Age related illnesses, General | September 8, 2015 | Author: The Super Pharmacist
Chronic Kidney Disease (CKD), or chronic renal failure, describes a wide range of abnormal kidney functions and/or structural issues. The clinical definition of CKD is based on the presence of kidney damage or decreased function (i.e. a glomerular filtration rate less than 60mL/minute per 1.73m² for three months or more. The most severe symptoms of CKD can only be treated with transplantation or dialysis, with kidney failure defined as a glomerular filtration rate of less than 15mL/minute per 1.73m² or the need for treatment for dialysis or transplantation. CKD is common, and can often go undiagnosed alongside other co-morbidities such as diabetes or cardiovascular disease. The risk for developing CKD increases significantly with age. CKD is often asymptomatic and is not formally diagnosed until its later stages. Specific symptoms are typically associated with severe CKD only and include nausea, vomiting, fatigue, weakness, insomnia, muscle cramps, nocturia, and headaches.
More than 50% of all patients with CKD also have high blood pressure (hypertension) and it increases the chance that CKD will get markedly worse. Keeping blood pressure under control is an essential component of most CKD treatment plans, with the most commonly prescribed solution a combination of a healthy diet, regular exercise, and an appropriate pharmaceutical treatment regimen. In patients with proteinuria (the presence of abnormal quantities of protein in the urine), a number of trials have shown ACE (angiotensin converting enzyme) inhibitors and ARBs (angiotensin receptor blockers) to be particularly beneficial in protecting and maintaining long term kidney function (2). There are a limited number of meta-analyses and systematic reviews that have compared the efficacy and safety of pharmacological agents to lower blood pressure. A 2015 study, published by a global network of public health academics, uncovered a number of different findings after reviewing 157 studies that covered nearly 45,000 participants. The study found that no combination of ARB and ACEs was better than placebo in regards to reducing all-cause mortality. However, ARB-ACE combination therapy and ARB monotherapy treatment were evidenced to significantly reduce the likelihood of end-stage renal disease compared to placebo. Although successful in helping to avoid or delay the onset of end-stage renal disease, the Lancet study also noted that any benefits of combination therapy need to be balanced against the potential harms of acute kidney injury or hyperkalaemia (3). The body removes unwanted fluid by filtering blood through the kidney to draw out any excess water. An optimal balance of sodium and potassium helps this process to run smoothly, but a high salt diet can alter the sodium balance and reduce the efficacy of the kidney and cause it to have a significantly reduced function. There is a growing body of evidence to suggest that patients with CKD and a high salt intake can cause further deterioration and hasten the onset of more complicated stages of the disease. Although there is a lack of consensus regarding the benefits of reducing salt intake in CKD, a systematic review carried out by The Cochrane Collaboration in 2014 found that salt reduction in people with CKD did significantly reduce blood pressure and proteinuria. However, a lack of studies on the longer term effects of salt restriction means that the direct effects of sodium restriction on mortality and progression to end stage renal failure remain unknown (4). Patients with CKD have specific hydration requirements as a result of the kidney’s diminished function for being able to get rid of excessive water in the body. Clinically this is referred to as fluid overload and it can cause high blood pressure and contribute to the development of heart disease (5). Regulating fluid intake is essential, as untreated excessive fluid can settle in the lungs and cause pulmonary oedema. Daily fluid recommendations vary by patient, although as a general rule the more urine a patient is able to produce, the more they are permitted to drink. The presence of kidney stones is often a risk factor for chronic kidney disease in patients who have rare hereditary disorders such as cystinuria (an autosomal recessive disease) and primary hyperoxaluria (the increased build up of oxalate, which is the main component of kidney stones). A recent study conducted in Minnesota concluded that patients with kidney stones were at an increased risk of CKD, but there was no increased risk of end-stage renal disease or death with CKD in the same patient group (6). Any abnormality in the structure of the kidney, or medical complications such as kidney stones, can significantly increase the risk of cystitis due to an incomplete emptying of the urinary system. Reflux nephropathy, a condition in which urine passes backwards up to the kidney when the bladder contracts rather than being passed outside, can also cause ongoing problems with cystitis. It is an illness commonly associated with kidney disease, which a much higher prevalence rate in patients with CKD than the general population. Reflux neuropathy is often associated with kidney damage and scarring. Patients with CKD are often primarily advised to modify lifestyle factors that have contributed to their condition such as stopping smoking, eating a balanced diet, doing regular exercise and restricting salt intake. Pharmaceutically, patients are also advised not to use nonsteroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen as they have been associated with the development of acute kidney injury or sudden kidney failure in patients with CKD. If acute injury does occurs then NSAIDs should be stopped, and they should always be avoided in patients who have recently developed or have a history of interstitial nephritis (7). Groups who are particularly at risk of NSAID induced acute kidney injury include individuals with chronic hypertension, atherosclerosis, pre-existing glomerular disease or renal insufficiency. The use of ACE inhibitors and ARBs can also prevent efferent arteriole vasoconstriction which is important in the maintenance of glomerular filtration rate, causing a significant drop in kidney function (8).