Acute kidney injury

Red Flags

Severe AKI with oliguria + hyperkalaemia (K+ ≥6.5 with ECG changes) or refractory acidosis or fluid overload — emergency RRT (haemodialysis or CRRT)^[1]
AKI with rhabdomyolysis (CK ≥5000) — aggressive IV crystalloid; monitor compartments; alkalinise if clinically indicated^[1]
Sudden anuria with palpable bladder or hydronephrosis on bedside scan — post-renal obstruction; urgent catheter or nephrostomy^[1]
Drug-induced AKI from nephrotoxin (NSAIDs, aminoglycosides, vancomycin, contrast, ACE-i in volume depletion) — stop drug; volume optimise; consider alternatives^[1]

Resuscitation and source control^[1]
Identify and treat precipitating cause: sepsis (early antibiotics + source control), volume depletion (crystalloid), cardiogenic shock (inotropes), nephrotoxin removal
Volume optimisation^[1]
Crystalloid (balanced solution preferred over 0.9% saline in non-traumatic AKI per BaSICS/PLUS); avoid synthetic colloids; assess volume status repeatedly — over-resuscitation causes congestion-induced AKI
Avoid further nephrotoxins^[1]
Stop NSAIDs, ACE-i/ARB if hypotensive, aminoglycosides, vancomycin (where alternative possible), iodinated contrast where deferable. Dose-adjust all drugs per current eGFR (assume GFR ~10 in oligo-anuric AKI)
Renal replacement therapy (RRT)^[1]
Indications (AEIOU): refractory Acidosis, Electrolytes (hyperkalaemia, hypercalcaemia), Intoxication (e.g., toxic alcohols, salicylates, lithium), Overload (refractory pulmonary oedema), Uraemic complications (encephalopathy, pericarditis). Earlier vs later initiation neutral in stable patients (STARRT-AKI)

Drug	Class	Adult	Paediatric	Notes
Hyperkalaemia management^[1]	Acute potassium-lowering bundle	Calcium gluconate 10% 10 mL IV slow push (cardiac membrane stabilisation if ECG changes); insulin 10 U + dextrose 50 mL of 50% IV; salbutamol 10–20 mg nebulised; bicarbonate 50–100 mmol IV if acidaemic; sodium polystyrene sulfonate (Kayexalate) 15–60 g PO/PR	Per weight per paediatric guidelines	Definitive treatment is RRT if refractory or recurrent
Loop diuretic (furosemide)^[1]	Loop diuretic	40 mg IV bolus then titrate; furosemide stress test (1 mg/kg) predicts progression to RRT	1 mg/kg IV	Symptomatic fluid overload only; does NOT change AKI trajectory or mortality; do not give for oliguria alone

Hyperkalaemia management^[1]

Acute potassium-lowering bundle

Adult: Calcium gluconate 10% 10 mL IV slow push (cardiac membrane stabilisation if ECG changes); insulin 10 U + dextrose 50 mL of 50% IV; salbutamol 10–20 mg nebulised; bicarbonate 50–100 mmol IV if acidaemic; sodium polystyrene sulfonate (Kayexalate) 15–60 g PO/PR
Paediatric: Per weight per paediatric guidelines

Definitive treatment is RRT if refractory or recurrent

Loop diuretic (furosemide)^[1]

Loop diuretic

Adult: 40 mg IV bolus then titrate; furosemide stress test (1 mg/kg) predicts progression to RRT
Paediatric: 1 mg/kg IV

Symptomatic fluid overload only; does NOT change AKI trajectory or mortality; do not give for oliguria alone

Maintain hydration but avoid over-drinking; track urine output and fluid balance daily during illness^[1]
Stop NSAIDs, ACE-i, ARBs, and SGLT2 inhibitors during acute illness with vomiting, diarrhoea, or fever — they can worsen AKI; restart only when stable^[1]
Recovery may take days to weeks; some patients have residual CKD — follow up creatinine and ACR after discharge^[1]

AKI Stage 3 OR refractory hyperkalaemia OR pulmonary oedemaICU and nephrology for RRT^[1]
Suspected glomerulonephritis (haematuria, dysmorphic RBCs, proteinuria, RBC casts)Nephrology for urgent biopsy and immunosuppression decision^[1]
Post-renal obstruction (hydronephrosis on US)Urology for catheterisation or nephrostomy^[1]
AKI not recovering at 7 daysNephrology^[1]

Diagnosis, staging, and management of AKI per KDIGO criteria with bundle-based care for prevention, source control, and renal replacement decisions.

1.KDIGO 2012 Clinical Practice Guideline for Acute Kidney Injury (current; 2024 KDIGO CKD update for ongoing CKD-AKI overlap) (2012)