Renal Flashcards
GFR is most accurately evaluated in a clinical setting via what parameter?
A) serum creatinine
B) inulin clearance
C) creatinine clearance
D) plasma clearance of radio-isotope EDTA/DTPA or iohexal
Plasma disappearance of radio isotope EDTA/DTPA or iohexal
- DMSA scan does not provide info on GFR clearance.. looks at parenchymal function, shows scarring if areas don’t light up
What is the Schwartz equation ? (Estimates GFR)
eGFR = 36.5 x height (cm) x creat (umol/L)
Not accurate in ESKD
Renin release from the juxtaglomerular cells is stimulated by:
Sodium depletion
Sympathetic stimulation
Reduced vagal stimulation
How do you differentiate between acute GN and nephrotic syndrome (minimal change disease)
Onset of oedema - acute vs gradual (GN acute)
Haematuria in nephritic
Hypertension - most acute GN present with HTN (not nephrotic)
The epithelial Na channel in the collecting duct is regulated by which hormone ?
Aldosterone
Blocked by amiloride
What are the 4 clinical features of glomerulonephritis?
Haematuria
Reduced GFR
Hypertension
Oedema (Na & H2O retention)
Which types of GN have low complement levels ?
Post-infectious
MPGN aka mesangiocapillary
SLE
What are the clinical clues pointing you towards IgA nephropathy or Alports/Thin Basement Membrane ?
“Synpharyngitic”
Gross haematuria
Family history
What is the most common cause of GN?
Post infectious GN
- age 2-12
- group A strep causing immune complex deposition
- 7-14 days post throat; later after skin
- low c3
- recurrence rare
- supportive management
What should you suspect with a history of episodes of gross haematuria at the same time as URTI??
IgA nephropathy
- IgA deposition in mesangium
- persistent microscopic haematuria
- normal complement
- can be progressive
- can not tell difference with HSP on biopsy (same disease?)
What is the most common vasculitis of childhood?
HSP Younger children 1/3 recurrence Renal involvement can occur 2 months after initial illness - weekly urine protein checks Early steroids not shown to reduce future renal involvement Treatment: Steroids, azathiprine RPGN: cyclophosphamide
What should you suspect with: adolescent girl, Indian/Maori/Pacific Islander
Low WCC
Low C3/C4
Haematuria/proteinuria
Lupus nephritis
- commonest presentation of SLE
- renal biopsy to determine class and treatment
What should you suspect with boy, haematuria & proteinuria with family history ?
Haematuria with URTI, persistent microscopic haematuria
Sensorineural hearing loss
Alports
X linked mutation of type 4 collagen (basement membrane)
Dx Electron miscroscopy of biopsy
Can progress to ESKD
Treatment with ACEI aims to delay progression - the earlier the better
What should you suspect for
Microscopic haematuria
Macro haematuria with URTI
Family members with micro haematuria
Thin basement membrane disease (aka benign familial haematuria)
Autosomal dominant
Can actually progress therefore not totally benign
What are the causes of Rapidly progressive GN?
What is the defining feature on biopsy ?
HSP
ANCA disease
Goodpastures (anti GBM)
Presence of crescents (clumps of epithelial tissue within Bowman’s capsule)
How do you differentiate between the ANCA assoc small vessel vasculotides (Wegeners vs MPO)
Wegeners
C ANCA pos
Granulomas in resp tract & kidneys
Both progress to RPGN
Treatment strong immunosuppression
Plasmaphoresis (if pulmonary haemorrhage)
What should you suspect with pulmonary and kidney involvement - pulmonary haemorrhage & crescentic nephritis
Anti GBM on serology ?
Goodpastures (aka pulmonary renal syndrome)
Caused by autoimmune complex (anti GBM) deposition in GBM
Treatment steroids, plasmapharesis, cyclophosphamide
Doesn’t recur
Which types of GN have family history?
Alports (boys)
TBM
IgA
What are the defining clinical features of nephrotic syndrome?
Proteinuria
Hypoalbuminaemia (<25g/L)
Oedema
Hyperlipidemia
What are the causes of nephrotic syndrome ?
Idiopathic (MCD 70%, FSGS, MPGN)
Hep B
Systemic inflammatory diseases (lupus, HSP)
Part of a syndrome (Denys drash, nail patella, Frasier, Pierson)
How do you define remission of nephrotic syndrome?
0/ trace albumin on Albustix for 3 consecutive days
Frequent relapsing = > 2 relapses in 6 months
Steroid dependent = 2 consecutive relapses within 2 weeks of stopping steroids
Steroid resistant = no remission after 4 weeks of steroids
What is the recommended treatment of steroid dependent nephrotic syndrome?
Cyclophosphamide
MMF
Cyclosporine
What are the complications of nephrotic syndrome?
Infection (due to low IgG, low complement, impaired lymphocyte function, immunosuppressive drugs)
Cellulitis
Bacterial peritonitis
thrombosis
How do you differentiate between CKD and AKI?
Chronic - short/stunted growth, relatively normal potassium, high phosphate, anaemia
AKI- hyperkalaemia
Both might have metabolic acidosis
What are the causes of tubular disease (acute and chronic)
Acute - tubulointerstitial nephritis
Chronic - nephronophthisis
How do you calculate the fractional excretion of sodium?
FENa = Urine Na x Plasma Cr
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Urine Cr x Plasma Na X 100%
How does FENa help distinguish between causes of renal failure?
Low FEN = prerenal AKI
High FEN = renal cause AKI (inappropriately losing Na)