Acute and Chronic Renal Failure Flashcards
Functions of the kidney
- Excretion of waste products
- Urine formation
- Water and salt balance
- Acid-base balance
- Hormone secretion
- Control of blood pressure
- Erythropoietin production (RBC)
- Synthesis of vitamin D to active form ( low Ca)
Renal failure results in:
– Altered fluid balance
– Electrolyte imbalance
– Acid-base imbalance
Causes of kidney failure include:
– Hypertension
– Diabetes
Kidney failure may be:
Acute or chronic
Acute renal failure (ARF)
• Rapid decrease in kidney function
• Leading to the collection of metabolic wastes in the body
• Potentially reversible condition
Lasts < 3 months
Etiology/Types of ARF:
– Prerenal failure
– Intrarenal/intrinsic renal failure
– Post renal failure
Prerenal failure
decreased blood flow to the kidneys - ischemia in the nephrons;prolonged hypoperfusion can lead to tubular necrosis and ARF.
Prerenal failure: causes
- Conditions that cause decreased cardiac output.
- Shock
- HF
- Pulmonary embolism
- Anaphylaxis
- Pericardial tamponade
- Sepsis
Intrarenal/intrinsic renal failure
actual tissue damage to the kidney caused by inflammatory or immunologic process or from prolonged hypoperfusion.
Intrarenal/intrinsic renal failure:causes
- Acute interstitial nephritis
- Exposure to nephrotoxins
- Acute glomerulonephritis
- Vasculitis
- Hepatorenal syndrome
- ATN
- Renal artery or vein stenosis/thrombosis
Post renal failure
obstruction of the urine collecting system anywhere from calyces to urethral meatus; obstruction of the bladder must be bilateral to cause post renal failure unless only one kidney is functional
Post renal failure: causes
- Urethral or bladder cancer;
- Renal, ureteral or bladder stones;
- Atony of bladder
- Prostatic hyperplasia or cancer;
- Cervical cancer;
- Urethral stricture (narrowing)
Acute tubular necrosis
- Syndrome of abrupt and progressive decline in tubular and glomerular function
- Most intrarenal failure is from ATN
- Etiology: Nephrotoxic substances
Potentially Nephrotoxic Substances/ Drugs
– PCN, Vancomycin, NSAIDs – Radiocontrast dyes – Heavy metals – Snake bites – Pesticides – Transfusion reaction
Phases of ARF
- Onset
- Oliguric
- Diuretic (high output)
- Recovery
Onset phase
until oliguria develops; accumulation of nitrogenous wastes may be noted (BUN, serum creatinine); hours - several days.
Oliguric phase
100-400 / 24 hours urine output that does not respond to fluid chalenges or diuretics; 1-3 weeks; SC and BUN up; K, P, Mg up ; Ca down ; Na up but masked by water retention ;bicarbonate deficit - acidosis ;
Diuretic phase ( hight output phase)
2-6 weeks after oliguric; sudden onset ; urine flow increased over several days; 10 L /day of dilute urine ; electrolyte losses; BUN down; normal renal tubular function .
Recovery phase (convalescent phase)
Recovery may take up to 12 months; pt has lower energy level; residual renal insufficiency may be noted through renal monitoring; renal function may never return to pre illness level; but renal function likely good for healthy life.
ARF: management
1.Fluid challenges
2. Diuretics (Lasix)
3. Calcium channel blockers
4. Diet therapy
5. Renal replacement therapy
– Peritoneal dialysis
– Hemodialysis
– Hemofilteration
Cardiac glycosides: Digoxin ( Lanoxin)
Increases ventricular contraction, stroke volume, cardiac output; teach pt to take pulse before taking the drug ( below 60 call !); Digoxin toxicity: blurred vision; changes in color vision; sensitive eyes; halos around bright lights; changes in mental status; chest pain or palpitations. Not to take antacid within 2 hours (prevent drug absorption). Listen to apical for 1 full minute.
Vitamins and Minerals: Folic acid and Ferrous sulfate (iron)
Replacement needed because of dialysis; Take drug after dialysis; Take iron with meals ( reduce N&V); Take stool softener ( oral iron causes constipation); Iron change the color of the stool.
Synthetic erythropoietin: Epoetin alfa (Epogen, Procrit)
Prevents anemia by stimulating RBC growth and maturation in the bone marrow; Side effects: chest pain, difficulty breathing, high BP, rapid weigh gain,( risk for MI infarction); Hemoglobin levels monitored weekly ( blood viscosity increases - high BP - risk for MI ).
Phosphate binders: Aluminium hydroxide gel (Amphojel, Nephrox)
High Phosphate levels cause hypocalcemia and osteodystrophy; Drug lowers P levels by binding P present in food; Take with meals ( binding in food) ; Take Digoxin separately but at least 2 hr ; Take stool softener ( constipation) ; Report: muscle weakness, slow or irregular pulse, confusion - hypophosphatemia.