Renal Flashcards
What stimulates Na reabsorption?
Na reabsorption increases extracellular volume
decreased BP and decreased NaCl @ macula densa -> renin release -> aldosterone release -> more Na/K pumps
what increases water reabsorption?
increased osmolality or decreased BP
-> ADH release
endocrine function of the kidney?
secretion of renin by juxtaglomerular apparatus
EPO synthesis
1α-hydroxylation of vitamin D (controlled by PTH)
carbonic anhydrase inhibitors?
MOA
inhibit carbonic anhydrase in PCT
- > ↓ HCO3 reabsorption → small ↑ Na loss
e. g. acetozalamide
use: glaucoma
SE: drowsiness, renal stones, metabolic acidosis
Loop diuretics MOA?
e.g. furosemide, bumetanide
MOA: inhibit Na/K/2Cl symporter in thick ascending limb
Effect: massive NaCl excretion, Ca and K excretion
Use: Tx of oedema – CCF, nephrotic syndrome, hypercalcaemia
SE: hypokalaemic met alkalosis, ototoxic, Hypovolaemia
e.g. of loop diuretics?
furosemide
bumetanide
e.g of carbonic anhydrase inhibtors?
acetazolamide
thiazide diuretics MOA?
e.g. bendroflumethiazide
MOA: inhibit NaCl co-transporter in DCT
Effect: moderate NaCl excretion, ↑ Ca reabsorption
Use: HTN, ↓ renal stones, mild oedema
SE: ↓K, hyperglycaemia, ↑ urate (CI in gout)
e.g. of thiazide diuretics?
bendroflumethiazine
K-sparing diuretics?
e.g. spironolactone - aldosterone antagonist
amiloride- blocks DCT/CD luminal Na channel
Effect: ↑ Na excretion, ↓K and H excretion
Use: used w loop or thiazide diuretics to control K loss, spiro has long-term benefits in aldosteronism (LF, HF)
SE: ↑K, anti-androgenic (e.g. gynaecomastia)
e.g. of k sparing diuretics?
spironolactone
amiloride
osmotic diuretics moa?
e.g. mannitol
MOA: freely filtered and poorly reabsorbed
Effect: ↓ brain volume and ↓ ICP
Use: glaucoma, ↑ICP , rhabdomyolysis
SE: ↓Na, pulmonary oedema, n/v
false +ve haematuria?
myoglobin, porphyria
menstrual blood
causes of proteinuria?
commonest:
DM
minimal change disease
membranous nephropathy
amyloidosis
SLE
other: HTN, UTI, ATN
definition of nephrotic syndrome?
proteinuria > 300mg/dL
what is a protein in the urine that wont be picked up on urine dipstick?
Bence-Jones proteins
(immunoglobulin light chain)
-> electrophoresis of urine
White cell casts in urine?
pyelonephritis
interstitial nephritis
what factors influence creatinine measurement?
creatinine synthesised during muscle turnover
increased muscle -> increased creatinine
age, sex, race
what influences urea measurement?
urea is produced from ammonia by liver
increases w protein meal (e.g. supplements, upper GI bleed)
decreases w hepatic impairment
decreased urine flow -> increased urea reabsorption (e.g. in dehydration)
raised Ur and Cr vs isolated raised Urea?
isolated raised urea = hypoperfusion/ dehydration -> decreased renal flow
increased urea and creatinine = decreased filtration ie. renal failure
causes of renal AKI?
glomerulonephritis
e.g. minimal change, membranous, post strep, IgA, rapidly progressive
acute tubular nephritis
interstitial disease
causes of post renal AKI?
obstruction
e.g. in renal pelvis, ureters, bladder or urethra
Stone
Inflammation: stricture
Neoplasm
Prostatic hypertrophy
Infection: TB, schisto
Neuro: post op, neuropathy
posterior urethral valves
causes of pre renal AKI?
shock
renal artery stenosis:
RAS
toxins: NSAIDS, ACEi
Thrombosis
Hepatorenal syndrome
presentation of renal failure?
uraemia
protein loss and Na+ retention
acidosis
hyperK
Anaemia
Vit D deficiency
how may uraemia present in a pt?
signs and symptoms
symptoms:
pruritus
anorexia, n/v, weight loss
lethargy
confusion
paraesthesia: neuropathy
pericarditis
signs:
pale, sallow skin
fits
coma
uraemic flap
confusion
how may protein loss and Na+ retention present in patients?
signs and symptoms
symptoms:
polyuria, polydipsia
oliguria, anuria
breathlessness
signs:
oedema
raised JVP
HTN
how may acidosis present in a pt?
signs and symptoms
signs:
Kussmaul respiration
symptoms:
breathlessness
confusion
how may hyperK present in a pt?
signs and symptoms
signs:
peaked T waves
flattened P waves
broad QRS
prolonged PR interval
sine wave pattern -> VF
symptoms:
palpitations
chest pain
weakness
how may anaemia present in a pt?
