Disorders of the Urinary System

Acute Kidney Failure20

Acute kidney failure is the rapid (less than two days) loss of kidney function. There are many possible causes of acute kidney failure, including the following:

• Acute tubular necrosis (damage to the renal tubules)
• Autoimmune kidney disease
• Decreased blood flow to the kidneys due to very low blood pressure, which can result from dehydration, hemorrhage, serious illness or injury, or surgery
• Disorders that cause clotting within the kidney’s blood vessels
• Infections that directly injure the kidney, such as acute pyelonephritis (severe infection of the kidneys)
• Pregnancy complications, including placental abruption (separation of the placenta from the uterine wall) or placenta previa (placenta blocking the cervix)
• Urinary tract blockage
• Illicit drugs such as cocaine and heroin
• Medicines including nonsteroidal anti-inflammatory drugs (NSAIDs), certain antibiotics and blood pressure medicines, intravenous contrast (dye), HIV medications, and some types of cancer

Acute kidney failure is diagnosed through blood and urine tests that measure creatinine, urea nitrogen, and protein levels in the blood and urine. Acute kidney failure is typically treated with dialysis and medications.

Bladder Cancer21

Bladder cancer is the most common malignancy affecting the urinary system. Symptoms of bladder cancer are hematuria, urinary frequency, urgency, dysuria, and nocturia. Treatment and prognosis is based on the severity of the disease and if the cancer has metastasized. If cancer has not invaded the bladder muscle tissue, treatment typically includes removal of the tumor followed by chemotherapy administered directly into the bladder. Muscle-invasive bladder cancer is treated with radical cystectomy, meaning removal of the bladder and regional lymph nodes. In males, radical cystectomy also includes the removal of the prostate and seminal vesicles. When a patient’s bladder is removed, urinary flow must be redirected, referred to as urinary diversion. Clients with metastatic cancer are typically treated with chemotherapy,  immunotherapy, or targeted therapies.

Chronic Kidney Disease8

Chronic kidney disease (CKD) is a condition in which the kidneys become progressively damaged and don’t filter blood effectively, causing fluids, electrolytes, and toxins to remain in the body instead of being appropriately eliminated in the urine. People with early stages of CKD may not feel ill, but blood and urine tests indicated elevated levels of creatinine and/or protein. Symptoms of later stages of CKD include urinating less frequently; edema (swelling) from fluid retention; shortness of breath from fluid buildup in the lungs; fatigue from anemia due to decreased production of erythropoietin; nausea; vomiting; or itchy skin from electrolyte imbalances and toxin buildup.

CKD usually gets worse over time, though treatment has been shown to slow progression. Chronic kidney disease can cause complications affecting multiple organ systems, including cardiovascular disease, mineral and bone disorders, metabolic acidosis, and neurological issues. As the disease progresses, these complications become more severe. When the kidneys stop functioning, it is called chronic kidney failure or end-stage renal disease. Dialysis (artificial cleaning of the blood) or a kidney transplant is needed for survival.

Diabetes Insipidus10

Diabetes insipidus (DI) is a condition where the body produces abnormally large amounts of dilute urine, leading to dehydration and excessive thirst. DI occurs due to deficient levels of antidiuretic hormone (ADH) released by the posterior pituitary gland or lack of response by the kidneys to ADH. DI is caused by head injuries, infections, or surgery near the pituitary gland; kidney disease; or as a side effect of certain medications. DI is typically treated with medications to stimulate ADH production or help the kidneys respond to it better, while also treating dehydration and the underlying causes of the condition. Note that diabetes insipidus is not related to diabetes mellitus, but the elevated levels of blood glucose that can occur in diabetes mellitus can also cause excessive urination.

Glomerulonephritis11

Glomerulonephritis is inflammation of the glomeruli (the small blood vessels in the kidneys that filter blood), causing them to lose their ability to filter wastes and excessive water. Protein and red blood cells may leak into the urine while toxins that are normally removed by the kidney are retained in the bloodstream. A common cause of acute (sudden) glomerulonephritis is the immune system’s overreaction to infection, especially those caused by Streptococcus (commonly known as “strep throat”), Pneumococcus, the varicella virus (commonly known as chicken pox), and malaria (a type of parasite). Chronic (long-term) glomerulonephritis can be caused by genetic disorders, autoimmune disease, or exposure to hydrocarbon solvents.

