Renal Flashcards
Neonates have a ____GFR and ____ tubules
Lower GRF and immature tubules
RTA with failure of bicarb reabsorption. Which type?
Proximal RTA (Type 2)
RTA that fails to acidify urine. Which type of RTA?
Distal (Type I)
Normal GFR
100ml/hr
What does AF tell you about the kidneys?
Amniotic fluid volume Oligohydramnios: Poor function Obstruction vs. intrinsic May or may not be amenable to intervention (in utero or after birth) • Polyhydramnios Polyuric conditions (e.g., Bartter syndrome)
T or F
If serum Cr doubles, GFR falls by 50%
True
T or F
GFR is NOT altered by prematurity
True
Name causes of hypercalcemic hypercalciuria
Subq fat necrosis Hyper parathyroid Hypophosphatasia Williams syndrome Vit D toxicity Idiopathic infantile hypercalcemia
Who receives postnatal antibiotic management for hydronephrosis?
Moderate b/l hydronephrosis in female
Severe unilateral or b/l hydronephrosis in male or female
What has the highest positive predictive value for the development of fetal nephropathy?
Anteroposterior diameter of the renal pelvis
As in hydronephrosis
Increase in GFR during fetal development depends on?
Number of glomeruli
What is the GFR threshold for chronic kidney disease vs chronic kidney failure?
Chronic kidney disease
60ml/min/1.7 m2
Chronic kidney failure
15ml/min/1.7 m2
Which diuretic does not require sufficient tubular drug concentration in order to exert its effect?
Spironolactone
It is an aldosterone antagonist that competes with aldosterone by binding on collecting tubule receptors
Name the different sites for H20 and solute absorption in the nephron?
Proximal Convoluted tubule
Na active transport across tubule wall
H20 passively follows
Loop of Henle and distal convoluted
Active reabsorption of solutes
Impermeable to H20
Collecting ducts
Reabsorption of h20 is TIGHTLY regulated by arginine vasopressin or ADH
Fanconi syndrome
Defect in proximal tubular réabsorption
Glucose AA Uric acid Phosphate Hco3
(Think Faconi + proximal RTA
No HCO3 réabsorption)
Whar GA is nephrogenesis complete?
34-36 weeks
After that the nephrons begin to enlarge
Effects of drugs used for PDA closure
Decrease afferent arteriole dilation (ibuprofen, indomethacin)
- prostaglandin inhibitor
- causing vasoconstriction
Which meds effect efferent arteriole system?
Block efferent arteriole (kidney)constriction —-> decreasing renal blood flow and decreasing time spent in glomeruli) —> thereby vasodilating
- ACE inhibitors
- NSAID
What are the most common causes of acute renal failure?
Severe perinatal adphyxia (40%)
Sepsis (22%)
Feeding intolerance (18%)
Metabolic acidosis with defect in H secretion. Which RTA?
Distal Type I
Metabolic acidosis due to defect in bicarb reabsorption. Which defect?
Proximal Type II RTS
Urine pH is alkaline
Metabolic acidosis, hyperkalemia and salt wasting. Which acidosis?
Type IV RTA
Mechanism of beta blockers
Decrease HR
Decrease Stroke Volume
Decrease Renin
Renin ultimately stimulates _____ to make more ________.
- ACE— throughout body, but highest in vascular endothelium of lungs.
- Angiotensin II—potent vasoconstrictor
Location and mechanism of action of thiazides
Distal convoluted tubule (the Na-Cl cotransporter)
Causes decreased Na, K and Cl reabsorption but INCREASED Ca++
Leads to smaller osmotic gradient so don’t reabsorb water
Renin is made in the ___
Angiotensinogen is made in the ___
Angiotensinogen is converted to Angiotension I in the ___
Angiotensin II is made in the ____
Aldosterone is made in the ___ and acts at the _____
Kidneys
Liver
Plasma
Lung vasculature (by ACE)
Adrenals
Cortical collecting ducts (CCD) and DCT
What are the effects of Bicarb administration for acidosis (5)?
