Pathophysiology

Pathophysiology Study Guide

©2018 of 131 is characterized by a moderate fall in GFR, which now ranges between 30- 59. The level of GFR severely decreases to 15- 29 in the fourth stage. The last stage is termed as kidney failure in which the GFR goes below 15. Electrolyte Imbalances In chronic renal failure, when the compensatory responses fail to maintain glomerular filtration rates above 10ml/min, it causes significant imbalances in fluid and electrolytes in the body. The urine osmolality gets isostenuric and causes the symptoms of nocturia and polyuria. The overload of water leads to hyponatremia, while the deficit causes hypernatremia. However, hypoatremia is more likely to occur in chronic renal failure. This disorder is further characterized by the increase in electrolytes, such as potassium, phosphate, and magnesium, while the other electrolytes, like sodium and calcium, fall significantly. The occurrence of anion gap metabolic acidosis is also very likely. The body also suffers from the accumulation of urea, cretanine, uric acid, phosphorous, sulfate, lipids, cholesterol, amino/organic acids, and neutral fats. The albumin level decreases. Physiological Changes Signs and symptoms include nausea, vomiting, loss of appetite, fatigue, weakness, sleep apnea, abnormal output of urine, muscle twitching, cramping, disturbed mental state, hiccups, swelling of the feet and ankles, persistent itching, shortness of breath, uncontrolled hypertension, and chest pain. Patients that are within the first and third stages of chronic renal failure do not normally show any symptoms. It is only in the fourth and fifth stage that the derangements of endocrine or metabolism manifest imbalances of fluid and electrolytes. Metabolic acidosis is the last stage of chronic renal failure and includes protein-energy malnutrition, weakness in muscles, and loss of lean body mass. In stage five, when the salt and water imbalances occur, the physiological changes are peripheral edema, hypertension, and pulmonary edema. The person becomes anemic and shows symptoms of fatigue, reduction in the capacity to exercise, impaired cognitive and immune function of the body, cardiovascular diseases, cardiovascular mortality, and heart failure. Dialysis Kidney dialysis is one of the treatments for end stages chronic renal failure. It is a life-support treatment through which a special machine is used to filter the accumulation of harmful wastes, electrolytes, and excess fluid from the blood. In other words, when the kidney is not able to perform normal function, dialysis acts as a substitute for the filtration function of kidneys. Dialysis is of two types: hemodialysis and peritoneal dialysis. Hemodialysis is the more common form of dialysis and uses an artificial kidney termed as hemodialyzer to clean the excess fluids and waste substances from the blood. It is done through vascular access in the blood vessels by which a large amount of blood is filtered and purified. It can be performed through either arteriovenous fistula connecting the artery and vein, or arteriovenous graft, which is a looped tube. Peritoneal dialysis is a kind of surgery in which a catheter is implanted in the stomach. At the time of treatment, special fluid called dialysate is made to flow from this catheter such that the waste Achieve Page 83