Chronic Kidney Disease Flashcards
What are the functions of the kidney?
1 - Water and salt homeostasis (H+, Na+, K+, PO4-, others)
2 - Filters the blood - removal of toxins and waste
3 - Endocrine Function
4- Urea Production
What are the endocrine functions of the kidney?
Renin - regulates blood pressure and water levels
Kallikrein - coagulation
EPO - RBC Production
Calcitriol - Final activation of vit d3
What are the RF for CKD
Male
Hypertensive
Smoking
Diabetes
Age >50 years old
Black and Hispanic
FHX
Autoimmune diseases
What is CKD defined as?
Chronic kidney disease (CKD) can be defined by the presence of kidney damage or reduced kidney function for >3MONTSHS
What investigations can be used to assess renal function or structure
Renal Chemistry:
Serum: Electrolytes (K+H+Na+), Glucose, Urea, Creatinine, EPO
Bloods - Anaemia - Normocytic?
Serum creatinine
Urine analysis: Haematuria +/- Proteinuria, Glucosuria
**GOLD STANDARD - KDIGO Classification
Urinary albumin: creatinine ratio
Estimated of eGFR (glomerular filtrations rate) **
Imaging -
Renal US: eGFR G4/G5
- Kidney swelling, atrophy, hydronpheresis, stones
Biopsy - Nephrotic or nephritic
What can cause CKD? Name 7 causes
MC - Diabetes - Diabetic nephropathy glycation of glomerular endothelium and arterioles leading to fibrosis
2. Hypertension and CVD - Thickening of arterioles - less perfusion
3. Glomerulopathies - Nephritic / Nephrotic
4. Congenital causes -Polycystic kidney disease
5. Obstruction - renal colic, BPH, Tumour
6. Nephrotoxic drugs - NSAIDs, Anti-depressants, Loop diuretics
7. Pyelonephritis - Persistent infection/inflammation of the kidneys
Pathophysiology of CKD
Regardless of the aetiology, the end result is structural alterations-> interstitial fibrosis and tubular atrophy
Damage/loss of nephrons -> persistent inflammation -> Scarring and loss of function
- glomerular hypertrophy to compensate for loss
- WCC and inflammatory mediator infiltration
- Increase in glomerular permeability - loss of macromolecules & exposure to nephrotoxic molecules
- Renin-angiotensin 2 - excess collagen release
The resultant kidney failure is responsible for a number of complications including:
Metabolic derangement (uraemia and hyperkalaemia),
Anaemia (reduced erythropoietin),
CKD-mineral bone disease (CKD-MBD).
What is the classification system used for CKD? and what a parameter is used?
KDIGO Kidney Disease: Improving Global Outcomes (KDIGO) classification
KDIGO classifies CKD based on cause (C), glomerular filtration rate category (G), and albuminuria category (A).
Cause : Identified via patient history (HTN, DM, Drugs)
What are the classification ranges for GFR rate according to KDIGO?
Glomerular filtration rate (GFR) category is based on GFR (mL/minute/1.73 m²):
What are the classification ranges for Albuminuria according to KDIGO?
Albuminuria category is based on albumin excretion rate (AER) or albumin to creatinine ratio (ACR):
The recommended method to evaluate albuminuria is to measure urinary ACR in a spot urine sample
If both creatinine and albumin are measures of kidney excretion, why would we measure the ratio of both?
Concentration of creatinine and albumin in urine can vary. Thus there is a need for standardization.
The ACR corrects for these differences by dividing the amount of albumin in the urine by the amount of creatinine in the urine
Creatinine is excreted at a relatively constant rate and so creatinine levels in urine can act as a standardizing factor.
This allows us to compare ACR values across different samples and get a better sense of the amount of albumin being excreted relative to creatinine.
RISK STRATIFICATION OF KDIGO CLASSIFICATION SYSTEM
How would CKD Present?
Asx until ESRF ~ fatigue, nausea, pruritus
Symptoms and signs are associated with function
1.Anemia (EPO)
Anemia Sx- headache, pallor, fatigue, intermittent claudication, tachycardic, exertional dyspnoea
- Uraemia (Less urea excretion)
Sx- Uraemic frost, pruritus, Nausea, Reduced appetite, restless legs - Oliguria (reduced urination) ~ 0.5ml/kg/hr or less than 500ml/day
= Fluid retention - peripheral adn pulmonary Oedema, increase JVP
- Hyperkalaemia - Arrhythmias, msucle cramps, weakness, reduced tone
- Metabolic acidosis - excess H+ retention
- MBD Mineral bone disease due to: Hypocalcaemia, hyperphosphatemia, and reduced active vitamin D into calcitriol. Hypocalcaemia leads to secondary Hypoparathyroidism.
What other investigation should be considered to rule out differentials/identify cause
Fundoscopic eye examination - Identifies diabetic/htn retinopathy -markers of microvascular complications
DRE - BPH associated with obstructive uropathy
How to treat CKD
Treatment
To slow progression:
Maintain BP, treat hypertension (<130/80)
E.g.
ACEi/ARB - Ramipril
2nd line other Anti-HTN drugs: CCBs (verampril) , BB(Atenolol),
Diuretic (thiazide)
Adjunct:
+ SGLT2i - Dapagliflozin
+ Statin - Atorvastatin
+ Vitamin D - MBD
+ Epoetin alfa - if Anaemic
Stage 4-5 Refer to nephrology
For end-stage kidney disease: stage 5
Dialysis:
- Peritoneal dialysis (daily, abdominal
catheter)
- Haemodialysis (3x/week, need fistula)
3rd line: Transplant + lifelong immunosuppression
