Peritonitis

Question 1

Define peritonitis

Answer 1

Irritation of the peritoneum and inflammation of the peritoneal cavity

Localised – acute inflammatory conditions e.g. acute appendicitis

Generalised – irritation of the peritoneum caused by rupture of an abdominal viscus e.g.
infectious irritation due to perforated appendix, chemical irritation due to perforated ulcer

Question 2

What are the causes/risk factors of peritonitis?

Answer 2

Infectious causes
• Perforation of the GI tract
• Disruption of the peritoneum e.g. trauma, peritoneal dialysis
• Systemic infection
• Spontaneous bacterial peritonitis
• Pelvic inflammatory disease

Non-infectious causes
• Leakage of body fluids into peritoneum e.g. blood (trauma), gastric juice (ulcer)
• Abdominal surgery

Risk factors
• Previous history of peritonitis
• History of alcoholism
• Liver disease
• Fluid accumulation in the
abdomen
• Weakened immune system
• Pelvic inflammatory
disease

Question 3

What are the symptoms of peritonitis?

Answer 3

• Abdominal
pain/tenderness

Development of ileus paralyticus
• Nausea
• Vomiting
• Bloating

Question 4

What are the signs of peritonitis?

Answer 4

• Abdominal tenderness/guarding
• Diffuse abdominal rigidity (“washboard stomach”)
• Fever
• Sinus tachycardia

Question 5

What investigations are carried out for peritonitis?

Answer 5

• FBC - leukocytosis
• U&Es - may show signs of dehydration (isolated elevated urea, with high sodium) or signs of AKI in sepsis
• LFTs - may show dysfunction, especially if the patient is ascitic and the cause is hepatic.
• Amylase - raised if peritonitis is due to pancreatic leakage.
• CRP - elevated
• Blood Cultures - may flag up as positive for bacteria in the case of sepsis
• ABG - respiratory failure and acidosis.
• Clotting Screen and G&S - since peritonitis is often treated surgically.
• CXR - erect, showing pneumoperitoneum.
• AXR - can show intra-abdominal pathology and GI obstruction.
• Other Ix - abdominal USS, CT Abdomen, Investigative Laparoscopy.
In patients with ascites: Ascitic tap and cell count –SBP if neutrophils > 250/mm3. Gram-stain and culture of the ascitic tap

Question 6

What is the management for peritonitis?

Answer 6

Localised
• Treatment of the underlying cause
• Surgery indicated for appendicitis; Abx for most other conditions.
• Analgesia may be given for the pain until the inflammation subdues.

Generalised:
• Patient is at risk of death from sepsis and shock. Sepsis 6 and correct electrolyte imbalances and give inotropes and vasoconstrictors to prevent fluid loss to third space.
• Urgent laparotomy should be performed to remove the infected or necrotic tissue, treat the cause and perform peritoneal lavage with copious irrigation to remove all the exudate.
• Exception: Acute non-necrotising pancreatitis.
• Primary peritonitis is treated with antibiotics, but this diagnosis is often not apparent until after attempted operative intervention

Question 7

What are the complications of peritonitis?

Answer 7

Early: 
• Septic shock  
• Respiratory failure  
• Multi-organ failure  
• Paralytic ileus  
• Tertiary peritonitis (persistence of intra-abdominal infection) 
• Abscesses 
• Hepatic abscesses –portal pyaema 

Late:
• Adhesions
• Incisional hernias