GI17 - Gastrointestinal Emergencies

Question 1

3 general features of peritonitis

Definition
Symptoms
Treatment x3

Answer 1

1.) Definition - inflammation of the serosal membrane that lines the abdominal cavity

2. ) Symptoms - gradual or acute abdominal pain
   - perforated viscera causes diffuse abdominal pain
   - any movement makes the pain worse
3. ) Treatment
   - surgery to control the infectious source
   - antibiotics to remove bacteria and toxins
   - intensive care to maintain organ system function

Question 2

5 features of primary peritonitis

Definition
Susceptible People
Ascites
RAAS Activation
Investigation

Answer 2

1. ) Definition - spontaneous bacterial peritonitis (SBP)
   - infection of ascitic fluid that cannot be attributed to any other conditions

2.) Susceptible People - patients with end stage liver disease (liver cirrhosis)

3. ) Ascites - fluid accumulation in peritoneal cavity
   - portal hypertension -> high HP in portal venous system
   - less albumin produced –> ↓ oncotic pressure
   - net movement of fluid into peritoneal cavity

4.) RAAS Activation - ascites causes drop in blood volume

5. ) Investigation - aspirating ascitic fluid
   - neutrophil count will be >250 cells/mm3

Question 3

2 features of secondary peritonitis

Definition
Common Causes x6

Answer 3

1.) Definition - inflammation secondary to inflammation, perforation, or gangrene of an intra-abdominal or retroperitoneal structure

2. ) Common Causes - often due to perforation
   - peptic ulcers, appendicitis, diverticulitis, IBD
   - toxic megacolon, ischaemia, trauma, post-surgery
   - impacted faeces, ectopic pregnancy, ovarian cysts

Question 4

4 features of bowel obstruction

Definition
Clinical Features
Ileo-Caecal Valve
Imaging

Answer 4

1.) Definition - mechanical (blockage) or functional (nerve issue) problem that inhibits the normal movement of gut contents

2. ) Clinical Features - different orders depending on location
   - SI: N/V—> colicky abdominal pain—> distension—> constipation
   - LI: constipation—> distension/pain —> N/V
3. ) Ileo-Caecal Valve - valve separating SI and LI
   - if incompetent, the colon cannot decompress proximally causing a closed loop obstruction —> small + large bowel obstruction
   - this makes ischaemia and perforation more likely
4. ) Imaging - plain abdominal X-ray (location)
   - SI: central swelling, valvulae conniventes, smaller lumen
   - LI: peripheral swelling, haustra, larger lumen
   - CT scans used to determine cause

Question 5

Causes of Bowel Obstruction

Small Bowel (extrinsic, intrinsic, intraluminal)
Large Bowel (extrinsic, intrinsic, intraluminal)
Intussusception
Volvulus

Answer 5

1. ) Small Bowel - common: adhesions, hernia
   - extrinsic: adhesions, incarcerated hernia
   - intrinsic: intussusception, volvulus, Crohn’s, cancer
   - intraluminal: bezoar/foreign body, gallstone ileus
2. ) Large Bowel
   - common: cancer, diverticulosis, volvulus
   - extrinsic: adhesions, incarcerated hernia
   - intrinsic: diverticulitis, intussusception, volvulus, Crohn’s, cancer
   - intraluminal: faecaloma, foreign body
3. ) Intussusception - part of the gut tube telescopes into an adjacent section (can extend quite far and even cause a rectal proplase)
   - oedema occurs when lymphatic and venous drainage is impaired and can impede arterial supply –> infarction
   - symptoms: abdominal pain, vomiting, haematochieza
   - treatment: air enema and surgery
4. ) Volvulus - colon twists around its own mesentery
   - commonly in the sigmoid colon (60%) and caecum
   - can occur due to constipation as extra mass elongates the colon, causing small or large bowel obstruction

Question 6

Small bowel obstruction vs Large bowel obstruction

Age Affected
Abdominal Pain
Vomiting and Constipation

Answer 6

1. ) Age Affected - SI = young, LI = old
   - large bowel obstruction often develops over time
2. ) Abdominal Pain - colicky in both however,
   - lasts 3-4 mins in SI but 10-15 mins in LI
3. ) Vomiting and Constipation
   - vomiting occurs earlier in small bowel
   - constipation occurs earlier in large bowel

