after rapid resuscitation. 1, 2
• Abdominal rigidity is an involuntary contraction of the abdominal wall in response to peritoneal inflammation, distinguishing it from voluntary guarding. 1
• The presence of rigidity indicates peritonitis and requires urgent evaluation for life‑threatening intra‑abdominal pathology. 2

Initial Assessment and Resuscitation

• Evaluate for septic‑shock signs—including hypotension, lactic acidosis, oliguria, and altered mental status—when rigidity is observed. 1, 2
• Look for systemic inflammatory response (fever, tachycardia, tachypnea) accompanying rigidity. 1

Diagnostic Work‑up in Hemodynamically Stable Patients

• Obtain a complete blood count, serum creatinine, and inflammatory markers (C‑reactive protein, procalcitonin, lactate) to gauge severity. 3
• Perform contrast‑enhanced CT angiography of the abdomen and pelvis as the gold‑standard imaging modality. 2, 4
• CT imaging identifies the source of peritonitis, detects free intraperitoneal air, assesses bowel ischemia, and reveals abscesses or other complications. 2
• When CT is unavailable, upright and supine plain abdominal X‑ray combined with ultrasound can cost‑effectively detect free air, bowel obstruction, and fluid collections. 1, 2

Surgical Indications and Immediate Management

• Presence of free intraperitoneal air on imaging together with clinical peritonitis warrants immediate surgery. 1, 2
• Evidence of bowel ischemia or necrosis also mandates urgent operative intervention. 4
• Surgical goals include:
  
  • Identifying and controlling the source of contamination. 1, 2
  • Resection of non‑viable bowel. 4
  • Application of damage‑control techniques in critically ill patients. 4, 5

Open Abdomen and Damage‑Control Strategies

• In patients with severe sepsis, leaving the abdomen open may prevent abdominal compartment syndrome, especially when primary fascial closure would create excessive tension. 6, 5
• Intra‑abdominal pressure measurement intraoperatively can guide the decision to maintain an open abdomen. 5

Post‑operative Considerations and Pitfalls

• Incomplete or delayed source control markedly worsens outcomes; a planned second‑look laparotomy at 24–48 hours is recommended when bowel viability is uncertain. 4
• Over‑resuscitation with crystalloids can precipitate abdominal compartment syndrome; clinicians should monitor for intra‑abdominal hypertension (decreased urine output, increased peak airway pressures, hemodynamic instability). 4, 5
• Direct measurement of intra‑abdominal pressure assists in early detection of abdominal hypertension. 5

Initial Management of Abdominal Rigidity

Immediate Assessment and Resuscitation

• The American College of Surgeons recommends assessing hemodynamic stability first by checking blood pressure, heart rate, mental status, and peripheral perfusion in patients with abdominal rigidity 7
• Obtain IV access immediately and begin crystalloid resuscitation with at least 30 mL/kg within the first 3 hours if hypotension or signs of sepsis are present, as recommended by the American College of Surgeons 7

Diagnostic Algorithm Based on Hemodynamic Status

• The Society of Critical Care Medicine recommends proceeding directly to laparotomy without delay if diffuse abdominal rigidity is present with hypotension, tachycardia, or signs of shock 8
• Do not wait for imaging studies in unstable patients with clear peritonitis, as recommended by the World Journal of Emergency Surgery 9

Antibiotic Administration

• The Infectious Diseases Society of America recommends administering effective IV antimicrobials within the first hour of recognizing severe sepsis or septic shock associated with abdominal rigidity 7
• Use empiric broad-spectrum antibiotics covering aerobic gram-negative organisms and anaerobes once intra-abdominal infection is diagnosed, as recommended by the American College of Surgeons 8

Surgical Decision-Making

• The American College of Surgeons recommends immediate surgery for diffuse peritonitis with hemodynamic instability, signs of shock, gangrene, or bowel perforation 8
• The World Journal of Emergency Surgery recommends open laparotomy for unstable patients or those with diffuse peritonitis 10

Critical Pitfalls to Avoid

• The American College of Surgeons recommends not delaying diagnosis through over-reliance on imaging when clinical suspicion is high, and diagnostic laparoscopy should be performed if imaging is negative but rigidity persists 8
• Target mean arterial pressure ≥65 mmHg with norepinephrine as first-line vasopressor if hypotension persists despite fluid resuscitation, as recommended by the American College of Surgeons 7