During administration:
- Can worsen acidosis if poor pulmonary blood flow/ventilation ratio because cannot eliminate CQ
- Increased risk of hypernatremia
- Calcium decreases since HCO; causes Ca to bind to albumin and thus decreases ionized Ca concentral
- K* may decrease
- Increased risk of developing intraventricular hemorrhage secondary to hypertonicity,
Why are neonates prone to becoming acidotic fairly easy?
Low serum Bicarb threshold in the proximal tubule and once surpassed bicarb is excreted in urine
Limited ability to excrete acid load (reduced distal urinary acidification?
Most common renal anomalies
1/200
Horshoe kidney
Unilateral renal agenesis (L>R)
Pelvic kidney (L>R)
Infant with proteinuria, hyperlipidemia, edema. Large placenta noted at the time of delivery. Dx? Inheritance?
Finnish congenital nephrotic syndrome
AR, Chromosome 19, NPHS1 gene
90% w symptoms by 1 mo
Why are infnats with congenital nephrotic syndrome at risk for infection and thromboemboli?
Secondary to urinary losses of IgG and coagulation proteins
Fetal Us with large echogenic kidneys, oligohydramnios, empty bladder. What is the most likely diagnosis?
ARPKD
1/20,000
Chromosome 6p, PKHD1 expressed on cilia of renal cells and bile duct cells.
Cysts in collecting ducts usually with “snowstorm” appearance on US.
Have renal and liver involvement only Severe Hypertension (respond to acei or loop diuretics)
May have pulm hypoplasia, potters facies, club foot frok oligohydramnios
30% mortality w severe neonatal presentation
50% end stage renal disease by 10 yo
Male neonate with cataracts, hypotonia, renal tubular dysfunction. What test to reach diagnosis?
Lowe syndrome/oculocerebrorenal syndrome
Skin biopsy to asses nucleotide pyropjosphatase in skin fibroblasts
Xlinked recessive , due to gene defect leading to enzyme deficiency disrupting golgi apparatus
Tx: symptom directed, no treatment will reverse enzyme deficiency and golgi dysfunction
You suspect a neonate has an ectopic ureterocele. What findings in VCUG would be consistent with your diagnosis?
Filling defect in the bladder (the ureterocele)
Ectopic ureteroceles are more common in females, usually unilateral, renal pelvis and ureter are duplicated.
One of the ureters (the one that drains the upper pole of the duplex kidney) enters ectopically unto the neck of the bladder.
Which genetic condition is associated with horseshoe kidney?
Turner syndrome (Monosomy X)
You get a call about an infant with GU abnormality, notably with a single opening in the perineum. What diagnosis are you concerned about and other associated findings to look for?
Extrophy of cloaca sequence
defect of early mesoderm
Remember OEIS Omphalocele Extrophy of cloaca Imperforare anus Spinal defects (incomplete development of lumbosacral vertebrae with hydromelia)
May have cryptoorchidism
Females w bifid uterine horns
Triad of renal vascular thrombosis?
Enlargement of kidney (flank mass), hematuria and renal failure
Which disorders are associated with neohrocalcinosis?
Williams syndrome
Type 1 distal RTA
Neonatal primary hyperparathyroidism
Barrter’s syndrome
Remember its associated with hypercalciuric states
Risk factors for Hypertension
BPD
Central lines
Postnatal acute renal failure
Will upper or lower extremities give you a higher BP?
Lower extremities gave higher BP
Which anti hypertensive is contraindicated in neonates?
Verapamil
Name the most common nephrotoxic drugs
Acyclovir
Aminoglycosides
Amphotericin V
Vancomycin
Definition of chronic renal failure
Decrease in GFR<25% normal for a period of >3 months
Majority secondary to congenital urinary tract abnormalities
Need dialysis or transplant
Complications for those with chronic renal failure?
Failure to thrive
Normal GH, IGF but low IGFBP
Give high cals 120-180% of daily rec
Renal osteodystrophy
Secondary to decreased Vit D hydroxylation from loss of renal tissue.
Give 1,25OH Vit G to prevent hypocalcemia
Neuro complications from excess aluminum, HTN, electrolyte abnls
How to distinguish RTA type I vs II?
