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Diseases of the Kidney. Kidney Physiology Kidney Functions: • activate vitamin D (renal 1-alpha hydroxylase) • produces erythropoietin which stimulates RBC formation • helps regulate blood pressure • ELIMINATES METABOLIC WASTE PRODUCTS • HELPS MAINTAIN FLUID, ELECTROLYTE,
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Diseases of the Kidney Kidney Physiology Kidney Functions: • activate vitamin D (renal 1-alpha hydroxylase) • produces erythropoietin which stimulates RBC formation • helps regulate blood pressure • ELIMINATES METABOLIC WASTE PRODUCTS • HELPS MAINTAIN FLUID, ELECTROLYTE, AND ACID-BASE IMBALANCES
Kidney Diseases of Note • Glomerulonephritis (acute or chronic) • Nephrotic Syndrome • Acute Renal Failure • Chronic Renal Failure • Dialysis • Urinary Calculi
A Few Definitions Renal Filtrate: fluid from the blood filtered by the kidneys that forms urine. GFR: Glomerular Filtration Rate the rate at which the kidney forms renal filtrate. Normal: 90-120 ml/min Renin: enzyme secreted by kidney in response to low blood flow; results in adrenal signal (aldosterone) to cause kidney to retain Na and water.
A Few More Definitions Nephrotic Syndrome: a cluster of symptoms • proteinuria • low serum albumin • edema • hyperlipidemia Sometimes an early sign of renal failure. Caused by: infections, certain drugs, toxins, DM, renal blood clots.
Consequences of Nephrotic Syndrome Proteinuria Albumin Immunoglobulins (immunity) Transferrin (anemia) Vitamin D-BP (rickets) Low serum proteins fluid shift into interstitial spaces Low Blood Volume Edema Kidneys Respond Retain Na and fluids!!!!
Diet in Nephrotic Syndrome Energy: 35 kcal/ kg Protein: 0.8-1.0 g / kg Fat: < 30% of kcals; low in saturated fatty acids. Sodium: During edematous phase 250 mg/day As edema resolves to ~ 1500 mg/ day
Prerenal Postrenal Intrarenal LOW RENAL OBSTRUCTION KIDNEY DAMAGE BLOOD FLOW IN URINARY TRACT Acute Renal Failure SUDDEN PRECIPITOUS DROP IN GFR, URINE OUTPUT
DEFINITIONS: KIDNEY FAILURE UREMIA/ AZOTEMIA: Build-up of urea nitrogen in the blood (BUN). Normal: 10-20 mg/dl Uremia: 50-150 mg/dl ESRD: 150-250 mg/dl ARF Phases: 1. Oliguric= reduced urine volume; 2. Diuretic= large fluid/electrolyte losses; 3. Recovery= NL renal function
Uremic Syndrome Build-up of toxic waste products in the blood (e.g., urea, potassium) Symptoms: Weakness, Fatigue “Dull” mental state Anorexia, N/V/D, altered taste, subdermal hemorraging
Causes of Chronic Renal Failure • Diabetic or HIV-Related Nephropathy • Recurrent Glomerulonephritis or Pyelonephritis • Acute Non-Responsive Kidney Failure • Nephrosclerosis • Cardiac Failure • Extensive Atherosclerosis • Malignant Hypertension
Early & Accurate Assessment • Anthropometrics (< 20 BMI or < 80% body weight • Biochemistry (albumin, prealbumin, cholesterol, K, creatinine, BUN) • Clinical Assessment (edema, GIT) • Dietary Intake( protein, calories, K, PO4)
Without Adequate Protein/ Kcals: Hypermetabolic state= Break down visceral protein stores; Hyperkalemia worsens. Kcal needs: 30-50 kcal/kg (depending on level of catabolism) Oliguric phase: Diuretics, restrict fluids, Na and K. Diuretic phase: Fluids and K supplements
Measuring fluid needs: Measure urinary output, then add 500 ml for insensible losses.
Protein Needs in ARF Non-Dialyzed Pts Dialyzed Pts 0.6 to 1.0 g/ kg 1.1-2.5 g/ kg Feeding in Enteral and Parenterally-Fed Patients Less Protein, Electrolytes Lower amino acid [ ] High Kcal Density Higher Dextrose [ ] Insulin may be used to control hyperglycemia
Medications • Hyperkalemia - Exchange resins (po or enema) • e.g.polystyrene sulfonate to increase fecal • potassium losses by exchanging sodium. • Hyperphosphatemia - Phospate binders e.g. • Phosphlo & Tums (Ca based); Magnabid (Mg • based); Amphogel (Al based); Renagel (polymer) • Anemia - Iron • Edema - Diuretics
Dialysis Removal of blood waste products through a semi-permeable membrane via diffusion/osmosis. Hemodialysis Large blood vessel tapped,blood routed through dialysis machine, excess fluid/ electrolytes are removed. Dialysed blood returned to body. Peritoneal Dialysis Dialysis is accomplished using peritoneal cavity as the semi-permeable membrane.