How long glomerulonephritis lasts depends on its cause and the severity of kidney damage. When glomerulonephritis follows an infection, it typically resolves within weeks to months. For example, children who develop glomerulonephritis following a strep infection typically recover completely. In other cases, glomerulonephritis becomes a chronic condition that lasts for years and can eventually lead to kidney failure.

Mild cases of glomerulonephritis may not cause any symptoms and may only be discovered if protein or blood is found in the urine during a routine urine test. In other cases, the first symptom of glomerulonephritis may be high blood pressure. Other symptoms may include edema in the feet, lower legs, and eyes; shortness of breath due to fluid build up in the lungs; reduced frequency of urination; and dark-colored urine due to the presence of red blood cells. High levels of protein in the urine can also cause it to appear foamy. Complications of glomerulonephritis include severe chronic kidney disease and kidney failure that may require lifelong treatment with dialysis or a kidney transplant.

Gout12

Gout is a common type of inflammatory arthritis that causes pain, swelling, and redness in one or more joints. It typically occurs as a flare in the big toe or lower limb that can last for a week or two and then resolve.

Gout occurs when too much uric acid (urate) builds up in the body over a long time. Uric acid is a waste product formed when the body breaks down purines. Purines are substances that are in the body’s tissues and in many foods. When the body breaks down old cells or digests foods that contain purine, most of the uric acid that is made dissolves in the blood. The kidneys filter the uric acid out of the blood, and it leaves the body in the urine. However, sometimes the body can make too much uric acid or the kidneys do not remove enough of it, causing the uric acid levels to build up in the blood, which is called hyperuricemia. In some people, uric acid forms needle-like crystals that deposit in the joints, causing gout. The crystals can also cause kidney stones. With lifestyle changes and medications, gout flares can be treated and prevented.

Calcium pyrophosphate arthritis, sometimes called pseudogout, is a related inflammatory disease that causes similar symptoms as gout, but it is caused by a buildup of calcium phosphate, not uric acid.

Kidney Stones13,14

Kidney stones are clusters of crystals that form from substances in the urine that can cause severe pain as they pass through the urinary tract. Urolithiasis refers to stones present anywhere in the urinary tract.

Urine has various substances like minerals, acids, and salts dissolved in it. When there is too much of a certain substance in a small amount of fluid, crystals can begin to form that attract other elements which join together to form a solid. In most people, having enough water in the urine flushes these crystals out of the urinary tract. Some people have chemicals in their urine which prevent stones from forming. After it is formed, a kidney stone may stay in the kidney and continue to grow larger or travel down the urinary tract into the ureter. In mild cases, tiny stones the size of sand move out of the body in the urine without causing much pain. However, larger stones can cause severe pain and a back-up of urine in the urethra, bladder, ureter, or kidney, affecting the kidney’s ability to filter and possibly causing damage to the kidneys. See Figure 15.17 for an image of a variety of kidney stones.

Figure 15.17 Kidney Stones (“Kidney_stones_%28_renal_calculi_%29,_Бубрежни_камења_15.jpg” by Jakupica is licensed under CC BY-SA 4.0)

A:“Kidney_stones_%28_renal_calculi_%29,_Бубрежни_камења_15.jpg” by Jakupica is licensed under CC BY-SA 4.0

Common symptoms of kidney stones include severe pain in the lower back, abdomen, or flank (side of the back); blood in the urine; nausea or vomiting; fever and chills; inability to urinate or frequent urination; or urine that smells bad or looks cloudy.

There are four types of kidney stones: calcium oxalate, uric acid, struvite, and cystine. Calcium-based stones are the most common type of kidney stones. They can form when a person eats high-oxalate or low-calcium foods and doesn’t drink enough fluids. Uric acid stones can form from eating animal proteins such as beef, poultry, pork, eggs, and fish. Bacterial infections can cause struvite stones. Cystine stones are formed when two cysteine amino acids bind together due to an inherited condition.

People with small kidney stones may be prescribed pain medications while waiting for the stone(s) to pass through their urine. It can take as long as three weeks for kidney stones to pass on their own, and even some small stones can cause extreme pain as they pass through the urinary tract. Larger kidney stones often require pain medication and medical treatment to break them up and remove them from the urinary tract.

Nocturnal Enuresis (Bedwetting)15

Passing urine without conscious control while sleeping is called nocturnal enuresis, commonly known as bedwetting. Nocturnal enuresis occurs in more than five million people in the United States. Most children by the age of five can control their bladder during the day and night. However, bedwetting occurs in approximately 10% of six-year-olds, 5% of 10 year-olds, and 1% of teenagers and young adults.

