Crash course: Renal Flashcards
What is AKI? What is it measured by?
acute decline in renal function, leading to fall in urine output
Measured by rise in creatinine + urea
What is CKD? How is it measured?
Decline in renal function due to progressive damage present for >3 months
Measured via decline in eGFR
What are the stages of CKD based on eGFR?
1: >90
2: 60-89
3a: 45-59
3b: 30-44
4: 15-29
5: <15 = end stage, dialysis
What are the caveats of stage 1 and 2 CKD grades?
If stage 1/2 based on eGFR but NO Sx, NOT CKD
What are the 2 most common causes of CKD?
Diabetes
HTN
Give 2 less common causes of CKD
Autosomal dominant polycystic kidney disease
Untreated AKI (Pyelonephritis, ATN, obstruction)
What are the 3 broad causes of AKI?
PRE-renal: decrease in flow to the kidneys.
RENAL: direct damage to nephrons
POST-renal: ‘Surgical causes”- physical outflow obstruction
From most to least common, what are the broad causes of AKI
Pre-renal
Post-renal
Renal
Give 5 causes of pre-renal AKI
Hypovolaemia
Sepsis
CCF
Renal artery stenosis
ACE inhibitors
Give 6 causes of renal AKI
Ischaemia
Nephrotoxins
Glomerulonephritis
Interstitial nephritis
Hepatorenal syndrome
HUS / TTP
Give 4 causes of post-renal AKI
Stone
Tumour
Prostate
Blocked catheter
Which 3 structures can be damaged to result in renal causes of AKI?
Glomerulus: Nephrotic + Nephritic syndrome
Blood vessels: HUS + TTP
Tubules: ATN + acute interstitial nephritis
Give 4 causes of nephrotic syndrome
Minimal change
Membranous
FSGS
Secondary causes
What triad characterises Nephrotic syndrome?
Peripheral oedema
Proteinuria (3g/day or PCR >300mg)
Low serum albumin
Give 2 other features of nephrotic syndrome
Increased cholesterol
Increased clotting tendency- Antithrombin III is lost
What is the pathophysiology in all causes of nephrotic syndrome?
Breakdown of PODOCYTES (filtration barrier)
Large molecules e.g. Protein not filtered out - lost in urine
What is the broad management of nephrotic syndrome?
Steroids
What is the most common cause of nephrotic syndrome in kids?
Minimal change disease
What is seen on histology in minimal change disease?
Light microscopy: Nothing
Electron microscopy: Loss of podocyte foot processes
Immunofluorescence: Nothing
What is the prognosis for minimal change disease?
Majority respond to Prednisolone ~(90%)
In which population is membranous glomerulonephropathy seen?
Adults
What do immunofluorescence microscopes detect?
Immune complexes
What is seen on histology in membranous glomerulonephropathy?
Light microscopy: Diffuse basement membrane thickening
Electron microscopy: Spikey immune complex deposits
Immunofluorescence: Immune complexes across all of basement membrane
How does membranous glomerulonephropathy respond to steroids?
Poor response
Give 2 associations to Membranous glomerulonephropathy
SLE
Anti-phospholipase A2 antibodies
What is focal segmental glomerulonephritis? (FSGS)
Focal = Only some glomeruli are damaged (vs diffuse)
Segmental = Only some regions of each individual glomerulus damaged
Which population is affected by focal segmental glomerulonephritis?
Adults
What is seen on histology in Focal segmental glomerulonephritis?
Light microscopy: Focal + segmental scarring
Electron microscopy: Loss of foot processes
Immunofluorescence: Nothing
How does focal segmental glomerulonephritis respond to steroids?
Not great (better than membranous glomerulonephropathy)
Give 2 secondary causes of nephrotic syndrome. What is seen on histology?
Diabetes: Kimmelstiel Wilson nodules
Amyloidosis: apple green birefringence on Congo red stain
What are the 2 types of amyloidosis? What causes each?
AA: chronic inflammation (e.g RA, SLE)
AL: Light chains (MM): plasma cells produce Abs, Abs clog up kidneys + cause damage