Peritonitis*

Question 1

What are some causes of peritonitis?

Answer 1

Primary:

• aka ‘spontaneous bacterial peritonitis’/SBP
• Infection develops in the peritoneum = rare
• Can occur in children and those with ascites
• Treated differently

Secondary:
- Can be infective or non-infective

Infection secondary to:

• Perforation of the GI or reproductive tract e.g. ingestion of sharp object, trauma, ulceration, ruptured ectopic or fallopian tube
• G-ve and anaerobic bacteria from GI tract e.g. E.coli*
• Disruption of the peritoneum e.g. by surgery, trauma, peritoneal dialysis - bacteria from external environment e.g. S.aureus*
• Systemic infections e.g. TB = rarer
• SBP

Non-infective:

• Leakage of sterile body fluids into peritoneum e.g. blood, bile, urine; these are sterile at first but become colonised and infective peritonitis within 24-48hrs
• Autoimmune e.g. Lupus

Question 2

What is the pathophysiology of peritonitis?

Answer 2

Inflammation of the peritoneum

Generalised or localised

• Almost always some localised when just a single organ is affected as a result of a specific disease process e.g. cholecystitis
• Generalised = more serious as it leads to a significant production of inflammatory factors leading to intestinal dilatation and paralytic ileus

Question 3

How does peritonitis present?

Answer 3

Sudden, acute onset abdominal pain exacerbated by movement
- May be generalised then become localised (as visceral fibres initially affected are poorly localising, then parietal nerve fibres will relate more directly to skin outside) - may then become generalised again if serious inflammation

Nausea + vomiting 
Abdo distension 
Fever 
Sinus tachycardia 
Washboard rigidity and rebound tenderness 
Shock

Question 4

What are some complications of peritonitis?

Answer 4

Loss of fluids and electrolyte imbalance - due to ascites, or haemorrhage

Difficulty breathing - due to pressure of fluid on diaphragm

(Peritoneal) abscess

Sepsis

Question 5

How do you investigate peritonitis?

Answer 5

Bloods:
- Usual profile e.g. FBC for WCC, amylase - to rule out pancreatitis, ABG - to monitor systemic shock response etc

Erect CXR:
- To check for air under the diaphragm

AXR/CT +/- barium/enema or other contrast
- To check what is going on inside

Question 6

How do you manage peritonitis?

Answer 6

NBM

Oxygen

IV fluids - for hypovolaemia

Correct electrolyte abnormalities

IV Abx:
- For infective peritonitis and those suspected to need surgery

Analgesia

Laparotomy:
- To repair any perforations, fix any other problems + a cavity washout