Rigler's Sign: Clinical Significance and Management
Rigler's sign is a radiographic finding of pneumoperitoneum characterized by visualization of both sides of the bowel wall due to the presence of free intraperitoneal air, which indicates a potential bowel perforation requiring prompt surgical evaluation.
Definition and Clinical Significance
- Rigler's sign (also called the "double wall sign") occurs when free intraperitoneal air outlines both the inner and outer walls of the bowel, making both surfaces visible on radiographs 1
- It is one of several radiographic signs of pneumoperitoneum, with a sensitivity of approximately 32% for detecting free intraperitoneal air 2
- Pneumoperitoneum most commonly indicates perforation of a hollow viscus that requires urgent surgical intervention 3, 1
- The presence of Rigler's sign should prompt immediate evaluation for potential bowel perforation, as delay in diagnosis beyond 24 hours significantly increases morbidity and mortality 4
Diagnostic Value
- Rigler's sign is most commonly identified on supine abdominal radiographs but can also be seen on chest radiographs 2
- Other radiographic signs of pneumoperitoneum include:
- CT scan is more sensitive than plain radiographs for detecting pneumoperitoneum and should be performed when clinical suspicion is high despite negative or equivocal radiographs 1
Causes of Pneumoperitoneum
Surgical Causes (Requiring Intervention)
- Perforated peptic ulcer
- Perforated diverticulitis
- Perforated appendicitis
- Iatrogenic colonoscopy perforation (0.016-0.8% of all colonoscopies) 4
- Traumatic bowel perforation 4
Non-Surgical Causes (Benign Pneumoperitoneum)
- Post-procedural (after laparoscopy, endoscopy without perforation) 5
- Peritoneal dialysis
- Pneumatosis intestinalis
- Pneumomediastinum with air tracking down to the peritoneum
- Gynecological causes (vaginal douching, sexual intercourse, pelvic inflammatory disease) 3, 6
- Idiopathic spontaneous pneumoperitoneum (extremely rare) 6
Management Algorithm
Initial Assessment
- Evaluate vital signs and hemodynamic stability
- Assess for signs of peritonitis:
- Abdominal pain and tenderness
- Guarding/rebound tenderness
- Abdominal distension
- Fever, tachycardia 4
Diagnostic Workup
Laboratory tests:
- Complete blood count (leukocytosis suggests infection)
- C-reactive protein (elevated in inflammation)
- Pro-calcitonin (useful in delayed presentation >12 hours) 4
Imaging:
Management Decision Tree
For Hemodynamically Unstable Patients with Peritonitis
- Immediate surgical exploration is mandatory 4
- Resuscitation with IV fluids and antibiotics before surgery 4
- Damage control laparotomy may be necessary in critically ill patients 4
For Hemodynamically Stable Patients with Peritonitis
- Surgical exploration is recommended 4
- The approach (laparoscopic vs. open) depends on surgeon expertise and patient factors 4
For Stable Patients with Pneumoperitoneum but No Peritonitis
- Consider non-surgical causes of pneumoperitoneum 3, 6
- Close observation with serial physical examinations for 48 hours 4
- Repeat imaging if clinical condition changes 4
Surgical Management Options
- Primary repair of perforation when feasible 4
- Resection with primary anastomosis in healthy tissue with minimal contamination 4
- Diversion (stoma creation) may be necessary in cases of:
- Significant fecal contamination
- Delayed diagnosis (>24 hours)
- Hemodynamic instability
- Multiple comorbidities 4
Clinical Pitfalls and Caveats
- Not all pneumoperitoneum requires surgery - benign pneumoperitoneum can occur after colonoscopy without perforation 5
- Absence of free air does not exclude perforation - sensitivity of plain radiographs is limited 1, 2
- Clinical signs may be masked in elderly, immunocompromised, or diabetic patients (similar to Murphy's sign in cholecystitis) 7
- Delay in diagnosis beyond 24 hours significantly increases morbidity and mortality 4
- CT findings must be correlated with clinical presentation - not all radiographic pneumoperitoneum requires surgical intervention 3, 6