Approach to Diagnosis of Acute Kidney Disease Flashcards
definition of kidney disease
- alteration in kidney structure or function
- GFR < 60
if kidney disease has been going on for more than 3 months it is considered
- chronic kidneys disease
if kidney disease has been going on for less than 3 months it is considered
- acute kidney disease
if the kidney disease has been going on for hours to days (2-7 days), it is considered
- acute kidney injury
AKI and AKD can occur in
- CKD
AKI and AKD can lead to
- CKD
decreased urine output is a sign of
- AKD/AKI
small, echogenic kidneys on ultrasound is a sign of
- CKD
causes of AKD can be classified into
- pre-renal
- intra-renal
- post-renal
cause of pre-renal kidney disease
- reduced renal perfusion
cause of intra-renal kidney disease
- vascular
- glomerular
- tubular
- interstitial injury
cause of post-renal kidney disease
- obstructed kidney
- interference with normal urine flow
causes of decreased renal perfusion
- low ECF volume
- altered renal blood flow or hemodynamics
causes of low ECF volume
- GI losses
- hemorrhage
- diuretics
causes of altered renal blood flow or hemodynamics
- sepsis
- heart failure
- cirrhosis/hepatorenal syndrome
- hypercalcemia
- medications
- vascular disease
causes of intra-renal kidney disease
- glomerular disorders
- acute interstitial nephritis
- tubular obstruction
- acute tubular necrosis
causes of acute interstitial nephritis
- medication induced
- autoimmune
- infection related
causes of tubular obstruction
- crystals
- tumor lysis
- myeloma casts
causes of acute tubular necrosis
- ischemic
- nephrotoxic
ischemic causes of acute tubular necrosis
- decreased effective renal perfusion
- prolonged renal state
nephrotoxic causes of acute tubular necrosis
- nephrotoxic medications
- heme pigments
- iodinated radiocontrast
initiating phase of acute tubular necrosis lasts how long
- hours to days
definition of initiating phase of acute tubular necrosis
- time from onset of precipitating event until tubular injury occurs
maintenance phase of acute tubular necrosis lasts how long
- 1-3 weeks
maintenance phase of acute tubular necrosis characterized by
- marked decrease in GFR
- risk of electrolyte abnormalities
recovery phase of acute tubular necrosis is the period during which what takes place?
- repair of renal tissue
abnormal urine with RBCs, RBC casts, and proteinuria will lead us to what condition
PRE-RENAL
- glomerulonephritis
- vasculitis
- thrombotic microangiopathy
- Atheroemboli
abnormal urine with WBCs, WBC casts, and eosinophils will lead us to what condition
- pyelonephritis
- interstitial nephritis
- atheroemboli
- glomerulonephritis
abnormal urine with RTE cells and pigmented cells will lead us to which conditions
- tubular injury (acute tubular necrosis)
acute tubular necrosis will have what in the urine
- granular “muddy brown” casts
if fractional excretion of Na is <1% the condition is mostly due to
exceptions
- pre-renal
- glomerulonephritis/vasculitis
- radiocontast and heme pigement ATN
- ATN + chronic pre-renal condition
- nonoliguric ATN
if fractional excretion of Na is > 1% the condition is mostly due to
exceptions
- acute tubular necrosis
- chronic kidney disease
- diuretic use in past 24-48 hours
how to calculate fractional excretion
Urine_Cr * BUN
fractional excretion of urea < 35% suggests what cause
- pre-renal
fractional excretion > 50% suggests what cause
- acute tubular necrosis
urine hyaline casts suggest what causes
- pre-renal
urine granular casts suggest what causes
- acute tubular necrosis
how do kidneys try to compensate for diminished perfusion
how do NSAIDs stop this
- increasing afferent arteriolar dilation
- block intra-renal prostaglandins and block afferent dilation causing reduction in GFR
definition of renal papillary necrosis
- necrosis and sloughing of the papillae from impairment of blood flow
renal papillary necrosis associated with
- NSAIDS
- Diabetes Mellitus
- Sickle Cell Disease/Trait
treatment of renal papillary necrosis
- supportive
