What is an abdominal catastrophe?
An abdominal catastrophe is an event within or behind the abdominal cavity that poses an imminent threat to life
What is referred pain?
Referred pain is pain perceived at a site distant from the site causing the pain
What is somatic referred pain?
Somatic referred pain is pain caused by a noxious stimulus to the proximal part of a somatic nerve that is perceived in the distal dermatome of the nerve
How does visceral referred pain occur?
Visceral referred pain occurs when visceral afferent pain fibres (thorax and abdomen) follow sympathetic fibres back to the same spinal cord segments that gave rise to the preganglionic sympathetic fibres
What causes visceral pain?
- Abnormally strong muscle contraction and stretch
Identify the three common regions where visceral pain is felt
Where is gastric and duodenal pain felt?
Where is gallbladder pain felt?
Where is splenic pain felt?
Where is pain due to acute appendicitis felt?
Where is pancreatic and abdominal aorta pain felt?
Where is small bowel colic felt?
Where is large bowel colic felt?
Where is renal/ureteric colic felt?
Where is pain due to peritonitis felt?
In terms of pain, how do patients with peritonitis present?
- Severe pain all over abdomen
- Pain may be referred to shoulder tips
- Shallow rapid breathing (diaphragmatic and abdominal wall movement)
- Very tender abdomen (on examination)
- ‘Rebound tenderness' (early stages)
Explain why an inflamed peritoneal cavity can exude litres of fluid
- Large surface area
- Fluid can collect in abdomen
- Perfusion rate can increase
In a bowel obstruction, dehydration and increased haematocrit occur due to increased fluid loss.
Why is this?
- Accumulation of fluids
- Increased secretion
- Decreased reabsorption
In four steps, explain why several patients with bowel obstructions are in hypovolaemic shock at the time of presentation
⇒ 3-4 L of isotonic fluid sequesters in gut
⇒ Vomiting begins & fluid is lost
⇒ More space for fluid to sequester
⇒ Hypovolaemic shock (±7 litres lost)
Identify 2 useful indicators of dehydration in the context of bowel obstruction
- Raised haematocrit (>55%)
- Raised serum urea
Identify 5 types of abdominal catastrophes
- Blood loss
- Perforation of a viscus (inflammation, hypovolaemia, sepsis)
- Acute pancreatitis
- Acute cholangitis
- Acute gut ischaemia
Where is blood lost to in an abdominal catastrophe?
- Into the gut
- Into the retroperitoneum
- Into the peritoneal cavity
Identify three common causes of bleeding into the gut and briefly describe how they present
- Bleeding oesophageal varices (haematemesis and melaena)
- Bleeding peptic ulcer (haematemesis and melaena)
- Bleeding diverticular disease (haematochezia)
What is haematemesis?
Haematemesis is the vomiting of blood
What is haematochezia?
Haematochezia is bright red bleeding from the rectum, often seen with/in stools
What do haematemesis and haematochezia indicate?
Patient is bleeding massively from the upper GI tract
What is melaena?
Melaena is the passage of black tarry stools
What causes melaena and when does it occur?
- Caused by alteration of blood by digestive enzymes and intestinal bacteria
- Occurs with bleeding anywhere from the mouth to caecum
Patients taking oral iron have black stools.
What is the difference between this and melaena?
The smell will reveal the difference
How do bleeding duodenal ulcers present?
Bleeding duodenal ulcers nearly always present as a posterior duodenal ulcer that has eroded into the gastroduodenal artery