Proteinuria Flashcards
(39 cards)
How can proteinuria be quantified?
- dip stick
- sulphosalicylic acid test
- 24hr protin loss
- UPC
- protein electrophoresis
- albumin quantification methods
Is dipstick measurement reliable? Pros and cons
\+ cheap \+ convenient \+ qualitative - trace 1+ usually normal - must consider with USG - only useful in identifying severe proteinuria
What is UPC?
- urine protein creatinine ratio adjust level of protein for concetnratino of urine (^ conc = ^ creatinine)
- practice for routine clinical use
- high day-today variability so ideally measure several times OR pool samples (cheaper)
How is UPC used for IRIS staging?
0.4 (caats) or 0.5 (dogs) = proteinuric
Where can protein be lost within the kidney?
> pre-glomerular - ^ amount low molecular weight proteins presented to filter - cannot all be reabsorbed > renal - glomerular - tubular > post-glomerular/renal - addition of protein to urine after formation in the kidney
Which proteins specifically are commonlyl lost in the urine d/t pre-renal causes?
> bencejones proteins : IG light chains
- plasma cell tuymours (or serious inflam?? maybes)
Causes of post-renal proteinuria
> LUT
- haemorrhage
- inflam/infection
- neoplasia
* importance of blood contamination over-emphasised - urine must be grossly contaminated before this casues proteinuria)
UTI
- effect highly variable and difficult to predict
- should be r/o before proceding with work up for glomerular causes of proteinuria
Is any protein usually excreted by the kidney?
YES small amount always
- mild increases may be d/t glomerular hypertension or tubular dysfunction
- serious pathological increases likely d/t 1* glomerular dz
How id gross proteinuria defined?
UPC >3 (by hattie, no actual definition)
What is PLN
> Protein losign nephropathy
- clinical syndrome of severe gross proteinuria
- may -> hypoproteinaemia
- caused by glomerular disease
What is the glomerular barrier made up of?
- fenestrated endothelial cells
- basement membrane
- epithelial cell foot processes/slit pores (modified adherent junction)
When should you suspect PLN?
- routine screening UA
- hypoalbumenaemia (specifically disopproportionate albumen v cf. pan hypoproteinaemia)
- breeds at risk
- associated diseases
- r enal failre
- clinical signs of PLN
Ddx for panhypoproteinamiea and hypoalbumenaemia
> v albumen - PLN - hypoadenocorticism (?) - liver failure > v protein in general - PLE - haemorrhage
What is nephrotic syndrome?
- proteinuria
- hypoalbumenaemia
- hyperlipidaemia
- oedema/fluid accumulation in body cavities
> NOT necessarily always azotaemic
> may occour in 1/3 glomerular disease dogs
Clinical signs of PLN
- nephrotic syndrome e
- muscle wasting/weight loss/malaise
- azotaemix CKD (sometimes)
- Azotaemic AKI (rarely)
- signs of underlying dz
- hypertension
- thromboembolism
Why do PLN pateitns get thromboemboli?
- loss of anti-thrombin (same size as albumen)
- frequently fatal
- only part of the explanation
Diagnostic plan for PLN patietns
> in all proteinuric patients - urea/creatinine/USG - albumin/cholesterol - urine culture - blood pressur - fundic exam > to ID a underlying cause - CBC/chemistry - imaging - serology - CSF/joint taps - FeLV fiv - specific tests
What needs to be attempted in PLN cases?
> identify underlying cause
- NIN (neoplastic, infectious or non, inflammatory)
- many patients cannot identify underlying cause
What are the different causes of glomerular disease and how can these be dx?
> amyloidosis > immune-complex glomerulonephritis - ICGN - many different types > minimal change dz - lesions only visible with electron microscopy > glomerulosclerosis - scarring of glomeruli - many types > familial glomerulopathy - check pure breeds - consider in young dogs - look up PDF - no specifics Tx - breeding programmes *can only be distinguished on biopsy*
How may travel history assist with dx of PLN
- leishmania
- heartworm (dirofilaria)
- Lyme dz (borrelia burgderfori)
How may drug Hx assist with dx of PLN?
> steroids - ^ proteinuria - glomerulosclerosis > sulphonamides - esp dobermans > tyrosine kinase inhibitors (MCT chemo) - freq -> proteinuria - minimal change dz
Outline non-specific Tx options for PLN
> glomerular haemodynamics
- v glomerular pressure hence GFR -> v proteinuria
- slows dz progression
- v inflam response
diet
- mild protein restriction (counterintuitive)
- reduce proteinuria
- protein high biological value
- omega 3 fatty acid (DHA/EPA)supplements
- sodium restriction
ACEI
- proven benefit (idiopathic and familial glomerular disease)
- indicated in all patients with GROSS proteinuria
- angiotensin receptor blockers (ARBs) reasonable alternative
anti-thrombotic Tx
- aspirin (low dose 0.5-1mg/kg)
- reduced thromboembolism
- clopidogrel an alternative
- delay starting this if potential renal biopsy
antihypertensive Tx
- guided by BP measurement
- ACEI or ARB
- combo with amlodipine if BP remains high
Tx oedema /ascites
- sodium restriction
- thoracocentesis
- abdomenocentesis (only if significant abdo discomfort)
- diuretics (avoid if poss)
- colloids if necessary prior to biopsy
Pros and cons of renal biopsy
*PROS* > specific Tx - immunosuppression - aim to induce remission > breed management > prognostication *CONS* > risks - haemorrhage - renal injury > complications 10% dogs 20% cats > expensive
Outline practical technique of renal biopsy
> US guided or surgical wedge biopsy > cortical tissue > specialist fixative - formalin (H&E, Congo red, PAS) - Michels (IHC) - gluteraldehyde (electron microscopy)
