FEN/Renal Flashcards
neonatal evaporative water loss attributed to
respiratory tract 1/3
skin 2/3
when is ADH present
11 weeks
where is ADH produced
paraventricular and supraoptic nuclei of hypothalamus –> posterior pituitary
where does ADH act
late distal tubule
cortical and medullary collecting ducts
increases urine osmolality
factitious hyponatremia from:
hyperlipidemia 0.002
hyperproteinemia 0.25
hyperglycemia 1.6
Na deficit =
(na desired - na current) X 0.6 x weight
u wave on ekg
hypokalemia
alkalosis related hypokalemia pathophys
H+ exits cell and K+ enters cell
acidosis effect on K+
for every 0.1 reduction in pH
every 0.1 reduction in arterial pH –> 0.6 mEq/L increase in K+
intracellular buffers
bone apatite
hemoglobin
organic phosphates
extracellular buffers
HCO3-
phosphates
proteins
mechanisms of acid-base balance in kidney
- reabsorption of HCO3- (PT)
- H+ excretion via ammoniagenesis in PT
- formation of titratable acids in cortical/medullary collecting tubule
anion gap =
Na+ - {Cl- + HCO3-}
side effects of NaHCO3 administration
- worsening acidosis if poor pulm blood flow/ventilation because CO2 cannot be removed
- increase risk hypernatremia
- hypocalcemia: Ca decreases as HCO3 causes Ca to bind to albumin decreasing ionized Ca+
- K+ may decrease
- increase risk IVH due to hypertonicity
RTA4 subtypes and labs
subtype 1: NaCl wasting, decreased urine aldosterone
a.w Addisons and CAH
subtype 4: NaCl wasting, increased urine aldosterone
Pseudohypoaldosteronism
subtype 5 (MCC): NaCl reabsorption normal, tubule insensitive
secondary causes of RTA II
prematurity
tyrosinemia
tubular disorders (fanconi, cystinosis, Lowe)
secondary causes of RTA I
interstitial renal disease
genetic
autoimmune
hypotonic states
drug induced
Bartter syndrome pathophysiology
- hypertrophy + hyperplasia of renal juxtaglomerular apparatus
- defect in Cl transport in ascending loop preventing reabsorption
- increased renin, increased aldosterone, hypokalemic metabolic alkalosis, normal PTH
Management of Bartter
potassium, +/- thiazide, +/- indomethacin
what dermal layer does kidney come from?
mesoderm
what are the 3 structures of kidney embryology
pronephros-transient
mesonephros - epididymis, vas deferens, seminal vesicles
metanephros - pevicalyceal system, 5th week
when do nephrons appear
8 weeks
FGR affects size or number of nephrons?
number
number of nephrons increase until ____ weeks then start increasing in size
34-35
which area are nephrons most mature at birth
juxtaglomerular nephrons
when does urine start being produced?
