CKD is a silent, progressive disease that affects millions (around 10% of the global population) of people worldwide. According to the NKF (National Kidney Foundation), 1 in 7 adults in the United States has CKD. In the United States alone, more than 30 million (1 in 7 adults) people are affected by this disease.

CKD occurs when your kidneys can no longer filter blood as efficiently as they should. The disease develops in five stages and can cause serious health problems. There are several causes and risk factors for Chronic Kidney Disease causes, and understanding them can help prevent or manage the condition.

There are two main types of CKD causes: pathological and physiological. 

• Physiological causes of CKD include lifestyle factors like diabetes (44% of the total CKD cases), high blood pressure (29%), obesity, alcohol, and smoking. These factors can lead to reduced blood flow through the kidneys and damage their ability to effectively filter waste from the body.

• Pathological causes of CKD include conditions that directly damage the kidneys, such as glomerulonephritis, polycystic kidney disease causes, chronic pyelonephritis, interstitial nephritis, and Lupus. These diseases can cause inflammation in the kidneys, leading to blockages in the renal system. Kidney stones and tumors can also lead to chronic kidney disease by blocking urine flow.

Common Physiological Causes Of Chronic Kidney Disease (CKD) 

Physiological causes refer to the factors (both dietary and lifestyle) contributing to physical or bodily dysfunction. These can be anything from birth defects, injuries, infections, diseases, and genetic disorders. Understanding the physiological causes of CKD is important for effective treatment and management plans. Common ones include;

• Diabetes

Diabetes has been identified as the number 1 cause of chronic Kidney Disease (CKD) worldwide. This metabolic disorder affects the ability of body cells to regulate blood sugar levels. Over time, high sugar levels in the blood can damage various organs in the body, including the kidneys. When left untreated, diabetes can cause progressive kidney damage, eventually leading to CKD.

The link between diabetes and CKD is due to diabetic nephropathy, a complication that damage the blood vessels in the kidneys. This reduces kidney function over time and may ultimately lead to kidney failure. According to statistics from Diabetes UK, nearly 44% of people who develop diabetes will experience some form of diabetic nephropathy during their lifetime.

• High Blood Pressure (HBP)

HBP is a common condition that affects millions of people worldwide. Unregulated high blood pressure can cause narrowing of the blood vessels. Over time, this can cause significant harm to various organs in the body, including the kidneys.

When blood pressure is high, the kidneys are under stress and overworked. This strain can damage the delicate blood vessels inside the kidneys. Over time, this damage can reduce the kidney’s ability to function correctly.

If left untreated, HBP can lead to CKD, which affects about 14% of the global population. When CKD develops due to high blood pressure, it’s called hypertensive nephropathy. This type of CKD can progress slowly and may not show symptoms until significant damage occurs.

• Obesity

Obesity is a growing epidemic worldwide, with alarming rates of people being overweight or obese. Obesity has been linked to multiple chronic diseases, such as diabetes, atherosclerosis, hypertension, and chronic kidney disease (CKD).

The link between obesity and CKD is complex. Obesity can cause changes in the normal functioning of the kidneys through various mechanisms, such as insulin resistance, inflammation, and oxidative stress. Obese individuals often have high blood pressure, contributing to kidney damage.

• Alcohol

Alcohol causes dehydration by increasing urine production, which strains the kidneys. This can lead to reduced flow of blood to the organs and damage to renal cells. In addition, alcohol has been shown to increase blood pressure and cholesterol levels, both of which are known risk factors for CKD.

Furthermore, long-term alcohol use can lead to fatty liver disease, which causes inflammation and scarring of liver tissue. This condition can also damage other organs, such as the kidneys, and increase insulin resistance leading to type 2 diabetes.

• Smoking

Smoking causes damage to the kidneys in several ways, both directly and indirectly.

Directly – it increases blood pressure and reduces blood flow to the kidneys. This leads to a reduced supply of oxygen and nutrients to the kidneys which can damage delicate tissues. Additionally, smoking causes inflammation throughout the body including in the kidneys. Chronic inflammation damages tissues over time, leading to scarring, further impairing kidney function.

Indirectly – it increases proteinuria- an excess of protein in the urine. It also worsens existing renal problems by accelerating their progression toward end-stage renal disease (ESRD).

