What are the clinical features and management of a peritonitic abdomen?

Clinical Features of Peritonitic Abdomen

A peritonitic abdomen is characterized primarily by abdominal pain and tenderness with rebound tenderness and guarding, often accompanied by systemic inflammatory responses including fever, tachycardia, and tachypnea. 1, 2

Cardinal Clinical Features

• Abdominal pain and tenderness are present in 74-95% of patients, typically accompanied by rebound tenderness and guarding, which are hallmark signs of peritoneal inflammation 1
• Tachycardia is observed in 62.5% of patients as part of the systemic inflammatory response 1
• Fever greater than 38.5°C is present in 38% of patients 1
• Decreased or absent bowel sounds due to developing ileus 1
• Abdominal rigidity, which strongly suggests the presence of peritonitis 2
• Hypotension and hypoperfusion signs (lactic acidosis, oliguria, altered mental status) indicate ongoing sepsis 2

Additional Clinical Manifestations

• Leukocytosis with a left shift (band neutrophils >20%) is a common laboratory finding 1
• Elevated C-reactive protein (CRP) levels are observed 1
• Isolated abdominal distension is seen in 6.6% of patients 1
• Ileus symptoms, including vomiting and absence of defecation 1
• Rectal bleeding may be observed in 15% of patients, depending on the underlying cause 1

Diagnostic Approach

• Diagnosis is primarily based on clinical assessment, especially in resource-limited settings 2
• Laboratory evaluation should include white blood cell count and C-reactive protein to assess inflammation severity 3
• In patients not requiring immediate surgery, CT scan is the imaging modality of choice to determine the source of intra-abdominal infection 3
• CT is more sensitive than standard abdominal radiographs for detecting free air 3
• Ultrasound can be a valuable tool in resource-limited settings to identify free fluid in the abdomen 2

Types of Peritonitis

Primary Peritonitis (Spontaneous Bacterial Peritonitis)

• Develops without gastrointestinal tract disruption, typically in patients with cirrhosis 1
• Ascitic fluid analysis showing neutrophil count >250/mm³ is diagnostic 1
• Usually only one microorganism is isolated from ascitic fluid culture 1

Secondary Peritonitis

• Results from gastrointestinal tract perforation 1
• Ascitic fluid culture usually shows multiple microorganisms 1
• Ascitic fluid analysis may show high total protein levels, elevated LDH, and low glucose levels (<50 mg/dL) 1

Tertiary Peritonitis

• Defined as recurrent intra-abdominal infection occurring 48 hours after successful control of secondary peritonitis 4
• Associated with high mortality and often involves multidrug-resistant organisms 4

Management Considerations

• Rapid restoration of intravascular volume should begin immediately when hypotension is identified 3
• Antimicrobial therapy should be initiated once intra-abdominal infection is diagnosed or considered likely 3
• For patients with septic shock, antibiotics should be administered as soon as possible 3
• Diffuse peritonitis requires emergency surgical procedure as soon as possible 3
• Appropriate source control procedure is recommended for nearly all patients with intra-abdominal infection 2
• For intra-abdominal infections including peritonitis, antimicrobial therapy should cover both aerobic bacteria (especially E. coli) and anaerobic bacteria (especially B. fragilis) 5, 6

Common Pitfalls and Caveats

• Delay in diagnosis and treatment significantly increases mortality rates, especially in patients with diffuse peritonitis 2
• Peritoneal signs may be masked in elderly patients, immunocompromised individuals, or those on corticosteroids 3
• Absence of fever or leukocytosis does not rule out peritonitis, especially in elderly or immunocompromised patients 1
• Inadequate source control is associated with significantly elevated mortality rates 2
• Overreliance on imaging when clinical signs clearly indicate diffuse peritonitis requiring immediate surgical intervention can lead to harmful delays in treatment 3