The Acute Abdomen

Question 1

State the differential diagnoses for the acute abdomen.

Answer 1

• Non-specific pain (30-45%)
• Acute appendicitis (20-35%)
• Acute cholecystitis/colic (7-8%)
• Peptic ulcer perforation (4%)
• Urinary retention (4%)
• Acute pancreatitis (3%)
• Small bowel obstruction (3%)
• Trauma (3%)
• Urinary stones (3%)
• Large bowel obstruction (2-4%)
• Acute diverticulitis (2-4%)
• Malignancy (2%)
• Medical disorders (2%)
• Vascular conditions (2%)
• Gynaecological conditions 1%)

Question 2

Describe the principles of investigation of a patient with acute abdomen.

Answer 2

• Ward tests: urine
• Lab tests: FBC, U+E, LFT
• Radiology: plain US, axial CT
• Laparoscopy vs. laparotomy

Question 3

Describe the principles of clinical assessment of a patient with acute abdomen.

Answer 3

1. GP –> hospital admission

2. GP –> walk-in/ambulatory clinic –> hospital admission/home

Question 4

Describe the symptoms for patients presenting with an acute abdomen.

Answer 4

• Abdominal pain: character (visceral, somatic, referred), site, severity, system upset

Question 5

Describe the signs for patients presenting with an acute abdomen.

Answer 5

• Most patients appear ill

- Lie very still due to severe pain

Question 6

Discuss the management of patients with acute abdominal pain (including conditions such as peritonitis, obstruction and pancreatitis).

Answer 6

• Assess (+ resuscitate)
• Investigate
• Observe
• Treat
  Consider capacity and level of care required (intervention vs. palliation).

Question 7

Describe the aetiology of intestinal obstruction.

Answer 7

• Adhesions
• Hernias
• Tumours
• Gallstones/foreign body

Question 8

Describe the presentation of intestinal obstruction.

Answer 8

Cardinal features;
- Pain 
- Vomiting
- Distension
- Constipation
- Borborygmi
(All depend upon site of obstruction.)

Question 9

Define the acute abdomen.

Answer 9

A combination of symptoms and signs, including abdominal pain, which results in a patient being referred for an urgent general surgical opinion.

Question 10

Describe the routes of infection of peritonitis.

Answer 10

• Perforation of GI/biliary tract
• Female genital tract
• Penetration of abdominal wall
• Haematogenous spread

Question 11

Localised vs. generalised peritonitis

Answer 11

Generalised peritonitis represents failure of localisation and occurs when;

1. Contamination occurs too rapidly.
2. Contamination persists.
3. Abscess ruptures.

Question 12

Describe visceral pain.

Answer 12

• Pain receptors in smooth muscle.
• Afferent impulses run with sympathetic fibres accompanying segmental vessels (CP, SMA, IMA).
• Poorly localised.

Question 13

Describe somatic and referred pain.

Answer 13

• Receptors in parietal peritoneum or abdominal wall.
• Afferent signals pass with segmental nerves.
• Accurate localisation but can be referred.

Question 14

Describe the effects of peritonitis and obstruction.

Answer 14

Fluid loss/sepsis –> circulatory collapse –> death

The first 2 steps can cause one another.

Question 15

Describe the resuscitation procedure of a patient with acute abdomen.

Answer 15

• Restore circulating fluid volume
• Ensure tissue perfusion
• Enhance tissue oxygenation
• Treat sepsis
• Decompress gut
• Ensure adequate pain relief

Question 16

Describe active observation.

Answer 16

Useful when diagnosis is uncertain and risk of alternative intervention is greater.

Question 17

Describe the treatment of the acute abdomen.

Answer 17

• Pain relief
• Antibiotics
• Surgery