• Aging

As we age, our kidneys become less efficient in filtering wastes and toxins from the blood. This gradual decrease in renal function can lead to CKD over time. One of the main reasons aging causes CKD is due to changes in the anatomy (structure) and function of the kidneys.

These changes include decreased blood flow, reduced glomerular filtration rate (GFR), and thickening of the basement membrane, among other factors (such as diabetes, high blood pressure, smoking, etc.). Additionally, as we age, our bodies are more susceptible to damage from environmental toxins and medications that can harm our kidneys.

• Genetics

Certain faulty genes can increase the risk of developing CKD. For example, gene mutations that regulate blood pressure or glucose metabolism have been linked to an increased risk of kidney damage over time. Other genetic factors, such as gene variations related to inflammation or immune function (such as polycystic kidney disease (PKD) and glomerulonephritis), may also play a role.

• Overuse of certain medications

Overusing NSAIDs such as ibuprofen and naproxen has been linked to kidney damage. They block the production of pain hormones called prostaglandins. However, long-term use or overuse of NSAIDs can lead to chronic kidney disease. NSAIDs reduce blood flow to the kidneys, causing damage to the small blood vessels over time. This can eventually lead to decreased kidney function and even kidney failure.

Common Pathological Causes Of Chronic Kidney Disease (CKD) 

Pathological causes refer to the underlying medical conditions that lead to the development of symptoms in a patient. These conditions can be chronic or acute, and their severity can vary from mild to life-threatening. The following are some of the common pathological causes of CKD.

Glomerulonephritis

Glomerulonephritis refers to the inflammation and damage of the glomeruli (tiny filters in the kidneys). Glomeruli filter waste products, toxins, and excess fluid from the blood. When these filters become inflamed or damaged, they may not function properly, leading to CKD.

Glomerulonephritis can be acute or chronic, with chronic cases lasting more than three months. It can affect anyone but is more common in those with infections such as strep throat or viral hepatitis B or C. Other risk factors include lupus and vasculitis, as well as family history and exposure to certain drugs or toxins.

Polycystic kidney disease

PKD is a genetic disorder and the leading cause of CKD in adults. It causes the formation of multiple cysts within the kidneys, leading to malfunction, enlargement, and eventual failure. 

PKD is one of the leading causes of chronic kidney disease (CKD) in adults. It can be inherited from either parent or occur spontaneously due to genetic mutations. The condition usually develops slowly over many years, with symptoms typically not appearing until middle age. 

Unfortunately, PKD has no cure, but managing its symptoms can help slow its progression. Patients are often prescribed medication to control high blood pressure and may need dialysis or a kidney transplant if their kidneys fail completely. Early diagnosis through regular check-ups and testing is crucial for successfully managing this condition.

Chronic pyelonephritis

Chronic pyelonephritis is a persistent inflammation of the renal pelvis and kidney tissue, which can lead to permanent damage if left untreated. This condition can cause chronic kidney disease (CKD).

The primary cause of chronic pyelonephritis is a bacterial infection, usually caused by bacteria that enter the urinary tract. The inflammation caused by this infection can eventually lead to scarring and damage to the renal tissue. Over time, this damage can progress and worsen until it leads to CKD.

Interstitial nephritis

Interstitial nephritis is a condition that causes inflammation in the small spaces between the kidney tubules and surrounding tissues. This condition can lead to chronic kidney disease (CKD) if left untreated. Interstitial nephritis can be caused by various factors such as medications, autoimmune diseases, infections, and exposure to toxins.

The most common cause of interstitial nephritis is the use of certain medications such as antibiotics (like penicillin and cephalosporins), diuretics, proton pump inhibitors, and NSAIDs. These drugs can trigger an immune response in the kidneys leading to inflammation and damage over time. Autoimmune diseases like lupus (SLE) or rheumatoid arthritis can also cause interstitial nephritis by triggering an immune response that attacks the kidney tissue.

Systemic lupus erythematosus (SLE)

SLE is an autoimmune disease that is known to cause various complications, including kidney disease or CKD in young adults.

The exact mechanism by which SLE leads to CKD is not fully understood. However, the immune system’s attack on healthy tissues and cells is believed to damage the kidneys’ filtering units called glomeruli. This damage can lead to proteinuria, hematuria, hypertension, and progressive decline in renal function. Early detection and management of SLE-associated CKD are crucial in preventing further kidney damage.