Differential Diagnosis for Bilateral Flank Pain
Single Most Likely Diagnosis
- Nephrolithiasis (Kidney Stones): This condition is a common cause of bilateral flank pain, especially if the stones are moving or obstructing the ureters. The pain is often severe and can radiate to the groin.
Other Likely Diagnoses
- Pyelonephritis: An infection of the kidneys that can cause flank pain, fever, and other urinary symptoms. It's more common in women and can be bilateral.
- Urinary Tract Infection (UTI): While often causing lower urinary tract symptoms, severe or upper UTIs can lead to bilateral flank pain.
- Musculoskeletal Strain: Overuse or strain of the back muscles can cause flank pain, which might be perceived as bilateral if the strain affects both sides of the back.
Do Not Miss Diagnoses
- Sepsis from a Urinary Source: A severe infection that can lead to life-threatening sepsis. Early recognition and treatment are crucial.
- Obstructive Uropathy: Bilateral obstruction of the urinary tract, which can lead to acute kidney injury if not promptly addressed.
- Retroperitoneal Hemorrhage: Bleeding into the space behind the peritoneum, which can be due to trauma, anticoagulation, or other causes, and requires immediate medical attention.
Rare Diagnoses
- Polycystic Kidney Disease (PKD): A genetic disorder characterized by the growth of numerous cysts in the kidneys, which can cause chronic flank pain.
- Vasculitis (e.g., ANCA-associated vasculitis): Inflammation of the blood vessels that can affect the kidneys and cause flank pain among other symptoms.
- Retroperitoneal Fibrosis: A rare condition where fibrotic tissue forms in the retroperitoneum, potentially encasing and obstructing structures like the ureters.