KIDNEY PROBLEMS IN ELDERLY
- Why are kidney problems increasingly seen in the elderly?
Kidney problems are more frequently recognized in elderly with increasing life expectancy and awareness. The incidence of Diabetes Mellitus (DM), Hypertension and diseases affecting heart and blood vessels increases with age.
- Do kidneys undergo aging changes?
Yes, kidneys undergo structural and functional changes as age advances.
- What are the structural changes in an aging kidney?
Aging kidneys become smaller in size with progressive narrowing of major blood vessels and capillaries supplying the filters and deposition of fibrous materials between the nephrons. Kidneys may develop cysts (swellings containing watery fluid) which may not be of any consequence unless they bleed or get infected.
- What are the functional implications of these structural changes?
These structural changes result in gradual decline in kidney function (1% decline for every year of life after 40 years). The capacity of the kidneys to maintain filtration function in the setting of reduced blood flow is deranged with aging; so also the ability to conserve water and electrolytes during deficiency and to excrete during overload is impaired.
- What is the impact of these functional changes on day to day life?
These functional changes are subtle and not detected by routine biochemical tests (including serum creatinine, a marker for filtration function); they do not interfere with the maintenance of the body’s internal environment for daily function. However it reduces the renal reserve and makes them more vulnerable to kidney disease when exposed to a challenge.
- Is it possible to calculate kidney function in these individuals?
Yes, it is possible using certain mathematical formulae; these formulae should be used to know the level of kidney function to prescribe drugs (that are excreted by the kidneys) in appropriate doses.
- What is the impact of these functional changes when exposed to a clinically challenging situation?
The elderly population is more vulnerable to a) acute kidney injury in the setting of dehydration and volume loss (due to vomiting, loose stools, bleeding), postoperative period, heart failure, infection and use of intravenous contrast (substance used to enhance the contrast of structures and fluids within the body during radiography) and certain drugs, b) progression of chronic kidney disease to irreversible damage and c) electrolyte disturbances like hyponatremia (reduction in serum sodium concentration resulting from water in excess of sodium in the blood), hypernatremia (increase in serum sodium concentration resulting from sodium in excess of water in the blood), hypokalemia (decrease in serum potassium concentration), hyperkalemia (increase in serum potassium concentration) and metabolic acidosis (accumulation of acid in blood) in the setting of the above mentioned insults.
- What are the kidney ailments that occur in the aged?
Narrowing of major kidney blood vessels, hypertension and DM related kidney diseases, diseases affecting the filters (membranous nephropathy, vasculitis), diseases related to abnormal immunoglobulin (proteins involved in body defense) production and cholesterol embolism (see below) are some of the kidney ailments that affect the kidneys more commonly in the elderly.
- Why should we be careful in prescribing medicines in elderly?
As mentioned above, there is reduced kidney function reserve and impaired capacity to handle water, electrolytes and acid load in the elderly. Medications which are metabolized and excreted by the kidneys are not eliminated properly in such patients; they predispose them to side effects of the drugs, some of which may further impair kidney function and cause electrolyte disturbances. Prescription of such drugs, if absolutely required, will require dose modification for kidney function (as calculated by formula) and monitoring for kidney function and electrolyte values apart from the drug side effects.
- What is cholesterol embolism?
It is a small vessel disease resulting from detachment of cholesterol fragments from the blood vessel walls. The fragments travel to the smaller blood vessels within the kidneys and elsewhere and result in occlusion of the circulation. It can happen following angiogram (a diagnostic procedure in which contrast material is injected into blood vessels to study their abnormalities) and angioplasty (a treatment procedure in which an attempt is made to correct the narrowing of the blood vessels). Occasionally it occurs spontaneously in elderly.
- What problems can happen in elderly in the urinary tract?
Older people can develop urinary frequency, difficulty in starting urination, urgent desire to pass urine, sensation of incomplete emptying and inability to hold urine. These symptoms are related to lower urinary tract (Lower Urinary Tract Symptoms) and are most often due to mechanical obstruction and neurological diseases.
- What are the causes of urinary tract obstruction in the elderly?
Urinary obstruction is most commonly due to enlargement of prostate gland (a gland in the male reproductive system) in males and narrowing of urethra in females. It can also be the result of cancer in the female genital tract and cancer in the lower urinary tract and lower intestinal tract inboth sexes.
- How and why should LUTS be treated?
Patients with above symptoms need evaluation using ultrasound abdomen, uroflowmetry (assessment of urinary flow using a machine) and other tests before further (surgical or medical) intervention. If left untreated, urinary obstruction can result in urinary bladder infection and infection of the kidneys (pyelonephritis) and kidney failure
- Is the management of renal disease different in elderly?
The management of renal disease in elderly is no different. However they are more vulnerable to infections with immunosuppression when used for management of glomerular disease. They are more likely to have incomplete recovery from acute kidney injury. Elderly patients having irreversible advanced kidney disease are generally not considered for renal transplantation as they are more likely to have coexisting blood vessel problems in the heart and brain that can have a significant impact on the survival.
- Will elderly tolerate dialysis?
It is a misconception that old people will not tolerate dialysis; in fact, in a patient with advanced kidney disease, dialysis will improve quality and quantity of life. However getting a permanent vascular access for maintenance hemodialysis can be problematic because of diseased blood vessels and poor skin quality. For peritoneal dialysis, they may require help from others. Social and economic factors play a major role in decision making regarding maintenance dialysis in the elderly.
- How do we prevent kidney disease in the elderly?
Prompt replacement of fluid loss during dehydration, appropriate therapy of infections, control of blood pressure and blood sugar, avoidance of unnecessary and nephrotoxic medications and attention to symptoms of urinary obstruction apart from cessation of smoking and healthy life style are some of the measures to prevent kidney problems in the elderly.