Upper + lower GI bleeding Flashcards
Define haematemesis
vomiting blood
Define melaena
blood from upper GI tract passed PR
digested blood
smells bad
Define haematochezia
blood from back passage
red
Define occult bleeding
hidden blood
people don’t realise they’re passing it
Oesophageal arterial anatomy
upper 1/3 = inferior thyroid artery
middle 1/3 = thoracic aorta
lower 1/3 = oesophageal artery (branch of left gastric artery)
Oesophageal venous anatomy
upper 2/3 = oesophageal veins to azygous vein to SVC
lower 1/3 = left gastric vein to portal venous system
What can happen to the oesophagus when there is portal venous hypertension?
portal pressure >12mmHg = gradient of 10mmHg (comparing portal pressure to IVC pressure)
gradients >10mmHg = blood is redirected to area of lower venous pressure and collaterals form in lower oesophagus
these vessels are thin walled and become more so as they engorge = tendency to bleed
Main causes of portal hypertension
liver cirrhosis:
- alcohol
- Hep B + C
- non-alcoholic fatty liver disease
- primary biliary cirrhosis
portal vein thrombosis
congenital
What is a Mallory-Weiss tear?
partial thickness mucosal tear of lower oesophagus
typically due to lots of vomiting
What is the most common cause of upper GI bleeding?
gastric/duodenal ulcers
What can cause gastric/duodenal ulcers?
H pylori
NSAIDs
steroids
What is Dieulafoy’s malformation?
large tortuous arteriole in sub mucosa which erodes through
(treated with endoscopic clip)
How do gastric neoplasms often present?
anaemia symptoms
Management of acute upper GI bleeds
ABCDE
endoscopy (inject with adrenaline, clips)
surgery?
What is the most common malformation of the GI tract?
Meckel’s diverticulum - common congenital abnormality of the small intestine caused by incomplete obliteration of the vitelline (omphalomesenteric) duct
Investigation + treatment of mesenteric ischaemia/thrombosis
angiography/CT
interventional radiology/vascular surgery
Rarer causes of lower GI tract bleeding
Crohn’s
small bowel neoplasms
Colonic bleeds causes
diverticular bleeds
angiodysplastic lesions
ulcerative colitis
colonic polyps/malignancy
Are diverticular bleeds painful?
no (however diverticulitis is painful)
What are angiodysplastic lesions?
degenerative lesions
likely caused by intermittent contraction of colon interrupting venous drainage
What is it called when ulcerative colitis is limited to the rectum?
proctitis
Arterial supply to the rectum
upper 1/3 = superior rectal artery (branch of inferior mesenteric artery)
middle 1/3 = middle rectal artery (internal iliacs)
lower 1/3 = inferior rectal artery (branch of internal pudendal artery)
What is a haemorrhoid?
engorgement of haemorrhoidal cushions
painless (but uncomfortable)
bright red fresh blood
blood on wiping
What is an anal fissure?
tear of break in skin of anus
very painful (will not tolerate PR)
What causes an aorto-enteric fistula most commonly?
infected prosthetic graft (eg. from AAA repair) eroding through into GI tract
can also happen where no previous repair
life threatening - dealt with by vascular surgeons
Define shock
acute circulatory failure with inadequate tissue perfusion causing cellular hypoxia
Key history points for GI bleed
differentiate between lower + upper GI bleed
idea about volume of blood lost (patient estimates often inaccurate)
anticoagulant medications
coagulopathies