Chronic kidney disease and nephrotic syndrome

Several diseases cause structural or functional changes in the urinary system. Chronic kidney disease, end-stage renal disease, nephrotic syndrome, neurogenic bladder, renal calculi, and urinary incontinence are common disorders that cause structural or functional changes.

Additional diseases include the following:

• Acute tubular necrosis: Rapid destruction of the tubular sections of the nephrons due to blood flow impairment or toxins.
• Anterior prolapse: Also called cystocele, prolapse, or dropped bladder. Anterior prolapse is a bulging or dropping of the bladder into the vagina caused by the weakening and stretching of supportive tissues and muscles.
• Bladder outlet obstruction (BOO): Blockage at the opening of the bladder or in the urethra.
• Minimal change disease: Damage occurs to the glomeruli, though the cause is unknown.
• Reflux nephropathy: Urine backflows from the bladder, causing kidney damage. Can be due to a ureter defect, obstruction, or swelling.

The following sections describe the common diseases that cause structural or functional changes in the urinary system.

Chronic kidney disease

Chronic kidney disease is also called chronic kidney failure. With this condition, kidney function is gradually lost. During the early stage of chronic kidney disease, there may be few symptoms. As the kidney function diminishes, more symptoms occur.

Many diseases can lead to chronic kidney disease, including hypertension, diabetes mellitus, glomerulonephritis, interstitial nephritis, PKD, and vesicoureteral reflux. Signs and symptoms may be minimal at first. As the kidney function diminishes, the person may experience nausea, vomiting, loss of appetite, weakness, fatigue, muscle cramps, twitching, itching (pruritus), hypertension, decreased amounts of urine, sleep issues, and a reduction in mental sharpness.

After a history and examination, the provider may order urine and blood tests to assess kidney function. Imaging tests may be done to assess the kidney size, shape, and structure. A kidney biopsy can also be done. For chronic kidney disease, there is no cure. Treatment is focused on slowing the progression of the disease and reducing complications. Underlying conditions, such as hypertension and diabetes, are also treated.

End-stage renal disease (ESRD)

End-stage renal disease (ESRD), also called end-stage kidney disease and kidney failure, is advanced-stage chronic kidney disease. ESRD occurs when the kidneys are no longer filtering waste from the blood. Dangerous levels of electrolytes, waste products, and fluids build up in the bloodstream. More than 660,000 Americans have kidney failure. Over 44% of those patients are between the ages of 45 and 64.

The top two causes of ESRD are diabetes mellitus and hypertension. Additional causes include glomerulonephritis, polycystic kidney disease, prolonged obstructions, recurrent kidney infections, and vesicoureteral reflux. Using tobacco increases the risk of ESRD. Men, African Americans, and being 45 years or older can also increase the risk. The kidneys can slowly stop functioning over the course of 10 to 20 years before ESRD occurs. The signs and symptoms are the same as for chronic kidney disease.

Besides performing a physical exam, providers will order blood work and a bone density test. The blood work usually includes tests that evaluate the patient’s complete blood count (CBC), electrolytes (e.g., potassium, sodium, calcium, and magnesium), albumin, and parathyroid hormone. The patient’s blood pressure will be monitored closely.

ESRD is often treated with dialysis or kidney transplantation. Dialysis works like a kidney by filtering out the waste products, extra fluids, and electrolytes. There are two different types of dialysis:

• Peritoneal dialysis: A catheter is surgically placed in the abdomen. The patient can then infuse a special sterile solution through the catheter into the abdomen. The peritoneal membrane is used as a natural filter, and waste from the blood moves into the infused solution. After a few hours, the patient drains the fluid out of the abdomen via the catheter. New fluid is then infused into the abdomen. There may be four to six exchanges of fluid a day. This type of dialysis allows the person to work, travel, or sleep during the process.
• Hemodialysis: A vascular access (i.e., catheter, arteriovenous [ahr teer ee oh VEE nuhs] graft, arteriovenous fistula) is placed. The patient is hooked up to a dialysis machine using the vascular access. The person’s blood flows through the special filter inside of the machine. The filter cleans the blood of waste products and extra fluids. Typically, patients need to have hemodialysis three times a week at the dialysis center.

Besides dialysis and kidney transplantation, other treatments are available:

• Dietary modifications, such as low protein, limiting fluids, and electrolyte supplements
• Antihypertensive medication and supplements (i.e., iron and vitamin D)

Nephrotic syndrome

Nephrotic syndrome consists of a collection of symptoms that indicate kidney damage. The syndrome is caused by other disorders that eventually lead to kidney tissue destruction.

Nephrotic syndrome occurs more often in males than in females. It can affect children, usually 2 to 6 years of age, and adults. Minimal change disease is the most common cause of nephrotic syndrome in children. Membranous glomerulonephritis is the most common cause in adults. Nephrotic syndrome can also occur as the result of cancer, chronic disease (e.g., diabetes, systemic lupus erythematosus), infections, immune and genetic disorders, and with certain drugs. The most common sign is swelling of the face, extremities, and abdomen. Additional symptoms can include poor appetite, weight gain, seizures, skin sores, and foamy-appearing urine. Blood and urine tests show proteinuria, hyperlipidemia , and hypoalbuminemia .

Providers will do a physical exam, laboratory testing (blood testing [albumin, blood chemistry tests, BUN, and creatinine] and urine testing [creatinine clearance and urinalysis]), and a kidney biopsy. Additional testing may be ordered to identify the specific cause of nephrotic syndrome. Infection with the human immunodeficiency virus (HIV), hepatitis, and syphilis are just a few of the diseases that could lead to nephrotic syndrome. The treatment goals are to reduce symptoms, delay kidney damage, and prevent additional complications. The following are common treatments:

• Antihypertensive medications to keep the blood pressure in the normal range
• Vitamin D supplements
• Corticosteroids , anticoagulants , antihyperlipidemics , and diuretics
• Dietary modifications, such as low-fat, low-cholesterol, low-salt, and low-protein diets