Acute Renal Failure: Etiology, Risk Factors, Pathogenesis, Pathology, Laboratory Findings, Progression, and Complications

Introduction

Acute renal failure (ARF), also known as acute kidney injury (AKI), is a sudden decline in kidney function, leading to the accumulation of waste products, electrolyte imbalances, and fluid dysregulation. Understanding its etiology, risk factors, pathogenesis, pathology, laboratory findings, progression, and complications is crucial for effective management.

Etiology

• Prerenal Causes: Hypovolemia, decreased cardiac output, systemic vasodilation.
• Intrinsic Causes: Acute tubular necrosis, glomerulonephritis, interstitial nephritis.
• Postrenal Causes: Obstruction due to stones, tumors, or strictures.

Risk Factors

• Advanced age
• Diabetes mellitus
• Hypertension
• Sepsis
• Nephrotoxic drugs (NSAIDs, aminoglycosides)

Pathogenesis

ARF results from impaired renal perfusion, direct nephron damage, or obstruction. The reduction in glomerular filtration rate (GFR) leads to azotemia and electrolyte disturbances.

Pathology

• Prerenal ARF: Normal kidney histology.
• Intrinsic ARF: Tubular necrosis, inflammatory infiltrates.
• Postrenal ARF: Hydronephrosis, tubular atrophy.

Laboratory Findings

• Elevated serum creatinine and blood urea nitrogen (BUN)
• Electrolyte imbalances (hyperkalemia, metabolic acidosis)
• Urinalysis abnormalities (proteinuria, hematuria, casts)

Progression

ARF can progress from an initial injury phase to an oliguric or non-oliguric phase, followed by a recovery phase. In severe cases, it may lead to chronic kidney disease (CKD).

Complications and Long-Term Impact

• Fluid overload and pulmonary edema
• Electrolyte imbalances leading to cardiac arrhythmias
• Increased risk of infections
• Progression to CKD or end-stage renal disease (ESRD)
• Neurological complications due to uremia

Conclusion

Acute renal failure is a serious medical condition requiring prompt diagnosis and management. Understanding its causes, progression, and complications can aid in early intervention and improve patient outcomes.