514470
Description
Mind Map by v.djabatey, updated more than 1 year ago
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Created by v.djabatey
over 10 years ago
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Assessment of kidneys & urinary tract
- GFR is low
in newborn
& esp low in
preterm
- GFR @ 28
weeks'
gestation =10%
of term infant
- in term infants corrected
GFR (15-20 ml/min per
1.73m2) rapidly rises to 1-2
years old when adult rate
(80-120 ml/min per 1.73m2)
achieved
- GFR @ 28
weeks'
gestation =10%
of term infant
- plasma creatinine conc (PCr)
- main test of renal function
- rises progressively
throughout childhood
accord to height & mm
bulk
- may not be outside lab 'normal range'
until renal function has dropped to <
1/2 normal
- main test of renal function
- estimated glomerular filtration rate (eGFR)
- =k x height (cm)/ creatinine (micromol/L)
- k= 40 (Cr
measured using
Jaffe method) or 30
(Cr measured
enzymatically)
- k= 40 (Cr
measured using
Jaffe method) or 30
(Cr measured
enzymatically)
- better
measure of
renal func
than
creatinine
- useful to measure
renal func serially in
kids w/ renal
impairment
- =k x height (cm)/ creatinine (micromol/L)
- insulin or EDTA GFR
- more accurate
- clearance from plasma of substances
freely filtered @ glomerulus, is not
secreted or reabsorbed by the tubules
- clearance from plasma of substances
freely filtered @ glomerulus, is not
secreted or reabsorbed by the tubules
- use limited in kids
- need for repeated blood tests
- need for repeated blood tests
- more accurate
- creatinine clearance
- requires timed urine collection & blood tests
- rarely done in kids
- because
inconvenient
& inaccurate
- because
inconvenient
& inaccurate
- requires timed urine collection & blood tests
- plasma [urea]
- increased in renal failure often before Cr starts rising
- raised levels may be symptomatic
- increased by high protein diet & if in catabolic state
- increased in renal failure often before Cr starts rising
- radiological ix
- ultrasound
- standard imaging procedure
- provides anatomical not functional assessment
- great @ visualising urinary tract dilatation,
stones & nephrocalcinosis (small multiple Ca
deposits in renal parenchyma)
- adv: non invasive, mobile
- disadv:
operator-dependent,
won't detect all
renal scars
- standard imaging procedure
- DMSA scan (99mTc dimercaptosuccinic acid)
- static
scan of
renal
cortex
- detects
functional
defects like
scars
- v sensitive
- need to wait
minimum 2 months
after UTI to avoid
diag of false 'scars'
- need to wait
minimum 2 months
after UTI to avoid
diag of false 'scars'
- static
scan of
renal
cortex
- micturating cystourethrogram (MCUG)
- can visualise bladder & urethral anatomy
- detects vesicoureteric reflux
(VUR) & urethral obstruction
- disadv: invasive & unpleasant ix
esp beyond infancy, high radiation
dose
- can visualise bladder & urethral anatomy
- MAG3 renogram (mercapto-acetyl-triglycine, labelled with 99mTc)
- dynamic scan
- isotope labelled substance
MAG3 secreted from blood
into urine
- measures drainage
- best
performed
w/ high
urine flow
- in kids old enough to
cooperate (usually >4
years), scan during
micturition is used to ID
VUR
- dynamic scan
- plain abdominal x-ray
- IDes unsuspected spinal abnormalities
- may ID renal stones
- poor at showing
nephrocalcinosis
- IDes unsuspected spinal abnormalities
- ultrasound
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