Question

Please define the pathology Acute Renal Failure, how does it affects on the body system and what are the associated anatomy parts of the body affected?

Answer 1

Acute kidney injury (AKI), previously called acute renal failure (ARF), is an abrupt loss of kidney function that develops within 7 days. ARF, characterized by sudden loss of the ability of the kidneys to excrete wastes, concentrate urine, conserve electrolytes, and maintain fluid balance.

Its causes are numerous. Generally it occurs because of damage to the kidney tissue caused by decreased kidney blood flow (kidney ischemia) from any cause (e.g., low blood pressure), exposure to substances harmful to the kidney, an inflammatory process in the kidney, or an obstruction of the urinary tract that impedes the flow of urine. AKI is diagnosed on the basis of characteristic laboratory findings, such as elevated blood urea nitrogen and creatinine, or inability of the kidneys to produce sufficient amounts of urine. AKI may lead to a number of complications, including metabolic acidosis, high potassium levels, uremia, changes in body fluid balance, and effects on other organ systems, including death. People who have experienced AKI may have an increased risk of chronic kidney disease in the future. Management includes treatment of the underlying cause and supportive care, such as renal replacement therapy.

The kidneys play key roles in body function, not only by filtering the blood and getting rid of waste products, but also by balancing the electrolyte levels in the body, controlling blood pressure, and stimulating the production of red blood cells. The kidneys are located in the abdomen toward the back, normally one on each side of the spine. They get their blood supply through the renal arteries directly from the aorta and send blood back to the heart via the renal veins to the vena cava. (The term "renal" is derived from the Latin name for kidney.)

When blood flows to the kidney, sensors within specialized kidney cells regulate how much water to excrete as urine, along with what concentration of electrolytes. For example, if a person is dehydrated from exercise or from an illness, the kidneys will hold onto as much water as possible and the urine becomes very concentrated. When adequate water is present in the body, the urine is much more dilute, and the urine becomes clear. This system is controlled by renin, a hormone produced in the kidney that is part of the fluid and blood pressure regulation systems of the body.

Kidneys are also the source of erythropoietin in the body, a hormone that stimulates the bone marrow to make red blood cells. Special cells in the kidney monitor the oxygen concentration in blood. If oxygen levels fall, erythropoietin levels rise and the body starts to manufacture more red blood cells. Urine that is made by each kidney flows through the ureter, a tube that connects the kidney to the bladder. Urine is stored within the bladder, and when urination occurs, the bladder empties urine through a tube called the urethra.

Kidney failure may occur from an acute situation that injures the kidneys or from chronic diseases that gradually cause the kidneys to stop functioning.

In acute renal failure, kidney function is lost rapidly and can occur from a variety of insults to the body. Since most people have two kidneys, both kidneys must be damaged for complete kidney failure to occur. Fortunately, if only one kidney fails or is diseased it can be removed, and the remaining kidney may continue to have normal kidney (renal) function. If a both patient's kidneys are injured or diseased, a donor kidney(s) may transplanted.

Initially, kidney failure may be not produce any symptoms (asymptomatic). As kidney function decreases, the symptoms are related to the inability to regulate water and electrolyte balances, clear waste products from the body, and promote red blood cell production.

If unrecognized or untreated, the following symptoms of kidney failure may develop into life-threatening circumstances.

• Lethargy
• Weakness
• Shortness of breath
• Generalized swelling (edema)
• Generalized weakness due to anemia
• Loss of appetite
• Fatigue
• Congestive heart failure
• Metabolic acidosis
• High blood potassium (hyperkalemia)
• Fatal heart rhythm disturbances (arrhythmias) including ventricular tachycardia and ventricular fibrillation
• Rising urea levels in the blood (uremia) may lead to brain encephalopathy, pericarditis (inflammation of the heart lining), or low calcium blood levels (hypocalcemia)

Kidney failure in itself does not cause pain. However, the consequences of kidney failure may cause pain and discomfort in different parts of the body. Often, a patient is seen for another medical condition and the diagnosis of kidney failure is a consequence of the patient's disease or injury. In patients with chronic kidney disease due to diabetes, high blood pressure, or another related medical condition his or her medical care team most likely monitors kidney function as part of the his or her routine long-term medical care plan.

