Differential Diagnosis for Acute Kidney Injury (AKI)

Single Most Likely Diagnosis

• Pre-renal AKI: This is often the most common cause of AKI, resulting from decreased blood flow to the kidneys (e.g., due to dehydration, blood loss, or heart failure). It's a likely diagnosis because it can occur in a wide range of clinical settings and is often reversible with prompt treatment.

Other Likely Diagnoses

• Acute Tubular Necrosis (ATN): A common cause of intrinsic renal AKI, often resulting from ischemia or nephrotoxicity (e.g., from certain medications or contrast agents). It's a likely diagnosis in patients with a history of exposure to nephrotoxic agents or severe hypotension.
• Post-renal AKI: Obstruction of the urinary tract (e.g., due to kidney stones, tumors, or benign prostatic hyperplasia) can cause AKI. This diagnosis is likely in patients with symptoms of urinary obstruction or a history of urological disorders.

Do Not Miss Diagnoses

• Rhabdomyolysis: Although not as common, this condition (causing muscle breakdown and release of myoglobin, which is toxic to the kidneys) can lead to severe AKI and is potentially life-threatening if not promptly recognized and treated.
• Sepsis: Sepsis can cause AKI through a combination of hypoperfusion, inflammation, and direct renal injury. Missing this diagnosis can have severe consequences, including high mortality.
• Atheroembolic Disease: This condition, where cholesterol crystals embolize to the kidneys, can cause AKI and is often associated with recent vascular procedures or anticoagulation. It's crucial not to miss this diagnosis due to its potential for severe and irreversible kidney damage.

Rare Diagnoses

• Vasculitis: Conditions like ANCA-associated vasculitis or lupus nephritis can cause AKI but are less common. They are important to consider in patients with systemic symptoms or known autoimmune diseases.
• Thrombotic Microangiopathy: Disorders such as thrombotic thrombocytopenic purpura (TTP) or hemolytic-uremic syndrome (HUS) can lead to AKI and are characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. These conditions are rare but critical to diagnose due to their specific treatments and potential for severe outcomes.
• Glomerulonephritis: Various forms of glomerulonephritis (e.g., post-streptococcal, IgA nephropathy) can cause AKI. While not as common as other causes, they are important to consider, especially in patients with recent infections or those presenting with hematuria and proteinuria.