Aeromedical certification of aircrew and controllers with renal calculi.

Acute renal colic is an incapacitating condition. Advances in understanding the pathogenesis of calculi and their detection and treatment require a new approach to aeromedical risk assessment. Can this new information support the stratification of aeromedical risk into "High" and "Low" categories, and fulfill the paramount responsibility of the Civil Aviation Safety Authority, Australia's aviation regulator, which isthe maintenance of aviation safety? This article reviews the epidemiology of calculi and finds 2-10% annual risk of a symptomatic event following incidental detection of a calculus. While calculi 4 mm or less in size may not require surgical intervention, this does not equate to a pain-free passage. Similarly, calculus recurrence rates may vary in different anatomical locations, but no location can be considered "safe." The recognition of parenchymal calcification and Randall's plaques as precursors to the development of calculi places such individuals at elevated risk of developing calculi. More recently evidence has supported a link between metabolic syndrome and calculus formation. In an occupational group where there is potential for elevated radiation exposure, appropriate imaging is of particular importance. CT, X-ray, and ultrasound modalities are reviewed with recommendations presented for aeromedical assessment and surveillance based on identification of those at high risk of colic and minimization of investigational radiation exposure.