Approach to Proteinuria, Oliguria, and Polyuria Flashcards
What are the criteria for CKD?
Markers or kidney damage OR decreased GFR
for greater than 3 months
What is the criteria for AKI?
GFR less than 60 and/or markers of kidney damage
less than 3 months
In the absence of kidney damage neither GFR category stage 1 or stage 2 can fulfill the criteria for what condition?
CKD
What are the risk factors for CKD?
What is the major cause?*
DM*
HTN*
CVD
AKI
What are some s/s of CKD?
often asymptomatic
Edema
HTN
decreased UOP
Foamy urine (proteinuria)
uremia (n/v/confusion, metalic taste)
Pericardial friction rub
asterixis
uremic frost
What are the three simple tests to ID most CKD pt’s?
eGFR
urine-albumine-to-creatinine ratio or urine protien-to-creatinine ratio
urinalysis
What renal U/S findings are significant for CKD?
atrophic or small kidneys
cortical thinning
increased echogenicity
elevated resistive indices
What is renal replacement therapy?
hemodialysis
peritoneal dialysis
renal transplantation
What are the indications for dialysis?
AEIOU
A-severe acidosis
E-Electrolyte disturbance
I-Ingestion
O-volume Overload
U-Uremia
staging of AKI is based on what two things?
Serum Creatinine
or
Urine Ouput
(whichebver is worse)
What will a prerenal etiology of AKI look like?
hypotension
hypovolemia
reduced cardiac output with HF, tamponade or PE
systemic vasodilation (sepsis, SIRS, hepatorenal)
What will a postrenal etiology of AKI look like?
bladder outlet obstruction (BPH, cancer)
ureteral obstruction (stones, malig., fibrosis)
renal pelvis issues (stones, necrosis)
What are the three intrinsic etiologies of AKI?
ATN (ischemia > toxins)
Interstitial nephritis
Glomerulonephritis
What are the s/s of AKI?
Same as CKD
(duration is shorter)
What are the common diagnostic tests for AKI?
UA with micro
Urine alb/cr ratio or protein/cr ratio
Renal US
What BUN/Cr ratio is suggestive of PRerenal Azotemia?
>20:1
What FENA score indicates prerenal azotemia and ATN?
<1% prerenal azotemia
>2% ATN
What FeUrea indicates prerenal azotemia and aTN?
<35% prerenal azotemia
>50% ATN
If you see renal tubular epithelial cells, transitional cells, granular or waxy casts in the urine, what is the cause?
ATN
If you see WBC, WBC casts, or urine eosinophils int he urine what is the cause?
AIN or pyelonephritis
IF you see dysmorphic RBCs or RBC casts in the urine what is the cause?
vasculitis or glomerulonephritis
If you see proteinuria <3.5g/day, hematuria, dysmorphic RBCs and casts what is the cause?
NEphritic syndrome
If you see heavy proteinuria >3.5g/day, lipiduria, minimal hematuria, what is the cause?
NephrOtic syndrome
What is the cause of hyaline casts?
nonspecific, prerenal azotemia
What is the cause of WBCs, RBCs, bacteria in urin?
UTI
What is the treatment of AKI?
depends on etiology
correct underlying issue
supportive (fluids, renal replacement, avoid hypotension and nephrotxins)
What are the key features of NephrOtic syndrome?
>3.5g/day of Protein
hypoalbumemia
edema
hyperlipidemia
lipiduria
*if albumin is normal, pt does not have nephrotic syndrome
How is nephrOtic syndrome diagnosed?
Renal biopsy
How is nephrItic syndrome defined?
What key feature is seen in urine?
Hematuria
HTN
minimal proteinuria
renal failure common
*Active urinary sediment (casts)
How is nephrItic syndrome diagnosed>
renal biopsy
What is a common urinary symptom of diabetes inspidus?
Polyuria (solute diuresis or water diuresis)
What can cause solute diuresis?
glucosuria (hyperglycemia)
urea (resolution of aztoemia)
sodium (IVF)
mannitol (tx of ICP)
What can cause water diuresis?
primary polydipsia
central or nephrogenic Diabetes inspidus
How is ADH released in response to increased serum osmolality?
How is ADH released in response to decreased BP or increased BV?
serum osmolality is detected by osmoreceptors in the anterior hypothalamus which causes ADH release
These are sensed by the arterial baroreceptors and atrial stretch receptors leading to ADH release
When ADH is released, what does it bind to?
How does this relate to dehydration?
binds to V2R and increased cAMP leading to insertion of AQP2 and urea transporters on the apical membrane
In dehydration, this is why urea levels increase
What is central diabetes insipidus?
caused by decreased release of ADH
usually idiopathic
What is nephrogenic diabetes inspidus?
caused by decreased response to antidiuretic hormone (ADH)
rare hereditary form seen in children
can be caused by lithium or hypercalcemia
how does hypercalcemia lead to polyuria?
Then how does it cause nephrogenic DI?
basolateral calcium sensor (CaSR) in TAL leads to inactivation of luminal K channel which inactivates NKCL2 transporter (like a loop diuretic)
in the CD on the apical membrane, the CaSR is activated by high Ca levels. The CaSR induces degradation of the AQP2 channels leading to nephrogenic DI
How is DI diagnoseD?
24hr urine volume collection
urine osm <300
water deprivation test
how is DI treated?
how is hypernatremia treated?
central-give vasopressin
nephrogenic-decrease solute intake, thiazide diuretics, NSAIDs, vasopressin
hypernatremia-replace free water deficit with water or IV D5W
