NHHC chapter 22 ppt

Nutrition for Health and Health Care, 5th Edition DeBruyne ■ Pinna © Cengage Learning 2014

Nutrition andRenal Diseases

Chapter 22


Introduction

• Kidneys– Filter the blood and remove excess fluid and

wastes for elimination in urine– Nephron: working unit of the kidney

• Glomerulus: filters water and solutes from the blood

• Bowman’s capsule: surrounds the glomerulus; collects the filtrate that is passed to the tubules


Introduction (cont’d.)

• Kidneys– Regulate the extracellular fluid volume

• Control osmolarity, electrolyte concentrations, and acid-base balance

– Excrete metabolic waste products• Urea and creatinine; various drugs and toxins

– Other roles• Secretes renin, produces erythropoietin, and

converts vitamin D to active form


The Nephrotic Syndrome

• Disorders causing severe glomerular damage: significant proteinuria– Damage to glomeruli

• Increases permeability to plasma proteins

• Causes– Glomerular disorders, diabetic nephropathy,

immunological and hereditary diseases, infections (kidneys or other), etc.


The Nephrotic Syndrome (cont’d.)

• Consequences of the nephrotic syndrome– Attempting to compensate: liver increases

synthesis of various plasma proteins • Some or the proteins produced in excess

– Edema• Hypoalbuminemia: contributes to a fluid shift

from blood plasma to the interstitial spaces • Impaired sodium excretion: sodium and water

retention



• Consequences of the nephrotic syndrome– Blood lipid abnormalities

• Elevated levels of LDL, VLDL, and lipoprotein(a)– Blood clotting abnormalities

• Increased risk of deep vein thrombosis– Other effects

• Susceptibility to infection; increased risk of rickets (children); PEM and muscle wasting



• Treatment of the nephrotic syndrome– Requires diagnosis and management of the

underlying disorder– Medications for complications

• Diuretics, ACE inhibitors, lipid-lowering drugs, anti-inflammatory drugs, and immunosuppressants

– Nutrition therapy• Helps to prevent PEM, correct lipid abnormalities,

and alleviate edema



• Nutrition therapy– Protein and energy

• Adequate to meet needs: helps minimize muscle tissue losses

• Why are high-protein diets not advised?– Lipids

• Dietary measures: usually inadequate for controlling blood lipids

• Lipid-lowering medications: usually prescribed



• Nutrition therapy– Sodium and potassium

• Low-sodium: helps control edema (Table 22-1)• Foods rich in potassium encouraged

– Vitamins and minerals• Supplements help patients avoid nutrient

deficiencies: particularly vitamin B6, vitamin B12, folate, iron, copper, and zinc



• Nutrition therapy– Vitamins and minerals

• Calcium and vitamin D supplements also advised


Acute Kidney Injury

• Kidney function deteriorates rapidly, over hours or days– Reduced urine output and build-up of

nitrogenous wastes in blood• Causes of acute kidney injury

– Consequence of severe illness, injury, or surgery


Acute Kidney Injury (cont’d.)

• Causes of acute kidney injury– Prerenal factors: cause a sudden reduction in

blood flow to the kidneys• Often involve a severe stressor such as heart

failure, shock, or blood loss– Intrarenal causes: factors that damage kidney

tissue• Infections, toxicants, drugs, or direct trauma



• Causes of acute kidney injury– Postrenal factors: prevent excretion of urine

due to urinary tract obstructions



• Consequences of acute kidney injury– Altered composition of blood and urine

• Kidneys unable to regulate levels of electrolytes, acid, and nitrogenous wastes in the blood

• Conditions of oliguria or anuria– Fluid and electrolyte imbalances

• Sodium retention: edema• Hyperkalemia: alters heart rhythm; heart failure• Hyperphosphatemia: leads to bone calcium losses



• Consequences of acute kidney injury– Uremia

• Nitrogen-containing compounds and various other waste products: may accumulate in the blood

– Uremic syndrome: cluster of disorders • Impairments in multiple body systems



• Treatment of acute kidney injury– Combination of drug therapy, dialysis, and

nutrition therapy • Restore fluid and electrolyte balances• Minimize blood concentrations of toxic waste

products



• Treatment of acute kidney injury– Drug treatment in acute kidney injury

• Why may it be necessary to lower doses of some usual medications, while others may need to be increased?

