Peritonitis

Question 1

Definition

Answer 1

Inflammation of the peritoneal lining of the abdominal cavity. It can be localised to one
part of the peritoneum or generalised

Question 2

Aetiology/Risk factors (localised peritonitis)

Answer 2

o Appendicitis
o Cholecystitis
o Diverticulitis
o Salpingitis

Question 3

Aetiology/Risk factors (primary generalised peritonitis)

Answer 3

o Bacterial infection of the peritoneal cavity without an obvious source
• Could be via haematogenous or lymphatic spread or ascending infection
from the female genital tract)

o Risk Factors
• Ascites
• Nephrotic syndrome

Question 4

Aetiology/Risk factors (secondary generalised peritonitis)

Answer 4

o Caused by bacterial translocation from a localised focus

o Could be non-bacterial due to spillage of bowel contents, bile and blood (e.g. perforated peptic ulcer)

Question 5

Epidemiology

Answer 5

• Primary peritonitis is RARE
• Primary peritonitis is usually seen in adolescent females
• Localised and secondary generalised peritonitis is COMMON in surgical patients

Question 6

Presenting symptoms

Answer 6

• Do a full SOCRATES for peritonitis
• Inflammation of the parietal peritoneum is usually continuous, sharp, localised, exacerbated by movement and coughing
• Symptoms may be vague in those with liver disease and ascites (due to confusion caused by encephalopathy)

Question 7

Signs on physical examination

Answer 7

Check vital signs and look for signs of dehydration or compromised perfusion (e.g. due to sepsis or hypovolaemia)

• Localised Peritonitis
o Tenderness on examination
o Guarding
o Rebound tenderness

• Generalised Peritonitis
o Very unwell
o Systemic signs of toxaemia or sepsis (e.g. fever, tachycardia)
o The patient will lie still
o Shallow breathing
o Rigid abdomen
o Generalised abdominal tenderness
o Reduced bowel sounds (may be absent due to paralytic ileus)
o DRE may show anterior tenderness (suggests pelvic peritonitis)

Question 8

Investigations (bloods)

Answer 8

o FBC
o U&Es
o LFTs
o Amylase
o CRP
o Clotting
o Group & Save or Cross-match
o Blood cultures
o Pregnancy test 
o ABG

Question 9

Investigations (imaging)

Answer 9

o Erect CXR (check for air under the diaphragm)
o AXR (check for bowel obstruction)
o USS or CT abdomen
o Laparoscopy

Question 10

Investigations (if ascites)

Answer 10

o Ascitic tap and cell count
o SBP = > 250 neutrophils/mm3
o Gram stain and culture

Question 11

Management plan (localised peritonitis)

Answer 11

o Depends on CAUSE
o Some causes may require surgery (e.g. appendicitis)
o Some causes can be treated with antibiotics (e.g. salpingitis)

Question 12

Management plan (generalised peritonitis)

Answer 12

o Patient may be at risk of DEATH from sepsis or shock
o IV fluids
o IV antibiotics
o Urinary catheter
o NG tube
o Central venous line (to monitor fluid balance)

o Laparotomy
• Remove the infected or necrotic tissue
• Treat cause
• Peritoneal lavage

o Primary Peritonitis - should be treated with antibiotics

Question 13

Management plan (spontaneous bacterial peritonitis)

Answer 13

o Quinolone antibiotics

OR

o Cefuroxime + Metronidazole

Question 14

Possible complications (early)

Answer 14

o Septic shock
o Respiratory failure
o Multiorgan failure
o Paralytic ileus
o Wound infection
o Abscesses

Question 15

Possible complications (late)

Answer 15

o Incisional hernia

o Adhesions

Question 16

Prognosis

Answer 16

• Localised peritonitis usually resolves with treatment of the underlying cause
• Generalised peritonitis has a much higher mortality (30-50%)
• Primary peritonitis has a good prognosis with antibiotic treatment
• SBP has a mortality > 30% if diagnosis and treatment is delayed