Acute renal failure, or ARF, is a condition in which the kidneys become acutely unable to perform their normal functions. Typical causes of ARF include some medications such as nonsteroidal anti-inflammatories, decreased blood supply to the kidney, or obstruction of urine flow to the bladder and out of the body, according to Dr. Andre Kaplan, in "Current Diagnosis & Treatment Critical Care." While the causes of ARF are numerous, the effects of a damaged kidney are predictable, given the normal functions of the kidney. Most importantly, the kidney is responsible for maintaining the right amount of water and salt in the blood in order to optimize the functioning of the other organs in the body.
Fluid Overload
The kidney is a major modulator of the water content of the blood. When the kidney becomes acutely damaged, its ability to excrete water in the form of urine is diminished. In acutely sick patients, this can cause pooling of this extra water in the lungs otherwise known as pulmonary edema, according to Kaplan. Pulmonary edema is a potentially dangerous condition, as the water in the lungs blocks movement of oxygen from the inhaled air into the blood.
Electrolyte Abnormalities
The kidney is responsible for maintaining a balance among the many ions present in the blood that the body relies on. Specifically, potassium, phosphorus and calcium levels are carefully controlled by the normal kidney in order to allow the cells of the body to function normally. When the kidney is acutely damaged, its ability to maintain the balance of these ions diminishes, leading to higher or lower than normal levels of potassium, phosphorus and calcium. These can be dangerous particularly to the heart muscle where derangements can cause abnormal heart rhythms or cessation of the heart all together.
Uremia
The kidneys are responsible for eliminating a waste product called urea from your body through the urine. If allowed to build up in the body, urea can cause confusion and an alteration in mental status as it is irritating to the cells of the brain, according to the American College of Physicians. Similarly, it is irritating to the fibrous sac surrounding the heart and causes pericarditis, or thickening of the fibrous sac. This can lead to ineffective pumping of the heart. Both of these effects from abnormally high levels of uremia are indications for dialysis, a way of filtering the blood of these substances by bypassing the kidneys.
References
- Current Diagnosis & Treatment Critical Care, 3rd Edition; "Chapter 13. Renal Failure"; Andre A. Kaplan, MD; 2008
- ACP PIER, Journal Club & AHFS DI® Essentials; "Acute Kidney Injury"; American College of Physicians; 2010
