Renal Flashcards
What are the three effects of Angiotensin II?
- systemic vasoconstriction
- constriction of efferent arteriole
- Increased aldosterone synthesis
Concentration of tubular fluid in proximal tubule
isotonic with plasma (300 mosm/L)
Concentration of tubular fluid in descending loop of henle
Increasing (water permeable)
400-1200mOsm/L
Concentration of tubular fluid in ascending loop of henle
Decreasing (salt permeable)
1200-200mOsm/L
Lowest osmolality site in nephron, assuming low ADH
Distal convoluted tubule. Impermeable, so fluid stays hypotonic with increased reabsorption of solutes
When does ARPKD present?
At birth. In contrast, dominant form comes years later.
Urea acts on which segment of the collecting duct?
medullary segement to increase urea and water reabsorption
When does the pronephros degenerate?
4 weeks
Mesonephros
Functions as kidney for the first trimester
Metanephros appears wheN?
5th week of gestation. It becomes the permanent kidney
Ureteric bud comes from
caudal end of mesonephros
Ureteric bud gives rise to:
ureter, pelvises, calyces, collecting ducts
what interaction needed to form normal kidney
ureteric bud pokes the metanephric tissue
–induces metanephric tissue to format glomerulus to distal tubule
most common site of obstruction in fetus
ureteropelvic junction
Potter’s syndrome
Oligohydramnios–>
limb deformities
facial deformities
pulmonary hypoplasia
Causes of Potter’s
ARPKD
posterior urethral valves
bilateral renal agenesis
IF YOU CAN”T PEE in utero, you get potters
Horseshoe kidney assoc’d with
Turner syndrome
Nonfunctional kidney with cysts and connective tissue in utero. What caused this?
abnormal interaction btw ureteric bud and metanephros
Describe path of blood into the kidney
renal artery segmental artery interlobal artery arcuate artery interlobular artery
Which kidney do you harvest for donation?
Left kidney=it has a longer renal vein
ureters pass over/under the ductus deferens/uterine artery?
under
60-40-20 rule
60% weight is TBW
40% ICF
20% ECF
measure plasma volume
radiolabeled albumin
measure extracellular volume
inulin
what gives negative charge in GFR?
heparan sulfate
clearance eq:
C=UV/P
U=urine concenctration
V=urine flow rate
P=plasma concentration
how to calc GFR
clearance of inulin or creatinine
When is creatinine clearance not accurate for GFR?
When GFR is very low. will have higher concentration of creatinine in urine
Calculation for effective renal plasma flow (ERPF)
clearance of PAH
PAH=filtered AND secreted into the proximal tubule. all that enters the kidney is excreted
RBF=
RPF/(1-Hct)
–ERPF underestimates true RPF by 10%
Filtered load=
GFR*plasma concentration
NSAIDs
constrict afferent arteriole
ACE-I
dilate efferent arteriole
prostaglandins
dilate afferent arteriole
angiotensin II
constricts efferent arteriole
increased plasma protein
decrease GFR
decrease FF
constriction of ureter
decrease GFR
decrease FF
Hartnup’s disease
deficiency of tryptophan(neutral amino acid) transporter in proximal tubule. neutral AA excreted in urine.
results in pellagra
blood glucose level when glucosuria starts? max saturation?
160 mg/DL
350mg/DL
which part of nephron generates ammonia?
Prox tubule
PTH and ATII on prox tubule
PTH: inhibits Na/Phosphate cotransport
ATII: stimulates Na/H exchange=contraction alkalosis. Holding onto sodium at expense of alkalosis
What % Na absorbed at each nephron segment?
- Prox tubule=65-80%
- L of H=10-20
- DCT=5-10%
- 3-5%
Thick loop of henle
Na/K/2Cl resorption
- -paracellular resorption of Mg2+ and Ca2+
- -dilution of urine as it passes
What allows paracellular resorption in thick ascending limb?
potassium backleak.
