Intro to Renal Failure Lecture Flashcards
Urine
Serum
Radiography
3 ways to assess kidney function
Goes up quickly in ARF due to ischemia and radio contrast (complication of x-ray dye studies such as IVP, CT scans)
- Peaks 3-5d after contrast
- Peaks 7-10d after ischemia
Creatinine
*not correlative with symptoms
Sodium reflets _____ status
volume
I&Os
Urine sodium
Body weight
Toxin levels
Ways to monitor kidney function
Can people with kidney disease concentrate their urine?
No..
urine concentration is low
Collectively, the measure of renal function
*If low, leads to azotemia
Can be estimated by serum creatinine
*Affected by age, sex, weight, fluid status, and medical condition (illnesses, nutritional status, drugs on board, etc.)
GFR
Creatinine is secreted in the….
proximal tubule
Men:(140-age) x (wt in kg) divided by 72 x serum creatine
Cockcroft-Gault equation
*calculates GFR
Defined as excess of urea and nitrogenous compounds in blood
Due to breakdown of protein
Azotemia
Metabolism of carbs and fats yields…
water and CO2
Best first radiographic test…
will exclude obstruction of kidney
Ultrasound
Non invasive
No risky contrast dye
Readily available
Advantages to ultrasound
Avoid contrast in…
ARF and CRF
Biopsy may be needed in ____ for intrinsic disease
ARF
Volume overload
Hyponatremia
Hypocalcemia (paresthesia, cramps, seizures, confusion)
Complications of ARF
Whats more common in renal failure, HyperNa or HypoNa?
HypoNa
- Hyperkalemia, phosphatemia, magnesemia
- Metabolic acidosis
- HTN
Complications of ARF
ARF is usually….
reversible
Due to renal hypoperfusion
Usually reversible if restoring renal blood flow (RBF)
Parenchyma usually not damaged
In severe cases, ischemia/injury
Prerenal azotemia
- Hypovolemia (Fluid loss, Decreased cardiac output, Decreased systemic vascular resistance)
- Renal hypoperfusion
Prerenal azotemia
- Leads to epinephrine release and subsequent vasoconstriction
- Also activations of renin angiotensin system–>Vasoconstriction
- Release of arginine vasopressin (AVP)
Hypovolemia
- Renal vasoconstriction due to epinephrine
- ACE inhibitors
- Cyclooxygenase inhibitors (i.e.: NSAID’s)
- Hyperviscosity syndromes
Can cause renal hypoperfusion
- Cirrhosis leads to intrarenal vasoconstriction
- Sodium retention
- Precipitated by bleeding, paracentesis, diuretics, vasodilation, cyclooxygenase inhibitors
Hepatorenal syndrome
Symptoms: Thirst, dizzy
Signs: Low blood pressure, tachycardia, orthostasis, Low UOP
Pre-renal
- Renovascular obstruction..lg vessel dz
- Glomerular or microvascular diseases
Intrinsic renal failure
Glomerulonephritis Vasculitis Acute tubular necrosis Ischemic or nephrotoxic Interstitial nephritis Renal allograft rejection
Glomerular diseases
Ischemia from prerenal azotemia
Most common cause of acute tubular necrosis
Radiocontrast (Intrarenal vasoconstriction) Aminoglycosides (Decrease GFR) Cyclosporin Chemotherapy (Cisplatin) Solvents (ethylene glycol)
Nephrotoxins
Mechanism: Intrarenal vasoconstriction resulting in acute tubular necrosis (ATN) abrupt onset 24-48h aftercontrast exposure
Radiocontrast induced nephropathy
Biggest risk factor for radiocontrast induced nephropathy
Age**!
Features: Decreased GFR, Sediment, Reversible, Elevation of BUN and creatinine
Avoidance: Use non ionic contrast (more expensive but safer
Outcome: Typically resolves in 1-2 weeks
Radiocontrast induced nephropathy
Rhabdomyolysis (Due to crush, injury, ETOH)
Hemolysis (toxic to renal tubule)
Uric acid (Same thing that causes gout)
Myeloma (Plasma cell malignancy)
Hypercalcemia (Causes renal vasoconstriction)
Endogenous nephrotoxins
Allergic (Antibiotics such as beta-lactams), NSAID’s, diuretics
Infection (Bacterial-pyelonephritis, viral-CMV, Fungus-Candidiasis)
Infiltration (Lymphoma, leukemia, sarcoidosis)
Idiopathic
Interstitial nephritis
Symptoms-Often none
May have history of nephrotoxin exposure
Signs-Azotemia on lab testing
Nephritic syndrome (Oliguria, edema, HTN, Urine sediment)
intrinsic renal failure
Oliguria, edema, HTN, urine sediment
Nephritic syndrome
Microscopy:
Muddy brown casts (ischemia and nephrotoxic)
Red cell casts (acute glomerular injury or nephritis)
White cell casts (interstitial nephritis)
Eosinophilic casts (allergic nephritis)
Often no casts
Hematuria
Intrinsic renal failure lab results
This can be seen in intrinsic renal failure and is due to impaired reabsorption at proximal tubules
Proteinuria
Prostate disease Neurogenic bladder I.e.: spinal cord injuries Anticholinergics Blood clots Stones Tumor or other extrarenal obstruction
Post renal
Bladder distension
Abdominal pain-colic
Renal distension (ultrasound)
History of risk factors (prostate disease, stones, etc.)
Post renal signs and symptoms
