Differential Diagnosis for Purple Urine
- Single most likely diagnosis
- Porphyria: This is a group of disorders that can cause purple urine due to the accumulation of porphyrins, which are pigments that can give urine a purple or reddish color. The most common type of porphyria that causes purple urine is porphyria cutanea tarda.
- Other Likely diagnoses
- Medication side effects (e.g., metronidazole, Flagyl): Certain medications can cause urine to turn purple or reddish due to their chemical properties.
- Beetroot or blackberry consumption: Eating large amounts of beetroot or blackberries can temporarily cause urine to turn purple or reddish due to the pigments in these foods.
- Dehydration: Concentrated urine can sometimes appear darker or more purple than usual.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Rhabdomyolysis: This is a serious condition where muscle tissue breaks down, releasing myoglobin into the bloodstream, which can cause urine to turn dark or purple. If left untreated, rhabdomyolysis can lead to kidney failure.
- Hemorrhagic cystitis: This is a condition where there is bleeding in the bladder, which can cause urine to turn purple or reddish. In some cases, hemorrhagic cystitis can be a sign of a more serious underlying condition, such as cancer.
- Rare diagnoses
- Alkaptonuria: This is a rare genetic disorder that affects the breakdown of certain amino acids, leading to the accumulation of homogentisic acid, which can cause urine to turn dark or purple.
- Melanuria: This is a rare condition where melanin, the pigment responsible for skin color, is present in the urine, giving it a dark or purple color. Melanuria can be a sign of a serious underlying condition, such as melanoma.