Explain what happens physiologically with chronic renal failure and the GFR. Support with evidence. Include important labs that are monitored in the process.
Chronic renal failure can also be described as chronic kidney disease (CKD). According to McCance and Huether (2018), “chronic kidney disease (CKD) is the progressive loss of renal function associated with systemic diseases such as hypertension, diabetes mellitus, systemic lupus erythematosus, or intrinsic kidney disease, including acute kidney injury, chronic glomerulonephritis, chronic pyelonephritis, obstructive uropathies, or vascular disorders.” CKD is directly related to the decline of the glomerular filtration rate (GFR). There are stages of CKD depending on the value of the GFR. There are many factors that can contribute to the development of CKD, however, the two main things that have been consistent to be main contributors are proteinuria and increased angiotensin II activity. McCance and Huether (2018) states that, “proteinuria contributes to tubulointerstitial injury by accumulating in the interstitial space and activating complement proteins and other mediators and cells, such as macrophages, that promote inflammation and progressive fibrosis.” Angiotensin II causes glomerular and systemic hypertension that directly impacts the nephrons, which are the main filters in your kidneys. It also increases glomerular capillary permeability, contributing to proteinuria. In addition, “Angiotensin II also may promote the activity of inflammatory cells and growth factors that participate in tubulointerstitial fibrosis and scarring” (McCance & Huether, 2018). As fibrosis and scarring takes place, the nephrons become damaged and are unable to filter the blood properly leading to end stage renal disease.
When diagnosing CKD, multiple labs should be ordered. A complete metabolic panel should be ordered as the first test to check for BUN, creatinine and GFR levels. Blood urea nitrogen (BUN) measures the amount of urea nitrogen in your blood, which is one test to see how well your kidneys are working. Creatinine is released from your muscles and can also test how well your kidneys are working. As the GFR rate decreases, BUN and creatinine will elevate showing signs of decreased kidney function. GFR levels will vary and can show what stage of kidney disease a person has. Stage I consists of a GFR greater than 90 ml per minute of plasma flow which is normal, stage II is classified as a GFR between 60 to 89 indicating mild damage, stage III has a GFR of 30 to 59 indicating moderate damage, Stage 4 includes a GFR of 15 to 29 indicating severe damage, and stage V, or End-Stage Renal Disease (ESRD), entails a GFR of less than 15 (McCance & Huether, 2018). A urinalysis should also be done to check for protein.
McCance K., L., & Huether, S., E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Elsevier.
Chronic kidney disease (CKD) is a condition characterized by a gradual loss of kidney function over time. It is the progressive loss of renal function associated with systemic diseases such as hypertension, diabetes mellitus (most significant risk factor), hypertension, systemic lupus erythematosus, or intrinsic kidney disease, including acute kidney injury, chronic glomerulonephritis, chronic pyelonephritis, obstructive uropathies, or vascular disorders (McCance et al., 2018, p. 1267). It is referenced to a declining Glomerular filtration rate (GFR), which shows the kidneys filtration rate and tells how the kidneys are functioning and filter blood. CKD decreases filtration and tubular functions that is shown throughout all organs in the body. Decreased renal function interferes with the kidneys' ability to maintain fluid and electrolyte homeostasis. The ability to concentrate urine declines early and is followed by decreases in ability to excrete excess phosphate, acid, and potassium which is reflected in the GFR. Obtaining a complete medical history of the patient and family history is crucial when identifying risks for decreased kidney function. Doctors determine the stage of kidney disease using the glomerular filtration rate (GFR), a math formula using a person's age, gender, and their serum creatinine level (identified through a blood test). Creatinine, a waste product that comes from muscle activity, is a key indicator of kidney function. When kidneys are working well they remove creatinine from the blood; but as kidney function slows, blood levels of creatinine rise. Lab tests such as complete urinalysis (U/A), urine albumin-to-creatinine ratio (UACR), creatinine with estimated GFR, blood urea nitrogen (BUN), electrolytes, glucose, calcium, phosphorus, albumin, and a complete blood count (CBC) are used in diagnosing CKD and determining the level of kidney disease in an individual. CKD is divided into five different levels and depending on the level of the GFR will assist in determining what additional diagnostic work ups are needed (Chen et al., 2019, p. 1295).
Chen, T. K., Knicely, D. H., & Grams, M. E. (2019). Chronic Kidney Disease Diagnosis and Management: A Review. JAMA, 322(13), 1294–1304. https://doi.org/10.1001/jama.2019.14745
McCance K., L., & Huether, S., E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.) St Louis, MO: Mosby Inc; ISBN-13: 978-0323583473