The kidneys help the body to filter waste products from the blood, balance the electrolyte levels in the body, control blood pressure, and stimulate the production of red blood cells.
The kidneys are located in the abdomen toward the back, on each side of the spine. Their blood supply comes from the aorta and send blood back to the heart through the renal veins to the vena cava.
There are numerous causes of kidney failure, and treatment of the underlying disease may be the first step in treating the condition.
Some causes of kidney failure are treatable and the kidney function may return to normal. However, kidney failure may be irreversible in some other cases.
The diagnosis of kidney failure usually is made by blood tests measuring BUN, creatinine, and glomerular filtration rate (GFR).
How do the kidneys function?
When blood flows to the kidney, sensors within specialized kidney cells control how much water to excrete as urine, along with the appropriate concentration of electrolytes. If a person is dehydrated from exercise or from an illness, the kidneys will retain as much water as possible and the urine becomes highly concentrated. However, the urine becomes more dilute and clearer when sufficient water is in the body. This system is controlled by renin, a hormone produced in the kidney.
Also, kidneys are the source of erythropoietin (hormone that stimulates the bone marrow to produce red blood cells) in the body. Special cells in the kidney monitor the oxygen concentration in blood. If oxygen levels fall, erythropoietin levels rise and the body begins to make more red blood cells.
Urine that is made by each kidney flows through the ureter (tube that connects the kidney to the bladder). Urine is stored within the bladder which is subsequently passed out of the body through a tube called the urethra.
Signs and symptoms of kidney failure
Kidney failure may be not produce any symptoms initially. However, as the kidney function decreases. At this stage, symptoms may include:
- inability to regulate water and electrolyte balances
- difficulty to clear waste products from the body
- inability to promote red blood cell production.
If left untreated, the following symptoms of kidney failure may develop into fatal circumstances. Symptoms at this stage may include:
- shortness of breath
- edema or generalized swelling
- loss of appetite
- High blood potassium
- Congestive heart failure
- metabolic acidosis
- fatal heart rhythm disturbances (arrhythmias) including ventricular tachycardia and ventricular fibrillation
- Rising urea levels in the blood may lead to brain encephalopathy, inflammation of the heart lining, or low calcium blood levels (hypocalcemia)
Causes of kidney failure
Kidney failure may be caused by an acute injury to the kidneys or from chronic diseases that causes the kidney functions to deteriorate.
Kidney function is lost rapidly in acute renal failure. Since most people have two kidneys, both kidneys must be impaired for complete kidney failure to occur. Luckily, if only one kidney fails or is diseased it can be removed, and the remaining kidney may continue to have normal kidney function. If both kidneys are injured or diseased, a donor kidney may transplanted.
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The list of causes of kidney failure is often classified based on where the injury has occurred.
Prerenal causes: These are causes due to decreased blood supply to the kidney. Examples of prerenal causes of kidney failure are:
- Insufficient fluid intake
- Hypovolemia (low blood volume) due to blood loss
- Dehydration from loss of body fluid
- Medication like diuretics may cause excessive water loss
- Abnormal blood flow to and from the kidney due to obstruction of the renal artery or vein.
Causes of acute kidney failure
Causes of damage directly to the kidney itself can be classified into:
- Renal causes
- Post-renal causes
Renal causes of kidney failure
Sepsis: Sepsis occurs when the body’s immune system is subdued by infections and causes inflammation and stoppage of the kidneys. This usually does not occur with simple urinary tract infections.
Rhabdomyolysis: This condition occurs when there is significant muscle breakdown in the body, and the damaged muscle fibers congest the filtering system of the kidneys. Rhabdomyolsis can also be caused by some medications used to treat high cholesterol.
Multiple myeloma: This condition is also called acute glomerulonephritis or inflammation of the glomeruli. Many diseases can cause this inflammation including:
- Wegener’s granulomatosis
- Goodpasture syndrome
- Systemic lupus erythematosus.
