Renal and Hepatic Diseases Review

Renal Diseases

Structure of the Kidney

  • Function: The kidneys filter blood, removing waste products and excess water via the renal artery through nephrons, the functional unit of the kidney.

Functions of the Kidney

  • Excretory Functions: Maintain homeostasis for fluids and electrolytes.

    • Water Balance: Controlled primarily by the Antidiuretic Hormone (ADH) from the posterior pituitary. Reduces ADH release in excess water leading to increased urination. Can produce concentrated (500ml) or dilute urine (up to 12 liters).
    • Excretion of Waste: Primarily nitrogenous wastes from protein metabolism (e.g. urea, creatinine, ammonia). Accumulation leads to azotemia.
    • Electrolyte & Acid-Base Balance: Regulates Na, K, Cl, bicarbonate, and phosphorus. Controls pH by excreting acids or bases.
    • Excretion of Foreign Substances: Includes medications and food additives.

  • Endocrine Functions: Secretes hormones regulating various bodily functions.

    • Rennin: Enzyme that forms angiotensin I, converted to angiotensin II, a vasoconstrictor increasing blood pressure.
    • Erythropoietin: Stimulates red blood cell maturation in the bone marrow.
    • Calcium & Phosphorus Homeostasis: Produces active vitamin D, regulates calcium and phosphorus elimination.

Tests for Kidney Functionality

  1. Glomerular Filtration Rate (GFR): Normal is 90-125 ml/min. Decreased indicates reduced kidney function.
  2. Creatinine Clearance: Measures kidney function as creatinine is not reabsorbed. Normal is 95-135 ml/min; levels above 1.2 (women) and 1.4 (men) indicate potential issues.
  3. Blood Urea Nitrogen (BUN): Normal levels 7-20; elevated levels suggest kidney issues.

Key Terms in Kidney Diseases

  • Oliguria: Low urine output (≤ 500ml/day).
  • Anuria: Very low urine output (< 100ml/day).
  • Azotemia: Accumulation of nitrogenous wastes in the blood.
  • Uremia: Clinical syndrome from high nitrogenous wastes causing symptoms like weakness and nausea.

Types of Kidney Diseases

Glomerulonephritis

  • Definition: Inflammation of glomerular capillaries (acute/chronic).
  • Causes: Streptococcal infection, shock, drugs, surgery.
  • Symptoms: Nausea, hematuria, proteinuria, edema, oliguria, elevated BUN, hypertension.
  • Management: Dietary restrictions (sodium, protein), manage fluid retention.

Chronic Glomerulonephritis

  • Outcome: Continued nephron loss leading to nephrotic syndrome.
  • Nephrotic Syndrome Symptoms: Edema, large proteinuria (>3.5g), hypoalbuminemia, elevated blood lipids.
  • Management: Diet adjustment based on fluid retention and protein intake.

Acute Renal Failure

  • Definition: Sudden onset of kidney failure, often reversible.
  • Causes: Dehydration, blood loss, drugs, obstruction.
  • Symptoms: Decrease in urine output, accumulation of wastes, hyperkalemia.
  • Treatment: Supportive management, diet therapy, potential dialysis.

Chronic Renal Failure (CRF)

  • Outcome: Permanent damage leading to loss of all kidney functions.
  • Stages:
    1. Stage 1: 50% renal function lost, often asymptomatic.
    2. Stage 2: 25% damage, noticeable symptoms.
    3. Stage 3: Severe damage, noticeable high creatinine levels.
    4. Stage 4: 90% damage, severe symptoms, requires dialysis or transplant.
  • Management: Dietary restrictions, dialysis, and transplantation options.

Dietary Management in Kidney Diseases

General Guidelines

  • Protein: Adjust based on kidney function and requirements (0.6-1.0 g/kg body weight).
  • Energy: Provide adequate calories (35-40 kcal/kg) to prevent malnutrition.
  • Sodium: Watch for fluid retention; adjust based on blood pressure and symptoms.
  • Fluid: Tailor based on urine output and weight changes.
  • Vitamins: Supplement water-soluble vitamins, particularly B vitamins.

Hepatic Diseases

Liver Structure and Functions

  • Primary Functions: Metabolizes carbohydrates, proteins, lipids, and stores vitamins and minerals; detoxifies harmful substances.

Causes of Liver Disease

  • Toxins: Alcohol and drugs.
  • Infections: Viral hepatitis.
  • Metabolic: Obesity, malnutrition.

