Block 4: AKI and CKD Flashcards
What are the excretory functions?
- Glomerular filtration
- Secretion
- Reabsorption
What occurs during glomerular filtration?
Passive process: water and small MW ion and molecule cross membrane in Bowman’s capsule and get secreted in the PT
What occurs during secretion?
Active process that utilize transporters → eliminates compounds from renal circulation to tubular lumen
What occurs during reabsorption?
Active and passive: Water and solutes reabsorbed throughout the nephron
What are the endocrine functions of kidneys?
- Renin secretion
- Production and metabolism of PG and kinins
- EPO production
What are the metabolic functions of the kidneys?
- Activation of vitamin D
- Gluconeogenesis
- Metabolism of insulin and endogenous steroids
- Enzymatic processes
How do we evaluate kidney functions? When do we use each component? Which is the best?
- Proteinuria (CKD and increased mortality and ESRD risk)
- GFR (Best)
- Urine albumin:Cr ratio (Severe CKD and progression monitoring)
How often do you evaluate kidney function? What do you evaluate?
Yearly
1. sCr and electrolyes
2. Urine albumin (cr, pH, specific gravity, sediment)
3. Renal ultrasound
What is the presentations of early vs late CKD?
e: No distress
L: edema
Signs and symptoms of Early CKD?
N/A
Lab tests for early CKD?
- Microalbuminuria
- Mildly elevated sCr and BUN
Lab tests for late CKD?
- Persistent proteinuria
- Reduced GFR or CrCl
- Abnormal urinalysis
Normal pH? Elevation?
4.5-7.8
Bacteria
Heme lab of CKD?
Indicates presence of hemoglobin or myoglobin
Risk factor for worsening CKD or death
Protein in urine?
Amount of protein/Albumin used to assess severity and progression of CKD
What is the specific gravity indicate?
1.003-1.03
Urine vs serum osmolarity
What does ketones in urine mean?
Normal is none
Excreted in DKA and starving/fasting
Indications of nitrates in urine?
Bacterial infection
What is proteinuria?
Protein loss → nephron injury
Persistant = 3x over period of 3-6 months
What are the cut offs of albuminuria?
A1 → <30 mg normal
A2 → 30-300 microalbuminuria
A3 → >300 macroalbuminuria
What is the normal sCr/BUN ratio? Decreased effective circulating volume?
Normal: 5-15
Dysfunction: >20
Water and urea get absorbed but not creatine
What does sCr measure?
Balance of creatine production (muscle) and renal excretion
What is normal sCr?
0.5-1.5 mg/dL
How is UCr eliminated?
Glomerular filtration
What is GFR?
Volume of plasma filtered across glomerulus per unit of time
What do we use to calculate CrCl?
Cockcroft-Gault
What are examples of qualitative diagnostics for CKD?
- KUB (size)
- IV urogram
- CT
- US
- MRI
- Biopsy
What is the indication of BUN <20 vs >20?
Intrinsic vs Prerenal
What is AKI? How does it effect sCr?
Abrupt reduction in kidney function shown in sCr, BUN, UOP
Change in sCr 50% in 7 days or 0.3mg/dL in 24-48 hrs
How do we classify AKI?
KDIGO
Functional and structural criteria of CKD?
GFR <60 for >3 months, Kid damage >3 minth
What are the causes of AKI?
- Hospital and community acquired
- Sepsis, shock, drugs, major surgery, comorbidities
What are the functional criteria of NDK?
GFR >60, Stable sCr, no damage
What are the treatment goals of pre renal?
Restore and ↑ RBF
Causes of pre renal injury?
- Reduced IV volume (hemorrhage, GI losses, burns, diuretics)
- Reduced effectivecirulatory BV (↓ CO, vasodilation)
How does the body compensate for prerenal? Why is that bad?
SNS, RAAS, ADH increase H2O and Na retention
PG, kinins, NO dilate afferent arteriole
Ang II contract efferent arterioles
Prolongation of compensatory mechanism → overwhelms the kidneys
What are the types of pre renal injury?
- Cardiorenal syndrome
- Hepatorenal syndrome
- Nephrotic syndrome
How do you treat cardio renal?
Fluid overload → give loops
How do you treat hepatorenal?
↑ oncotic pressure → spiranolactone