Renal and genitourinary concerns

Abstract

Genitourinary (GU) disorders are pervasive in the adult population and broadly include the diagnoses of 15-20% of patients who are discharged from hospitals in the United States, with even higher percentages for ambulatory visits. Along with susceptibility to the common disorders of the general population, the GU system of astronauts is additionally vulnerable to spaceflight-related stresses, both in flight and immediately pre- and postflight. These stresses may include rigorous exercise, microgravity, dietary changes, limited availability of drinking water, thermal stress, and the effects of other spaceflight-related disorders, such as space motion sickness, as well as the influence of medications used to treat them. Some of these conditions may increase the risk of genitourinary disorders or complicate their presentation. Exposure to microgravity causes a number of metabolic and physiological changes that can affect the GU organs. Fluid volume, electrolyte levels, and bone and muscle undergo changes as the human body adapts to weightlessness. Changes in urinary chemical composition occurring as a part of this adaptation process may lead to the potentially serious consequence of renal stone formation. With the length of human exposure to microgravity extending as we maintain a permanent presence on the International Space Station (ISS), the probability of GU-related illnesses, such as renal stones or infections, will undoubtedly increase. Exploration-class lunar missions for long duration settlement and missions to Mars will pose even greater challenges for the diagnosis and management of GU conditions, as immediate return to Earth will not be possible. This chapter reviews the influence of space flight on GU function, the disorders that might arise involving this system, and possible treatment methods and countermeasures.