Een jonge vrouw met kristallen in de urine

A nineteen year old female was admitted with fever, headache and lethargy after 5 days after returning from a trip to east Asia. She was diagnosed with bacterial meningitis and treated with high dose amoxicillin (12 gram/day), ceftriaxone and dexamethasone. Thereafter, she developed acute kidney injury with oliguria and hematuria. Urinary evaluation showed a pH of 5.5, and was notable for the presence of crystals. Amoxicillin crystalluria was suspected and amoxicillin was discontinued. The hematuria disappeared in 1-2 days and her kidney function recovered.

Amoxicillin is excreted by the kidneys through tubular secretion and glomerular filtration. Crystallization is favored by a high urinary drug concentration, low urinary flow and low urinary pH. Crystals appear as needles with a ‘broom brush-like’ shape . Amoxicillin crystalluria can lead to asymptomatic crystalluria, macroscopic hematuria and acute injury. After discontinuation, urinary crystals disappear followed by recovery of kidney function. Clinicians should be aware of the potential for acute kidney injury due to this frequently prescribed antibiotic.

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