signs and symptoms
signs:
conjunctival pallor
pallor
tachycardia
flow murmurs (ESM @ apex)
symptoms:
breathlessness
lethargy
faintness
tinnitus
how may Vit D deficiency present in pts?
signs and symptoms
signs:
osteomalacia
- looser’s zones (pseudofractures)
- cupped metaphyses
symptoms:
bone pain
fractures
definition of UTI?
symptomatic w +ve culture or dipstick
what is urethral syndrome?
symptomatic of UTI but no bacteriuria
uncomplicated vs complicated UTI?
uncomplicated: normal GU tract and fn
complicated: abnormal GU tract, outflow obsturction, decreased renal fn, impaired host defence, virulent organism
presentation of pyelonephritis?
fever, rigors
loin pain and tenderness
vomiting
oliguria if AKI
UTI symptoms
presentation of cystitis?
freq and urgency
haematuria
dysuria
polyuria
suprapubic tenderness
foul smelling urine
presentation of prostatitis?
flu-like symptoms
low backache
dysuria
tender swollen prostate on PR
what may cause a sterile pyuria?
pus in urine, but no bacteria cultured
TB
treated UTI
appendicitis
calculi
Tubulointerstitial nephritis
PCKD
chemical cystitis e.g. cyclophosphamide
risk factors of UTI?
female
sex
pregnancy
menopause
DM
abnormal tract: stone, obstruction, catheter, malformation
most common organism responsible for UTI?
e coli
in women - 2nd most common staphylococcus saprophyticus
ix of UTI?
urine dipstick - +ve leucocytes and nitrites
send MSU for MCS
Bloods: FBC, WCC, Blood cultures (if systemic signs), U+E
US: recurrence, children, pyelonephritis
mx of UTI?
analgesia
drink plenty, urinate often
ABx: usually trimethoprim, nitrofurantoin 50mg QDS for 3 days
mx of pyelonephritis?
cefotaxime 1g IV BD for 10 d
prevention of UTIs?
drink more, urinate often
abx prophylaxis
what is glomerulonephritis?
group of disorders resulting from glomerular damage
can -> proteinuria + haematuria
can -> AKI or End stage renal failure
causes of glomerulonephritis?
idiopathic
immune: Goodpastures, SLE, Vasculitis
infection: Strep, HBV, HCV, HIV
Amyloid
Drugs: penicillamine, gold
ix of glomerulonephritis?
Bloods: FBC, U+E, ESR
Complements (C3 and C4) -> may be low in SLE
Abs: ANA, ANCA, dsDNA, GBM
serum protein electrophoresis and IgA
infection: ASOT titre
urine: dip, spot PCR, MCS, Bence-Jones protein
Imaging: CXR: infiltrates (goodpastures, wegeners)
renal US +/- biopsy
general mx of glomerulonephritis?
refer to nephrologist
tx HTN aggressively (less than 130/80)
ACEi/ ARB
causes of asymptomatic haematuria?
IgA nephropathy
Thin Basement membrane
Alport’s
what is IgA nephropathy?
aka Berger’s disease
commonest GN in developed world
young male w episodic macroscopic haematuria 24-48h after URTI
Raised IgA
can -> nephritic syndrome
ix of IgA nephropathy?
biopsy: IgA deposition in mesangium
mx of IgA nephropathy?
steroids or cyclophosphamide if renal fn impaired
HTN mx: ACEi/ ARBs (IgA nephropathy often causes high BP)
no cure: some ppl experience complete remission, some progress -> RF
what is thin basement membrane disease?
autosomal dominant
commonest cause of asymptomatic haematuria
persistent, asymptomatic microscopic haematuria
V small risk of end stage renal failure
what is Alport’s syndrome?
85% X-linked
affects type IV collagen -> basement membranes in kidney, inner ear and eye are affected
Haematuria, proteinuria -> progressive renal failure
Sensorineural deafness (bilat)
lens dislocation and cataracts
retinal ‘flecks’
females: haematuria only
what is nephritic syndrome?
haematuria + red cell casts
proteinuria -> oedema (esp periorbital)
HTN
oliguria and progressive renal impairment
causes of nephritic syndrome?
- Post-streptococcal
- Crescentic/ Rapidly progressive GN
features of post strep GN?
young child develops malaise and nephritic syndrome w smoky urine 1-2 wks after sore throat or skin infection
raised ASOT titre
low C3
ix of Post strep GN?
ASOT titre: high
Biopsy of kidney: IgG and C3 deposition at BM
mx of post strep GN?
supportive
95% children recover fully
minority develop rapidly progressive GN
what is rapidly progressive GN?
most aggressive GN which can -> end stage renal failure in days
3 types
- Anti-GBM (goodpastures)
- Immune complex deposition e.g. SLE, post strep, Bergers (45%)
- Pauci immune (50%)
- e.g. Wegeners, Churg-strauss, microscopic polyangiitis
what is Goodpastures syndrome?
