[Dehydration in older persons-Current state of knowledge, trends and challenges]

Due to comorbidities, medication, lower fat-free mass and the often diminished sense of thirst in old age, older adults are at particularly high risk of developing dehydration. Therefore, dehydration is among the most common diagnoses in older patients. Despite its high prevalence, there are no uniform diagnostic criteria and the diagnosis often remains uncertain. All individual diagnostic criteria have insufficient sensitivity and specificity, so that the diagnosis can only be made by holistic consideration of all symptoms and sometimes only after successful trial treatment. The symptoms of dehydration are frequently nonspecific but its consequences can be severe. In addition to the immediate symptoms, dehydration promotes a variety of other illnesses. Acute treatment is relatively simple, while behavioral approaches for chronic dehydration are less known and barely evaluated.