Renal Flashcards
Functions of Kidney
Excretory: excretion of metabolic waste products
Regulatory: maintain fluid & electrolyte homeostasis + interconversion of metabolic intermediates
Endocrine: synthesis/metabolism of hormones
Renal Failure
Increase in urea conc & SCr, decline in CrCl/eGFR & revelop uremic symptoms
*Know eqn to calculate CrCl
Chronic Kidney Disease (CKD)
Abnormalities of kidney structure/function, present >3 months (either of the following)
- albuminuria
- urine sediment abnormalities
- electrolyte & other abnormalities
- abnormalities by histology
- structural abnormalities by imaging
- history of kidney transplantation
-GFR<60ml/min/1.73 m^2
Azotemia
- accumulation of nitrogenous waste products (increased urea, SCr) from reduction in renal function
Uremia
- fluid, electrolyte, hormone imbalances & metabolic abnormalities due to deterioration of renal fn
- azotemia + clinical signs & symptoms
CKD Classification
Stage 1: GFR >= 90 Stage 2: GFR 60-89 Stage 3a: GFR 45-59 Stage 3b: GFR 30-44 Stage 4: GFR 15-29 Stage 5: GFR <15
Albuminuria A1: AER/ACR < 30
A2: AER/ACR 30-300
A3: AER/ACR >300
Causes of CKD/ESRD
- DM
- Glomerulonephritis (GN)
- Hypertension (HTN)
Others: Urinary obstruction (kidney stones) Chronic infections Genetic disorders Immune diseases Vascular diseases Drugs HIV-associated nephropathy
Clinical Presentation of CKD
Early stages: No clear signs with possible bubbles/blood in urine
Mid stage: loss of appetite, swelling ,fatigue
Late stage: ammonia breath, loss of appetite/diarrhoea, difficulty breathing, swelling, nausea/vomiting, loss of consciousness, anaemia
Uremic symptoms: fatigue, weakness, SOB, mental confusion etc
Signs: edema, changes in urine output, abdominal distension, pericardial rub, asterixis
Clinical Presentation of CKD (Lab abnormalities)
- Increased: SCr, urea, K, P, PTH, BP, glucose, lipids, Ca (if on vit D therapy)
- Decreased: GFR, CrCl, CO2 (metabolic acidosis), Hgb (anemia, iron stores, vit D, albumin, glucose, Ca (early stages), HDL
Complications with CKD
CV disease Fluid & electrolyte abnormalities Metabolic acidosis Malnutrition Anemia Secondary hyperparathyroidism; mineral & bone disorder Endocrine GI Dermatological Uremic bleeding Pulmonary Immune system Neurologic Psychological
Goals in CKD Management
- Slow down progression of disease + delay need for renal replacement therapy (RRT)
- Maintain fluid & electorlyte homeostasis
- Adequate nutritional & metabolic support
- Prevent extra-renal (anemia & bone disease)
- Reduce morbidity & mortality
DM Management in CKD
***Avoid use of glibenclamide in elderly & renal-impaired
SGLT2-i for Type 2 DM
- SGLT2-i + metformin for HbA1c > 7% despite mono
- SGLT2-i + sulfonylurea for HbA1c > 7% despite mono
- SGLT2-i + metformin + sulfonylurea despite optimal doses of dual therapy
- SGLT2-i + insulin +/- metformin
***eGFR<30 initiation not recommended for Canaglifozin, Dapaglifozin; Empagliflozin not recommended but may continue therapy
Benefits of SGLT2-i
- Weight loss
- Osmotic diuresis & natriuretic
- Reduce eGFR
- Reduce albuminuria
- Synergistic effects with antiHTN therapies
How to manage DM in CKD
- ACEi/ARB for pt with diabetes, HTN & albuminuria
- quit smoking
- consume diet high in veg, fruits, grains, fibre etc, lower process food & carbs
- maintain protein intake of 0.8g protein/kg
- Na intake <2g per day
- moderate-intensity physical activity for at least 150 mins/wk
- use HbA1c to monitor glycemic control
- HbA1c target <6.5% to <8%
more stringent if lower risk - Lifestyle therapy + metformin + SGLT-2i
- if T2D + CKD + eGFR > 30: metformin, SGLT2-i
- if metformin + SGLT2i not enough, use long-acting GLP-1 RA
- discontinue metfomrin if eGFR<30/dialysis
- do not initiate SGLT2i if eGFR<30 / discontinue if dialysis
Risk factors for CVD in CKD
Traditional: age, gender, smoking, DM, HTN, dyslipidemia
Non-traditional: malnutrition, uremic toxins, inflammation, oxidative stress, vascular calcification
CVD in CKD: HTN
cause & complication of CKD Goals of therapy: 1. lower bp 2. reduce risk of CVD 3. slow progression
Multiple interventions
- smoking cessation
DM & dyslipidemia management
- dietary & lifestyle modifications
Recommendation:
BP < 140/90 (no proteinuria; albumin excretion <30mg/24h)
BP < 130/80 (proteinuria; albumin excretion >30mg/24h)
ACEi/ARB (reduce BP, proteinuria, slow progression of CKD, prevent CVD events)
*avoid combi ACEi + ARB
CVD in CKD: HTN (side effects of ACEi & ARBs)
- Hypotension
- Worsening kidney function
- Hyperkalemia (more common with ACEi)
- Cough
- Angioneurotic edema
AntiHTN agents: ACEi & ARBs
- continued if increase in SCr < 25-30% from baseline value
- continued if serum K <= 5.5 mmol/L
SHOULD NOT BE USED:
ACEi: pregnancy, history of angioedema, cough due to ACEi, allergy
ARB: allergy, pregnancy, cough due to ARB
AntiHTN agents: Diuretics
- Reduce extracellular vol
- Lower BP
- Used w ACEi, ARB
- Thiazide-type diuretic in all patients
- Excessive diuresis –> worsening renal function
AntiHTN agents: Beta blockers
Atenolol, bisoprolol - undergo renal elimination
AntiHTN agents: CCBs - DHP / non DHP
DHP: SE: peripheral edema, flushing, HA
Less potent BP reduction but can reduce proteinuria
AntiHTN agents: Direct acting vasodilators
SE: fluid retention, tachycardia
AntiHTN agents: alpha-blockers
good for pts with BPH, SE: postural hypotension
CVD in CKD: Dyslipidemia
- increased risk for CVD
- common complication esp pts with nephrotic syndrome
- some pts may present with low serum cholesterol
- high & low LDL increase mortality risk in CKD
- as eGFR declines, magnitude of excess risk with increased LDL decreases –> LDL levels not used to determine if CKD pts should receive statin therapy
**When CrCl is < 30ml/min (stage 4/5), fibrates are contraindicated