Types of Liver Disease

Hepatitis

  • Definition: Inflammation of liver tissue.
    • Types:
    • Type A: Fecal-oral transmission, vaccine available.
    • Type B: Bloodborne, more severe, vaccine available.
    • Type C: Bloodborne, high risk of chronicity.
  • Management: High protein, high carbohydrate diet, moderate fats.

Cirrhosis

  • Definition: Chronic liver disease resulting in fibrosis and loss of function.
  • Management: Individualized protein intake, restrict sodium for edema, monitor fluid intake.

Hepatic Encephalopathy

  • Definition: Neurological dysfunction due to liver failure.
  • Symptoms: Confusion, altered consciousness.
  • Dietary Management: Restrict protein initially, use vegetable proteins, increase caloric intake primarily from carbohydrates.

Nutritional Needs in Burns

  • Characteristics: High metabolic rate, increased protein loss, fluid loss.

Nutritional Management Goals

  1. Support wound healing and recovery from burn injuries.
  2. Prevent complications, including infections.
  3. Attain and maintain normal nutritional status.

Stages of Nutritional Care

  • Stage 1 (Ebb Phase): Focus on fluid resuscitation, electrolyte balance.
  • Stage 2 (Recovery Phase): Oral feeding resumption; energy and nutrients increase due to hyper metabolism.

Dietary Management Suggestions

  • High protein and high calorie diet for recovery; specific formulas calculated based on body surface area burned.

General Guidelines for Dietary Management

  • Fluid & Electrolyte: Ensure hydration and electrolyte balance.
  • Small Frequent Meals: To enhance intake, especially post-surgery or during recovery from significant illness.
  • Nutritional Support: Adjust according to individual needs, especially for those with chronic conditions or burns, who may require specialized formulas.
  • Monitoring: Regularly assess nutritional intake and adjust diets as necessary based on clinical status and recovery progress.

Structure of the Kidney

  • Function: The kidneys filter blood and remove waste products through nephrons, the functional units of the kidney.

Functions of the Kidney

  • Excretory Functions: Maintain fluid and electrolyte balance.
  • Water Balance: Controlled by Antidiuretic Hormone (ADH), which regulates urine concentration.
  • Excretion of Waste: Removes nitrogenous wastes (urea, creatinine, ammonia); accumulation leads to azotemia.
  • Electrolyte & Acid-Base Balance: Regulates key electrolytes and controls pH by excreting acids or bases.
  • Endocrine Functions: Secretes hormones like renin and erythropoietin; produces active vitamin D for calcium and phosphorus balance.

Tests for Kidney Functionality

  1. Glomerular Filtration Rate (GFR): Normal range is 90-125 ml/min; lower indicates reduced function.
  2. Creatinine Clearance: Normal is 95-135 ml/min; higher levels indicate potential issues.
  3. Blood Urea Nitrogen (BUN): Normal levels are 7-20; elevated levels suggest kidney problems.

Key Terms in Kidney Diseases

  • Oliguria: Low urine output (≤ 500ml/day).
  • Anuria: Very low urine output.

Types of Kidney Diseases

Glomerulonephritis
  • Definition: Inflammation of glomerular capillaries.
  • Causes: Infections, shock, medications.
  • Symptoms: Nausea, blood in urine, protein in urine, swelling, low urine output, high blood pressure.
  • Management: Dietary restrictions and fluid management.
Chronic Glomerulonephritis
  • Outcome: Progressive nephron loss leading to nephrotic syndrome.
  • Symptoms: Swelling, high protein in urine, low albumin, high blood lipids.
  • Management: Dietary adjustments.
Acute Renal Failure
  • Definition: Sudden kidney failure, often reversible.
  • Causes: Dehydration, obstruction, medications.
  • Symptoms: Reduced urine output, waste accumulation, high potassium.
  • Treatment: Supportive care and diet management.
Chronic Renal Failure (CRF)
  • Outcome: Permanent damage and loss of function.
  • Stages:
    1. Stage 1: Asymptomatic, 50% function loss.
    2. Stage 2: Noticeable symptoms, 25% loss.
    3. Stage 3: Severe damage, high creatinine.
    4. Stage 4: 90% damage, severe symptoms requiring dialysis.
  • Management: Dietary restrictions, dialysis, and transplantation.

Dietary Management in Kidney Diseases

General Guidelines
  • Protein: Adjust according to kidney function (0.6-1.0 g/kg).
  • Energy: Provide sufficient calories (35-40 kcal/kg).
  • Sodium: Monitor and adjust based on symptoms.
  • Fluid: Tailor based on urine output.
  • Vitamins: Supplement with B vitamins where necessary.