Grin AKI & CKD Flashcards
what is AKI
abrupt decline in renal function, it is a clinical syndrome with many causes not just one disease
What defines AKI?
Any of these:
- increase in serum creatinine by >0.3 w/n 48 hrs
- Increase in serum creatinine to >1.5 times baseline w/n 7 days
- Urine vvolume <0.5 for six hrs
What is creatinine?
metabolite of creatine phosphate from muscle used to estimate GFR
Anuria?
urine less than 50-100 ml per day
oliguria
urine outuput less than 400-500 ml/day
Azotemia
elevated BUN no sx
Pre renal azotemia
elevaton in BUN out of proportion to serum creatinine due to poor renal perfusion
Uremia
elevated serum BUN with sx such as N/V confusion metallic tase in mouth, fatigue, anorexia
What happens if the kidney cant maintain normal volume status?
Volume overlaoad occurs
- dyspnea
- edema
- pulmonary edema
What happens if kidney cant maintain electrolyte homeostasis?
- hypertension
- hyperkalemia
- asx
Severe consequences
- hypertensive emergency
- arrhythmia
- sudden cardiac death
What happens if kidney cant maintain acid base balance?
- metabolic acidosis
- Dyspnea due to respiratory compensation
Serious consequences
- arrhythmia
What happens when the kidney cant eliminate waste
- increased urea
- uremia
- N/V, altered taste, fatigue confusion
severe:
- encephalopathy
- uremic paericarditis
What does prerenal AKI mean?
- hypovolemia
- hypervolemia
- systemic vasodilation
- drugs causing impaired renal function
things not directly involving the kidney
What is an intrinsic renal AKI?
- Acute tubular necrosis
- Acute interstitial nephritis
- Glomerular disease
- Vascular
processes occuring inside the kidney
What is a post renal AKI
- bladder outloest obstruction
- ureteral obstruction
occurs after the kidney
What is the most common type of pre renal AKI?
hypovolemia due to bleeding, vomiting, diarrhea, overdiuresis, dehydration
What causes hypervolemia in prerenal aki?
congestive heart failure
what causes systemic vasodilation in a pre renal aki
- Sepsis
- SIRS
- Cirrhosis
What drugs cause pre renal aki>
- NSAIDs and ACEi
How does tubular necrosis cause intrinsic renal AKI?
most common cause of intrinsic AKI
- prolonged pre renal, kidneys lack blood flow for too long (sepsis is common cause)
- toxins such as myoglobin, uric acid, myeloma light chains, and IV contrast can cause tubular damage
How does acute interstitial nephritis cause intrinsic AKI
infiltration of immune cells into the interstitium of the kidneys commonly caused by PPIs, NSAIDs, and some abx
How does acute interstitial nephritis cause intrinsic AKI
- infiltration of immune cells into the interstitium of the kidneys commonly caused by PPIs, NSAIDs, and some abx
In an intnrisic AKI, the kidney has damage to the glomerulus, tubules, or interstitium which leads to two problems. what are they? what will labs show?
- problems with filtration
- problems with reabsorption and secretion
- Urine Na >40
- BUN/Cr <15:1
- Urine osm <350
What are the two types of bladder outlet obstruction that can cause post renal AKI?
- BPH is most common cause of bladder outlet obstruction
- blood clots can also cause this
How does uretereal obstruction cause post renal AKI?
stones or external compression from a malignancy, but it has to be bilateral ureteral obstruction to cause this
What history should be asked for a patient with suspected AKI?
- volume status
- urine volume color changes
- sx of urinary obstruction
- recent infection, dysuria
- Recent IV contrast
- complete medication hx
What PE should be doen with suspected AKI?
