8. Abdominal catastrophes

Question 1

what is haematochezia and what is its most common cause

Answer 1

• bright red bleeding per rectum

- diverticulitis

Question 2

name 2 common causes of haematemesis and melaena

Answer 2

1. bleeding oesophageal varices

2. bleeding peptic ulcer

Question 3

what is the most common location for bleeding peptic ulcers and which artery do they erode through

Answer 3

• posterior duodenal ulcers

- erode into gastroduodenal a.

Question 4

name a blood test that can help diagose upper GIT bleeds and explain why this parameter changes

Answer 4

• increased serum urea
• bleeding from stomach/oesophagus causes presence of much blood protein in small intestine which is then converted to urea by liver

Question 5

name 2 common causes of retroperitoneal bleeding

Answer 5

1. ruptured abdominal aortic aneurysm

2. torn retroperitoneal veins in Ps on anticoagulants

Question 6

name the 2 most common causes of viscus perforation

Answer 6

1. perforated peptic ulcer

2. perforated diverticular disease

Question 7

what is the consequence of a perforated peptic ulcer

Answer 7

acidic gastric contents leads into lesser sac… moves into greater sac via epiloic foramen… chemical peritonitis (10% mortality)

Question 8

what is the consequence of a perforated diverticulum

Answer 8

bacteria-filled intestinal contents leaks into peritoneal cavity… peritoneal sepsis and septicaemia (50% mortality)

Question 9

what is pneumoperitoneum and what does it indicate

Answer 9

• air under diaphragm (seen on chest/abdominal Xray)

- usually indicates a perforated viscus

Question 10

name 4 causes of small bowel obstruction

Answer 10

1. adhesions from prev. surgery
2. femoral/inguinal hernia
3. volvulus
4. carcinoma of caecum

Question 11

name 3 causes of large bowel obstruction

Answer 11

1. carcinoma (esp. L-sided)
2. sigmoid volvulus
3. diverticular disease

Question 12

explain how bowel obstruction causes dehydration and hypovolaemia

Answer 12

i) fluid acculumation, increased secretion and decreased reabsorption at obstruction area… loss of isotonic salt water… isotonic contraction of ECF volume… increased secretion and dehydration
ii) vomiting begins… loss of fluid to exterior… increased isotonic fluid sequestration in gut… etc. … hypovolaemic shock

Question 13

explain how bowel obstruction can results in hypochloremic, hypokalaemic metabolic alkalosis

Answer 13

i) vomiting… loss of H+ and Cl ions (HCl)… metabolic alkalosis
ii) renal compensation… H+ preservation at expense of K+ (H/K exchanger)… hypokalaemia

Question 14

why must fluid and electrolyte balance be corrected in dehydrated Ps prior to anaesthesia

Answer 14

anaesthetic agents:

1. dramatically reduce sympathetic tone, and many have negative inotropic effect. In dehydrated Ps, SNS is maximally activated to maintain vital organ perfusion. If dehydration isn’t corrected, P may become profoundly hypotensive and die at induction of anaesthesia.
2. affect cardiac muscle conduction/function - requires correction of hypo-/hyperkalaemia