DCT transporter
Na/Cl apical cotransporter
–urine becomes hypotonic
PTH effect on DCT
Stimulates Ca/Na Xchange on basolateral surface increasing Ca resorption
Thiazide mechanism
Blocks Na/Cl apical cotransporter
–>indirectly blocks Na/Ca2+ exchanger
Mechanism of amiloride/triamterene
Blocks ENaC channel in principal cell of CT
[Tubular Fluid]/[Plasma] ratio
If >1, solute is reabsorbed less quickly than water
If <1, solute reabsorbed more quickly than water
very high TF/P
PAH/creatinine/inulin
moderate TF/P
urea/Cl
TF/P=1
K/Na
TF/P <1
phosphorus
bicarb
TF/P «1
amino acids and glucose (virtually completely reabsorbed
Tx: hypovolemic hyponatremia
NS
tx: hypervolemic hyponatremia
Salt and fluid restriction, furosemide
Euvolemic hyponatremia
free water restriction (NOT hypertonic saline–otherwise will fluid overload them)
SIADH hyponatremia
do NOT give normal saline! will excrete sodium and retain water. Give convaptan and water restrict
when should you give hypertonic saline?
hyponatremia with NEURO deficits or seizures
Six effects of angiotensin II
- Vascular smooth muscle
- constricts efferent arteriole
- aldosterone
- ADH
- Increased prox tubule Na/H
- Stimulates hypothalamus
ADH regulates
osmolarity (except in extreme low blood volume)
Aldo regulates
blood volume
How do beta blockers decrease BP?
inhibiting B1 receptors on the JGA
How much K is reabsorbed along the nephron?
65% PCT
30% ascending L of H
5-100% at DCT
How does ANP work?
Increases Na filtration and GFR at PCT with no compensatory Na resorption distally.
–>Na and H2O loss
PTH effect on kidney
Increased Ca resorption (DCT)
Decreased PO4 resorption (PCT)
Increased activation of vitamin D
Causee of hyperkalemia
digitalis hyperosmolarity insulin deficiency cell lysis acidosis Beta adrenergic antagonist
Hyponatremia Sx
nausea, malaise
stupor coma
hypernatremia sx
irritability
stupor coma
hypokalemia sx
arrhythmias, muscle weakness
-U wave on ECG, flattened T waves
hypokalemia
hypocalcemia sx
tetany and seizures
–decreases threshold potential
Hypomagnesia
tetany and arrhythmias
hypermagnesia
cardiac arrest hypocalcemia decreased DTRs bradycardia hypotension
hypophosphatemia
osteomalacia
Hyperphosphatemia
renal stones
metastatic calcifications
hypocalcemia
How to tell if there is a mixed disorder (acid base)?
pCO2 and HCO3 move in opposite directions
OR
pCO2 predicted is very different
predicted pCO2=
(1.5 HCO3 + 8) +/-2
Henderson-Hasselbach
pH=6.1+log [HCO3]/(0.03*pCO2)
When do you check anion gap
metabolic acidosis present
Eq for anion gap
Na-Cl-HCO3
–Over 12 is abnormal
Increase anion gap metabolic acidosis
Methanol Uremia Diabetic ketoacidosis Propylene glycol Iron/INH Lactic acidosis Ethylene glycol Salicylic acid
Causes of normal anion gap acidosis
Hyperalimentation Addison's disease Renal tubular acidosis Diarrhea Acetazolamide Spironolactone Saline infusion
Causes of primary metabolic alkalosis
loop diuretics
vomiting
antacid use
hyperaldosteronism
Type 1 RTA
CT cannot excrete H+
Type 2 RTA
Cannot resorb bicarb
Type 4 RTA
lack of aldosterone effect
RTA: pt with urine pH > 5.5 and is hypokalemic
Type 1
RTA: Pt has a urine pH < 5.5 and is hypokalemic
Type 2 RTA
RTA: hyperkalemic patient with low urine pH and low BP
Type 4 RTA
Increased urine pH puts you at risk for
calcium phosphate stones
Type 2 RTA associated with
Fanconi’s syndrome
WBC caste:
tubulointerstitial inflammation
acute pyelonephritis
transplant rejection
fatty casts or oval fat bodies
nephrotic syndrome
granular muddy brown casts
acute tubular necrosis
Waxy casts
advanced renal disease
Hyaline casts
normal
Nephrotic syndromes
Minimal change disease Membranous nephropathy Focal segmental glomerulosclerosis Amyloidosis Diabetic glomerulonephropathy
Nephritic syndromes
Acute poststreptococcal GN
Rapidly progressive GN
Berger’s IgA GN
Alport
Combined Nephritic and Nephrotic syndromes
Diffuse proliferative GN
Membranous GN
Sx of nephrotic syndrome
proteinuria
hyperlipidemia
fatty casts
edema
Why are pts with nephrotic syndrome at risk for thromboembolism and infection?