• Nephrotoxic drugs: must be avoided until kidney function improves



• Treatment of acute kidney injury– Drugs for acute kidney injury: depend on

cause of illness and complications• Immunosuppressants: inflammatory conditions• Diuretics: edema• Hyperalkalemia: potassium-exchange resins; may

require insulin• Other medications



• Treatment of acute kidney injury– Energy and protein

• Sufficient energy and protein: preserve muscle mass

• Protein recommendations : influenced by kidney function, degree of catabolism, and use of dialysis



• Treatment of acute kidney injury– Fluids

• Estimate needs: measure urine output and add 500 milliliters for water lost from skin, lungs, and perspiration

– Electrolytes• Serum electrolyte levels monitored closely:

determine appropriate electrolyte intakes



• Treatment of acute kidney injury– Enteral and parenteral nutrition

• In cases requiring additional nutritional support, why is enteral support preferred over parenteral nutrition?

– Case Study – Woman with Acute Kidney Injury


Chronic Kidney Disease

• Gradual, irreversible deterioration• Kidneys: large functional reserve

– Chronic disease typically progresses over many years without causing symptoms

• Most common causes– Diabetes mellitus and hypertension– What are other causes of chronic kidney

disease?


Chronic Kidney Disease (cont’d.)

• Consequences of chronic kidney disease– Early stages

• Nephrons compensate by enlarging to handle the extra workload

– End-stage renal disease• Advanced stage of chronic kidney disease: dialysis

or a kidney transplant is needed to sustain life– Many symptoms: nonspecific

• Delays diagnosis of the condition



• Assessing kidney function– Glomerular filtration rate (GFR)

• Rate at which the kidneys form filtrate• Estimated using predictive equations: based on

serum creatinine levels, age, gender, race, and body size

• Categorized into stages (Table 22-4)– What other tests can assess kidney function?



• Altered electrolytes and hormones– As GFR falls:

• Remaining neurons increase activity to maintain electrolyte excretion

– Electrolyte disturbances• May not develop until third or fourth stage of

chronic kidney disease



• Altered electrolytes and hormones– Some hormonal adaptations to regulate

electrolyte levels create new complications• Increased aldosterone ► hypertension• Parathyroid hormone ► renal osteodystrophy

• Clinical effects of uremic syndrome– Hormonal imbalances

• Lead to anemia, bone disease, etc.



• Clinical effects of uremic syndrome– Altered heart function/increased heart disease

risk– Neuromuscular disturbances

• Malaise, irritability, sensory deficits, seizures, etc.– Other effects

• Defects in platelet function and clotting factors; increased skin pigmentation and severe pruritus; suppressed immune responses



• Protein-energy malnutrition– Anorexia: contributes to the poor food intake

• Due to hormonal disturbances, nausea and vomiting, restrictive diets, uremia, and medications

– Nutrient losses• Consequence of vomiting, diarrhea,

gastrointestinal bleeding, and dialysis– Catabolic state



• Treatment of chronic kidney disease– Treatment goals

• Slow disease progression• Prevent or alleviate symptoms

– Drug therapy for chronic kidney disease• Antihypertensive drugs• Erythropoietin (epoetin): anemia• Others: phosphate binders, sodium bicarbonate,

and active vitamin D



• Treatment of chronic kidney disease– Dialysis: removes excess fluid and wastes

from the blood• Hemodialysis: blood is circulated through a

dialyzer– Nutrition therapy for chronic kidney disease

(Table 22-5)



• Nutrition therapy for chronic kidney disease– Energy: adequate intake to maintain a healthy

weight and prevent wasting– “How To” Increase kCalories and Protein in

Meals (Chapter 23)– Protein: enough protein to meet needs and

prevent wasting• Between 0.6 and 0.8 g/kg of body weight per day in

later stages



• Nutrition therapy for chronic kidney disease– Lipids: restrict intakes of saturated fat, trans

fat, and cholesterol• Why are persons with chronic kidney disease often

encouraged to consume high-fat foods?– Sodium and fluids

• Mild sodium restriction may be beneficial• Fluids: not restricted until urine output decreases• What water intake restrictions apply during dialysis?



