13. Abdominal Catastophes

Question 1

What is the definition of an abdominal catastrophe?

Answer 1

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

Question 2

What nerves supply the parietal peritoneum and so pain is perceived as being at the site of the inflammation?

Answer 2

Same nerves that supply the skin of the abdomen.

Question 3

What nerves supply the visceral peritoneum and therefore produce deferred pain?

Answer 3

Autonomic nervous system.

Question 4

What is somatic pain?

Answer 4

Pain detected by nerves in the skin and deep tissues.

Question 5

What is somatic referred pain?

Answer 5

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 6

What is visceral pain?

Answer 6

Pain detected by nerves in organs.

Question 7

What is visceral referred pain?

Answer 7

Pain perceived by the CNS as coming from the somatic portion of the body supplied by the spinal cord segments that give rise to the preganglionic sympathetic fibres that the visceral afferent pain fibres follow back to the spinal cord.

Question 8

What 2 things cause visceral pain?

Answer 8

Abnormally strong muscle contraction and stretch.
Inflammation.
Ischaemia.

Question 9

Where is foregut pain felt?

Answer 9

Epigastric region.

Question 10

Where is midgut pain felt?

Answer 10

Periumbilical region.

Question 11

Where is hindgut pain felt?

Answer 11

Suprapubic region.

Question 12

If a patient suddenly drops down on the floor, rolling around in pain, what is the likely diagnosis?

Answer 12

Ureteric colic.

Question 13

Why do patients with a small intestinal obstruction become rapidly dehydrated?

Answer 13

Fluid loss occurs due to accumulation of fluids, increased secretion and decreased reabsorption. This causes loss of isotonic salt water resulting in isotonic contraction of the ECF volume and so dehydration occurs. 3-4 litres of isotonic fluid can sequester in the gut, and so when vomiting begins this is removed, leaving space in the gut for more to be sequestered. Therefore rapidly lose fluid from ECF.

Question 14

What can be seen in a blood test as indicators of dehydration in small intestine obstruction?

Answer 14

Raised haematocrit and raised serum urea.

Question 15

Give 3 common causes of bleeding into the gut and how is the bleeding seen clinically with each?

Answer 15

Bleeding oesophageal varices - haematemesis and melaena.
Bleeding peptic ulcer - haematemisis and melaena.
Bleeding diverticulum disease - haematochezia.

Question 16

What artery is likely to be eroded in a bleeding duodenal ulcer, and so where on the duodenum is the ulcer?

Answer 16

Posterior duodenal ulcer - gastroduodenal artery.

Question 17

What is happening is a patient has haematemesis and haematochezia?

Answer 17

Patient is bleeding massively from the upper GI tract.

Question 18

If serum creatinine is normal, what does a rise in blood urea in a patient with oesophagus/gastric bleeding help indicate?

Answer 18

The source of the bleeding (stomach or oesophagus).

The higher the blood urea rise, the larger the bleed.

Question 19

What are the 2 commonest causes of retroperitoneal bleeding?

Answer 19

Ruptured abdominal aortic aneurysm.

Patient on anticoagulants bleeding from torn retroperitoneal veins.

Question 20

What is usually the INR of a patient who is bleeding from torn retroperitoneal veins?

Answer 20

> 5.0.

Question 21

Give 3 ways that a patient with a ruptures AAA can present.

Answer 21

Sudden death.
Sudden onset of severe abdominal and back/loin pain.
Sudden collapse.
Presents to the emergency department with ‘shock’.

Question 22

A women presents to A and E with lower abdominal pain, vaginal bleeding, collapse and left shoulder top pain on lying down. She is also of reproductive age. What is the likely diagnosis?

Answer 22

Ruptured ectopic pregnancy.

Question 23

How might fluid that has entered into the lesser sac from a perforated gastric ulcer enter into the greater sac?

Answer 23

Epiploic (mental) foramen.

Question 24

What leads to chemical peritonitis?

Answer 24

Perforated peptic ulcer.

Question 25

What does a pneumoperitoneum usually indicate?

Answer 25

A perforated viscus.

Question 26

Why should a patient who is dehydrated have their fluid levels corrected as much as possible prior to anaesthesia?

Answer 26

In the dehydrated patient, the sympathetic nervous system is maximally activated to maintain vital organ perfusion. Anaesthetic agents dramatically reduce sympathetic tone as they paralyse the autonomic nervous system. Therefore if dehydrated, when given anaesthesia the patient may become profoundly hypotension and die.

Question 27

Why should a patient who is dehydrated have their electrolyte levels corrected as much as possible prior to anaesthesia?

Answer 27

Anaesthetic agents affect cardiac muscle/conduction function.
In hyperkalaemia membrane depolarises a bit, inactivated some V-gated Na+ channels, slowing the upstroke. This can lead to asystole.
In hypokalaemia the action potential is lengthened which delays repolarisation. Leads to early after depolarisations, oscillations in membrane potential and VF.

Question 28

Give 3 causes of small bowel obstruction

Answer 28

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

Question 29

Give 2 causes of large bowel obstruction

Answer 29

Carcinoma, particularly left-sided.
Sigmoid volvulus.
Diverticula disease.

Question 30

What can happen as a result of vomiting in bowel obstruction?

Answer 30

Firstly isotonic hypovolaemia, as fluid released into gut is not being reabsorbed. Vomiting as a result leads to loss of hydrogen and chloride ions, which leads to a metabolic alkalosis (H+ moves from blood into stomach). Renal compensation for this metabolic alkalosis is to preserve H+ at the expense of potassium. Hypokalemia ensues.
End result is hypochloremic, hypokalemic metabolic alkalosis.

Question 31

What seen in a blood test can help diagnose acute pancreatitis?

Answer 31

Raised serum amylase.

Question 32

What is the comments cause of acute gut ischaemia?

Answer 32

Embolism as a result of atrial fibrillation.

Question 33

A patient presents with severe abdominal pain. On examination you find them to be tender over the abdomen, hypotensive and they appear toxic. They also have a raised white cell count. What is the likely diagnosis? What should you do?

Answer 33

Acute gut ischaemia. Urgent laparotomy.

Question 34

What is acute cholangitis?

Answer 34

Infection of the bile ducts, usually caused by E. coli.

Question 35

What is the commonest cause of acute cholangitis?

Answer 35

Gallstone obstructing the common bile duct leading to jaundice and biliary stasis.

Question 36

What is the typical clinical presentation of acute cholangitis? What about if there is pus in the biliary ducts?

Answer 36

Charcot’s triad - jaundice, RUQ pain, fever.
Presence of pus in biliary ducts - Charcot’s triad, plus hypotension and confusion. Patients often have rigors and can rapidly develop septic shock.

Question 37

How is acute cholangitis treated?

Answer 37

ERCP, sphincterotomy and stone extraction.

Question 38

Why can an ectopic pregnancy lead to shoulder tip pain?

Answer 38

Phrenic nerve supplies parietal peritoneum, so if ectopic pregnancy here, can be felt in the shoulder as C3,4,5 have sensory supply to the shoulder.