Thirst is the desire to drink fluids in response to a water deficit. Social customs, dry mouth, accompanying food intake, fluid availability, and palatability all serve as signals to drink. Palliative care patients are at risk for thirst due to dehydration, electrolyte disturbances, hypotension, xerostomia, and immobility that can impede access to water.

Thirst is the desire to drink, while xerostomia is subjective or objective dry mouth. While xerostomia can contribute to thirst, not all patients with dry mouth experience thirst. Similarly, thirsty patients may not have xerostomia present. In patients reporting thirst, it is necessary to differentiate xerostomia and thirst, and identify potentially reversible causes of either symptom.

Around 80-90% of dying patients report significant thirst. Given its high prevalence, providers should routinely assess for thirst among dying patients who are able to report the symptom.
The use of artificial or medically-assisted hydration to alleviate symptoms of dehydration amongst the terminally ill remains controversial. The concern that dehydration-related symptoms, including thirst, can cause discomfort is weighed against the concern that iatrogenic overhydration can lead to pain and dyspnea from fluid retention. Studies of thirst in this group of patients conclude that there is little relationship between artificial hydration and thirst. Instead, daily oral care and sips of oral fluid administered for comfort can improve thirst and should be routinely offered.

See reference for more information.

Adapted from Zehm A, Mullin J and Do HZ . Palliative Care Network of Wisconsin. Fast facts and concepts #313. Thirst in palliative care. Internet. Accessed on December 19, 2017.