Green Urine - a Red Herring

A 31-year-old male presented to the emergency department with a 5-day history of low-grade fever, right flank pain, and green discoloration of the urine. The flank pain increased with inspiration and the green-colored urine appeared a day before his presentation. The patient, a foreign immigrant from Thailand who works in agriculture, had no relevant medical history.
On presentation the patient appeared cachectic and distressed. The vital signs were: temperature of 38.2°C, pulse of 95/minute, blood pressure of 115/61 mm Hg, respiratory rate of 22/minute and O2 saturation of 95% on ambient room air. Physical findings included decreased breath sounds over the right lower lung field and tenderness produced by percussion of the right flank. The rest of the examination was unremarkable. Bladder catheterization yielded 400 milliliters of green urine (Figure 1A).

Figure 1. (A) Green discoloration of the urine due to ingestion of a medication containing methylene blue. (B) The same patient’s urine sample 3 days following discontinuation of the medication.

The urine sediment and urinalysis were benign and urinary culture was negative. Peripheral blood work including blood count, serum electrolytes, and kidney and liver function tests was unremarkable. A chest radiograph revealed a loculated right posterior pleural effusion. This finding was confirmed by computed tomography of the chest. Thoracocentesis yielded an exudate with numerous lymphocytes and acid-fast bacilli that later proved to be Mycobacterium tuberculosis. A diagnosis of pleural tuberculosis was made and the patient was started on a regimen of isoniazide, rifampin, ethambutol and pyrazinamide. A thorough history obtained with the help of a Thai translator revealed that the patient was taking an over-the-counter Thai medication used for relief of urinary tract-related pain, containing potassium nitrate and methylene blue (Figure 2). A urine sample obtained 3 days following discontinuation of the drug was visibly normal in appearance (Figure 1B).

Figure 2. The medication label, brought in by the patient after a thorough history taken in his mother tongue.

References

1. Aycock RD, Kass DA. Abnormal urine color. South Med J. 2012;105(1):43-7.
2. Barbara DW, Whalen FX Jr. Propofol induction resulting in green urine discoloration. Anesthesiology. 2012;116(4):924.
3. Samo S, Parikh M, Sheth J, Krishnan S, Ganipisetti V. Treatment of methemoglobinemia resulting in green urine. QJM. 2014 Apr 27.  [Epub ahead of print]
4. Gillett MJ, Burnett JR. Medications and green urine. Intern Med J. 2006;36(1):64-6.

Authors:

Or Kalchiem-Dekel, MD¹

Leraz Tobias, MD¹

Gil Ben Yakov, MD¹

Nimrod Maimon, MD^1,2

¹ Department of Medicine B, Soroka University Medical Center; Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.

² Pulmonologic Institute, Soroka University Medical Center, Beer-Sheva, Israel.

Corresponding author:
Or Kalchiem-Dekel, Department of Medicine B, Soroka University Medical Center, PO Box 151, Beer-Sheva 84101, Israel. Tel.: +972-8-640-0622. Fax: +972-8-640-3534. Email: kalchiem@bgu.ac.il

Short author bio:

Or Kalchiem-Dekel, Attending physician, Department of Medicine B, Soroka University Medical Center, Beer-Sheva, Israel.

Leraz Tobias, Medical intern, Department of Medicine B, Soroka University Medical Center, Beer-Sheva, Israel.

Gil Ben Yakov, Attending physician, Department of Medicine B, Soroka University Medical Center, Beer-Sheva, Israel.

Nimrod Maimon, Head, Department of Medicine B; Senior pulmonologist, Pulmonologic Institute, Soroka University Medical Center, Beer-Sheva, Israel.