Clin Med Exam 3 Flashcards
Most common intrinsic cause
Acute Tubular Necrosis
Causes of Prerenal (decreased perfusion)
True volume depletion Hypotension Edematous state Selective renal ischemia Drugs (NSAIDs, ACE-I)
Intrinsic causes
Renal ischemia
Sepsis
Nephrotoxins
Acute Tubular Necrosis d/t IV Contrast
Contrast causes tubular epith cell toxicity and Renal medulary ischemia frm vasoconstriction
Risk factors:
Pre-existing renal dz
Volume depletion
Repeated dose of contrast
Reduction in GFR will only occur if:
there is a Bilateral obstruction or an issue LOW
Obstruction most commonly d/t
Prostatic dz (hyperplasia or CA)
or Mets
or Neurogenic bladder
Normal urine output
1-2 L /day
Oliguric (little urine)
<400 mL in 1 day
Anuric
<50- 100 mL in 2 day
Muddy brown casts
Acute Tubular Necrosis
FENa
How is kidney handling sodium? (Na)
% of filtered Na that is actually excreted in urine
FENa <1%
Pre-Renal
FENa >2%
Intra-renal (Acute tubule necrosis)
FENa is NOT useful for:
Pts on diuretics
pts in AKI (bc serum Cr is not stable)
When to perform Renal biopsy
No other explanation
Cr markedly elevated or significantly worsening quickly
Purpose: to prevent ESRD
Contra to Renal biopsy
Bleeding issues Severe HTN Pyelonephritis Renal tumor Solitary native kidney
Life threatening complications of Acute Kidney Injury
Volume imbalance Metabolic Acidosis Hyperkalemia, Hyperphosph Uremia HypOOOcalcemia
Severe AKI can cause
Altered mental status
First step to managing AKI
Correct volume status (this can improve or reverse AKI)
Fluid challenge
identify Pre-renal failure
Crystalloid isotonic IVF
Pt doesn’t respond to Fluid challenge
Likely Acute Tubular Necrosis or other forms of Intrinsic or Post renal
If pt is still producing urine,
give diuretic
BUT should not be used for prolonged tx
Metabolic acidosis happens in AKY why?
Not excreting the acid Not making bicarb Low GFR Many causes of AKI produce inc acids Diarrhea net loss of bicarb
Tx of Metabolic Acidosis
Dialysis or
Bicarb administration
Dialyze pts with Metabolic Acidosis IF
Not producing urine (or V little)
Volume overloaded
pH <7.1
Bicarb can make what worse?
Volume overload
When to give bicarb for Metabolic Acidosis?
Pt is not volume overloaded no other indication for acute dialysis ESP IF: diarrhea is cause ph <7.1 and awaiting dialysis
Low Calcium
Chvostek sign (face)
Trousseaus sign (arm)
Paresthesias
Tetany
NEED IV Calcium (but don’t replace too quickly)
If pt has no sx and Calcium is low,
correct the High phosphate with: Phosphate binders
Uremia
urine in the blood
Uremia can lead to
Pericarditis
Neuropathy
Decline in mental status
Uremia is more common in
CHRONIC kidney dz
Leading cause of kidney failure
DM and HTN
Those with CKD and DM are at much higher risk of also developing
Cardiovascular dz
CHRONIC Kidney Dz
3 OR MORE MONTHS OF:
Decreased kidney fx (GFR <60)
OR
Kidney Damage (Albuminuria ACR 30 or more, abnormal imaging, abnormal urinary sediment, hx transplant)
RBC casts
GLOMERULOnephritis
Pts “at risk” for developing CKD should be screened by:
Urine ACR
Serum Cr to estimate GFR (eGFR)
Uremic syndrome
accumulation of metabolic Waste products or Uremic toxins
Uremic syndrome
seen w profound decrease in GFR
Uremic syndrome
Fatigue, anorexia, n/v, pruritus, bruising, METALLIC tase in mouth, SOB, DOE, Pericarditis, restless leg syndrome, seizure, encephalopathy
Secondary hyperparathyroidism
Hyper-phosphatemia, hypocalcemia, decrease in vitamin D
