Acute Kidney Injury by Dr Ilsa from BIH.8

Management of acute kidney injury

1. Acute Renal Injury Dr ILSA AYAZ PGR MEDICINE BAHRIA INTERNATIONAL HOSPITAL

2. Outline Introduction Etiology of AKI Diagnostic evaluation Management Tumor lysis syndrome Rhabdomyolysis Contrast induced nephropathy

3. The term acute kidney injury describes the clinical syndrome in which an abrupt (hours to days) decrease in kidney function leads to the accumulation of nitrogenous waste products and, commonly, a reduction in urine output. up-to-date 2025   ACUTE KIDNEY INJURY:

4. KDIGO (2012) AKI criteria Serum creatinine ≥0.3mg/dL (≥26.5μmol/L): 48hr Serum creatinine ≥1.5 x baseline : 7 days Urine volume <0.5 mL/kg/ hr 6hr

5. KDIGO criteria Stages: Stage-1 : serum creatinine 1.5-1.9 times / serum creatinine > 0.3 mg/dl urine output < 0.5ml/kg/ hr 6-12 hours Stage 2: Serum creatinine 2-2.9 times urine output < 0.5ml/kg/ hr > 12 hours Stage 3 serum creatinine 3 times / serum creatinine > 4 mg/dl urine output < 0.3ml/kg/ hr 24 hours /anuria > 12 hrs Kidney replacement therapy

6. Etiology (PRE RENAL CAUSES ) (30-60%) Reduced Renal Arterial Perfusion Total body volume depletion Normal total body volume Total body volume overload Renal Venous Congestion Drugs Affecting Glomerular Hemodynamics

7. Etiology Intrinsic renal causes (40%) Renal Vascular disease Glomerular disease Tubular and interstitial diseases

8. ACUTE TUBULAR NECROSIS Ischemic/ Nephrotoxic insult Muddy brown cast Histopathology: tubular epithelial necrosis Dilation of tubules , necrotic cells obstruct the tubule lumen ACUTE INSTERTITIAL NEPHRITIS Drugs/Systemic diseases/Infection Features: fever, rash, arthralgia , eosinophilia, HTN, renal impairment Sterile pyuria white cell cast Histology: marked interstitial edema . Infiltrates in connective tissue

9. Etiology (Extrinsic) (10%) Prostatic disease Urothelial carcinoma Gynecologic/ metastatic CA Retro-peritoneal fibrosis

10. Diagnostic Evaluation History Concurrent illness Physical examination Signs of volume contraction Drug rash Volume overload and signs of heart failure Ascites and jaundice Urine output

11. Diagnostic evaluation ( Laboratory tests): Urine tests Urinalysis Protein excretion Sodium excretion  Blood tests Renal function test, BUN Electrolytes Glucose Serum calcium Complete blood count

12. pre-renal uremia Acute tubular necrosis Urine Sodium <20 mmol/l >40mmol/l Urine Osmolarity >500mOsm/K <350mOsm/kg Fraction Sodium Excretion <1% >1% Response to fluid challenge Good poor Urea/ creatinine ratio Raised Normal Fraction urea excretion <35% >35% Urine: plasma osmolarity >1.5 <1.1 Specific gravity >1020 <1010 Urine Normal/bland sediment Brown granular casts

13. Diagnostic evaluation ( Laboratory tests) : Additional tests ( Multiple Myeloma) Serum protein electrophoresis with immunofixation Urine protein electrophoresis with immunofixation Serum free light chain assay Imaging Biopsy 

14. Targeted additional assessment :  Clinical features Heart and liver failure Cancer Recent intra-aortic procedure Unexplained AKI Role of kidney Biopsy

15. Management  : Triage Evaluate for need of urgent kidney replacement therapy Subsequent management : treat the cause Remove any active insults to minimize new injury Identify and treat the complication Elimination and avoidance of potential insults

16. Management : Volume assessment and management Role of diuretics Role of kidney replacement therapy Electrolyte imbalance Acid base disturbances Nutrition

17. Monitoring and follow-up : DAILY Serum creatinine Electrolytes phosphate TWICE DAILY/FREQUENTLY Serum calcium  Ionized calcium 

18. TREATMENT OF ACUTE KIDNEY INJURY COMPLICATIONS: Fluid Overload Hyperkalemia Hyperphosphatemia  Hypocalcemia  Hypo/hypermagnesemia  Hyperurecemia   Acid base distrubance   Nutrition 

19. Tumor Lysis Syndrome : Cairo-Bishop scoring : > 2 of following , within 3 days before/ 7 days after chemotherapy. uric acid > 475umol/l or 25% increase potassium > 6 mmol /l or 25% increase phosphate > 1.125mmol/l or 25% increase calcium < 1.75mmol/l or 25% decrease

20. Tumor Lysis Syndrome (PREVENTION) : IV fluids rasburicase generally preferred now for patients at a higher risk of developing TLS allopurinol generally used for patients in lower-risk groups

21. Rhabdomyolysis: Aggressive volume repletion target urine output of 200 to 300ml/hr urine pH is <6.5, each liter of normal saline can be alternated with 850 mL of 5% dextrose plus 150 mmol of sodium bicarbonate. Mannitol may be considered

22. Contrast induced Nephropathy : 25% increase in creatinine within 3 days of the intravascular administration of contrast media.  Occurs 2-5 days after administration. Prevention: I/v 0.9% NaCl  1 mL/kg/hour for 12 hours pre- and post- procedure.