The kidneys are two bean-shaped organs located on either side of the spine, below the rib cage. These organs play a central role in maintaining overall health by filtering waste products and excess fluids from the blood, which are then expelled from the body as urine. When this filtering capacity diminishes over time, the condition is known as Chronic Kidney Disease (CKD), a long-term and progressive illness.
Understanding Chronic Kidney Disease
Each kidney contains approximately one million tiny filtering units called nephrons. A nephron consists of a glomerulus, which is a cluster of small blood vessels that filters blood, and a tubule, which returns needed substances to the blood and removes wastes. As blood flows into the glomerulus, smaller molecules, wastes, and fluids pass into the tubule, while larger molecules like proteins and blood cells remain in the bloodstream. The tubule then reabsorbs necessary water, minerals, and nutrients back into the blood, with the remaining fluid and waste becoming urine. In CKD, damage to these nephrons accumulates over months or years, leading to a buildup of dangerous levels of fluid, electrolytes, and wastes in the body.
Common Causes and Risk Factors
The two most common causes of CKD are type 1 and type 2 diabetes, and high blood pressure. High blood glucose levels in diabetes can directly harm the kidney’s filtering units, while uncontrolled high blood pressure can damage the blood vessels within the kidneys, impairing their function. Glomerulonephritis, an inflammation of the glomeruli, can result from autoimmune diseases like lupus or occur after certain infections. Polycystic kidney disease, an inherited disorder, causes fluid-filled cysts to grow in the kidneys, gradually reducing their function. Prolonged or heavy use of certain medications, including some over-the-counter pain relievers, can also negatively impact kidney health. Factors like obesity, smoking, and a family history of kidney disease further increase the risk of developing CKD.
Recognizing the Symptoms
Symptoms of CKD typically do not become apparent until the disease has reached more advanced stages, as the body can compensate for a significant reduction in kidney function. When symptoms do emerge, they often include persistent fatigue and weakness, resulting from the accumulation of waste products in the blood. Swelling, or edema, commonly appears in the legs, ankles, and feet due to the kidneys’ reduced ability to remove excess fluid and salt. Changes in urination patterns, such as urinating more or less frequently than usual, especially at night, can also indicate kidney issues. Other symptoms may include muscle cramps, nausea, loss of appetite, and dry, itchy skin.
Diagnosis and Staging
Diagnosis of CKD typically involves specific blood and urine tests. A blood test measures the estimated Glomerular Filtration Rate (eGFR), which indicates how well the kidneys are filtering blood. This test often relies on creatinine levels in the blood, a waste product that healthy kidneys efficiently remove. A urine test, specifically the urine albumin-to-creatinine ratio (uACR), checks for albuminuria, which is the presence of the protein albumin in the urine, signifying kidney damage.
CKD is categorized into five stages based on the eGFR, reflecting the extent of kidney function loss. Stage 1 indicates normal kidney function with an eGFR of 90 mL/min/1.73 m² or greater, along with mild kidney damage. As the eGFR declines, the stages progress, with Stage 5 representing kidney failure, characterized by an eGFR below 15 mL/min/1.73 m². Imaging tests, such as an ultrasound, may also be used to assess kidney structure and identify potential issues.
Managing the Condition
Managing CKD aims to slow its progression and alleviate symptoms, as there is currently no cure.
Lifestyle adjustments play a significant role, including adopting a healthy, balanced diet that limits sodium, potassium, and phosphorus intake. Regular physical activity, maintaining a healthy weight, and quitting smoking are also important steps. Avoiding certain over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) is often advised, as they can further harm the kidneys.
Medications are frequently prescribed to manage underlying conditions that contribute to CKD, such as high blood pressure and diabetes. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are commonly used to control blood pressure and offer kidney protection.
In advanced stages of CKD, when kidney function is severely diminished, treatments like dialysis or a kidney transplant may become necessary to sustain life. Dialysis artificially filters the blood, while a kidney transplant replaces the damaged kidney with a healthy donor organ.