Most people know that a major function of the kidneys is to remove waste products and excess fluid from the body. These waste products and excess fluid are removed through the urine. The production of urine involves highly complex steps of excretion and re-absorption. This process is necessary to maintain a stable balance of body chemicals.
The critical regulation of the body’s salt, potassium and acid content is performed by the kidneys. The kidneys also produce hormones that affect the function of other organs. For example, a hormone produced by the kidneys stimulates red blood cell production. Other hormones produced by the kidneys help regulate blood pressure and control calcium metabolism.
The kidneys are powerful chemical factories that perform the following functions:-
- remove waste products from the body
- remove drugs from the body
- balance the body’s fluids
- release hormones that regulate blood pressure
- produce an active form of vitamin D that promotes strong, healthy bones
- control the production of red blood cells
Your kidneys are two bean-shaped organs, each about the size of your fist. They are located in the middle of your back, just below your rib cage, on either side of your spine. Your kidneys weigh about 0.5 percent of your total body weight. Although the kidneys are small organs by weight, they receive a huge amount 20 percent of the blood pumped by the heart.
Major Parts of Kidney:-
- Renal capsule – a thin, outer membrane that helps protect the kidney
- Cortex – a lightly colored outer region
- Medulla – a darker, reddish-brown, inner region
- Renal pelvis – a flat, funnel-shaped cavity that collects the urine into the ureters
How it functions:-
- The cortex and medulla consits of many tiny, tubular structures that stretch across both regions perpendicular to the surface of the kidney.
- In each kidney, there are one million of these structures, called nephrons.
- The nephron is the basic unit of the kidney.
- It’s a long, thin tube that is closed at one end, has two twisted regions interspaced with a long hairpin loop, ends in a long straight portion and is surrounded by capillaries.
- When blood enters the glomerulus, it is filtered and the remaining fluid then passes along the tubule.
- In the tubule, chemicals and water are either added to or removed from this filtered fluid according to the body’s needs, the final product being the urine we excrete.
- The kidneys perform their life-sustaining job of filtering and returning to the bloodstream about 200 quarts of fluid every 24 hours.
- About two quarts are removed from the body in the form of urine, and about 198 quarts are recovered. The urine we excrete has been stored in the bladder for anywhere from 1 to 8 hours.
Blood in the Urine:-
- The filtrate only includes small molecules and water.
- No red blood cells get filtered.
- Therefore, no blood appears in the urine under normal conditions.
- If you find blood in your urine, you should contact your physician as soon as possible because it could be a sign of kidney problems.
Most kidney diseases attack the nephrons. This damage may leave kidneys unable to remove wastes. Causes can include genetic problems, injuries, or medicines. You are at greater risk for kidney disease if you have diabetes, high blood pressure, or a close family member with kidney disease. Chronic kidney disease damages the nephrons slowly over several years. Other kidney problems include:
Acute kidney problems come on quickly but the kidneys often recover after treatment.
Chronic kidney disease is the most common type of kidney disease and occurs when the kidneys are damaged or are not functioning as well for 3 months or longer. Chronic kidney disease worsens or progresses over time. There are 5 stages of chronic kidney disease, with the most severe being end-stage renal disease (ESRD). With end-stage kidney disease, your kidneys are functioning at less than 15% of what they should be.
- A kidney stone is a hard, crystalline mineral material formed within the kidney or urinary tract.
- Nephrolithiasis is the medical term for kidney stones.
- One in every 20 people develop kidney stones at some point in their life.
- Kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine.
- Dehydration is a major risk factor for kidney stone formation. Symptoms of a kidney stone include flank pain (the pain can be quite severe) and blood in the urine (hematuria).
- People with certain medical conditions, such as gout, and those who take certain medications or supplements are at risk for kidney stones.
- Diet and hereditary factors are also related to stone formation.
- Diagnosis of kidney stones is best accomplished using an ultrasound, intravenous pyleography (IVP), or a CT scan.
- Most kidney stones will pass through the ureter to the bladder on their own with time. Treatment includes pain-control medications and, in some cases, medications to facilitate the passage of urine.
- If needed, lithotripsy or surgical techniques may be used for stones which do not pass through the ureter to the bladder on their own.