Hemolytic uremic syndrome: This condition is caused by the abnormal destruction of red blood cells. It mostly occurs in children after certain infections, but also may be caused by pregnancy or certain medications.
Medications: Some medications are toxic to the kidney including:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen
- Medications containing iodine like radiology dyes
- Antibiotics like aminoglycosides gentamicin
- Lithium (Eskalith, Lithobid)
Post-renal causes of kidney failure
Post renal causes of kidney failure are caused by factors that affect outflow of the urine:
- A blockade of the bladder or the ureters can cause back pressure to build up as the kidneys continue to produce urine. The urine eventually backs up into the kidneys. The kidneys can get damaged when the pressure increases too high.
- Kidney stones can affect only one kidney and do not cause kidney failure. However, if there is only one kidney present, the stones can cause the other kidney to shut down.
- Prostate cancer may block the urethra and prevents the bladder from draining.
- Tumors in the abdomen that surround and obstruct the ureters.
Causes of chronic kidney failure
Chronic kidney failure does not usually develop suddenly, but gradually, extending over months and years. The most common causes of chronic renal failure are related to
- poorly controlled hypertension
- poorly controlled diabetes
- chronic glomerulonephritis.
Other less common causes of chronic renal failure include:
- Prostate disease
- Polycystic kidney disease
- Kidney stones
- Reflux nephropathy
- Nephrotic syndrome
Kidney failure and pain
Kidney failure is usually painless, but the significances of kidney failure may cause pain in different parts of the body.
Normal functioning kidneys filter a protein from the blood stream called amyloid. In kidney failure, amyloid proteins in the blood rise, and can separate and clump together forming amyloid deposits into a variety of tissue and organs, including joints and tendons. Symptoms at this point may include pain, joint stiffness, and swelling.
Diagnosis of kidney failure
In most cases, the diagnosis of kidney failure is a result of a patient’s disease or injury. Diagnosis of kidney failure can be established by:
Blood tests such as BUN, creatinine, and GFR – measure the accumulation of waste products in the blood.
Urine tests to measure the amount of protein, measure the concentration of electrolytes, or detect the presence of abnormal cells.
Other tests may include kidney biopsy or abdominal ultrasound.
Treating kidney failure
Once kidney failure is detected, the most important thing is to prevent further worsening of renal function. The kidneys will progress to complete failure if left untreated for long. However, if underlying illnesses are addressed and treated aggressively, kidney function can be preserved, though not always improved.
Kidney failure may be controlled by using different classes of medications. These includes:
- Phosphorus-lowering medications, for example, calcium carbonate, calcitriol, and sevelamer (Renagel)
- Erythropoietin for red blood cell production stimulation, for example, erythropoietin
- Iron supplements for red blood cell production
- Blood pressure medications
In cases where the kidneys completely fail, treatment options are limited to dialysis or kidney transplantation.
Best and Worst Foods for Kidney Failure
For those with impaired kidney function, consulting a dietician may be helpful to understand what foods may or may not be appropriate.
In this state of impaired kidney function, the kidneys cannot easily remove excess water, salt, or potassium from the blood, so foods high in potassium salt substitutes may be consumed in small quantities. Foods rich in potassium:
- Sweet potatoes
Foods rich in phosphorus may need to be avoided as they are linked with calcium metabolism and may be raised in the body in kidney failure. Excess phosphorus can leech calcium from the bones and cause fractures and osteoporosis. Examples of foods high in phosphorus include:
- Black beans
- Baked beans
- Kidney beans
- Soy beans
- Whole grain products
- Canned iced teas
- Dark cola drinks
- Organ meets
- Bran cereals
Sources: medicinenet.com, webmd. youtube.com, mayoclinic.org
Disclaimer: The content provided on healthdiary365.com is purely informative and educational in nature and should not be interpreted as medical advice. Please use the content only in consultation with an appropriate certified medical doctor or healthcare professional.