Lecture 18- GI emergencies 2/2

Question 1

Acute mesenteric ischemia

Answer 1

Symptomatic reduction in blood supply to GI tract

Question 2

• Risk factors of acute mesenteric ischemia
  *

Answer 2

More common in females (75%) and if you have a history of peripheral vascular disease

Question 3

causes of acute mesenteric ischaemia

Answer 3

• Acute occlusion (70%)
• Non-occlusive mesenteric ischaemia (20%)

Question 4

Acute occlusion (70%)

Answer 4

Arterial embolism in the SMA (50%)- midgut

Question 5

Non-occlusive mesenteric ischaemia (20%)

Answer 5

• Low CO
• Mesenteric venous thrombosis (5-10%)
• Systemic coagulopathy and malignancy

Question 6

most cases of acute mesenteric ischaemia are in

Answer 6

lderly patients. With CVD risk factors.

Question 7

• Symptoms of acute mesenteric ischaemia

Answer 7

• • Can be difficult to diagnose because symptoms can be fairly non-specific
    
    • Abdominal pain disproportionate to the clinical findings
      
      • Classic pain- comes on 30 mins after eating and lasts 4 hours
    • Nausea and vomiting

Pain on left hand side

Question 8

• why Pain on left hand side in acute mesenteric ischaemia-

Answer 8

• blood supply to the splenic flexure (point where transverse colon turns into the descending colon) is more fragile

Question 9

AMI Investigations

*

Answer 9

• Blood tests
  
  • Metabolic acidosis / increased lactate levels- ischaemic drugs
• Erect chest x-ray- check for perforation (gas under the diaphragm)
• CT angiography (90% sensitivity)- intravenous contrast

Question 10

Treatment AMI

Answer 10

• Surgery- resection of ischaemic bowel–> bypass graft
• Thrombolysis/angioplasty

Question 11

Prognosis of AMI

*

Answer 11

• Mortality is high (arterial thrombosis’s up to 70% mortality)
  
  • Often older pts with comorbidities

Question 12

2 examples of major upper GI bleeding

Answer 12

1. peptic ulceration
2. oesophageal varices

Question 13

peptic ulceration causes …….% of acute upper GI bleeding

Answer 13

20-50%

Question 14

what is peptic ulceration

Answer 14

• Disruption in gastric/duodenal mucosa that extends through the muscularis mucosa
• Greater than 5mm diameter

Question 15

which type of ulcer is most common

Answer 15

• Duodenal ulcers most common
  
  • First part of duodenum
  • Gastro-duodenal artery lies behind first part of duodenum

Question 16

where are peptic ulcers found in the stomach

Answer 16

• Lesser curve and antrum common sites

Question 17

gastric ulcer erosion is especially dangerous if it erosed the

Answer 17

splenic artery

Question 18

what are oesophageal varices

Answer 18

porto-systmeic anastomosis

• 12-14% of acure upper GI bleeding

Question 19

explain how oesophageal varices occur and how they can lead to major upper GI bleeding

Answer 19

• an example of porto-systemic anastomosis
• they are often caused by portal hypertension
  
  • back flow of blood from the portal vein –> left gastric –> which drains the distal portion of the oesophagus
• oesophagus also draine dby the azygous vein
• left gastric vein and azygous anastomose
• these anastomes distend with blood – rupture –> bleed

Question 20

causes of oesophageal varices

Answer 20

portal hypertension

• Caused by anything that slows blood flow through portal vein
  
  • Pre-hepatic (portal vein thrombosis)
  • Hepatic (cirrhosis schistosomiasis)
  • Post hepatic causes (hepatic vein thrombosis, RHF)

Question 21

• Normal pressure in portal vein

Answer 21

• 5-10mm Hg
  
  • Problem happens around 10 mmHg

Question 22

• porto-systemic anastomoses are areas that

Answer 22

have venous drainage through portal vein and systemic veins e.g. the distal portion of the oesophagus

Question 23

Treatment of oesophageal varices

Answer 23

• Fluid resus
• If bleeding not controlled by banding
  
  • Transjugular intrahepatic portosystemic shunt (TIPS)
• Drug treatment
  
  • Terlipressin- reduces portal venous pressure

Question 24

Transjugular intrahepatic portosystemic shunt (TIPS)

Answer 24

• expandable metal is palced within the liver
• bridge the portal vein to the hepatic vein
• decrompresses protal vein pressyre
• reduction in variccal pressure
• reduction in ascites

Question 25

**Abdominal aortic aneurysm – AAA**

Answer 25

*A permanent pathological dilation of the aorta with a diameter \>1.5 times the expected anteroposterior (AP) diameter of that segment, given the patients sex and body size. The most commonly adopted threshold is **3cm or more**. More than 90% of aneurysms originate below the renal arteries.*

Question 26

MOA of AAA

Answer 26

* Usually due to the degeneration of the media layer of the arterial wall * Media- smooth muscle cells with elastin and collagen * AAA forms due to degradation of elastin and collagen Lumen gradually starts to dilate

Question 27

AAA **Risk factors**

Answer 27

* Male * Inherited risk * Increasing age * **Smoking**

Question 28

AAA **Symptoms**

Answer 28

* Most are asymptomatic until acute expansion or rupture * pulsating mass or feeling is stomach * Can cause symptoms by compressing other nearby structures * Stomach (nausea) * Bladder (urinary frequency) * Vertebra (back pain)

Question 29

**Symptoms of a ruptures AAA**

Answer 29

* Abdominal pain * Back pain * shortness of breath * Pulsatile abdominal mass- surgical referral * Transient hypotension--\> syncope * Sudden cardiovascular collapse – 65% of ruptures AAA die before hospital

Question 30

why transient hypotension (esp in early AAA rupture)

Answer 30

* Retroperitoneum can temporarily tamponade the bleeding * syncope

Question 32

diagnosis of AAA

Answer 32

* **Physical exam** * Presence of pulsatile abdominal mass (less than 50%) * **Ultrasonography** * Non invasive and in the right hands very sensitive and specific * Can also detect free peritoneal blood * **Computed tomography (CT)** * Can detect a lot of surrounding anatomy that may be relevant * Planning for elective surgery * **Plain x-rays** * If aneurysm has calcified then can be seen on plain X-ray

Question 33

non surgical treatment of AAA

Answer 33

smoking cessation hypertension control

Question 34

* Surveillance of AAA

Answer 34

* Less than 5.5 cm (most grow slowly enough to not need treatment) * More than 5.5cm- refer to surgeons

Question 35

surgery to repair AAA (2 ways)

Answer 35

1. endovascular repair 2. open surgical repair

Question 36

* endovascular repair

Answer 36

Insert wire through femoral artery and over that wire you pass an endograft- this will expand and hook into place- seal below renal arteries and above common iliacs

Question 37

* open surgical repair

Answer 37

* Clamp aorta * Open the aneurysm (remove thrombus and debris) * Suture in a synthetic graft to replace diseased segment

Question 38

types of AAA

Answer 38

90% of AAA's are infrarenal