Proteinuria Flashcards
How is proteinuria most commonly quantified?
Dipstick
Protein-creatinine ratio
What are the advantages/disadvantages of using a dipstick to quantify proteinuria?
+ Cheap
+ Convenient
- Must consider with USG
- Only useful in identifying severe proteinuria
What is the UPC?
Urine protein:creatinine ratio
How does the IRIS system categorise different UPCs into levels of proteinuria? What else must be considered?
<0.2 (D+C) - Non-proteinuric
0.2 to 0.4 (C)/ 0.5 (D) - Borderline
>0.4(C)/0.5(D) - Proteinurici
Must consider creatinine conc and BP
Define proteinuria. Why are only small levels of protein found in the urine normally?
Pathological increase of protein present in the urine.
Large proteins cannot pass through glomerular filter
Glomeruli are negatively charged with repel anionic proteins
Majority of filtered proteins are reabsorbed in PT
The presence of which protein in the urine is always abnormal? And why?
Globulin
V large protein and thus glomerular filter must be distrupted
What urinary tract diseases can cause proteinuria and should be ruled out before investigating the kidneys?
Infection
Inflammation
Neoplasia
Haemorrhage
Why should you be careful not to over interpret the UPC value?
UPCs fluctuate normally
Severe decrease in functioning nephrons -> Fall in UPC
Outline the 4 types of proteinuria and their causes…
Pre-glomerular - increased small proteins presented to glomerular filter
Glomerular - increased capillary pressure > proteins forced through barrier
Tubular - decreased resorption of proteins in tubules
Post-glomerular - inflam/haemorrhage/neoplasia contaminates blood/urine with proteins
What can cause glomerular proteinuria?
Glomerulonephritis
Amyloidosis
Familial glomerulopathise
Outline the pathophysiology of glomerulonephritis…
Circulating ag-ab complexes form or get trapped in the glomerulus > cellular proliferation and thickening of the glomerular basement membrane > Hyalinisation and sclerosis > nephron destruction and renal failure
Outline the pathogenesis of amyloidosis
Which species/breeds are predisposed?
Chronic inflammation or neoplasia > serum amyloid A produced > insoluble so desposits in renal tissue > renal failure or NS
Chinese Shar-Pei dog
Abyssinian cat
Can blood in the urine contaminate protein level readings?
Yes but contamination must be v severe to alter UPC
What UPC value is considered gross proteinuria which can be caused by primary glomerular disease (PLN)?
> 3
What are DDx with:
Low alb alone?
Low alb and glob?
Low alb
Liver failure
HypoAC
PLN
Low alb and glob
PLE
Haemorrhage
What are clin signs of PLN?
Proteinuria Hypoalb, hyperchol Ascites, pleural effusion Inappetance, depression, Exercise intolerance Thromboembolism Hypertension Signs of underlying disease Muscle wasting, wt loss \+/- azotaemia
Why can thromboembolism occur with PLN?
Anti-thrombin is lost with albumin
What diagnostic test should be carried out in all patients with proteinuria?
Urea, creatinine, USG Albumin, chol Urine culture Blood pressure Fundic exam
How can glomerular disease be distinguished? What should be ruled out before this?
Renal biopsy
Familial amyloidosis or glomerulonephropathies
Which breeds suffer from hereditary nephritis? What is the defect? How is it prevent?
English Cocker Spaniels
Defect in type IV collage of the basement membrane of glomerular filter
Genetic tests
What should be a DDx of proteinuria if the dog has travelled to the Med?
Leishmania
Lyme’s disease
What are possible iatrogenic causes of proteinuria?
Steroids
Sulphonamides
Tyrosine kinase inhibitors
What dietary changes can slow progression of proteinuria?
Mild-mod protein restriction
Good quality protein
Omega-3 fatty acid supplementation
Na restriction
Which class of drugs is indicated in all patients with gross proteinuria?
ACEi
