chronic kidney disease

Question 1

What is chronic kidney disease?

Answer 1

Abnormality of kidney structure or function (GFR <60 mL/minute/1.73 m²) that is present for ≥3 months or the presence of one or more of the following markers of kidney damage: albuminuria/proteinuria, urine sediment abnormalities (e.g., haematuria), electrolyte abnormalities due to tubular disorders, abnormalities detected by histology, structural abnormalities detected by imaging, or history of kidney transplantation

Question 2

How can you classify CKD?

Answer 2

Classification of CKD: 

G1: Normal 

eGFR > 90 ml/min per 1.73 m2 with other evidence of CKD (microalbuminuria, proteinuria, haematuria, structural abnormalities, biopsy showing glomerulonephritis) 

G2: Mild Impairment 

eGFR 60-89 ml/min per 1.73 m2 with other evidence of CKD  

G3a: Moderate Impairment 

eGFR 45-59 ml/min per 1.73 m2 

G3b: Moderate Impairment 

eGFR 30-44 ml/min per 1.73 m2 

G4: Severe Impairment 

eGFR 15-29 ml/min per 1.73 m2 

G5: Established Renal Failure 

eGFR < 15 ml/min per 1.73 m2 or on dialysis  

Question 3

What are the causes of CKD?

Answer 3

Hypertension - not enough blood flow through the renal artery 
Diabetes - non-enzymatic glycation of the efferent arteriole
other causes:
- lupus
- Rheumatoid arthritis
- HIV
- NSAIDs
- Tobacco

Question 4

What are the risk factors of CKD?

Answer 4

• Diabetes
• Hypertension
• Obesity
• Advanced age
• Substance use
• AKI
• Black or Hispanic ethnicity 

Question 5

what presenting symptoms of CKD can be found in the history?

Answer 5

*Uraemia [increased toxin/ urea in blood] and Hyperphosphatemia (lack of excretion of toxic substances)
*Anaemia (lack of EPO produced by kidney)
- Often Asymptomatic → may be finding of routine blood test or urine test
- Fatigue
- Oedema (Peripheral/Pulmonary) → due to Na/H20 retention
- Nausea
- Pruritus”itchy skin” → due to uraemia
- Hypertension
- Symptoms of Hypocalcaemia (due to 1-alpha-hydroxylase deficiency) → tetany, muscle twitching, paraesthesia, arrhythmias

Question 6

What signs of CKD can be found on physical examination?

Answer 6

• Skin pigmentation  
• Excoriation marks  
• Pallor  
• Kussmaul’s breathing (deep breathing at a consistent pace. It’s a sign of a medical emergency)
• Leuconychia 

Question 7

What investigations are used to diagnose/ monitor CKD?

Answer 7

1. Renal Profile → elevated creatinine, electrolyte abnormalities (hyperkalaemia)
2. GFR Estimation → <60 mL/minute/1.73 m² :
   - eGFR not good measurement if someone has high muscle mass (due to increased creatinine)
3. Urinalysis → haematuria and/or proteinuria
   - ACR (Urine albumin to creatinine ratio) ⇒ check for proteinuria (ACEi key for management of proteinuria).
4. Urinary Albumin → increased
5. Renal Ultrasound (1st line imaging technique for assessment of kidney structure) → small kidney size
6. Secondary Hyperparathyroidism → low calcium, low vitamin D, high phosphate

Hence for management, need to give vitamin D supplement (alfacalcidol) and reduce dietary intake of phosphate or be prescribed a phosphate binder (sevelamer)

Question 8

How is CKD managed?

Answer 8

Key = antihypertensives + optimize glycaemic control

1. G1-G2 → ACE inhibitor (lisinopril - if ACR>30) or ARB (losartan) + dapagliflozin (SGLT2 inhibtor) + statin.2nd Line = CCB.
2. G3-G4 → ACE inhibitor + dapagliflozin + statin
3. G5 or Uraemic → 1st line = dialysis (haemodialysis or peritoneal dialysis). 2nd line = kidney transplant (pre-emptive live donor kidney transplant = best form of RRT).
   - Haemodialysis (more common) → regular filtration of blood through dialysis machine in hospital 3/4x a week.
   - Peritoneal Dialysis → filtration occurs in patients abdomen, can be done at home.
4. Renal Replacement Therapy (haemodialysis, peritoneal dialysis, kidney transplant)
5. Fluid & Salt restrictions (Fluid Balance), EPO-Stimulating agents(correct iron deficiency first), Vitamin D supplements (Alfacalcidol → doesn’t require activation in kidneys), reduce dietary intake of phosphate or phosphate binders (sevelamer)
6. Nephrotoxic drugs, such as naproxen, should be stopped in patients with CKD

Question 9

What complications can be associated with CKD?

Answer 9

“CRF HEALS”

• Cardiovascular disease
• Renal osteodystrophy (disease that weakens your bones)
• Fluid (oedema)
• Hypertension
• Electrolyte disturbance (hyperkalaemia, acidosis)
• Anaemia
• Leg restlessness
• Sensory neuropathy