- Kidney cysts are round pouches of fluid that form on or in the kidneys. Kidney cysts can be associated with serious disorders that may impair kidney function. But more commonly, kidney cysts are a type called simple kidney cysts — noncancerous cysts that rarely cause complications.
- It’s not clear what causes simple kidney cysts. Typically, only one cyst occurs on the surface of a kidney, but multiple cysts can affect one or both kidneys. However, simple kidney cysts aren’t the same as the cysts that form with polycystic kidney disease.
- Simple kidney cysts are often detected during an imaging test performed for another condition. Simple kidney cysts that don’t cause signs or symptoms usually don’t require treatment.
Kidney cancer also called renal cancer is a disease in which kidney cells become malignant (cancerous) and grow out of control, forming a tumor. Almost all kidney cancers first appear in the lining of tiny tubes (tubules) in the kidney. This type of kidney cancer is called renal cell carcinoma. The good news is that most of kidney cancers are found before they spread (metastasize) to distant organs. And cancers caught early are easier to treat successfully. However, these tumors can grow to be quite large before they are detected.
The kidneys are two bean-shaped organs, each about the size of a fist. They lie in your lower abdomen on each side of your spine. Their main job is to clean your blood, removing waste products and making urine.
Doctors don’t know the causes of kidney cancer. But certain factors appear to increase the risk of getting kidney cancer. For example, kidney cancer occurs most often in people older than age 40.
These are some other risk factors for kidney cancer:-
Smoking . If you smoke cigarettes, your risk for kidney cancer is twice that of nonsmokers. Smoking cigars may also increase your risk.
Being male. Men are about twice as likely as women to get kidney cancer.
Being obese. Extra weight may cause changes to hormones that increase your risk.
Using certain pain medications for a long time. This includes over-the-counter drugs in addition to prescription drugs.
Having advanced kidney disease or being on long-term dialysis, a treatment for people with kidneys that have stopped working
Having certain genetic conditions, such as von Hippel-Lindau (VHL) disease or inherited papillary renal cell carcinoma
Having a family history of kidney cancer. The risk is especially high in siblings.
Being exposed to certain chemicals, such as asbestos, cadmium, benzene, organic solvents, or certain herbicides
Having high blood pressure. Doctors don’t know whether high blood pressure or medication used to treat it is the source of the increased risk.
Being black. The risk in blacks is slightly higher than in whites. No one knows why.
Having lymphoma. For an unknown reason, there is an increased risk of kidney cancer in patients with lymphoma.
What Are the Symptoms of Kidney Cancer?
In many cases, people may have no early symptoms of kidney cancer. As the tumor grows larger, symptoms may appear. You may have one or more of these kidney cancer
- Blood in your urine
- A lump in your side or abdomen
- A loss of appetite
- A pain in your side that doesn’t go away
- Weight loss that occurs for no known reason
- Fever that lasts for weeks and isn’t caused by a cold or other infection
- Extreme fatigue
- Swelling in your ankles or legs
- Kidney cancer that spreads to other parts of your body may cause other symptoms, such as:
- Shortness of breath
- Coughing up blood
- Bone pain
What Are the Stages of Kidney Cancer?
Your prognosis depends on your general health, as well as the grade and stage of your kidney cancer.
A tumor 7 centimeters or smaller that is only in the kidney
A tumor larger than 7 centimeters that is only in the kidney
- A tumor that is in the kidney and in at least one nearby lymph node
- A tumor that is in the kidney’s main blood vessel and may also be in nearby lymph node
- A tumor that is in the fatty tissue around the kidney and may also involve nearby lymph nodes
- A tumor that extends into major veins or perinephric tissues, but not into the ipsilateral adrenal gland and not beyond Gerota’s fascia
- Cancer has spread beyond the fatty layer of tissue around the kidney, and it may also be in nearby lymph nodes
- Cancer may have spread to other organs, such as the bowel, pancreas, or lungs
- Cancer has spread beyond Gerota’s fascia (including contiguous extension into the ipsilateral adrenal gland)
Surgery for kidney cancer:-
These are the main types of surgery for kidney cancer. Which type you have depends on how advanced your cancer is.
