Differential Diagnosis for Dark Colored Urine

• Single most likely diagnosis
  • Dehydration: This is the most common cause of dark-colored urine, as the concentration of the urine increases when the body has low fluid levels, resulting in a darker appearance.
• Other Likely diagnoses
  • Liver disease (e.g., hepatitis, cirrhosis): Liver conditions can cause changes in urine color due to the buildup of bilirubin, a byproduct of the liver's processing of old red blood cells.
  • Kidney disease or kidney stones: These conditions can cause a decrease in urine output, leading to more concentrated and darker urine.
  • Urinary tract infection (UTI): Certain UTIs, especially those caused by specific bacteria, can produce dark or cloudy urine.
  • Medications (e.g., certain antibiotics, laxatives): Some medications can alter urine color as a side effect.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Rhabdomyolysis: A serious condition where muscle tissue breaks down, releasing myoglobin into the bloodstream, which can cause dark-colored urine and lead to kidney failure if not promptly treated.
  • Hemolytic anemia: A condition where red blood cells are destroyed faster than they can be made, potentially leading to the release of bilirubin and causing dark urine.
• Rare diagnoses
  • Alkaptonuria: A rare genetic disorder that affects the breakdown of certain amino acids, leading to the accumulation of homogentisic acid, which can cause dark-colored urine.
  • Melanuria: A condition where melanin is present in the urine, giving it a dark color, often associated with melanoma or other conditions affecting melanin production.
  • Porphyria: A group of rare genetic disorders that can cause a buildup of porphyrins, leading to dark-colored urine among other symptoms.