Type 1 RTA (distal) failure if H+ resorption has nephrocalcinosis whereas Type II RTA (proximal) failure Bicarb reabsorption doesnt
Type I urinary pH >6.5 whereas type II is very high>7.5
Type 4 has hyperkalemic metabolic acidosis
Most common risk factor for RVT?
Asphyxia
Then maternal diabetes, polycythemia
Usually presents <3days
Effects of Angiotensin II
- stimulates the adrenal cortex to secrete aldosterone for Na réabsorption
In response to a decrease in renal blood flow, renin levels increase, which leads to increase
angiotensin I.
Angiotensin HI has several functions, including the following:
Increase in water and salt reabsorption in the renal tubules!
Vasoconstriction of systemic and renal arterioles?
Stimulation of the adrenal cortex to produce aldosterone, further increasing sodium réabsorption in
renal tubules and nonrenal sites
Increase in glomerular filtration*
• Possible vascular smooth muscle cell and myocardial hypertrophys
Ques 26
Nephrogenesis is complete at what GA?
34-36 weeks
What stimulates renin secretion?
Decrease in Afferent arteriole stretch
Increased in renal sympathetic activity
Decreased na cl transport to macula densa
Nephrocalcinosis in a short bowel pt is due to _______.
Increase in oxalate excretion in the urine (leads to excess calcium oxalate urine deposits)
Typical laboratory findings associated with Type1 Distal RTA ?
Hypercalciuria
Hypokalemia: potassium replaces hydrogen as a cation in the urine
- Hypocitraturia: citrate is reabsorbed to create bicarbonate
- Hypercalciuria: increased calcium secretion from bone to serve as a buffer
- High urine pH with hyperchlorèmic metabolic acidosis and normal anion gap
Most common sight of urinary obstruction in hydroneohrosis is?
Uretopelvic junction obstruction
Which conponent of the RAS pathways is necessary for normal nephrogenesis?
Angiotensin II bc it serves as a renal growth factor
What causes réabsorption of HCO3 in kidneys?
Decreased réabsorption with volume expansion or increaed PTH
HCO3 réabsorption is increased with acidosis, hypercapnia or volume contraction
Normocalcemic hypercalciuric nephrocalcinosis is seen with _______.
Distal renal tubular disease Bartter syndrome
hyper prostaglandin E syndrome Cushing syndrome
chronic lasix use
familial hypomagnesemia
Hypercalcemic hypercalciuric nephrocalcinosis is seen with _______.
Hyperparathyroidism hypophosphatasua
subcutaneous fat necrosis
Williams syndrome
Location of action for a acetazolamide (Diamox)
Proximal convoluted tubule
Remember PCT is where you Pee out bicarb
(Acetazolamide increases HCO3 excretion, such as when trying to correct contraction alkalosis)
Hemofiltration utilizes _________ to remove solutes from plasma.
Convection
Hemodialysis utilizes __________ to remove solutes from plasma.
Dialysis
Infant kidneys receive what percentage of cardiac output?
10% compared to adults which is 25%
Name renal vasodilators
Prostaglandin
Nitric oxide
What is endothelin?
Renal Vasoconstrictor
Produced by the renal vascular endothelial cells
Release is stimulated by angiotensin II, bradykinin, epinephrine or stress
What is the cause of FTT in RTA?
Decreased secretion of growth hormone as a result of metabolic acidosis
Neonate w eye clouding, hypotonia, renal tubular dysfunction, and cryptorchidism. Dx?
Lowe syndrome. X linked recessive affecting enzymatic fumction of golgi apparatus
Oculocerebro-renal syndrome
Dx: increased nucleotide pyrophosphatase in skin fibroblasts
Describe findings of bartter syndrome
Hypokalemia, metabolic alkalosis, hypercalciuria
Defects in Na, Cl, K transport in loop of henle
Antenatal presentation polyhydramnios
Triangular facies, protruding ears, large eyes w strabismus, drooping mouth. Can develop hypotension w salt wasting
