Acute Renal Failure

Acute Renal Failure

1. Causes

   • Preprenal
     • Hypoperfnusion due to: 1-CHF 2-Renal artery stenosis 3-thrombosis 4-dehydration
       • BUN/CR ratio >15 FEna <1% Urine osm >500nn
     • Hypovolemic shock
   • Renal
     • 1-acute tubular necrosis
       • Ischemic: Hypotension-shock-Renal vascular diseases.
       • Nephrotoxic: Toxins (drugs-radigraphic contrast- mercury-Heamoglobinuria – myoglobinuria)
     • 2-tubule-interstitial nephritis
       • Infectious type. Mostly bacterial :"Pyelonephritis”
       • Non-infectious types: drugs (hypersensitivity), toxins, physical(obstruction), Multiple myeloma, immunologic, and vascular causes
   • Postrenal
     • Obstruction below kidney’s level: 1-tumor 2-stones 3-prostate hypertrophy
       • Early stage *acute*: BUN/CR ratio >15 FEna <1% Urine osm >500
       • Chronic long term: BUN/CR ratio <15 FEna >2% Urine osm <500

2. Definition

   • a rapid decline in kidney function that can lead to long-term kidney damage and death. It is often preventable or reversible

3. Epidemiology

   • Affects 5-7% OF ALL HOSPITALISED PATIENTS 20-70% MORTALITY RATE

4. Signs & Symptoms

   • azotemia (High BUN/creatinine) Oliguria or polyuria Fluid retention (edema) Shortness of breath Fatigue and Confusion Seizures or coma Chest pain or pressure Foamy or bubbly urine
   • Can be Asymptomatic!

5. Investigations

6. Management

   • Hydration hyperkalemia Pulmonary edema Fluid retention Acidosis
   • Diuretics
     • Tubular Reabsorption function

7. Complications

   • Fluid buildup Chest pain Muscle weakness Chronic Renal Failure

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