Differential Diagnosis for Foam in Urine

• Single most likely diagnosis

  • Proteinuria: This is the most common cause of foamy urine. Proteins in the urine, such as albumin, can create a foamy appearance due to their surface-active properties, which reduce the surface tension of water and create bubbles.

• Other Likely diagnoses

  • Dehydration: Concentrated urine can appear foamy due to the higher concentration of waste products and minerals.
  • Urinary Tract Infection (UTI): While not directly causing foam, UTIs can lead to changes in urine composition that might result in a foamy appearance.
  • Kidney Stones: Though not a direct cause, the discomfort and frequent urination associated with kidney stones might lead to observations of foamy urine, especially if there's an associated infection or concentration of the urine.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • Nephrotic Syndrome: A condition characterized by severe proteinuria, hypoalbuminemia, and edema. It's crucial to identify and treat promptly to prevent long-term kidney damage.
  • Acute Kidney Injury (AKI): Any condition that suddenly causes the kidneys to stop working properly can lead to changes in urine appearance, including foaminess, due to the accumulation of waste products.

• Rare diagnoses

  • Amyloidosis: A group of diseases that result from the abnormal accumulation of amyloid proteins in various tissues, including the kidneys, leading to proteinuria and potentially foamy urine.
  • Multiple Myeloma: A type of blood cancer that can affect the kidneys and lead to proteinuria, among other symptoms.
  • Alport Syndrome: A genetic disorder affecting the type IV collagen in the kidneys, ears, and eyes, leading to kidney disease and potentially proteinuria.