- Radical nephrectomy removes the kidney, adrenal gland, and surrounding tissue. It also often removes nearby lymph nodes. It is the most common surgery for kidney cancer and can now be done through a small incision with a laparoscope.
- Simple nephrectomy removes the kidney only.
- Partial nephrectomy removes the cancer in the kidney along with some tissue around it. This procedure is used for patients with smaller tumors (less than 4 cm) or in those patients in which a radical nephrectomy might hurt the other kidney.
- You can survive with just a part of one kidney as long as it is still working. If the surgeon removes both kidneys or if both kidneys are not working, you will need a machine to clean your blood (dialysis) or a new kidney (kidney transplant). A transplant is possible if your cancer was found only in your kidney and a donated kidney is available.
- If surgery can’t remove your kidney cancer, your doctor may suggest another option to help destroy the tumor.
- Cryotherapy uses extreme cold to kill the tumor.
- Radiofrequency ablation uses high-energy radio waves to “cook” the tumor.
- Arterial embolization involves inserting material into an artery that leads to the kidney. This blocks blood flow to the tumor. This procedure may be done to help shrink the tumor before surgery.
Another way to treat kidney failure is to have a kidney transplant. This operation gives you a healthy kidney from a donor.
- A donor may be a living person.
- A living donor may be a blood relative, such as a parent, brother, sister, or child, or a close friend or nonblood relative, such as a spouse.
- A living kidney donation offers the best-quality kidney with the shortest wait time.
- Donating a kidney does not put the donor at risk for future health problems.
- If you cannot get a kidney from a living donor, your name can be placed on the national waiting list for a deceased donor kidney, or a kidney that is taken from a person who has just died or suffered brain death.
- The wait for a deceased donor kidney is often longer than the wait for a living donor kidney.
- Both living and deceased donor kidneys should be a good match for your body.
- Kidney infection is one of a number of infections that can involve the urinary tract.
- Infection of the kidney is very common, especially in young females.
- Causes of kidney infection are bacteria that have gained entry to the urinary tract, usually via the anus or vagina.
- Risk factors for kidney infection are pregnancy, sexual intercourse, a history of urinary tract infection, spermicide use, kidney stones, use of urinary catheters, diabetes, and surgery or instrumentation of the urinary tract.
Kidney infections are not contagious.
Symptoms of kidney infection are
- abdominal pain,
- painful urination, and
- a need to urinate frequently.
Treatment of kidney infection involves oral or intravenous antibiotics.
- Kidney infections can sometimes be prevented by changing urinary catheters frequently, good hygiene practices, and taking preventive antibiotics in certain people at high risk.
- If treated early and adequately, kidney infection generally has a good outcome.
Some people are at an increased risk of developing kidney disease. The risk factors for kidney disease include:
- high blood pressure
- having a family member with inherited forms of kidney disease (e.g., polycystic kidney disease)
- If you have these risk factors, it doesn’t mean that you will get kidney disease for sure, but you should have your kidney function tested regularly. Even if you don’t have any risk factors for kidney disease, you can still get it. So be sure to have regular check-ups with your doctor.
How can diabetes affect kidneys?
- Too much glucose, also called sugar, in your blood from diabetes damages your kidneys’ filters.
- If the filters are damaged, a protein called albumin, which you need to stay healthy, leaks out of your blood and into your urine.
- Damaged kidneys do not do a good job of filtering wastes and extra fluid from your blood. The wastes and extra fluid build up in your blood and make you sick.
- Diabetes is a leading cause of kidney disease. Diabetic kidney disease is the medical term for kidney disease caused by diabetes.
- Diabetic kidney disease affects both kidneys at the same time.
Looking after your kidneys:-
- drinking 6 – 8 glasses of water or other drinks (such as milk drinks or fruit juice) each day. Your kidneys like water best.
- eating a healthy diet so that you get all the minerals and vitamins that your body needs
- staying away from drugs like tobacco and alcohol – these make the kidneys’ job more difficult.
World Kidney Day:-
World Kidney Day (WKD) is a global health awareness campaign focusing on the importance of the kidneys and reducing the frequency and impact of kidney disease and its associated health problems worldwide. World Kidney Day is observed annually on the 2nd Thursday in March.