Chronic Kidney Disease (CKD)

Related Subjects: |Metabolic acidosis |Lactic acidosis |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD) |Anaemia in Chronic Kidney Disease |Analgesic Nephropathy |Medullary Sponge kidney |IgA Nephropathy (Berger's disease) |HIV associated nephropathy (HIVAN) |Balkan endemic nephropathy (BEN) |Autosomal Dominant Polycystic kidney disease

About

• Gradual loss of renal function over time
• Can end up with a need for renal replacement
• High risk of vascular and other diseases

Stage

Suffixes

• P suffix: the addition of p to a stage (e.g. 3Ap, 4p) means that there is significant proteinuria (more info)
• T - the addition of T to a stage (e.g. 3AT) indicates that the patient has a renal transplant.
• D - the addition of D to stage 5 CKD (e.g. 5D) indicates that the patient is on dialysis - See more at: here

Aetiology

• Hypertension, Diabetes, Glomerulonephritis
• Polycystic kidney disease, Lupus, Renal stones
• Obstructive uropathy, hereditary

CKD is a major cardiovascular risk factor: the average dialysis patient is at an approximately 20 times higher risk. The Goals of treatment are BP <120/80 and Proteinuria <0.3 g/24 h

Management

Renal protection

• Multiple trials have shown the benefits of BP control in renal disease, particularly in patients with proteinuria, where ACE inhibitors and ARBs (angiotensin receptor blockers) have particularly beneficial effects in protecting long term kidney function. Targets These apply to all stages of CKD. Patients with CKD and proteinuria with a PCR of 100, or ACR of 70, is approximately equal to 1g of protein per 24h should be considered
  • Targets Proteinuria <0.3 g/24 h
  • Target SBP 120–129 mmHg and DBP < 80 mmHg.
  • Lower BP without symptoms of hypotension
  • Start ACEI titrate to the maximum dose. Watch U&E closely.
  • Add ARB if goals are not achieved. Watch U&E closely.
  • Add diuretic to prevent hyperkalaemia and to help control BP
  • Add calcium-channel blocker (verapamil or diltiazem) if BP goals are not achieved
  • Statins to lower cholesterol to <4.5 mmol/L
  • Smoking cessation
  • Treat diabetes (HbA1c <7% 53 mmol/mol)
  • Normal protein diet (0.8-1 g/kg body weight)
  • As progress decide on the mode of therapy: haemodialysis versus peritoneal dialysis versus pre-emptive renal transplantation if a live related or spousal kidney donor is willing to donate
  • Plan access surgery: an AV fistula needs 6+ weeks before it can be used
  • In type 2 diabetes start with ARB
• Advice on above
  • If creatinine rises >30% or GFR fall >25%, repeat tests, stop drug and consider other causes including volume depletion, NSAID use. If no other explanation, consider investigation for renal artery stenosis. Do not discontinue for lesser changes in eGFR/creatinine, some change is expected.
  • If K>6, stop drugs that may be contributing, e.g. NSAIDs, potassium-retaining diuretics, and check diet (especially 'LoSalt' which is potassium chloride). If hyperkalaemia persists the ACE inhibitor or ARB should be stopped. Modest stable hyperkalaemia may be preferable to discontinuing a valuable therapy. It is appropriate to stop ACEi/ARB at times of high risk of AKI (for example, acute volume depletion) and resume therapy later.

Anaemia

• Target 11-12 g/dl. Anaemia not usually until Stage 3
• Check haematinics and investigate and exclude other causes e.g. OGD and colonoscopy where appropriate
• Correct any Iron deficiency or B12 or folate
• Erythropoietin: can only be given IV or by SC injection ×1-3 weekly. Epoetin alfa can only be given by IV route because of the increased risk of pure red cell aplasia (PRCA). Greatly improves the quality of life.

Hyperparathyroidism

• Measure and monitor PTH, Ca, P, ALP.
• Problems seen when Stage 3b disease
• Control phosphate: Dietitian and Phosphate-binding drugs, e.g. calcium carbonate, calcium acetate, Sevelamer, Aluminium hydroxide in selected cases.
• Vitamin D analogues (e.g. alfacalcidol).

Acidosis

• An average person generates 1 mmol of non-volatile acid/kilogram body weight/day. The kidneys cope with this by reclaiming filtered bicarbonate, and on the other hand by regenerating base via the excretion of ammonium and titratable acid. With CKD this becomes more difficult.
• Giving oral alkali may well be renoprotective for those with serum bicarbonate level <22 mmol/L. This can be with sodium bicarbonate or sodium citrate

Haematuria

• Visible (macroscopic) haematuria Usually fast track Urology referral for imaging and cystoscopy, unless strong pointers to acute renal disease.
• Refer to nephrology if urological investigations negative Invisible (microscopic) haematuria without proteinuria, GFR>60ml/min/1.73m2 Age >40, usually refer to Urology (recommended age may vary locally) Age <40, or >40 with negative urological investigations, manage as Stage 1/2 CKD Microscopic haematuria with prot/creat ratio >50mg/mmol Refer nephrology Lower levels of proteinuria, manage as Stage 1/2 CKD.

References

• NICE on CKD