4446renal.ppt
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Renal Disease
Kidney Function: to maintain normal composition and volume of the blood
Anatomy of Kidney
❧1 million Nephrons: Consists of● Glomerulus connected to a series of tubules
which can be broken into functional segments• proximal convoluted tubule• loop of Henle• distal tubule• collecting duct
● Glomerulus surrounded by Bowman’s capsule• mass of capillaries: blood is filtered to produce
ultrafiltrate
Kidney Function
❧Ultrafiltrate contains blood material that is less than 6500 molecular weight
❧No blood cells❧No protein❧No other large molecules
Kidney Function
❧Water and electrolyte conservation● Antidiuretic Hormone (ADH) secreted by
posterior pituitary when osmolality of blood rises
• Shuts off when osmolality falls● Kidney can concentrate urine as much as 1200
mOsm or as dilute as 50 mOsm● Urinary volumes vary based on need to excrete
extra fluid
Kidney Function
❧ADH: Diseased kidney doesn’t respond to ADH as well and tends to allow water retention
● Reduced urine output in Renal patients● oliguria: less than 500 ml/day
Kidney Function
❧Other Waste Products accumulate with renal failure
❧Azotemia: Build up of urea, uric acid, creatinine and ammonia
Kidney Function: Blood Pressure
❧Renin-Angiotensin System:● Decreased blood pressure induces glomerular
cells to secrete renin• Acts in plasma to form angiotensin I• converted to angiotensin II
– vasoconstrictor: elevates BP– stimulates aldosterone secretion by adrenal glands
» Causes kidneys to retain water and sodium
● In diseased kidney, this mecahism may be less functional: high or low blood pressure/water retention
Kidney Function: RBC Formation
❧Erythropoietin: kidney produces this hormone
● Acts on bone marrow to produce RBC’s● In diseased kidney, lack of Erythropoietin:
• results in severe anemia● Renal patients are given injections of
erthyropoietin to stimulate RBC rpduction
Kidney Function: Ca, P
❧Vitamin D activation happens in kidney❧With diseased kidney, this is slowed down❧Less active vitamin D
● Results in less absorption of Ca in gut● more bone release of Ca and weak bones
• Poor bone status
Diseases of the Kidney
❧Glomerular Diseases● Nephrotic syndrome● Nephritic syndrome
❧Tubule and interstitium diseases● Acute renal failure (ARF)● Other tubular diseases● Pyelonephritis
Nephrotic Syndrome
❧Group of diseases cause● Protein loss through glomeruli● hypoalbuminemia with edema
• concentrates blood● hypercholesterolemia● hypercoagulability● abnormal bone metabolism
Nephrotic Syndrome
❧Most often caused by:● Diabetes● systemic lupus eryththematosus(SLE)
• connective tissue disorder of immune origin• causes damage to many systems and noted by skin
eruptions, arthritis, neurological problems● amyloidosis:abnormal deposits of amyloid in
tissues• a starch-like glycoprotein primary cause unknown• secondary due to TB and rheumatoid arthritis
Nephrotic Syndrome: Nut Care
❧Objective: replace lost protein in urine❧High Biological Value Protein from 0.6 to
1.5 g/kg/d❧Energy 35 to 50 kcal/kg/d for adults; 100 to
150 kcal/kd/d for kids● to spare protein
❧Edema: mild sodium restriction❧Hypercholesterolemia: lipid lowering drugs
with chronic Nephrotic Syndrome
Nephritic Syndrome
❧Inflammation of capillary loops of glomerulus caused by several disease states
● acute glomerulonephritides: often caused by streptococcal infection damaging glomerular barrier to blood cells
• Blood in urine• Sudden onset/short duration• May proceed to complete recovery, chronic
nephrotic syndrome, End Stage Renal Disease(ESRD)
Nephritic Syndrome: Nut Care
❧Objectives: maintain good nutritional status❧Often focus is on treating underlying cause❧Usually no need to restrict protein, or K
unless uremia or hyperkalemia exists❧Sodium restriction with HTN
Diseases of Tubules & Interstitium
❧Acute Renal Failure: Sudden reduction in Glomerular Filtration Rate (GFR)
❧GFR: the quantity of glomerular filtrate formed per unit of time by the kidneys
❧Results in the inability to filter wastes from the blood
❧Causes are many
ARF : Causes 3 Categories
❧Prerenal❧Intrinsic❧Postrenal Obstructive❧Treatment: remove underlying problem❧Course of the problem depends on