Bedwetting is slightly more common in boys than in girls, and it is more common in children who have coexisting behavioral or psychiatric disorders. As children age and spend more nights away from home at sleepovers with friends and at camps, bedwetting can cause social anxiety, isolation from peers, and depression. Bedwetting can often be treated successfully with a combination of lifestyle modifications, such as fluid restriction before bedtime, voiding schedules throughout the day, a night time wakening schedule, and moisture-sensitive alarms that wake the child when bedwetting occurs. If these modifications are not successful, medications may be prescribed.

Polycystic Kidney Disease16

Polycystic kidney disease (PKD) is a genetic disorder that causes numerous cysts that are filled with fluid to grow in the kidneys. These cysts can enlarge the kidneys and damage the surrounding tissue, reducing kidney function and possibly leading to kidney failure. See Figure 15.18 for an image of PKD.

Figure 15.18 Polycystic Kidney Disease (“Polycystic_kidneys,_gross_pathology_CDC_PHIL.png” by CDC/ Dr. Edwin P. Ewing, Jr. is licensed in the Public Domain. )

A:(“Polycystic_kidneys,_gross_pathology_CDC_PHIL.png” by CDC/ Dr. Edwin P. Ewing, Jr. is licensed in the Public Domain.

In the United States about 600,000 people have polycystic kidney disease, which is the fourth leading cause of kidney failure. Men and women are equally at risk for the disease. Most people do not develop symptoms until they are 30 to 40 years old.

Symptoms of PKD can vary but may include high blood pressure, abdominal or back pain, blood in the urine, and swollen abdomen. About 25% of people with PKD have a coexisting defective valve in their heart that causes symptoms of heart fluttering or pounding, as well as chest pain. These symptoms may be the first clue that someone has polycystic kidney disease.

There is no cure for PKD, but medications may be prescribed to slow the growth of cysts, or surgery may be performed to drain or remove large cysts. In severe cases, a kidney transplant may be required.

Urinary Incontinence18

Urinary incontinence is involuntary loss or leakage of urine that can range from a small annoyance to significantly affecting a person’s quality of life. There are several types of urinary incontinence with different causes and treatments, including, but not limited to the following:

• Stress incontinence occurs when pressure is placed on the bladder, such as when coughing, sneezing, laughing, or exercising.
• Urge incontinence occurs when a sudden, intense urge to urinate leads to involuntary leakage.
• Overflow incontinence is caused by the bladder not emptying completely, causing frequent or constant leaking.
• Functional incontinence is caused by physical or mental limitations that prevent an individual from reaching the toilet in time.

Women are at higher risk for urinary incontinence due to the effects of pregnancy, childbirth, and menopause. Men are more likely to develop overflow incontinence with age because of normal prostate enlargement that prevents complete emptying of the bladder.

Treatment is based on the type of urinary incontinence and may include pelvic floor exercises, timed voiding, bladder training, medications, and surgery.

Urinary Tract Infection19

A urinary tract infection (UTI) is a common type of infection that occurs when bacteria enter the urethra and infect the urinary tract. Urinary tract infections include cystitis (bladder infections) and pyelonephritis (kidney infection).

Urinary tract infections are more common in females because their urethras are shorter and closer to the rectum and anus, making it easier for bacteria to enter the urinary tract. Other risk factors for urinary tract infections include previous history of UTI, sexual activity, pregnancy, age (older adults and young children are more likely to get UTIs), structural problems in the urinary tract (such as an enlarged prostate gland), and poor hygiene (such as in children who are toilet training).

Symptoms include burning during urination, frequent or urgent urination, and cloudy or foul-smelling urine. In severe cases, fever, chills, or back pain may also be present. UTIs are treated with antibiotics, as well as lifestyle changes to prevent future UTIs, such as staying hydrated, wiping from front to back, and urinating frequently.

Pyelonephritis (Kidney Infection)17,1

Pyelonephritis, commonly called a kidney infection, is a severe urinary tract infection that causes inflammation in the kidneys. Most kidney infections are caused by bacteria that first infect the bladder and then move up the ureters to one or both of the kidneys. Kidney infections lead to about 250,000 office visits and 200,000 hospital admissions in the United States each year.

Symptoms of pyelonephritis include fever; pain in the back, side, or groin; painful urination; cloudy or foul-smelling urine; and nausea or vomiting. Pyelonephritis is treated with antibiotics for 7 to 14 days. If not treated properly, pyelonephritis can cause chronic kidney disease.