Blood tests
Diagnosis of kidney failure can be confirmed by blood tests such as BUN, creatinine, and GFR; that measure the buildup of waste products in the blood.

Urine tests
Urine tests may be ordered to measure the amount of protein, detect the presence of abnormal cells, or measure the concentration of electrolytes.

Other tests
Other tests are used to diagnose the type of kidney failure such as:

• Abdominal ultrasound
• Kidney biopsy

Kidneys flush out the toxins and wastes from the body and help in the hurdle-free functioning of the entire body (including the other multi-organ systems). However, when the kidneys fail to function properly, as in the case of chronic kidney disease, the repercussions are faced by the entire body and have a direct effect on several systems of the body.

Systems affected by kidney disease

Cardiovascular system
Kidney failure can adversely affect the cardiovascular system due to the buildup of fluid around the lungs, body tissue, and heart, which exerts a greater pressure on the heart thus leading to blood pressure or a rise in it. The excess amount of urea in the body that accumulates due to loss of kidney function is toxic in nature and causes inflammation of the heart’s pericardium. Additionally, the buildup of salts and fluid due to kidney disease along with production of renin damages the blood vessels, thereby leading to atherosclerosis and hypertension. Thus, kidney disease has serious side effects on the cardiovascular system, which can even lead to strokes and heart attack.

Blood and circulatory system
Anemia and iron deficiency are consequences of damaged kidneys because the kidneys affect the production of the erythropoietin hormone, which in turn causes anemia. Further dizziness, shortness of breath, tiredness, and irritability are caused due to anemia, which can lead to organ or heart failure if left untreated.

Skeletal and musculoskeletal system
Kidney disease leads to high levels of parathyroid hormone, which in turn draws out the calcium content from the bones, thereby making the bones thin, weak, and malformed because of the mineral imbalance. The risk is greater for women who are post-menopausal and the elderly. Kidney failure also leads to deposits of amyloid protein within the joints and tendons, thus causing amyloidosis. This disorder causes fluid to build up in the joints along with stiffness and pain.

Integumentary system
The skin (integumentary system) is harmed due to the imbalance of minerals including calcium and phosphorus caused by kidney disease. Also, the presence in kidney disease patients of the parathyroid hormone, which draws calcium from the bones, leads to itching on the skin of the hands, legs, back, and chest. Severe scratching and itching can further cause wounds, sores, and punctures to the skin.

Digestive system
The high levels of urea in the body can cause gastrointestinal problems, such as poor appetite, nausea, diarrhea, vomiting, peptic ulcers, bad taste in mouth, and inability to consume required minerals, all due to kidney disease.

Circadian system
Renal failure leads to an inability to sleep or to remain asleep, thus affecting the sleep or circadian cycle. Sleep apnea, breathing problems, and restless leg syndrome, which causes pain and restlessness, all affect the quality of sleep, which further leads to lower immunity and exhaustion, thus affecting daily life. This further affects the ability to fight diseases.

Nervous system
All of the above effects of kidney disease on the body along with hormonal and mineral imbalance can cause depression, thus affecting day-to-day living.

Food forms the basis for the survival of all individuals. Apart from being the fuel that drives our bodies, the food we eat can also define the way we are, how our body operates, and what disorders or conditions develop or are likely to develop. Thus, it is safe to say that the food we eat defines how healthy or unhealthy we are. Foods can also help change the way we feel or improve the condition of the body in case of a disease or disorder. For instance, having food that is low in fat content and has less sugar helps improve blood sugar levels as well as keeps diabetes in check. The same is the case for chronic kidney disease. Patients suffering from kidney disease can feel better, prevent further damage, and even ease some of the symptoms by consuming food that is kidney friendly.