underlying cause
ARF: Intrinsic Problems
❧Possible causes:● toxic drugs● allergy to drugs● progressive glomerulonephritis● ischemia leading to acute tubular necrosis
• infections, severe trauma, surgical accidents• mortality about 70 %• treated with hemodialysis to reduce acidosis• Diuretic phase then return of waste elmination
ARF: Nut Care
❧Early: TPN may be used to maintain nutritional status
❧Hemodialysis, peritoneal dialysis or continuous arteriovenous filtration (CAVH)
● CAVH uses small ultra filtration membranes to produce an ultrafiltrate
• this is replaced with parenteral nutrition fluids to prevent fluid overload
ARF: Nut Care
❧Protein:Early, TPN with Glucose and some protein in form of essential A.A.s such as Aminosyn-RF(Abbot Labs)
❧Amount of Protein dependent on pt● 0.3 g/kg and progress toward 0.8 to 1 as pt
improves
❧Energy needs are high: 50 kcal/kg most from CHO and lipids via TPN or enterally with addition of formulas (Polycose, Ross)
Pyelonephritis: UTI
❧No specific nutritional management❧Chronic cases: cranberry juice
● Reduced adherence of E.coli to epithelial walls of urinary tract
Nephrolithiasis: Kidney Stones
❧10 % of men and 3 % of women have a stone during adulthood
❧Formed in kidney when substances in urine reach levels that cause crystallization
❧May be made from calcium salts, uric acid, cystine, struvite (ammonium, magnesium, and phosphate)
Kidney Stones: treatment
❧In all cases: High fluid intake (1.5 to 2 liter/day) to keep urine dilute
❧Other intervention depends on the cause❧80% of stones composed of Ca oxalate or
Ca phosphate❧Causes are multiple:
● hyperparathyroid ism, hyperuricosuria, renal tubule acidosis (RTA)
Kidney Stones: Treatment
❧Remove underlying cause:● e.g.: remove parathyroid adenoma if
Hyperparathyroid● Treat RTA with medications to reduce acidity● Hypercalciuria seldom treated with low Ca diet
❧Nutrition: Reduce Oxalate in diet, add additional Ca to diet to tie up oxalate in gut
Kidney Stones: Uric Acid
❧Associated with gout, an acid urine❧Treatment with raising urine pH to 6 to 6.5
through high alkaline-ash diet● milk, nuts, vegetables except corn and lentils,
all fruits except cranberries, prunes, plums, molassess
● avoid breads, meats, cheese, pnut butter, and vegies and fruits above
Glomerular Filtration Rate (GFR)
❧Defn: total plasma volume filtered by the kidney per unit of time
❧Normal is 120 ml/min
❧GFR = Urineinulin X Urine volume
❧ _____________________
❧ Plasmainulin
❧Can also be done with creatinine
Normal Kidney Function
❧How long does it take to filter all of a person’s blood? HINT: 6 L of blood
Other Labs Used to Determine Kidney Function
❧Blood Urea Nitrogen(BUN): How well urea is cleared by the kidney
● Normal is 8 to 23 mg/dl● High is indication of poor fxn
❧Creatinine: end product of creatine metabolism in muscle; cleared in urine
● Normal is 0.6 to 1.6 mg/dl● High is indication of poor function
Progressive Nature of Renal Disease
❧Slow, steady, decline in renal function❧Nutrition intervention depends on Renal
Function determined by GFR❧Protein Intake: major concern❧Protein GFR❧0.8 g/kg(60%HBV) >55 ml/min❧0.6g/kg(60% HBV) 25-55 ml/min
Progressive Renal Disease
❧Protein restriction: individualized● Must be weighed against possible protein
malnutrition● If elected, careful monitoring of protein status
must be made with anthropometric and lab values
End-Stage Renal Disease
❧Can be caused by several disease states❧90 % have Db, glomerulonephritis, or HTN❧Problems include:
● inability to remove wastes● maintenance of fluid and electrolyte balance● problems with hormone production
❧Uremia: high BUN, a major problem
Uremia: Symptoms
❧With BUN at 100 and Creatinine at 10-12 symptoms usually show up
❧Generally: weakness, nausea, cramping, itching, metallic taste
❧Further intervention required
ESRD: Treatment
❧Transplantation❧Dialysis
● Hemo● Peritoneal
• intermittent peritoneal dialysis (IPD)• Continuous ambulatory PD(CAPD)
Transplantation: Nut Care
❧Based on metabolic effects of immunosuppressive meds: corticosteroids and cyclosporine
❧Corticosteroids:● increase PRO metabolism, hyperlipidemia, Na