10-12 weeks
reasons for decreased concentrating capacity in preterm infants
- tubule insensitivity to ADH
- short loop of henle
- low osmolality of medullary interstitium
- low serum urea
sodium reabsorption in parts of kidney
65% proximal tubule
25% ascending loop of henle
10% DCT/collecting duct
reabsorption and secretion of K+ in kidney
- reabsorption PT and ascending loop
- secreted in DCT and CT
FENa =
(UNa x PCr)/(UCr x PNa) x 100
Ca reabsorption in kidney
reabsorption in PT, loop of Henle, DCT and CT
Phosphorus reabsorption in kidney
80% PT
10% DCT
tubular reaborption of phosphorus =
TRP = (UPhos x PCr)/(UCr x PPhos) x 100
Mg reabsorption in kidney
65percent PT and TAL
aldosterone effects on kidney
- Na reabsorption
- Cl passively
- secrete K+ and H+
pseudohypoaldosteronism pathophysiology
- XLR
- renal tubule unresponsive to aldosterone –> hypoNa, hyperK+, metabolic acidosis
- increased aldosterone and renin
protein reabsorption in kidney
95% PT
Estimated GFR =
0.45 x height(cm) / PCr
Difference between DMSA, DTPA, and MAG3
DMSA static
DTPA and MAG3 dyanamic images
epi of renal anomalies
1/200
MCC renal anomalies
horse shoe
unilateral renal agenesis (L>R)
pelvic kidney (L > R)
types of congenital nephrotic syndrome
Finnish
Diffuse mesangial sclerosis
Genetics of Finnish congenital nephrotic syndrome
chr 19 AR
NPHS1
nephrin protein
differences between finnish and dms in terms of placenta, AFP and BW
Finnish - large placenta, increased AFP, SGA
DMS - normal palcenta, normal AFP, normal weight
risk of renal agenesis
1/10000
40% still born
recurrence risk of renal agenesis
3-5%
genetics of ARPKD and ADPKD
ARPKD
- chr 6p21
- PKHD1
- fibrocystin/polyductin cilia related
ADPKD
- chr 16p13.3
- PKD1
- polycystin1
prognosis of ARPKD
30% mortality
50% ESRD
Syndromes of tubular dysfunction
Fanconi
Cystinosis
Lowe
Pathogenesis of Fanconi
- AD
- PT dysfunction
- losses of AA, glucose, phosphate and bicarbonate
Pathogenesis of Cystinosis
- AR
- defective carrier mediated transport of cystine –> excess cystine in lysosomes
Diagnosis of cystinosis
- normal plasma cystine
- need cornea slit lamp - cystine crystals
management of cystinosis
cysteamine and renal transplant
Pathogenesis of Lowe syndrome and other name
- oculocerebrorenal syndrome
- XLR
- enzyme deficiency disrupting golgi apparatus
clincal findings of lowe syndrome
occulo - cataracts, glaucoma
cerebo - MR, hypotonia/areflexia
renal - tubular dysfunction > nephrotic syndrome
diagnosis of lowe syndrome
- increased maternal and AF AFP
- increased nucleotide pyrophosphatase in skin fibroblasts
who gets prophylactic Abx in hydronephrosis?
- moderate if female and bilateral
- severe
ectopic urterocele epidemiology and definition
- F > M
- 10% bilateral
- duplicated renal pelvis and ureter which may drain into neck of bladder
pathophysiology of exstrophy of bladder sequence
- primary defect of intraumbilical mesoderm
- 6-7 weeks infraumbilical mesenchyme migrates giving rise to lower abdominal wall, genital tubercles and pubic rami
occurrence and recurrence of exstrophy of bladder
1/30,000
<1% if unaffected parent
1/70 if affected parent
what renal anomalies in Zellwegers
cortical renal cysts
what renal anomalies in Jeune?
- cystic tubular dysplasia
- glomerulosclerosis
- hydronephrosis
- horseshoe kidneys
what renal anomalies in Meckel-Gruber syndrome
polycystic/dysplastic kidneys
what renal anomalies in Tuberous sclerosis?
polycystic kidneys
renal angiomyolipomas
what renal anomalies in nail-patella syndrome
proteinuria and nephritic syndrome
stage 0 AKI
<0.3 Scr/no change
>0.5mL/kg/h UOP
stage 1 AKI
> 0.3 SCr change in 72 hr or 1.5-1.93 in 7d
<0.5mL/kg/h UOP for 6-12
stage 2 AKI
> 2.0-2.93 in SCr
<0.5mL/kg/h UOP for 12
stage 3 AKI
> 2.5 in SCr or 3x reference
<0.3mL/kg/h UOP for 24 or anuria for 12h
GFR threshold for CKD?
chronic renal failure?
60 mL/min/1.73 m^2
15 mL/min/1.73 m^2
highest PPV for fetal nephropathy
AP diameter of renal pelvis
MCC acute renal failure in neonates
perinatal asphyxia
secondary hyperoxaluria
SGS and malabsorption
PTH effect on bicarbonate reabsorption
decreases