Where are the lemons?

Unusual Urine 001

Observe these images of a urine catheter bag belonging to a patient with a cerebral abscess.

urine with an unusual appearance 1

Unusual urine (image 1)

Urine with an unusual appearance

Unusual urine (image 2)


What is unusual about the appearance of the urine?

The urine is orange!

What are the possible causes?

The causes of orange urine include:

  • Medications:
    Idarubicin — an anthracycline used for hematological malignancies
    Ferrioxamine — an iron chelator that classically causes ‘vin rose’ urine – tends to be orange to reddish-brown
    Oxamniquine — antischistosomal quinoline selective for S. mansoni
    Phenazopyridine — an azo dye used for analgesia in urinary tract infections – it can cause false-positive urine dipstick results for bilirubin and urobilinogen – can have nasty side-effects
    Rifampicin — see below
    Sulfasalazine — 5-aminosalicylate with a local effect on the bowel wall used in inflammatory bowel disease
    Warfarin — urine may be pink or orange
  • Foods, supplements, and vitamins:
    Carotenes — e.g. vitamin A, orange juice, pumpkin, and carrots
    B-complex vitamins
    Food dyes — what goes in must come out…
    Beets and blackberries — urine tends to be red-coloured
  • Disorders that cause hypercarotenemia:
    diabetes mellitus
    dietary excess of carotenoids


  • Urine may also appear ‘orange-ish’ as a result of dehydration or jaundice (hyperbilirubinemia).
  • Hypercarotenemia is associated with yellowish skin without scleral icterus (in contrast to jaundice). It can also cause orange discolouration of cerebrospinal fluid (CSF).


This patient had a cerebral abscess and was being being treated with rifampicin. The orange colour is benign. Other body secretions such as sweat and tears – as well as CSF – may also be discoloured.

Rifampicin is an RNA polymerase inhibitor that is active against most Mycobacteria, most Gram-positive bacteria and some Gram-negative bacteria, eg N. meningitidis, H. influenzae. It is generally reserved for MRSA, mycobacterial infections and prophylaxis of meningitis and epiglottitis. Resistance to rifampicin can occur rapidly if it is used as the sole agent for antibotic therapy.

Adverse effects of rifampicin include gastrointestinal disturbance and elevated liver enzymes. Rarely it may result in Clostridium difficile-associated disease, allergy or hepatitis.

Rifampicin decreases the concentration and reduces the activity of many other drugs. This occurs because rifampicin induces hepatic and intestinal CYP enzymes as well as transporter proteins (e.g. P-glycoprotein). Induction of enzymes and transporter proteins is maximal at about 1 week of therapy and lasts for about 2 weeks after discontinuation.


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