Chronic kidney disease occurs when there is a slowly progressive decline in the kidneys’ ability to filter metabolic waste products from the blood and the major causes are diabetes and high blood pressure. According to statistics from the CDC, it is estimated that 15 % of US adults have chronic kidney disease (CKD). About 96 percent of people with kidney damage or mildly reduced kidney function are not aware of having CKD and 48 percent of those with severely reduced kidney function but not on dialysis are not aware of having CKD.
What is the role of the kidney in our health?
The primary functions of our kidneys include maintenance of homeostasis through control of fluid, pH, and electrolyte balance and blood pressure. Our Kidneys also produce enzymes and hormones, excretion of waste products and by-products of metabolism through urine; including drugs, environmental toxins, uric acid, creatinine, and urea.
How are other body systems affected?
As CKD progresses the kidney function deteriorates, the ability of the kidney to excrete metabolic products of protein, regulate acid-base balance, produce adequate amounts of erythropoietin (a key hormone for the red blood cells production), activate vitamin D, regulate calcium, and phosphorus, potassium, sodium, and fluid excretion diminishes.
What are the symptoms of CKD?
Due to the kidneys’ high adaptability to compensate for lost function; signs and symptoms may not appear until irreversible damage has occurred. Many people with CKD are asymptomatic or have non-specific symptoms.
How is CKD diagnosed?
The diagnosis is made by blood and urine tests. The best available indicator of overall kidney function is the glomerular filtration rate (GFR), which is measured either via exogenous markers (eg, DTPA, iohexol), or estimated using equations. There are 5 stages. When the GFR falls under 15 ml/min, the patient is diagnosed with stage 5 CKD or end-stage renal disease (kidney failure).
What is the medical treatment for CKD?
Therapeutic strategies that might retard the progression of CKD include, but not limited:
I. Avoidance and/or correction of intermittent insults such as the indiscriminate use of non-steroidal anti-inflammatory drugs.
II. Adequate blood pressure control and reduction of proteinuria with diet and angiotensin-converting enzyme inhibitor (ACEI)-based or angiotensin receptor blocker (ARB)-based regimens.
III. Management of acidosis and hyperphosphatemia.
IV. Moderate dietary protein restriction.
V. Control of blood glucose in patients with diabetes mellitus.
VI. Certain types of CKD may benefit from disease-specific therapies.
VII. Identify and treat secondary hyperparathyroidism.
IX. Management of dyslipidemia.
What to do when kidneys stop working?
If the patient develops chronic renal failure (CRF), renal replacement therapy is needed.
I. Hemodialysis (HD): The hemodialysis removes toxic elements from the blood by filtering blood through a membrane while circulated outside of the body. Hemodialysis treatments are typically prescribed three times a week for an average of 4 hours per treatment.
II. Peritoneal dialysis (PD): A catheter is inserted into the abdomen, fills the peritoneal cavity with a dialysis solution that absorbs waste and excess fluids. Waste products are filtered through the lining membrane of the abdominal cavity. After a period of time, the dialysis solution drains from the body carrying the waste materials. There are two main types of PD: continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD). CAPD requires no machine. The usual time is 4–6 hours, followed by the draining of used dialysate and its replacement with fresh solution, requiring an additional 30–40 minutes.
III. Kidney transplantation: Transplanted kidneys can come from deceased or living donors. Patients will require medication for the duration of life to prevent the new kidney from being rejected.
Complications of stage 5 or ESRD include anemia due to reduced production of erythropoietin by the kidney; reduced red blood cell survival and iron deficiency. Erythropoiesis stimulating agents should be considered in all patients with anemia of CRF to improve their quality of life. Mineral bone disease can happen due to changes in vitamin D, calcium, and phosphate metabolism. As the CKD progresses, the mortality risk rises; with increased risk of death due to cancer or cardiovascular diseases.
Lifestyle modification and proper control of diabetes and hypertension are key on the prevention of CKD and may delay late stages kidney disease. Researchers are focusing on identifying genetic markers that may help predict those who may be at risk of developing kidney damage and finding strategies to prevent scarring of the kidney including the use of immunosuppressive therapy.
Look out for next week’s bulletin where we will discuss the general dietetic guidelines for stage 1-5 CKD.
Karen Alexander, MS, RDN, LD/N