Renal Flashcards
Classic findings include skin rash, fever, and eosinophilia, with UA showing many WBCs and WBC casts.
Drug-induced Allergic interstitial nephritis
(NSAIDs, Zosyn, PPIs, cephalosporins, penicillins, sulfonamides, diuretics, rifampin, phenytoin, allopurinol)
Tx = d/c offending agent
Kidneys normally compensate for intravascular volume depletion (vomiting, diarrhea) by secreting vasodilatory ____ which dilate the afferent arteriole to maintain GFR & renal perfusion.
prostaglandins (via ↑ COX production)
PDA: Prostaglandins Dilate Afferent
NSAIDs inhibit COX →
Resulting in renal afferent arterial _____ →
pre-renal azotemia (>20:1)
vasoconstriction
(Cox = vasodilation)
Kidney biopsy is used to diagnose ____ renal causes of acute kidney injury.
Intrinsic
(use if pt has: hematuria, proteinuria)
Patients with acutely elevated creatinine & clinical signs of obstruction require imaging (preferably ____) to assess for hydronephrosis.
renal ultrasound
Alcohol bingeing can lead to acute alcohol myopathy and ______, especially when combined with cocaine abuse.
rhabdomyolysis
(cx: AKI s/t dehydration & pigment-induced nephropathy)
Hypovolemic shock can cause what type of AKI?
acute tubular necrosis (ATN)
A BUN/Cr ratio of ___ is usually seen in Acute Tubular Necrosis (ATN)
10-15
Acute Tubular Necrosis (ATN) findings that support its diagnosis are:
BUN/Cr ratio 10-15
Urine Osm ____ mOsm/L
(but never __ mEq/L
Urine Na >__
FENa > __%
300-350 (but never <300)
> 20
> 2%
Broad casts are seen in patients with _____
chronic kidney disease (CKD)
*made in dilated tubules of enlarged nephrons that have undergone compensatory hypertrophy s/t ↓ renal function.
Waxy casts, which are shiny and translucent, are seen in patients with _____
chronic kidney disease (CKD)
Red blood cell casts are indicative of (3)
Glomerular disease (glomerulonephritis)
Vasculitis
HTN emergency
White blood cell (WBC) casts are seen in cases of (3)
*white = TAP
Allergic Interstitial nephritis
Pyelonephritis
Transplant Rejection
*are definitive evidence that urinary WBCs originate in the kidney
Fatty casts are seen in conditions causing ____.
Nephrotic syndrome
Hyaline casts are composed almost entirely of protein and are non-specific; these may be seen in asymptomatic individuals and in patients with ___
pre-renal azotemia
Muddy Brown cast are indicative of ____.
ATN
Granular Cast are seen in cases of (3)
Granular = GAP
Glomerular disease (glomerulonephritis)
ATN
Pyelonephritis
A [lab workup] is typically collected when a precise measure of renal function is needed (ex: renal transplant evaluation, preparation for hemodialysis).
24-hour creatinine clearance
*not required in most cases of AKI work-up
present with insidious onset of flank pain and systemic symptoms (fever, weight loss), typically in patients with a recent h/o UTI (1-2m ago) or extrarenal infection (bacteremia).
Renal and perinephric ___
abscesses
(+/- pyuria, bacteriuria, micro-hemturia, or proteinuria)
Pyelonephritis happens shortly after UTI not weeks later.
Prerenal AKI in an acute CHF exacerbation is most likely s/t Cardiorenal Syndrome, which involves:
↑ ___ & Renal venous pressures
resulting in
↓ ___
↑ CVP (R 💛 pre-load)
↓ GFR
High-dose intravenous ___ can cause crystalluria with renal tubular obstruction.
acyclovir
- giving IVFs with the drug can help ↓ risk of AKI
ACE inhibitors temporarily reduce GFR due to dilation of renal efferent arterioles and should not be initiated in the setting of ____.
AKI
Contrast-associated acute kidney injury is characterized by a rise in serum creatinine ____ after intraarterial contrast administration followed by a gradual return to baseline.
24-48 hours
(prevent by giving IVFs before)
Most cases of renal failure result in
[electrolyte abnormality]
due to reduced renal phosphorus excretion.
hypocalcemia
Patients who have acute renal failure and _____ often have an underlying malignancy.
hypercalcemia
(ex: Multiple Myeloma)
bc acute renal failure is supposed to cause hypocalcemia
multiple myeloma (MM) induced hypercalcemia can cause AKI due to clogging of the renal tubules with calcium deposits or _____.
immunoglobulin light chains
(classically presents with anemia, bone pain, hypercalcemia, and acute renal failure)
Elevated ____ is likely the major driver of AKI in cardiorenal syndrome.
central venous pressure
(leads to elevated renal venous pressure and congestion.
This reduces the glomerular capillary filtration gradient)
Acute renal allograft rejection is predominantly T-cell mediated and usually occurs within the first ___ following transplant.
6 months
Acute renal allograft rejection
results in an asymptomatic rise in serum creatinine.
The diagnosis is confirmed by renal biopsy showing ___ of the intima.
Treatment is with _____.
lymphocytic infiltration
high-dose IV glucocorticoids
____ results from excessive immunosuppression in renal allograft recipients and leads to tubulointerstitial nephritis.
Renal biopsy reveals intranuclear ____ and a mixed lymphocytic and neutrophilic infiltrate.
BK virus reactivation
intranuclear inclusions
(cx: ureteral stenosis/obstruction)
Acute toxicity to ____ involves vasoconstriction of the afferent and efferent renal arterioles, leading to prerenal AKI and hypertension.
calcineurin inhibitors (tacrolimus)
immunosuppresor in Kidney Transplant pt
metformin is renally cleared, the drug should be discontinued in ___
renal insufficiency/ AKI
Hepatorenal syndrome has acute renal failure (Cr >1.5) with a very low urine sodium level (<10 mEq/L), and an absence of blood, casts, or protein in urine. Creatinine does not improve with ___.
intravenous fluid resuscitation
Angiotensin II causes arteriolar vasoconstriction of ___ and systemic vessels, which improves GFR and blood pressure
efferent
ACE: AngII Constricts Efferent
Benign prostatic hyperplasia can cause an obstructive uropathy that presents as a slowly rising creatinine level.
A ___ examination, which should be performed in all patients being evaluated for creatinine elevation or CKD
renal ultrasound
70% of cases with interstitial nephritis are caused by drugs such as (8)
Discontinuing the offending agent is the treatment.
NSAIDs
Cephalosporins
Penicillins (Pip-Tazo) / Sulfonamides (TMP-SMX)
allopurinol
PPI
rifampin
phenytoin
High-dose intravenous ____ can cause crystalluria with renal tubular obstruction.
Administering fluids with the drug can help reduce the risk of AKI.
acyclovir
What antibiotic can cause acute tubular necrosis, usually after >5-7 days of use.
Aminoglycosides (amikacin, gentamicin)
Nonsteroidal anti-inflammatory drugs inhibit prostaglandin synthesis, which can cause ___.
prerenal azotemia/AKI
afferent vasoconstriction
(worse if pt is already volume down)
Evaluation of neonatal acute kidney injury includes a ____.
renal and bladder ultrasound (RBUS)
Acute ____ can cause hematuria, AKI, fever, and flank pain.
Most common in patients with analgesic overuse or sickle cell anemia.
papillary necrosis
HRS occurs due to _____, decreased vascular resistance (SVR), and local renal vasoconstriction with decreased perfusion.
splanchnic arterial dilation
The most common inciting factors of HRS include (2)
SBP
gastrointestinal bleeding
