Uraemia and uraemic toxins Flashcards
What is uraemia?
Clinical sydrome with various symptoms that arises as a result of progressive kindey failure
What are the characteristics of uraemia?
Build up of uraemic toxins
Solutes become retained as a result of declining kidney function
Symptoms are non specific - loss of apetite, nausea, vomiting
Is it known which uraemic toxins are the source of which symtoms?
No
How does the build up of the uraemic toxins lead to kidney damage?
Molecules cause inflammation
What are ways to classify uraemic toxins?
Size
They way they are carried around by the body
What are examples of uraemic toxins?
Urea - small, water soluble
Phenols - small, lipid soluble or protein bound
Beta 2 microglobulin - large molecule
Which molecule was originally thought of as the cause of uraemia?
Urea
What are some features of urea?
Osmotically active - rapid changes in concentration leads to water movement
Used to monitor effectiveness of dialysis - urea clearance
Very non-toxic molecule
How is it proven that urea does not play a major role in uremia?
Increased removal of urea does not have a major impact in renal failure
Addition of urae to dialyste does not induce symptoms of uraemia
What is the source of many uraemic toxins?
Related to nitrogen breakdown
What happens to carbohydrates and proteins not digested in the upper GI?
The colon salvages the energy from the undigested carbohydrates and nitrogen from the undigested proteins
What happens to proteins along the GI tract?
Digested into peptides in the gut
Peptides are acted upon in the large intestine by bacteria
Nitrogenous wastes products are formed
What is P-cresyl sulphate and Indoxyl sulphate?
Amino acids are broken down into PCS and IS by gut bacteria
Why are PCS and IS not easily removed by dialysis?
They are protein bound
What is the effect of PCS and IS in the kidneys?
Pro-inflammatory effects on various cells
Endothelial cells, epithelial cells and leukocytes
Where do PCS and IS become protein bound?
In the kidneys
What happens when PCS and IS become protein bound?
They recirculate and worsen kidney failure
What is AST-120?
Oral sorbent
Prevents absorption of IS and PCS from the gut
Rather than PCS and IS recirculating, they are egested via the faeces
What is another name for PCS and IS?
Indole compounds
What is the build up of uraemic toxins linked to?
CVD and poor survival
What are ways to remove protein-bound substances?
Adsorption
Oral compounds that bind them in the gut
What is an ADEPT device?
Adsorbent device that promotes toxin removal during haemodialysis
Fits in line with current dialysers
Removes protein bound uraemic toxins by non-specific adsorption from blood
What is the ADEPT device made of?
Carbon-based monolith
Made by synthetic resin
What are PCS and IS examples of?
Protein-bound uraemic toxins