Anti-GBM Ab to Type IV collagen
-> haematuria and haemoptysis
CXR shows infiltrates
-> TYPE 1 Rapidly progressive GN
mx of goodpastures disease?
plasmapheresis and immunosuppression
What could cause Type 2 rapidly progressive GN?
complication of any immune complex deposition
e.g. Berger’s, post strep, infective endocarditis, SLE
what is Pauci immune Type 3 Rapidly progressive GN?
may be due to cANCA +ve: Wegener’s
or pANCA +ve: microscopic polyangiitis, Churg-Strauss
what is nephrotic syndrome defined by?
proteinuria: PCR > 300mg/dL
hypoalbuminaemia: <35g/L
Oedema: periorbital, genital, ascites, peripheral
(JVP not raised - intravascularly depleted)
complications of nephrotic syndrome?
Infection: low Ig, low complement activity
VTE: up to 40%
Hyperlipidaemia: high cholesterol and triglycerides
ix of nephrotic syndrome?
Bloods: FBC, U+E, ESR
Complements (C3/4), lipid levels
Urine dip, MCS, Spot PCR
Imaging: Renal US +/- biopsy
- all adults should get biopsied
- steroids 1st in children: mostly minimal change
most common cause of nephrotic syndrome in children?
minimal change disease
causes of nephrotic syndrome?
primary:
minimal change disease
membranous nephropathy
Focal segmental glomerulosclerosis
Membranoproliferative/ mesangiocapillary GN
secondary:
DM: glomerulosclerosis
Amyloidosis
SLE: membranous
what is minimal change GN?
commonest cause of nephrotic syndrome in children
assoc w URTI
oedema - periorbital, genital
could present w AKI and High BP
biopsy of kidney showing normal BM on light microscopy, fusion of podocytes
Minimal change disease
mx of minimal change glomerulonephritis?
1st line: corticosteroids
2nd: cyclosporine
symptomatic mx: salt and fluid restriction to control swelling
in adults with high BP: ACEi
reduce risk of thrombosis, infection, hyperlipidaemia
1% -> ESRF
what is membranous nephropathy?
20-30% of adult nephrotic syndrome (common)
assoc w
Ca: lung, colon, breast
autoimmune: SLE, thyroid disease
infections: HBV
drugs: penicillamine, gold
biopsy shows: subepithelial immune complex deposits
mx of membranous nephropathy?
immunosuppression if renal function declines
prognosis: 40% spontaneous remission
what is focal segmental glomerulosclerosis?
commoner in Afro carribeans
Biopsy shows: focal scarring of the glomerulus, IgM + C3 deposition in the sclerotic segment
idiopathic or secondary: chronic pyelonephritis, vesicourethral reflux, berger’s, Sickle cell, HIV
mx of focal segmental glomerulosclerosis?
steroids or cyclosporin/ cyclophosphamide
30-50% -> ESRF (may recur in transplants)
What is membranoproliferative GN?
deposits in kidney glomerular mesangium and BM thickening, activating complement and damaging the glomeruli
may -> nephrotic or nephritic syndrome
assoc w HBV, HCV, endocarditis
50% -> ESRF
mx of nephrotic syndrome?
monitor U+E, BP, fluid balance, weight
treat underlying cause
symptomatic tx:
- oedema: fluid and salt restrict + furosemide
proteinuria - ACEi/ ARB decrease proteinuria
high lipids: statin
VTE: tinzaparin
tx HTN
definition of AKI?
significant decline in renal function over hrs or days manifesting as an abrupt and sustained increase in serum urea and creatinine
most common cause of AKI?
pre renal
due to shock, hypovolaemia or renovascular compromise (e.g. NSAIDS, ACEi)
what drugs may cause AKI?
contrast dye
gentamicin
Hb from rhabdomyolysis
causes of chronic renal failure?
diabetes
HTN
clinical assessment of AKI?
acute or chronic?
- Assess fluid status
- JVP, postural hypotension, tachycardia, poor skin turgor, dry mucous membranes, decreased UO - GU tract obstruction?
- suprapubic discomfort (urinary retention?)
palpable bladder
enlarged prostate
catheter blocked?
complete anuria?
- Rare cause?
- proteinuria + haematuria
vasculitis: rash, arthralgia, nosebleed
ix of AKI?
Bloods: FBC, U+E, LFT, Glucose, Clotting, ESR, Ca
ABG: hypoxia (oedema), acidosis, K+
GN screen: if cause unclear
Urine: Dip, MCS, PCR, osmolality
ECG: hyperK
CXR: pulmonary oedema
Renal US (hydronephrosis)
classification of AKI?
RIFLE classification
3 grades and 2 outcomes
Risk: UO < 0.5ml/kg/h for 6h
Injury: UO < 0.5 ml/kg/h for 12h
Failure: UO < 0.3ml/kg/h for 24h or anuria for 12h
Loss: persistent acute renal failure = loss of renal fn > 4 wks
End stage renal disease: complete loss of renal fn > 3 mo