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Kidney Disease: Signs and Symptoms

The kidneys, two bean-shaped organs roughly the size of a fist, maintain the body’s internal balance by filtering out excess water and waste from the blood, which is then eliminated as urine.

While healthy kidneys are essential for overall well-being, kidney disease can progress quietly, often showing no symptoms until it reaches a more advanced stage. Therefore, it’s important to understand kidney disease, identify its signs and symptoms, and familiarize yourself with the diagnostic methods that enable early detection and effective treatment.

What is Kidney Disease?

Kidney disease is any condition in which the kidneys are damaged and cannot filter blood as they should. Chronic kidney disease (CKD) is the most common form, characterized by kidney damage or a reduction in the glomerular filtration rate (GFR) to less than 60 mL/min/1.73 m² for three months or longer. CKD involves a gradual decline in kidney function, often leading to the need for dialysis or a kidney transplant.

Risk Factors for Kidney Disease

Several factors increase the risk of developing kidney disease. The most significant are diabetes and high blood pressure. Regular monitoring of kidney function is essential for individuals with these conditions. Other risk factors include a family history of kidney disease, age over 60, and pre-existing cardiovascular disease.

Kidney Disease Causes

The causes of CKD vary around the world but generally stem from a range of primary and secondary conditions that lead to kidney damage. Some of the most common causes include:

• Type 2 Diabetes
• Type 1 Diabetes
• Hypertension
• Primary Glomerulonephritis
• Chronic Tubulointerstitial Nephritis
• Hereditary or Cystic Diseases
• Secondary Glomerulonephritis or Vasculitis
• Plasma Cell Dyscrasias or Neoplasm
• Sickle Cell Nephropathy

These conditions can directly damage the kidneys or lead to systemic health issues that eventually affect kidney function.

Types of Kidney Disease

Kidney disease can be categorized based on the location and nature of the problem within the renal system:

1. Prerenal Disease

Prerenal disease arises from conditions that reduce blood flow to the kidneys, such as chronic heart failure or liver cirrhosis. Over time, decreased blood flow can lead to intrinsic kidney damage and increase the risk of chronic kidney disease.

1. Intrinsic Renal Disease

Intrinsic renal disease affects the kidneys directly and includes:

• Renal Vascular Disease

Conditions like nephrosclerosis or renal artery stenosis cause ongoing damage to the blood vessels within the kidneys, leading to ischemic nephropathy.

• Glomerular Disease

This can present as nephritic patterns, with blood in the urine and proteinuria, or nephrotic patterns, characterized by significant proteinuria. Common causes include:

• Lupus nephritis
• Diabetic nephropathy
• Post-infectious glomerulonephritis

• Tubular and Interstitial Disease

Polycystic kidney disease (PKD) is a typical example, where cysts develop within the kidney, leading to progressive renal failure.

1. Postrenal (Obstructive Nephropathy)

Postrenal disease results from blockages in the urinary tract that prevent urine from leaving the kidneys. Chronic obstructions can cause long-term damage and lead to CKD, whether due to prostatic disease, kidney stones, or tumors.

Symptoms of Kidney Disease

In its early stages, CKD is often symptomless, making it difficult to detect without specific tests. Symptoms become more apparent as the disease progresses to advanced stages and may include:

• Nausea and vomiting
• Loss of appetite
• Fatigue and weakness
• Sleep disturbances
• Reduced urine output
• Decreased mental clarity
• Muscle cramps
• Swelling of feet and ankles
• Persistent itching (pruritus)
• Chest pain 
• Shortness of breath (due to pulmonary edema)
• High blood pressure

In severe stages, physical signs such as changes in skin pigmentation, uremic frost, and hypertensive retinal changes may also be present.

Diagnosis of Kidney Disease

Kidney Function Test

The kidney function test or Glomerular filtration rate (GFR) is a key laboratory test used to evaluate kidney function; a decline in GFR indicates a reduction in kidney performance.

Although insulin clearance is considered the gold standard for measuring GFR, creatinine clearance is more frequently used in clinical practice due to its accessibility.

Proteinuria Test

Proteinuria, or the presence of excess protein in the urine, is a key indicator of kidney damage and a part of the urine analysis test. It is typically assessed through an early morning urine sample.

Imaging of Kidneys

Imaging tests such as ultrasound, CT scans, and renal angiography are essential for visualizing kidney structure and function. These tests can identify abnormalities such as reduced kidney size, cysts, or obstructions in the urinary tract.

Kidney Disease Complications

If not treated, kidney disease might cause the following complications:

• Hypertension
• Hyperkalemia
• Metabolic Acidosis
• Hyperphosphatemia
• Anemia
• Cardiovascular Disease
• Insulin Resistance

How to Prevent Kidney Disease

Taking proactive steps to protect your kidney health is essential for maintaining your overall well-being. By following prevention tips, you can reduce the risk of kidney disease, such as:

• Managing blood pressure
• Controlling blood sugar levels
• Staying hydrated
• Maintaining a balanced diet

Regular lab check-ups are equally important, as they allow for early detection of any potential issues, enabling timely intervention and treatment.

Remember, your kidneys are important, and with a few simple lifestyle changes and routine monitoring, you can help ensure they continue to function optimally for years to come.