AT III is lost in urine
Loss of IgG
Most common cause of nephrotic syndrome in adults
FSGS
LM: segmental sclerosis and hylinosis
EM: effacement of foot proceses
FSGS
LM: GBM thickening
EM: spike and dome with subepithelial deposits
IF: granular
membranous
causes of FSGS
HIV, kidney disease, heroin, obesity, interferon
causes of membranous
SLE< drugs, infection
LM: normal
EM: foot process effacement
minimal change
Tx of minimal change
corticosteroids
cause of minimal change
loss of polyanion in GBM causing ONLY albumin loss
LM: congo red stain with apple-green birefirencence
amyloidosis.
assoc’d with multiple myeloma, TB, RA
Subendothelial deposits with tram track appearance
IF: granular
type I MPGN
LM: Intramembranous dense deposits
MPGN
Type I MPGN associated with
HBV, HCV
Type II MPGN associated with
C3 nephritic factor
nephritic sx:
azotemia
oliguria
hypertension
proteinuria <3.5 g/day
LM: lumpy bumpy glomeruli
EM: subepithelial immune complexes
IF: granular C3, IgG, IgM
acute post strep GN. occurs a few weeks after infection
LM: crescent shape made of fibrin and C3b proteins
rapidly progressive GN
causes of rapidly progressive GN
- goodpasture’s syndrome
- Wegener’s granulomatosis
- Microscopic polyangiitis
LM: wire looping of capillaries
EM: subendothelial IgG with C3
IF: granular
Diffuse proliferative glomerulonephritis
LM: mesangial proliferation
EM: mesangial IC deposits
IF: IgA deposits in mesangium
Berger’s disease. occurs a few days after infection
Split basement membrane with GN, deafness, and eye problems
Alport syndrome
What’s mutate in alport syndrome?
type IV collagen.
alport inheritance
X linked
Which kidney stones can you NOT see on an Xray?
Uric acid stones
octahedron kidney stones
calcium oxalate
which stones precipitate at a high pH?
struvite
calcium phosphate
Most common kidney stone presentation
calcium oxalate stone in a pt with hypercalciuria and normalcalcemia
Treatment for calcium stones
thiazides and citrate
Causes of oxalate stones
ethylene glycol and vitamin C overdose
staghorn calculi
struvite stones (ammonium magnesium phosphate)
Tx for calcium stones
thiazides and citrate
Cause of struvite stones
urease positive bugs:
- proteus
- staph
- klebsiella
hexagonal crystals
cysteinuria
coffin lid stones
struvite
rhombus red brown stones
uric acid
renal cell carcinoma histology
clear limid filled cells
RCC associated with a gene deletion on
chromosome 3
RCC produces
EPO
ACTH
PTHrP
PPresentation of RCC
hematuria
flank mass
polycythemia
Tx: RCC
Resection. Resistant to conventional chemo and radiation
WWilm’s tumor (nephroblastoma) histology
embryonic glomerular structures. Child 2-4 has flank mass and hematuria
Wilm’s tumor deltion
WT1 tumor suppressor on chromosome 11
WAGR complex
wilm’s
aniridia
genitourinary malformation
mental retardation
biopsy of kidney: papillary growth lined by transitional epithelium with mild nuclear atypia
transitional cell carcinoma
Transitional cell carcinoma associated with
PeeSAC phenacetin Smoking aniline dyes cyclophosphamide
ppainless hematuria suggests
bladderr canceer
Where can transitional cell carcinoma occur?
calyces, pelvis, ureters, bladder
acute pyelonephritis affects which part of kidneys?
Cortex. glomeruli and vessels are spared
Cause of chronic pyelonephritis
vesicoureteral reflux or chronic kidney stones. Normal person shouldn’t get recurrent UTIs–>chronic pyelonephritis
WWhich parts affected in chronic pyelonephritis?
Corticomedullary scarring with blunted calyces. Tubules have eosinophilic casts
HIstology of chronic pyelonephritis
Lymphocytic invasion with fibrosis
presentation of drug induced interstitial nephritis
eosinophilic pyuria
azotemia
How long after drug will drug TIN happenn?
After 1-2 weeks..