Secondary hyperparathyroidism
PTH
High phosphorus
Low Ca2+
In an effort to raise Ca levels, we stimulate PTH
Meds that lower GFR
ACE-I
NSAIDs
ACE-I and ARBs
dilate Efferent arteriole, decreasing glomerular pressure
When ACE-I and ARBs can be harmful:
Bilateral Renal Artery Stenosis
caution in Acute Kidney Injury (may see acute reduction in GFR and hyperkalemia)
When to refer to nephrologist
GFR <30
Chronic intertubulo dz of kidney
Obstructive uropathy
Reflux uropathy
Analgesic uropathy
Chronic tubulointerstitial
spares the glomeruli
Chronic tubulointerstitial dz General findings
Polyuria
Hyperkalemia
UA nonspecific- proteinuria (<2), broad waxy casts
Obstructive sx
PAIN, change in UOP, HTN, hematuria, inc serum Cr
Obstructive pathology UA
Hematuria, pyuria, bacteriuria but often bland
Obstructive pathology US
Detect mass, hydroureter, hydronephrosis
Reflux Nephropathy
the result of Vesicoureteral Reflux (VUR)
VUR
urine can extravasate into the interstitium–> inflammatory response–> scarring/fibrosis of kidney
Reflux Nephropathy
typically in young children w hx of recurrent UTI
Analgesic Nephropathy
long term consumption of Analgesics (often seen in those w chronic back pain)
Analgesic Nephropathy labs
Often no sx
Labs show elevated serum Cr
UA: hematuria, sterile pyruia, mild proteinuria
Anemia
Analgesic Nephropathy
CT Scan:
Renal papillary necrosis/calcification
Nephrotic syndrome
Non-inflamm
Proteinuria: >3.5
“foamy” oval fat bodies
More edema than in the other
Proteinuria >3.5g/day
Nephrotic syndrome
Nephrotic synd: primary dz (3 subtypes)
Minimal change dz
Membranous nephropathy
Focal segmental glomerulosclerosis
Nephrotic synd: secondary dz
Diabetic nephropathy
Amyloidosis
Oval fat bodies
Lipiduria
Nephrotic synd
Minimal change dz (MCD)
Most common nephrotic synd in KIDS
Most idiopathic, but can be secondary following URI or Allergic rxn
1st line tx for Minimal change dz (primary nephrotic synd)
Prednisone
MCD Minimal change dz primarily affects
Podocyte
podocyte foot process fusion
Membranous nephropathy
adults
peak in 40s, 50s
Primarily idiopathic, thought to be immune mediated
Membranous nephropathy sx
Typical of Nephrotic synd
RISK OF CLOT
Tx for Membranous nephropathy
Supportive, immunosupp, transplant
Adverse risk factors for Membranous nephropath
Male sex, older age >50YO
FSGS
specific pattern under microscope given this name
FSGS
> 70% present with typical Nephrotic synd sx
FSGS greater risk
African American
3-4x more common men
FSGS
Damage to podocyte,
Sclerosis
FSGS tx
Supportive, Immunosupp, Dz specific tx for if secondary dz
Poor outcome for FSGS IF
Nephrotic range proteinuria
African american
Renal insuff
What to order if you suspect Minimal change nephropathy
UA
Serology
Diabetic Nephropathy (secondary dz)
Most common cause of ESRD in US
Diabetic nephropathy
usually in pts who have had DM for 10-20 yrs BUT may be present at time of dz in those with DM Type II
Diabetic nephropathy
Morphologic changes in kidney
inc proteins in urine
Albuminuria >300
Tx of Diabetic nephropathy
Strict glycemic control BP control ACE-I, ARBs Statin therapy Dialysis/ transplant
Renal Amyloidosis
abn shaped protein that CLUMP together, can deposit in gomerulus
Renal Amyloidosis screening
SPEP and UPEP
Renal Amyloidosis tx
Refer to nephro
Tx underlying cause
SPEP and UPEP
Multiple Myeloma
C-ANCA and P-ANCA
GPA
Microalbuminurie
Early sign:
Diabetic nephropathy
Kidney damage
Test of choice to RULE OUT obstruction
Renal US