• Nutrition therapy for chronic kidney disease– Potassium

• Early stages: normal potassium intake levels• Hyperkalemia conditions: potassium restrictions• Potassium-diuretics: potassium supplementation• Dialysis patients: control potassium intake (Table

22-6)



• Nutrition therapy for chronic kidney disease– Phosphorus, calcium, and vitamin D

• Serum phosphorus and calcium levels: monitored in kidney disease patients

• Elevated phosphorus levels: restrict intake• What accounts for the risk of hypercalcemia?• Vitamin D supplements



• Nutrition therapy for chronic kidney disease– Vitamins and minerals

• Multivitamin supplements: typically recommended for all patients with chronic kidney disease

• Limit vitamin C: 100 milligrams per day• Vitamin A supplements: not recommended• Hemodialysis patients: intravenous iron along with

erythropoietin therapy



• Nutrition therapy for chronic kidney disease– Enteral and parenteral nutrition

• Formulas: more kcalorically dense and lower protein and electrolyte concentrations than standard formulas

• What is intradialytic parenteral nutrition?



• Nutrition therapy for chronic kidney disease– Diet compliance: difficult aspect of treatment

(Table 22-8)– Case Study – Man with Chronic Kidney

Disease



• Kidney transplants– Benefits

• Restores kidney function, allows a more liberal diet, and frees the patient from routine dialysis

– What are barriers to kidney transplants?– Immunosuppressive drug therapy

• Prevent tissue rejection following transplant surgery

• Be aware of diet-drug interactions (listed in text)



• Nutrition therapy after kidney transplant– Most nutrients

• Consume at levels recommended for the general population

– Primary reason for dietary adjustments• Side effects of drugs


Kidney Stones

• Crystalline mass– Forms within the urinary tract

• Formation of kidney stones– Stone constituents become concentrated in

urine• Allowing crystals to form and grow

– Most common constituent• Calcium oxalate


Kidney Stones (cont’d.)

• Factors predisposing an individual to stone formation– Dehydration or low urine volume– Obstruction– Urine acidity– Metabolic factors– Renal disease



• Types of kidney stones– Calcium oxalate stones

• Hypercalciuria: common abnormality in people with calcium oxalate stones

– Uric acid stones• Urine: abnormally acidic; contains excessive uric

acid, or both• Frequently associated with gout



• Types of kidney stones– Cystine and struvite stones

• Cystine stones: people with inherited disorder cystinuria

• Struvite stones: composed primarily of magnesium ammonium phosphate; form in alkaline urine



• Consequences of kidney stones– Renal colic

• Severe, stabbing pain when stone passes through the ureter

• Hematuria: blood in urine– Urinary tract complications

• Urination urgency, frequent urination, or inability to urinate

• Urinary tract obstruction, and possibly infection



• Prevention and treatment of kidney stones– Drink 12 to 16 cups of fluids daily

• Maintain urine volumes of at least 2½ liters per day– Calcium oxalate stones

• Reduce urinary calcium and oxalate levels• Adjust calcium, oxalate, protein, and sodium

intakes• Medications: diuretics; drugs to inhibit crystal

formation; and drugs to reduce uric acid production



• Prevention and treatment of kidney stones– Uric acid stones

• Diets restricted in purines: may help to control urinary uric acid levels

• Drug treatments: allopurinol to reduce uric acid levels and potassium citrate to reduce urine acidity



• Prevention and treatment of kidney stones– Cystine and struvite stones

• High fluid intakes• Medications may be needed• What is a central strategy in preventing struvite

stones?



• Medical treatment for kidney stones– Medications

• Relax ureter• Increase urine flow

– Extracorporeal shock wave lithotripsy• High-amplitude sound waves to degrade the stone

– Surgical methods• Higher success rate• More invasive

NHHC chapter 22 ppt

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