A Review of Renal Diseases

Transcription

1 A Review of Renal Diseases NDFS 356 Amber McArthur April 3,

2 INTRODUCITON Tom Harkin stated, America s health care system is in crisis precisely because we systematically neglect wellness and prevention. The main causes of death in the US include heart disease diabetes, nephritis, nephrotic syndrome, and nephrosis. Diabetes and hypertension are major contributors of kidney disease. 1 in 3 American adults are currently at risk for developing kidney disease and 1 in 9 currently have kidney disease (1). Consequently, an increased poor management of health will result in an increase of renal failure. Because of the high occurrence of this disease and the long term need for treatment and counseling during each stage, it is pertinent to have a general knowledge of the disease as a registered dietitian. This paper will discuss the general description of the disease, the etiology, pathophysiology, medical diagnosis, therapies, tool for nutritional assessment, medical nutritional therapy, and long term prognosis of kidney disease. DISEASE DESCRPITON The kidneys are responsible for multiple tasks and in short, when those processes are no long able to be performed by the kidneys it is called renal failure. It is a progressive disease with multiple stages and is determined by a decrease in GFR. Chronic kidney disease is a worldwide public health problem (2). As stated before there are many people that currently have kidney disease and there are even more at risk of getting it (1). A study analyzing the prevalence of CKD had results stating that 11% of the US population was at some state of the disease; that is 19.2 million individuals (3). This is a very ubiquitous disease that is only getting more common as diseases such as diabetes and hypertension increase. 1

3 ETIOLOGY AND RISK FACTORS The leading causes of kidney failure is chronic diabetes mellitus (4). Diabetes is followed behind by chronic hypertension. Secondary causes included but are not limited to kidney stones, glomerulonephritis, nephrotic and nephritic syndrome, and exposure to drugs and toxins (5). All of these dysfunctions cause some kind of stress or damage to the kidney, decreasing its ability to perform to its maximal capacity. For example, nephritic syndrome is a disease that causes inflammation of the capillary loops of the glomerulus. The inflammation damages the barrier to blood cells and causes blood to be excreted in the urine. Nephrotic syndrome hypoalbuminemia, edema, hypercholesterolemia, hypercoagulability, and abnormal bone metabolism because of a large loss of protein in the urine (4). Complications such as these can lead to the stages of chronic kidney disease. PATHOPHYSIOLOGY Some of the normal physiological responsibilities of the kidney include: water balance, fluid osmolarity maintenance, ion concentration regulation, plasma volume maintenance, acid base balance, excretion of waste products, and production of erythropoietin, rennin, and converting vitamin D to its active form (6). When there is stress on the kidney and function is decreased, these processes to do not function as well as they originally would. But their loss of function takes time. Chronic renal failure happens over a period of years and because of the kidney s adaptive capabilities, the problem might not be noticed until less than 25% kidney function is achieved (7). There are five states of CKD each progressing to a decrease renal function. In stage one the renal function slowly diminishes to an egfr of less than 90ml/min with little to now clinical symptoms and an 2

4 elevated blood BUN and creatinine levels. Stage two is called renal insufficiency and the egfr is from 89-60ml/min and clinical symptoms may start to appear. During this stage nephrons will start to compensate for the deficiency causing death of nephrons. Stage three is classified as renal failure with an egfr of 59-30ml/min and symptoms are more established. Stage four is a more severe form of stage three with an egfr ranging from 15-29ml/min. The last stage, end-stage kidney disease, has little to no GFR with it being less than 15ml/min. This will lead to uremia, elevated urea and creatinine in the blood, causing fatigue, vomiting, anorexia, nausea, and neurological problems (4). Stage five also contributes to bone and mineral disorders because of a decreased phosphorus excretion leading to bone breakdown and vascular calcification. Other major complications that occur at this stage are sodium and water imbalance, phosphate and calcium imbalance, and potassium and acid base imbalance (5). Stage five results in death unless transplantation or dialysis is administered (4). Chart 1.0 is a great visual of the progression of kidney disease. This disease does not progress quickly overnight but it takes time and poor management to evolve to the end-stage symptoms. But because there are treatments to help slow progression and sustain life of individuals with CKD it is important to know how to diagnosis a patient. 3

