Chronic, inadequate fluid intake in the elderly is often due to choice. The patient may have trouble with pain, mobility or frequent urination and this can discourage them from getting themselves a drink. Cognitive deficits may affect their ability to recognise thirst, especially in summer. Chronic dehydration leads to many adverse consequences. Postural hypotension, dizziness, nausea and the risk of falling then further discourage the older patient from getting up to prepare a drink. Consequent urinary infections, constipation, and renal failure may result in significant morbidity. Although congestive cardiac failure (notably shortness of breath) may symptomatically improve with dehydration, mortality may increase, especially if the patient has renal impairment or diabetes and is taking diuretics and ACE inhibitors. In hot weather, heat stoke becomes a real danger to the elderly and advice about how to avoid this during summer should be reinforced.
A quick clinical examination for hydration takes less than thirty seconds: look at the tongue, feel the pulse for tachycardia and pulse pressure, and check the jugulovenous pressure (this is especially useful in patients known to have congestive heart failure). If dehydration is likely, check for a postural blood pressure drop. Once you explain these findings and the significance to the patient, they may be more receptive to increasing their fluid intake in spite of perceived inconvenience.