Can be months with NSAIDs
Which drugs cause TIN (allergic reaction to drug)
penicillin
diuretics
sulfonamides
rifampin
Diffuse cortical necrosis caused by
Vasospasm and DIC. Associated with obstetric catastrophes and septic shock
maintenance phase of acute tubular necrosis
oliguric for 1-3 weeks. Risk of hyperkalemia
Recovery phase of acute tubular necrosis
polyuric. Risk of hypokalemiia
Causes of toxic ATN
Aminoglycosides heavy metals myglobinuria ethylene glycol-->oxalate crystals radiocontrast dye urate
Renal papillary necrosis caused by
diabetes
acute pyelonephritis
chronic phenacetin (acetaminophen)
sickle cell
Difference in handling of BUN vs creatinine
BUN is reabsorbed
Creatinine is NOT reabsorbed
Acute renal failure: prerenal azotemia
BUN: Cr is increased >20
-urea retained by kidney to conserve volume
Intrinnsic renal failure
BUN: Cr ratio decreased <15
- caused by ATN/ischemia/toxins/crescentic GN
- granular casts
- Tubules filled with debris
- decreased BUN reabsorption
PPostrenal azotemia
BUN: Cr >15
-Caused by outflow obstruction (bilateral)
Urine osm: >500
Urine Na < 1%
prerenal
Urine osm: 40
FeNa >2%
Intrinsic or post-renal. Differentiate these by looking at the BUN: Cr ratio
Consequences of renal failure
Fluid/sodium retention (CHF) hyperkalemia metabolic acidosis anemia increased triglycerides
Side effect of increased BUN and Cr
Nausea asterixis pericarditis encephalopathy platelet dysfunction
Renal osteodystrophy
Failure of vitamin D hydroxylation
hypocalcemia
hyperphosphatemiia
–>2ndary hyper PTH
WWHy does hyperphosphatemia worsen renal osteodystrophy?
Tissue calcifications occur within tissues–>calcium phosphate instead of being excreted
Why do pts with ADPKD get hypertension?
Increased renin production
ADPKD associated with
berry aneurysms
mitral valve prolapse
benign hepatic cysts
AARPKD
presents in infant, often as potter’s syndrome
AARPKD associated with
congenital hepatic fibrosis. After birth, will have HTN, portal HTN, progressive renal insufficiency
Medullary cystic disease
tubulointerstitial fibrosis and renal insufficiency–>cannot concentrate urine.
Inherited with shrunken kidneys seen on ultrasound
where does mannitol affect the nephron?
The thin descending limb
where does acetazolamide work its effect?
Proximal tubule
mmannitol indications
Drug overdose
elevated ICP
Mannitol toxicity
pulmonary edema
when is mannitol contraindicated
CHF and anuria
iindications acetazolamide
urinary alkalization
altitude sickness
glaucoma
metabolic alkalosis
acetazolamide toxicity
metabolic acidosis
NH3 tox
sulfa allergy
calcium wasting diuretic
loop diuretics
furosemide indications
CHF, cirrhosis, nephrotic syndrome, pulmonary edema (too much fluid)
hypertension, hypercalcemia
Toxicity of loops
ototoxicity hypokalemia dehydration allergy (sulfa) nephritis Gout
Ethacrynic acid
Non sulfonamide loop diuretic. Virtually the same, can also cause gout
indications for hCTZ
HTN CHF
hypercalciuria
nephrogenic diabetes insipidus
Name the K sparing diuretics
Spironolactone
Triamterene
Amiloride
Mehcanism: spironolactone and eplerenone
Competitive aldosterone antagonists.
mmechanism triamterene and amiloride
Block ENaC at cortical collecting duct
IIndications for spironolactone
hyperaldosteronism
K depletion
CHF
side effects of spironolactone
Hyperkalemia
Antiandrogenic effects–man boobs
WWhich diuretics cause acidemia?
carbonic anhydrase inhibitors–decrease HCO3 reabsorption
aldosterone–blocks K/H secretion. Also, hyperkalemia increases H leak from cells
Which diuretics cause alkalemia?
loop and thiazide diuretics
- -Contractiion alkalosis
- -hypokalemia worsens alkalosis
Urine calcium increases with
loops
Why are ARBs better than ACE-Is?
they don’t increase bradykinin
–>no cough or angioedema. ACE is still able to break down bradykinin
What do ACEI do to GFR?
Decrease GFR, b/c efferent arterioles are opened
Why is ACE good for CHF?
prevents remodeling
ACE-I toxicity
Cough angioedema Teratogen decrease GFR Hyperkalemia hypotension
When are ACE inhibitors contraindicated?
bilateral renal artery stenosis
dysplastic kidney–how is it inherited?