- VS
- Volume status
- mucous membranes, JVP, cardio-pulm
- Prostate exam
- Examine bladder and kidneys
- Skin exam
Labs for suspected AKI
- BMP look at BUN/Cr
- UA with microscopy
- Urine electrolytes
- Urine microalbumine/Cr ratio or Urine protein/Cr ratio
ALL patients with AKI need a BMP and UA
On UA if you see hyaline casts what can that suggest
non specific pre renal axotemia
Renal tubular epithelial cells and granular casts (muddy brown) on UA suggests what kind of kidney disease?
ATN
What type of kidney disesase does WBC, WBC casts, or urine eosiniphils on a UA suggest?
Acute interstitial nephritis
What kind of kidney disease does Proteinuria (<3.5), hematuria, dysmorphic RBC and RBC casts suggest?
Nephritic syndrome
What kidney disase does heavy protein >3.5g/day, fatty casts, oval fat bodies, and minimal hematuria suggest?
Nephrotic syndrome
What is Fractional excretion of Sodium (FENa) used for?
- used to differentiate between pre renal AKI and ATN
- FENa <1% suggests pre renal AKI
- FENa >2% suggests ATN
When would you use FEUrea instead of FENa?
If a patient is on diuretics as you are inducing excretion of Na
When does FEUrea suggest AKI vs ATN?
- FEUrea <35% is prerenal AKI
- FEUrea >50% ATN
What is a post void residulal used for?
Used if suspecting bladder outlet obstruction, looks at volume of urine left in bladder after urination
What is a renal US used for?
Concern for ureteral obstruction or other post renal processes
What does a urine eosinophil assess for?
Historically used to look for AIN, but has poor sensitivity and specificity, not used
When is a renal bx done
Severe AKI rapidly progressive unclear etiology
How do you treat AKI generally?
- Depends on cause
- Avoid nephrotoxins
- renally dose all medications
- dialysis if needed
How do you treat pre renal AKI?
- correct hemodynamics
- low preeload give fluids
- high preload give diuretics
Intrinsic AKI treatment
- ATN is supportive care
- AIN stop medications consider steroids
- Glomerular depends on cause
Post renal AKI tx
- remove obstruction
- Bypass obsruction
- Catheter
Outcomes of AKI?
- likelihood of recovery depends on severity of injury and their baseline renal function
Indications for dialysys?
- AEIOU
- Acidosis (pH <7.2)
- Electrolytes
- Intoxication
- Overload
- Uremia
CKD definition?
- If it’s less than 3 months wit hGFR <60 and or markers of kidney damage patient has AKI
- After three months then it is CKD
Top causes of CKD
Diabetes and Htn
How does the lack of EPO production in CKD impact the body?
- Anemia
how does the kidneys inability to regulate calcium and phosphours metbaolism in CKD impact the body?
- secondary hyperparathyroididsm
- bone pain and fragility
- fractures
What labs are seen with secondary hyperparathyroidism cased by CKD?
- Calcium is decreased
- PTH is increased
- Phosphorus is increased
What is the pathophysiology of tertiary hyperparathyroidism with CKD?
- prolonged secondary hyperparathyroiodism
- Parathyroid gland hyperplasia
- autonomously functioning parathyroid gland and loss of function of calcium sensing receptors
Labs for tertiary hyperparathyroidism?
- Calcium is increased
- PTH is increased
- Phosphorus is increased
What is osteitis fibrosi cystica?
- excess PTH due to ossteoclast activation leading to bony breakdown
- leads to subperiosteal bone reabsorption
- Bone cyst formation
- brown tumors due to microhemorrhages
Pathologic fractures common in patients with advanced CKD due to renal osteodystrophy
Labs and tests for CKD?
- BMP looking at serum creatinine
- Estimate GFR
- UA with microscopy
- UA microalbumin/creatinine ratio
- Urine protein/Cr ratio
- Renal US
- Renal Bx
Treatement for CKD?
- Diuretics and fluid restrictiono to maintain volume
- Low K diet
- Bicarb supplement to correct acidosis
- Monitor for encephalopathy due to lack of waste elimination
- iron repletion and EPO agents
- Calcitrol and phosphorus binders
