Renal Disease Flashcards
What is the anatomy of the Kidney?
Two kidneys
Small, bean-shaped
Located either side at the back of your spine
Each kidney has ~ 1million nephrons
The nephrons have glomerulus (filter) and many tubules
The nephrons filter and clean the blood
What are the Vital Functions of the Kidney?
- Regulate fluid levels
- Activate vitamin D for healthy bones
- Regulate acid/base balance (HCO3)
- Regulate electrolyte levels ( i.e Na+, K+, Mg2+)
- Remove wastes and toxins (urea, creatinine, ammonia)
- Regulate blood volume
- Regulate blood pressure (renin-angiotensin-aldosterone)
- Hormone production Production of red blood cells (EPO – erythropoietin)
- Urine production
- Urine contains – water, nitrogenous wastes – mainly urea, small amounts of uric acid, creatinine, ammonia, electrolytes
What is Chronic Kidney Disease?
Also known as chronic renal failure (CRF)
Diagnosis: An eGFR or GFR < 60ml/min that is present for >3 months with or without kidney damage.
OR
Evidence of kidney damage with or without decreased GFR that is present for > 3 months irrespective of the underlying cause.
Requires minimum blood test + urine + imaging of the kidneys
What is GFR?
Also known as creatine clearance
Represents the amount of filtrate formed each minute in the nephrons of both kidneys
• Normal range > 90 ml / min (~125ml/min)
• We use a blood test and then an equation to determine
GFR -hence why we call it eGFR (e stands for estimation)
• eGFR can be less accurate in those with low or very high body weights or a protein diet.
Who is at more risk of developing CKD?
Diabetes HBP Smoker 60+ Aboriginal Family History History of acute kidney injury
What are the causes of CKD?
Diabetes: Diabetes can damage blood vessels in your kidney filters. It can also change the level of sugar in the blood or urine and lead to bacterial growth in the bladder which increases the risk of kidney infections.
Hypertension: High blood pressure damages the small vessels. Results in thickens blood vessel walls causing narrowing.
Polycystic kidney disease: inherited kidney disease that causes genetic defects, which lead to the growth of thousands of cysts in the kidney
Lupus: A chronic inflammatory/autoimmune disease that can injure the skin, joints, kidneys, and nervous system.
Nephritis: Inflammation of the glomeruli (kidney filters). The body immune system attacks the glomeruli causing scarring and swelling. It reduces the kidney’s ability to filter waste from the blood.
What are the stages of CKD?
Stage 1: >90 Kidney Damage (Protein in urine with Normal GFR)- No symptoms
Stage 2: 60-89 (Kidney Damage with mild loss of function)- No symptoms, maybe nocturia and HBP.
Stage 3a and b: 30-59 (Moderately loss in kidney function)- Sometimes now symptoms. Anemia and early bone disease.
Stage 4: 15-29 (Severe loss in kidney function)- Symptoms of uremia.
Stage 5: <15 (End-Stage Renal Disease requires dialysis and transplantation)- Pt will usually feel better due to a decrease in uremia, however still at risk of oedema/fluid overload.
How to treat kidney disease?
Renal Replacement Therapy (RRT)
Dialysis:
- Peritoneal Dialysis (PD) (CAPD or APD)
- Haemodialysis (at home or in the centre) – in the centre usually 3 times per week for 4-5 hours per week – Home 7-9 hours most nights
Transplantation:
- Live or deceased donor
- Wait times vary i.e. few months to many years
Supportive care (conservative management)
What are the symptoms of CKD?
- high blood pressure
- changes in the amount and number of times urine is passed
- changes in the appearance of your urine (for example, frothy or foaming urine)
- blood in your urine
- puffiness in your legs, ankles or around your eyes
- pain in your kidney area
- tiredness
- loss of appetite
- difficulty sleeping
What is the Medical Nutritional Therapy for CKD?
Stage 1-2: Healthy Eating Weight mx Co-morbidity mx Sodium
Stage 3:
same as above and;
Moderate Protein
Monitor for malnutrition
Stage 4-5:
Protein per DN prescription- higher protein if on dialysis
Restrict potassium or phosphate if elevated
Fluid restriction as per nephrologist
Symptom control i.e taste changes, LOA, constipation
Important things to know about protein in CKD patient diets?
• Too much protein may accelerate the decline in kidney function
• BUT low protein diets»_space;> high risk of malnutrition
• Appropriate protein intake individualised by DN
• On dialysis - higher protein intake recommended
- to maintain optimal nutrition
- prevent muscle breakdown
- replace losses through dialysis
Important things to know about potassium in CKD patient diets?
• Maintains bodily functions - muscle contraction, reg. BP and
heartbeat.
• Serum K+ levels are closely regulated by kidneys. Even small changes
outside cells have severe effects on the heart, nerves, muscles.
Normal range for serum K+ is 3.5-5.5mmol/L
• Hypokalemia (low serum K+) - weakness - cellular processes
impaired
• Hyperkalemia (high serum K+) - dangerous and usually no
symptoms - irregular heartbeat, nausea, slow/weak pulse
Examples of High K+ foods: hot chips, fruit juice, flavoured milk, potato chips
Important things to know about Phosphate in CKD patient diets?
• Used with calcium to make our bones
• Used by muscle and in other reactions within the body
• excess serum PO4- is usually excreted in the urine
Normal range for serum PO4- is 0.8 to 1.4 mmol/l
• low serum PO4 levels (hypophosphatemia) is usually
asymptomatic
• high serum PO4 levels (hyperphosphatemia) can cause
generalised itching may lead to Ca+ and PO4 being deposited
in tissues (calciphylaxis).
FRESH is best
• Less processed foods, Less takeaway foods
• Reduction in animal proteins
• Reduction in phosphate additives
Important things to know about Sodium in CKD patient diets?
In CKD a lower Na+ intake may help to control blood pressure
and slow progression
• In dialysis dietary sodium restriction is important for - regulation of Na+ and fluid balance
- controls fluid intake by reducing thirst
• Encourage patients to throw away the salt-shaker, flavor foods
with herbs and spices, eat fresh, encourage label reading
• Don’t use salt substitutes»_space;> high K+ (dangerous)
What is Acute Kidney Injury?
• Sudden damage to the kidneys (acute insult)
• Oliguric Phase < 500mls urine /day
• Fluid and electrolyte restrictions may be required, protein
modification may be required if the patient is requiring dialysis.
