Reduction in kidney function or structural damage or both, present for more than 3 months with associated health implications

Aetiology

• Diabetes and high blood pressure are the biggest causes globally - account for almost 3/4 of cases
• Polycystic kidney disease
• Glomerular disease
• Current or previous history of Acute Kidney Injury (AKI)
• Potentially nephrotoxic drugs, e.g.: aminoglycosides, ACEi, ARBs, bisphonates, calcineurin inhibitors, diuretics, lithlium, mesalazine, NSAIDs
• Obstructive uropathy
  • Calculi - along entire renal tract
  • Prostate - BPH, malignancy, prostatitis, abscess
  • Bladder - malignancy, chronic cystitis with bladder thickening and 'inflow obstruction'
  • Malignancy - entire urethelial tract
  • Strictures/stenosis - ureter or urethra, due to infections or prior injury
  • Extrinsic compression - lymph nodes, colonic or gynae masses, RPF
• Multisystem diseases with renal involvement - SLE, vasculitis (GPA, MPA, EGPA), myeloma
• Family history of CKD or a hereditary kidney disease such as ADPKD, Alport syndrome, familial glomerulonephritis
• Cardiovascular disease
• Obesity with metabolic syndrome

Pathophysiology

CKD should be diagnosed in people with 'markers of kindney damage' - 'THE ASS-H):

• Transplant - anyone with a history of kidney transplantation
• Histological abnormalities detected on kidney biopsy
• Electrolyte abnormalities due to tubular disorders
• ACR (urinary albumin: creatinine ratio) greater than 3 mg/mmol
• Sediment abnomalities in the urine (haematuria/casts)
• Structural abnormalities detected by imaging