Not inherited. COngenital malformation of renal parenchyma characterized by cysts and abnormal tissue, especially CARTILAGE. NOT BILATERAL LIKE ADPKD
baby with portal htn
ARPKD
berry aneurysm
ADPKD. cysts in the liver, kidney, and brain.
mitral valve prolapse
ADPKD association
how is medullary cystic kidney disease inherited?
autosomal dominant with SHRUNKEN kidneys
IF Fena is <1% this tells you
tubular function is intact=can resorb sodium. this happens in prerenal ATN
why is BUN:cr <15 in intrarenal renal failure
epithelial cells are not working, cannot resorb BUN, so it is excreted through the kidneys
Why is BUN:Cr>20 in pre-renal failure?
Kidneys reabsorb as much fluid as possible and BUN follows
Why is BUN:Cr>15 in post-renal failure?
High pressure in ureters “pushes” BUN and fluid back into the body from tubular fluid
If pre-renal failure doesn’t resolve…
becomes ischemic acute tubular necrosis. Prox tubule and medullary thick ascending limb are susceptible
What are consequences of ATN?
hyperkalemia with metabolic acidosis. Can’t excrete potassium or organic anions (lactic acid)
hyperlipidemia seen in
nephrotic syndrome
minimal change associated with
hodgkin’s lymphoma
most common cause of nephrotic syndrome in hispanics and A-As
FSGS
FSGS associated with
HIV
heroin
SCD
Minimal change and FSGS immunofluorexcence
None. Also poor response to tx/steroids. will progress to renal failure
Pt with lupus gets nephrotic syndrome
membranous nephropathy
Membranous nephropathy also associated with
Hep B/C
nephritic syndrome in lupus pt
DIffuse proliferative GN
granular immunofluorescence
immune complex deposition
- membranous
- membranoproliferative
type I membranoproliferative
subendothelial
HBV/HCV
more likely to have tram track
what determines if GAS can cause nephritic syndrome?
presence of M proteins
In adults with post-strep GN
more likely to present to crescent rapidly progressive GN
lupus patient with rapidly progressive glomerulonephritis
diffuse proliferative GN
Negative IF rapidly progressive nephritis
wegener, churg-strauss,
pt with rapidly progressive GN, hemoptysis, hematuria, and sinus infections
Perform cANCA–could be wegeners not goodpasteur’s (classic)
most common cause of nephritis world wide
Berger’s igA. Usually after mucosal infection, episodic.
churg strauss features not present in microscopic polyangiitis
Asthma
granulomatous inflammation
eosinophilia
tests for UTI
leukocyte esterase and nitrites
>10 WBC/hpf
culture: >100K CFU
sterile pyuria
chlamydia and n. gonorrhea
Most common pathogens for pyelonephritis
E. Coli
Klebsiella
Enterococcus
“thyroidization” of kidney
Chronic pyelonephritis
problem with staghorn calculi
can serve as a nidus for additional UTIs
what produces EPO
renal peritubular interstitial cells
why are crohn’s pts more likely to make calcium oxalate stones?
Not able to absorb calcium necessary to bind oxalate
shrunken kidneys with cysts
Dialysis patients. Pts at increased risk for RCC
Triad of RCC
hematuria
palapable mass
flank pain
Cause of RCC
loss of VHL
- increased IGF-1
- Increased HIF=VEGF PDGF
wilms tumor cell
blastema
beckwith-Wiedemann
wilms tumor
neonatal hypoglycemia
muscular hemihypertrophy
organomegaly (tongue)
Serum lab levels of calcium, phoshorus, and PTH in chronic kidney disease
- Phosphate retention
- Low calcium from low vitamin D
- Increased PTH
loop diuretics act on
thick ascending loop of henle. Decrease medullary concentration gradient
osmotic diuretics act on
thin descending loop
when do you see states of hypercalcemia and hypercalciuria?
Hyper PTH and sarcoidosis
Situations with hyperoxaluria
excesive intake
low calcium diets (less calcium in gut to bind oxalate for excretion)
VHL deletion
chromosome 3P
Upper part of ureter is supplied by
The renal artery
Explain what happens with hypoaldosteronism to Na, K, HCO3 and Cl
Low Na
High K
acidosis=Low bicarb (H+ATP pump)
High chloride to balance out HCO3-
Thiazide tox
Hyperuricemia
Hypercalcemia
Hyperglycemia
Hyperlipidemia
Hypokalemia and hypotension
how to treat post GN glomerulonephritis
loop diuretics and vasodilators.
–Kids recover well. Adults do not