Question 7

5 features of acute mesenteric ischaemia

Causes x3
Risk Factors x4
Symptoms x3
Investigations x3
Treatment

Answer 7

1. ) Causes
   - acute occlusion (70%) often embolism in SMA
   - low cardiac output (20%), (non-occlusive)
   - mesenteric venous thrombosis due to system coagulopathy or malignancy (5-10%)

2.) Risk Factors - female, elderly, cardiovascular risk factors, history of peripheral vascular disease

3. ) Symptoms - abdominal pain, nausea/vomiting
   - abdominal pain 30 mins after eating, lasting 4 hours
   - pain often left-sided because splenic flexure most fragile

4.) Investigations - blood tests (metabolic acidosis), CXR (check for perforations), CT angiography

5. ) Treatment
   - surgery to remove ischaemic bowel
   - thrombolysis/angioplasty
   - mortality is high in older patients with comorbidities

Question 8

2 causes of major upper GI bleeding

Answer 8

1. ) Peptic Ulceration - 20-50% of upper GI bleeding

2. ) Oesophageal Varices - 12-14% of upper GI bleeding

Question 9

4 features of oesophageal varicies

Porto-Systemic Anastamosis
Aetiology (3 sets of causes)
Normal Pressure
Treatment

Answer 9

1. ) Porto-Systemic Anastomosis - oesophaeal vein drains:
   - portal drainage: left gastric vein –> portal vein
   - systemic drainage: azygous vein –> SVC
2. ) Aetiology - portal hypertension, causes:
   - pre-hepatic: portal vein thrombosis
   - hepatic: cirrhosis (alcohol or viral), schistomiasis
   - post-hepatic: hepatic vein thrombosis, right sided HF
3. ) Normal Pressure - 5-10mmHg in portal vein
   - problems occur when the pressure > 10 mmHg
4. ) Treatment - surgery or drugs (terlipressin) to reduce portal venous pressure
   - transjugular intrahepatic portosystemic shunt (TIPS)
   - expandable metal placed within the liver, bridging the portal vein to an hepatic vein to reduce pressure
   - reduction in variceal pressure and ascites

Question 10

5 features of abdominal aortic aneurysms (AAA)

Definition
Aetiology
Risk Factors x4
Investigations x4
Treatment and Prevention

Answer 10

1. ) Definition - permanent dilation of the abdominal aorta > 3cm (or >1.5x expected diameter)
   - 90% originate below the renal arteries
2. ) Aetiology - degeneration of the tunica media (less elastin and collagen) causing the lumen to dilate
   - R.F: male, ↑age, smoking, HTN, hyperlipidaemia, FH, CT disease (e.g. Marfan’s, Ehler’s Danlos)
   - DM is a negative risk factor for AAA
3. ) Clinical Features - asymptomatic until large/rupture
   - abdominal pulsatile mass (<50% of cases)
   - abdominal pain and nausea (compresses stomach)
   - back/loin pain (compresses vertebrae)
   - acute limb ischaemia (distal embolisation)
   - transient hypotension (temporary tamponade)
4. ) Investigations
   - abdominal USS: can detect free peritoneal blood
   - screening: abdo US for all 65yr old men
   - CT w/ contrast if >5.5cm for anatomical details
   - AXR can only detect AAA if there is calcification
5. ) Treatment - >5.5 cm, refer to vascular surgeons
   - endovascular repair: relining the aorta using an endograft inserted through the femoral artery
   - open surgical repair
   - prevention: smoking cessation, hypertension control

Question 11

6 symptoms of abdominal aortic aneurysms (AAA)

Asymptomatic
Compress Nearby Structures x3
Transient Hypotension
Cardiovascular Collapse

Answer 11

1. ) Usually Asymptomatic - until it ruptures
   - can have a pulsating mass or feeling in the stomach
2. ) Can Compress Nearby Structures
   - stomach –> nausea and abdominal pain
   - bladder –> urinary incontinence
   - vertebra –> back pain
3. ) Transient Hypotension - due to blood loss
   - can lead to dizziness and syncope
   - transient because retroperitoneum can temporarily tamponade the bleed

4.) Cardiovascular Collapse - 65% die before hospital