Silica stones in humans

Area of Science:

• Nephrology
• Gastroenterology
• Mineralogy

Background:

• Magnesium trisilicate is commonly used as an antacid and anti-ulcer medication.
• Prolonged use may lead to adverse effects, including the formation of urinary calculi.
• Silica stones are rare and their etiology is not fully understood.

Observation:

• This study reviews twenty cases of silica stones, with the first documented case in 1952.
• All patients had a history of prolonged magnesium trisilicate use, some up to 40 years.
• The patients' ages ranged from 20s to 70s, with a mean age of 54 years, predominantly male (9 males, 1 female).

Findings:

• Silica stones were found in the kidneys, ureters, and bladder.
• Most stones (14/20) were passed spontaneously.
• The size and weight of the stones varied, with low radiodensity. Urinary silica levels in one case were 0.006% (1 mmol/l).

Implications:

• The findings suggest a causal relationship between long-term magnesium trisilicate use and silica stone formation.
• Clinicians should be aware of this potential side effect when prescribing magnesium trisilicate.
• Further research is needed to elucidate the exact mechanism of silica stone formation and to establish diagnostic criteria.