Fluid and Electrolyte Abnormalities Common in Elderly
Fluid balance is normally maintained by thirst perception, the kidneys and hormones comprising of antidiuretic hormone (ADH), atrial natriuretic hormone (ANH), and the renin-angiotensin-aldosterone system.
Age-related changes, diseases (especially those that result in vomiting or diarrhea) and drugs can lead to fluid and electrolyte imbalance. In elderly, this could result in inability to bear stress and increase susceptibility to disease. It could also result in low sodium levels, with subsequent falls, unsteadiness, and cognitive impairment.
Thus, elderly should be explained the importance of maintaining adequate hydration with proper electrolyte balance.
Elderly individuals often do not drink enough water. It could be due to a lesser tendency to be thirsty or they could avoid water so as to keep their urinary incontinence under control. They may also find it difficult to access water due to disease and/or disability. Elderly people with Alzheimer's disease are at a particular risk for developing fluid disturbance.
Elderly people are often treated with multiple medicines. These medications could also affect their fluid balance. These include diuretics that increase urine output, ACE inhibitors, some antipsychotic drugs and antidepressants.
The authors suggest that doctors should be aware of this increased susceptibility in elderly to fluid and electrolyte imbalance. They have also encouraged doctors and hospital pharmacists to monitor the elderly to prevent serious consequences of this imbalance.
Zagaria MA. Drug- and Age-Related Changes in Sodium and Water Regulation. US Pharm. 2011; 36(6):30-33.