5 DIAGNOSIS As mentioned before kidney failure does not have many signs and symptoms until it has progressed further along to the more end-stage. Thus, lab values are important in diagnosing patients with kidney disease. Some important labs include: sodium, potassium, calcium, BUN, creatinine, protein, albumin, and hct. Because of the high prevalence of renal failure it is important that individuals that have primary and secondary risk factors regularly have blood work drawn to assure proper kidney function (4). MEDICAL THERAPIES There are multiple treatment options for patients and physicians to choose from when deciding what kind of medical therapy is best. There is not an overall best treatment for renal failure because each individual is a new, different and unique case. Medical therapies available for kidney disease patients include drugs, hemodialysis, peritoneal dialysis, transplants, and alternative therapy. Drugs The decreased function of the kidneys causes an imbalance of many vitamins and minerals in the body. Drugs are prescribed to help fix these abnormalities. Phosphate binders are needed for some patients who have low control which could lead to poor bone health (8). With therapies like dialysis, a lot of vitamins can be lost via diffusion. It is important to supplement those water soluble vitamins that will be low. Iron can be administered orally or through IV. Iron is important to maintain bone health and avoid anima. As stated before the kidney is no longer able to activate vitamin D and thus a oral or IV supplement should be taken by those that are at risk for bone disease. 4

6 Biphosphates inhibit bone resorption by blocking osteoclast activity. This can be taken by IV or orally. Potassium is linked to the function of the heart. Hyperkalemia can cause arrhythmia and to fix this imbalance cation exchange resin can per prescribed (4). Keeping blood levels normal will make dialysis and transplant treatments more effective because of better compliance. Hemodialysis Hemodialysis is a blood filtration treatment that uses needles, a fistula, purified water, a dialyzer, and a dialysate to remove waste products and electrolytes from the blood. To prepare a patient for hemodialysis an artery and vein must be surgically connected to make a fistula (4). The fistula will be the permanent access site for the large needles that will connect a patient to the dialysis machine. If the blood vessels of an individual are too weak or fragile a graft can be implanted, creating an artificial vessel. In order to do hemodialysis there must be an availability of purified water. In clinics there is a purification room that softens hard water, takes out any minerals in the water to create simple pure H2O. The purified water is then mixed into different baths according to the patients needs (8). The purified water mineral baths that have similar electrolyte contet of normal plasma, is called dialysate and is filtered through a dialyzer moving waste products (4). The waste moves from the blood into the filter, dialyzer, and out of the filter to be discarded. The waste and electrolytes move by diffusion, ultrafiltration, and osmosis. Diffusion is the passage of particles through a semipermeable membrane. Osmosis is the movement of fluid across a semipermeable membrane. Diffusion and osmosis can occur at the same time. Filtration is the passage of fluids through a membrane. Ultrafiltration provides additional pressure to squeeze extra fluid through the 5

7 membrane (4). All of these processes help do what the kidney cannot do by itself. There are three main types of hemodialysis. Outpatient treatment is 3-5 hours long 3 times a week. Home dialysis is hours 5-6 times a week. Nocturnal dialysis is 8 hours while sleeping 3-6 times a week. Newer therapies can shorten duration of treatment by increasing frequency. This type of therapy has lower mortality rates similar to that of a transplant (4). All these options allow a patient to choose what works best for them. Peritoneal Dialysis Peritoneal dialysis is a form of dialysis that uses the body s semi permeable membrane, the peritoneum, to diffuse waste products (4). In this treatment a catheter is implanted in the abdomen and into the peritoneal cavity. A high dextrose concentration solution called dialysate is instilled into the peritoneum. Diffusion carries waste products from the blood through the semi permeable walls of the peritoneum into the peritoneal cavity into the dialysate. Water also moves through osmosis in this process. When the exchange is completed, the fluid is removed by gravity or machine and a new solution is added (4). The two main types of peritoneal dialysis are continuous ambulatory peritoneal dialysis (CAPD) and continuous cyclic peritoneal dialysis (CCPD). In CAPD the dialysate is placed in the peritoneum and then exchanged manually by gravity 4 to 5 times daily making it a 24 hour treatment. CCPD on the other hand uses one Dialysate for the day and the main treatment id done at night by a machine that does the exchange (4). A Cochrane review examines the 6

8 difference between CAPD vs. APD. APD was seen beneficial over CAPD because of a reduced incidence of peritonitis and mechanical complications. Results also showed that APD is more beneficial in younger PD populations due to the psychological advantages (9). Out of the two dialysis treatments PD is a better treatment because of the increased residual renal function, lower fluctuation in blood chemistry, and ability to live a more normal lifestyle. The three main complications associated with PD are peritonitis, hypotension, and weight gain because of the dextrose absorption from the dialysate (4). But the extended renal function outweighs the other risk factors for most. Transplants Kidney transplants are the most common solid organ transplants as seen in Table 1. Most transplant surgeries include the process of the surgeon placing the new kidney inside the lower abdomen and connecting it with a vein and artery through which blood can flow and urine can be created (10). Renal transplant is the preferred method of treatment for many end-stage renal disease patients. However, insufficient organ donation accounts for the discrepancy between the number of recipients and candidates(11). There are two types of donors: deceased and living. Patient survival rates are increased with a living donor kidney transplant (12). Though transplants are highly successful, it is important that proper care is given during the three phases of the organ transplant. Pretrasnplant treatment is evaluation of candidates. The most important issue with receiving a transplant is proper weight. A 7

