Differential Diagnosis for BUN 25 with Normal GFR

Single Most Likely Diagnosis

• Dehydration: A common cause of elevated BUN with normal GFR, as dehydration concentrates the blood, leading to an increase in BUN levels without affecting kidney function.

Other Likely Diagnoses

• High Protein Diet: Consuming a diet high in protein can increase BUN levels, as the body breaks down protein into urea, which is then excreted by the kidneys.
• Gastrointestinal Bleeding: Blood in the gastrointestinal tract can be absorbed and metabolized, leading to an increase in BUN levels.
• Corticosteroid Use: Corticosteroids can increase protein catabolism, leading to elevated BUN levels.

Do Not Miss Diagnoses

• Pulmonary Embolism: Although less common, pulmonary embolism can cause an increase in BUN levels due to decreased blood flow and potential dehydration.
• Heart Failure: Right-sided heart failure can lead to decreased renal perfusion, causing an increase in BUN levels, even with a normal GFR.

Rare Diagnoses

• Multiple Myeloma: A rare plasma cell disorder that can cause an increase in BUN levels due to high cell turnover and protein catabolism.
• Ureteral Obstruction: A blockage in the ureters can cause an increase in BUN levels, although this would typically be associated with other symptoms and abnormal urinalysis results.