General: Melena Flashcards
Describe the pathophysiology of melena
Black tarry offensive smelling stools
Alteration and degradation of blood by intestinal enzymes
What causes melena?
Peptic ulcer = NSAIDs, H.pylori, posterior duodenal wall into the gastroduodenal artery
Variceal bleeds = ruptured dilations of the porto-systemic anastomoses in the oesophagus due to portal hypertension sec to liver cirrhosis (alcoholic liver)
Upper GI malignancy = enquire about weight loss, relevant family history
Gastritis
Oesophagitis
Mallory-Weiss tear
Meckles diverticulum
Vascular malformations
What are the clinical features of melena?
Colour and texture = jet black, tar-like, and sticky
Associated symptoms = haematemesis, abdo pain, history of dyspepsia, dysphasia or odynophagia
PMH = smoking, alcohol status, IBD
DH = steroids, NSAIDs, anticoagulants, iron tablets
How should melena be investigated?
PR exam
Abdo exam = assess for epigastric tenderness or peritonism, hepatomegaly, any stigmata of liver disease
Bloods = FBC, U+Es, LFTs, and clotting, G+S, X-match – Hb drop (chronic), LFT in liver disease, drop in Hb and rise in the urea:creatinine ratio is very indicative of an upper GI bleed
ABG = assess sepsis
Oesophagogastroduodenoscopy (OGD)
CT abdo with IV contrast = assess active bleeding
Why is a drop in Hb and rise in the urea:creatinine ratio is very indicative of an upper GI bleed?
digested Hb produces urea as a by-product; this is readily absorbed by the intestine and consequently upper GI bleeds can show as a rise in urea levels
How should melena be managed?
A-E
Blood transfusion = low Hb
Correct any deranged coagulation
Peptic ulcer = adrenaline and cauterisation of the bleeding, high dose PPI
Oesophageal varices = endoscopic banding, prophylactic Abx, terlipressin (reduce splanchnic blood flow)
Upper GI malignancy = biopsy, surgical/oncological management
What are the possible complications of melena?
Shock
Death