9 healthy weight must be attained before transplant. Acute posttransplant treatment is immunosuppressive therapy. The goal in this stage is to provide adequate calories and protein for would healing, to prevent acute and chronic rejection, and minimize toxicity of the agents and rates of infection while achieving high patient and graft survival. Induction therapy is short term and provides antilymphocyte antibody medication. Anti rejection therapy is long term to prevent rejection of the transplant. Chronic posttransplant therapy starts 6 weeks post surgery. It includes monitoring of obesity, dyslipidemia, hyperglycemia, and osteoporosis. The new nutritional goals are similar to that of a healthy individual (11). Alternative therapy There are only a few complimentary therapies known for kidney disease. One alternative therapy is flaxseed oil. Researchers observed a decrease in c-reactive protein levels in chronic hemodialysis patients. However there was a possible correlation between their BMI and lipoprotein cholesterol levels (13). There is also experimentation with herbs and spices as complementary therapy in kidney disease but much more research must be performed before any claims of success can be made. As for know, it is important that renal failure patients to not consume herbs and spices that are known for worsening kidney state. TOOLS FOR NUTRITIONAL ASSESSMENT Nutritional assessment for individuals with kidney disease would start with medical and dietary history, anthropometric data and labs (11). From this information a further assessment for proper nutritional therapy can be attained by some kind of clinician. 8

10 MEDICAL NUTRITIONAL THERAPY The main nutrients of concern for dialysis are protein, calories, sodium, potassium, iron, phosphorus, and calcium. Depending on what the lab values are for the patient they will be recommended to restrict their diet of a certain nutrient or they will be recommended to have some kind of supplement. For example, PD patients are losing a lot protein in the peritoneum. This means that they must increase their protein intake to g/kg/day. It is also recommended that dialysis patients eat high biological protein such as animal sources. Calorie recommendations range between kcal/kg with lower amounts for late stage transplant and pd patients and high amounts for nutritionally depleted patients. For some treatments there will be a fluid, sodium, potassium, phosphorus, iron, and calcium restriction or supplementation but it depends greatly upon the patient s blood values. LONG TERM PROGNOSIS Kidney disease often leads to death either by renal failure alone or because of other medical complications compliance to medical and nutritional therapy will help increase the quality and quantity of life for individuals with this disease. Poor compliance to the therapies will increase the rate of renal failure leading to death. SUMMARY In summary, renal failure is the progressive loss of kidney functions. The main risk factors for loss of renal function are diabetes and hypertension. If these and other risk factors were taken care of in their early stages renal failure would not be developed. The main treatments for it include peritoneal and hemodialysis and transplants with medications. However, the best treatment for this disease is prevention. Good health is 9

11 the best guard against developing any health problem and dieticians are available to help in that area. Deepak Hiwale was quoted saying, preventing disease rather than curing them makes more sense Doctors of the future will be clinicians, dieticians and personal trainers rolled into one. If only people would understand that a healthy life was the answer to their health problems. 10

12 REFERENCES 1. National Kidney Foundation. Kidney disease facts. Available at Accessed March 30, UpToDate. Epidemiology of chronic kidney disease. Available at Accessed March 30, Coresh J, Astor BC, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third national health and nutrition examination survey. Am. J. Kidney Dis. 2003;41(1): Wilkens K. Medical nutrition therapy for renal disease. In: Mahan LK, Escott- Stump S, ed. Krause s Food, Nutrition, & Diet Theraphy. 13 th ed. Philadelphia: Elsevier; 2012: McCance KL, Huether SE. Pathophysiology the Biologic Basis for Disease in Adults and Children. 5 th ed. Mosby Elsevier Sherwood L. Human physiology from cells to systems. 6 th ed. Belmont, CA: Thomson Brooks; DaVita. Stages of chronic kidney disease. Available at Accessed March 30, Thompson C. Personal communication. DaVita Utah Valley Dialysis Clinic, Provo, UT, March 27, Rabindranth KS, Adams J, Ali T, Macleod AM, Vale L, Cody JD, Wallace SA, Daly C. Continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis for end-stage renal disease. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD DOI: / CD National Kidney Center. Chronic kidney disease. Available at Accessed March 30, Byham-Gray L, Stover J, Wiesen K. A clinical guide to nutrition care in kidney disease. 2 nd ed. Academy of Nutrition and Dietetics Ochsner. Kidney transplant statistics. Available at Accessed March 30,

13 13. Lemos J, Gascue de Alencastro M, Konrath AV, Cargnin M, Manfro RC. Flaxseed oil supplementation decreases C-reactive protein levels in chronic hemodialysis patients. J. Nutres. 2012;32: