S8) Abdominal Catastrophes

Question 1

What is an abdominal catastrophe?

Answer 1

An abdominal catastrophe is an event within or behind the abdominal cavity that poses an imminent threat to life

Question 2

What is referred pain?

Answer 2

Referred pain is pain perceived at a site distant from the site causing the pain

Question 3

What is somatic referred pain?

Answer 3

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

Question 4

How does visceral referred pain occur?

Answer 4

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

Question 5

What causes visceral pain?

Answer 5

• Abnormally strong muscle contraction and stretch
• Inflammation
• Ischaemia

Question 6

Identify the three common regions where visceral pain is felt

Answer 6

Question 7

Where is gastric and duodenal pain felt?

Answer 7

Question 8

Where is gallbladder pain felt?

Answer 8

Question 9

Where is splenic pain felt?

Answer 9

Question 10

Where is pain due to acute appendicitis felt?

Answer 10

Question 11

Where is pancreatic and abdominal aorta pain felt?

Answer 11

Question 12

Where is small bowel colic felt?

Answer 12

Question 13

Where is large bowel colic felt?

Answer 13

Question 14

Where is renal/ureteric colic felt?

Answer 14

Question 15

Where is pain due to peritonitis felt?

Answer 15

Question 16

In terms of pain, how do patients with peritonitis present?

Answer 16

• 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)

Question 17

Explain why an inflamed peritoneal cavity can exude litres of fluid

Answer 17

• Large surface area
• Fluid can collect in abdomen
• Perfusion rate can increase

Question 18

In a bowel obstruction, dehydration and increased haematocrit occur due to increased fluid loss.

Why is this?

Answer 18

• Accumulation of fluids
• Increased secretion
• Decreased reabsorption

Question 19

In four steps, explain why several patients with bowel obstructions are in hypovolaemic shock at the time of presentation

Answer 19

⇒ 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)

Question 20

Identify 2 useful indicators of dehydration in the context of bowel obstruction

Answer 20

• Raised haematocrit (>55%)
• Raised serum urea

Question 21

Identify 5 types of abdominal catastrophes

Answer 21

• Blood loss
• Perforation of a viscus (inflammation, hypovolaemia, sepsis)
• Acute pancreatitis
• Acute cholangitis
• Acute gut ischaemia

Question 22

Where is blood lost to in an abdominal catastrophe?

Answer 22

• Into the gut
• Into the retroperitoneum
• Into the peritoneal cavity

Question 23

Identify three common causes of bleeding into the gut and briefly describe how they present

Answer 23

• Bleeding oesophageal varices (haematemesis and melaena)
• Bleeding peptic ulcer (haematemesis and melaena)
• Bleeding diverticular disease (haematochezia)

Question 24

What is haematemesis?

Answer 24

Haematemesis is the vomiting of blood

Question 25

What is haematochezia?

Answer 25

**Haematochezia** is bright red bleeding from the rectum, often seen with/in stools

Question 26

What do haematemesis and haematochezia indicate?

Answer 26

Patient is bleeding massively from the upper GI tract

Question 27

What is melaena?

Answer 27

**Melaena** is the passage of black tarry stools

Question 28

What causes melaena and when does it occur?

Answer 28

- Caused by alteration of blood by **digestive enzymes** and **intestinal bacteria** - Occurs with **bleeding** anywhere from the **mouth to caecum**

Question 29

Patients taking oral iron have black stools. What is the difference between this and melaena?

Answer 29

The **smell** will reveal the difference

Question 30

How do bleeding duodenal ulcers present?

Answer 30

**Bleeding duodenal ulcers** nearly always present as a posterior duodenal ulcer that has eroded into the gastroduodenal artery

Question 31

Why is serum urea a helpful indicator of upper GIT bleeding?

Answer 31

- Patients bleeding from the stomach/oesophagus present a large protein meal to the small bowel where it is **converted by the liver into urea** - A **rise in serum urea** with a normal serum creatinine indicates: the **source & magnitude** of the bleeding

Question 32

What are the two commonest causes of retroperitoneal bleeding?

Answer 32

- Ruptured **abdominal aortic aneurysm** (AAA) - Patients on **anticoagulants** may bleed from torn retroperitoneal veins

Question 33

Describe the typical presentation of a ruptured AAA

Answer 33

- Sudden death (50%) - Sudden onset of severe abdominal, back or loin pain - Sudden collapse - Hypovolaemic shock

Question 34

Briefly outline the outcome of a ruptured AAA

Answer 34

- Overall survival is about 17% (hospital, operation, recover) - Overall mortality is 83% (sudden death/multi-organ failure in ITU)

Question 35

How does ectopic pregnancy present in women of reproductive age?

