PMC6308841_01
Pink urine sediment after centrifugation in a patient who received propofol.
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Urine sediment evaluation revealed a bright pink (Figure 1) pellet upon gross inspection, and light microscopy showed many amorphous crystals (Figure 2).
Amorphous crystals. Urine sediment examination demonstrating amorphous crystals. The left is x40 light microscopy and the right is the same image but polarized.
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Urine sediment evaluation revealed a bright pink (Figure 1) pellet upon gross inspection, and light microscopy showed many amorphous crystals (Figure 2).
The effect of pH on uric acid crystallization. One drop of 1 N HCl solution (1 normal = 36.5 g hydrochloric acid/1 liter) was mixed with 2 ml of patient's urine resulting in a reduction of pH, pinkish hue (a, left test tube) on gross inspection, and polychromatic birefringence uric acid crystallization with light microscopy (b). In a similar fashion, 1 drop of 1 N NaOH solution (1 N = 40 g sodium hydroxide/1 liter) was mixed with 2 ml of urine to serve as a negative-treatment response control. On NaOH addition, urine color became a dirty yellow (a, right test tube), urine pH increased, and amorphous crystals were present when analyzed with light microscopy (c).
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To identify the crystal type, the patient's urine was acidified and alkalized and reassessed under light microscopy (Figure 3a). On acidification, polychromatic birefringence rhomboid uric acid crystallization became prominent (Figure 3b), whereas when we alkalinized the urine, amorphous urate crystals were present (Figure 3c).