retention, wt gain, glucose intolerance, reduced Ca and Vit D metabolism
❧Cyclosporine: hyperkalemia, HTN, ^ lipids
Transplant Nutrition Care
❧First month Post-transplant:● PRO: 1.5 to 2 g/kg● Energy: 30 to 35 kcal/kg● moderate Na restriction to prevent fluid
retention (80-100 mEq/d); monitor K and P
❧After one month:● PRO: 1 g/kg● Adjust Kcal to maintain/achieve Ideal weight
Hemodialysis
❧Most common form of dialysis❧Fistula created by surgery connects an
artery and a vein usually on the forearm● may require an artificial vessel to enlarge the
vessel● Large needles are temporarily inserted to allow
blood to exit the body and circulate through the dialysis machine
● Usually required 3 x / week for 3 to 5 hours
Hemodialysis: Nut Care
❧Energy: 35 kcal/kg IBW❧PRO: 1 to 1.2 g/kg; 1.2 to 1.5 if needed❧Fluid: 800 ml/d + urine output❧Na: 2-3 grams/day❧K: 2-3 grams/day❧P: 1 to 1.2 g/d
Peritoneal Dialysis
❧Makes use of the semi permeable membrane of the tissues in the peritoneal cavity
❧Catheter surgically implanted in the abdomen
❧Dextrose containing dialysate is instilled into abdomen
● wastes diffuse into dialysate
Peritoneal Dialysis
❧Fluid is withdrawn and discarded; new fluid is then instilled
❧Less efficient then hemo❧10 to 12 hrs, 3 x week❧PRO: 1.2 to 1.5 g/kg due to larger Pro loss❧Energy: 30 kcal/kg (40-50 for repletion)❧Fluid, Na, K, and P same as hemo
Continuous Ambulatory Peritoneal Dialysis(CAPD)
❧Similar to peritoneal but the dialysate is exchanged manually without the help of a machine
❧Exchanged 4 to 5 x /day for 24-hour treatment
❧Increased loss of Protein, increased absorption of Dextrose, up to 800 kcal/d
CAPD Nut Care
❧PRO: 1.2 to 1.5 g/kg❧Energy: 25 kcal/kg❧Fluid: ad lib❧Na: 6 - 8 grams / d❧K: 3-4 g/d❧P: 1.5 to 3 g/d❧Weight gain is the norm for CAPD patients
ESRD: Other concerns
❧Psychological Support: large life changes● Depression: lack desire to eat● Thirst, lack of taste and taste changes due to
uremia
❧Vitamin D status: activation of Vit D happens in the kidney
● loss of function results in low status● Vit D supplements
Complications
❧Low Vit D results in low Ca in blood● Triggers release of PTH; this removes Ca from
bone● Results in osteitis fibrosa cystica: a
demineralized bone disease causing dull bone pain
● Serum P remains high because it is not cleared by kidney
● Calcium intake should be high, P should be low
Complications of Renal Disease
❧Calcium supplements help bind P in the gut● Ca carbonate, acetate, lactate or gluconate● Ca citrate is avoided because it helps absorb Al
❧Vit D orally or intravenous helps with hypocalcemia
❧Fluoride serum levels often high in dialysis pt: contributes to decalcification of bone
● Deionized Fl containing water before used in dialysis
Iron/Hemoglobin status
❧Kidney produces erythropoietin which induces bone to produce RBCs
● Synthetic EPO injections are used to treat
❧Vitamin deficiencies may occur● Reduced intake with P restriction: many P rich
foods are also vitamin rich, e.g.: fruits and vegetables
● Water soluble vitamins are dialyzed off
Complications
❧Vitamin supplements given: some specially formulated for dialysis pts
● Nephrocaps: Fleming and Co.
❧Carbohydrate: glucose intolerance due to tissue resistance to insulin
● may require control of glucose in diet in hyper● may require addition of dextrose to dialysate in
hypoglycemic
Complications
❧Atherosclerosis: most frequent cause of death in hemodialysis
● Caused by underlying disease: HTN, diabetes, nephrotic disease
● Plus abnormal lipid metabolism in ESRD● Increased synthesis of VLDL and decreased
clearance● diet restriction of fat; and use of lipid lowering
drugs may be used with high risk ESRD pts
Use of Parenteral Nutrition
❧When pt is too sick to eat, TPN may be required
❧More on TPN later
Renal Assignment
❧Page 801 Hemodialysis case study #1❧Do a nutrition assessment on pt❧Write in up in SOAP format that includes
Problem list in ‘A’ and solutions in ‘P’❧Include in the solution list a one day diet
based on appropriate intake of Kcal, fluid, Pro, K, P, and Na
❧Use exchange list on p 792 to help❧In addition, answer questions presented
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