Answer 35

- Lower abdominal pain - Vaginal bleeding - Collapse - Left shoulder tip pain on lying down

Question 36

What are the two commonest causes of perforation of the viscus?

Answer 36

- Perforated peptic ulcer - Perforated diverticular disease

Question 37

What are the two types of perforated peptic ulcers?

Answer 37

- Anterior perforated duodenal ulcer (more common) - Posterior perforated gastric ulcer

Question 38

What are the effects of the posterior perforation of a gastric ulcer?

Answer 38

- Initially allows gastric contents to enter the lesser sac - Then fluid can track into the greater sac via the epiploic foramen

Question 39

State the respective complications of perforated peptic ulcerations and perforated diverticular disease respectively as well as their associated mortality rates

Answer 39

- Perforated peptic ulceration leads to a **chemical peritonitis** (mortality 10%) - Perforated diverticular disease leads to **peritoneal sepsis and septicemia** (mortality rate 50%)

Question 40

What is a major clinical indicator of perforated viscus?

Answer 40

Pneumoperitoneum

Question 41

Which two abnormalities must be corrected before the administration of anaesthesia?

Answer 41

- Potassium imbalances (hyperkalaemia & hypokalaemia) - Fluid and electrolyte imbalances

Question 42

Why must potassium imbalances be corrected before the administration of anaesthesia?

Answer 42

Many anaesthetic agents affect cardiac muscle/conduction function

Question 43

Why must electrolyte and fluid imbalances be corrected before the administration of anaesthesia?

Answer 43

- Anaesthetic agents dramatically **reduce sympathetic tone** & have a **negative inotropic effect** - In a patient who is dehydrated the **SNS is maximally activated** to maintain vital organ perfusion & hence could develop **hypotension** and possible **die**

Question 44

Identify 4 causes of obstruction to the small bowel

Answer 44

- Adhesions due to previous surgery - Femoral/inguinal hernia - Volvulus - Carcinoma of the caecum

Question 45

Identify 3 causes of obstruction to the large bowel

Answer 45

- Carcinoma (particularly left-sided) - Sigmoid volvulus - Diverticular disease

Question 46

What is the end result of a bowel obstruction?

Answer 46

- Isotonic hypovolaemia - Hypochloremia - Hypokalemia - Metabolic alkalosis

Question 47

In 4 steps, describe how bowel obstructions lead to metabolic alkalosis and hypokalaemia

Answer 47

⇒ Vomiting leads to loss of H⁺ and Cl^- ⇒ Metabolic alkalosis ⇒ Renal compensation preserves H⁺ at the expense of K⁺ ⇒ Hypokalemia ensues

Question 48

What is acute pancreatitis?

Answer 48

**Acute pancreatitis** is a clinical condition involving the autodigestion by proteases of the retroperitoneum

Question 49

Describe the aetiology of acute pancreatitis

Answer 49

- Alcohol - Gallstones

Question 50

Describe the management of acute pancreatitis

Answer 50

- No specific treatment - Supportive management (fluid resuscitation & pain relief)

Question 51

What can be used to diagnose acute pancreatitis?

Answer 51

Raised serum amylase

Question 52

What is the commonest cause of acute gut ischaemia?

Answer 52

Embolism (atrial fibrillation)

Question 53

How do patients with acute gut ischaemia present?

Answer 53

- Severe abdominal pain - Tender over ischaemic gut (on examination) - Patients rapidly become ‘toxic’ and hypotensive

Question 54

How can acute gut ischaemia be diagnosed?

Answer 54

Very high white cell count \>20 x10⁹/l (normal – 4-11/l)

Question 55

What is the treatment for acute gut ischaemia?

Answer 55

Urgent laparotomy and resection of dead bowel

Question 56

What is acute cholangitis?

Answer 56

**Acute cholangitis** is a clinical condition involving an infection in the bile ducts

Question 57

What is the commonest cause of acute cholangitis?

Answer 57

Obstruction of the common bile duct by the gallstone, leading to jaundice and biliary stasis

Question 58

What is the commonest causative organism in acute cholangitis?

Answer 58

E.Coli