1. Pre-renal
   • "Circulatory"- see cardiac function / shock / fluid balance
2. Renal
   • Acute tubular necrosis (ATN) - Paracetamol
   • Glomerulonephritis
   • Reno-vascular -NSAIDS (blocks production of vasodilatory PGE₂)
   • Hepato-renal syndrome
3. Post-renal - obstruction
   • Luminal: calculi
   • Mural:
   • Extraluminal: - extrinsic compression from pelvic tumours, prostatic hypertrophy, Abdominal compartment syndrome

1. Pre-renal
2. Renal
   • Congential: PCKD (extra-renal - cysts in liver, pancreas, spleen; berry aneurysms in circle of bruce willis, MV prolapse)
   • Glomerular: GN, Diabetes, Amyloid
   • Reno-vascular: hypertension, vasculitis, RAS
   • Tubular/interstitial: interstitial nephritis, pyelonephritis
3. Post-renal
   • Chronic outflow obstruction: calculi, prostatic enlargement, pelvic tumours

1. Parenchymal ischaemia -> reduced perfusion pressure
   • Vasoconstriction of efferent arteriole (to maintain RBF); maintains pressure across Glomerulus
   • Results in reduced blood supply to tubules from efferent arteriole and vasa recta
   • Worsens cortical / medullary ischaemia
2. Tubular ischaemia + necrosis leads to shedding of cells into lumen
   • Results in luminal obstruction
3. Promotes "back leak" of tubular fluid into interstitium
   • Increases interstitial hydrostatic pressure
   • Worsens tubular fluid resorption

1. Oliguria
   • <400ml/day urine
2. Reduced GFR
   • Raised urea / creatinine
3. Electrolyte inbalance
   • Hyponatraemia
   • Hyperkalaemia
   • Metabolic acidosis
   • Hypocalcaemia
4. Urine composition changes

1. Blood results
   • trends from previously
2. Signs / symptoms of long-standing disease
   • skin pigmentation, chronic anaemia (lack of EPO), pruritis, nocturia
3. USS / imaging
   • Bilateral small kidneys
   • Scarred kidneys

1. Fluid dynamics
   • Acute pulmonary oedema / fluid overload
2. Electrolyte balance
   • Hyperkalaemia - arrythmias

1. Hypertension
   • (RAS)
   • Fluid retention
2. Anaemia
   • Deficiency in EPO
   • Bone marrow fibrosis (from osteitis fibrosa cystica)
   • Red cell fragility caused by uraemic toxins
3. Renal osteodystrophy
   • Reduced renal production of 1-alpha-OH Vit D
   • Leads to hypocalcaemia and secondary hyperparathyroidism (forming bone cysts - osteitis fibrosa cystica)
   • Reduced bone mineralisation and resultant osteomalacia
   • Hyperphosphataemia due to reduced renal function
4. Uraemia
   • From "uraemic toxins"
   • Skin pigmentation, nausea, malaise, itch
5. Neurological

 Management

1. Pre-renal
   • Optimise filling / cardiac output
   • Careful fluid-balance: aim for even balance (fluid charts etc)
2. Renal
   • Stop nephrotoxic drugs (care with drugs undergoing renal excretion)
   • Manage GN
3. Post-renal
   • Catherise
   • Monitor urine output

Fill
Furosemide boluses (if well filled)
Intropes: Dopamine (increase RBF + contractility)
"Renal rescue" - GTN / Dopamine / Aminophylline / Frusemide

Optimise nutrition

Renal replacement therapy

1. Hypertension
   • Loop diuretics
   • Fluid restriction
2. Anaemia
   • EPO injections
3. Bone disease
   • Improve mineralisation
   • Vitamin D supplements
   • Gut phosphate binders
4. Diet
5. Dialysis/filtration