ARF is a condition when both kidneys almost suddenly fail to perform their functions. The failure occurs within a few hours/ days. This may result from an acute disease of the kidneys, as a result of allergic manifestation operating gravely on the kidneys, i.e. acute GN, described earlier. Besides, sometimes blood pressure may be so acutely elevated, that it may knock down both the kidneys, resulting in their sudden/ acute failure. Further, an acute infection of the kidneys (pyelonephritis), following some obstructive lesion in the urinary tract, like a urinary stone, or benign enlargement of the prostate, may also cause ARF, if the infection is not controlled promptly. This aspect has already been discussed under the head of UTI urinary tract infection.

ARF may occur due to other conditions in the body, which cause reduced blood flow to the kidneys, so that the excretion of waste products from the blood is greatly hampered. Such conditions are common enough, and one needs to know about these. The most common is dehydration, due to loss of fluids in severe vomiting, diarrhoea, burns, crush injuries, etc. ARF develops when such conditions are not immediately attended to, and intravenous fluids are not administered in time.

Similarly, severe haemorrhage from the body, necessitating immediate blood transfusion, may cause this condition. A similar situation arises when there is a marked fall in blood pressure (hypotension) due to heart attack/failure, shock etc., so that blood supply to the kidneys is adversely affected.

Another important cause of ARF may be the indiscriminate use of drugs, especially those drugs which are toxic for the kidneys. If one studies the causes of renal failure in general, one will find a substantial number - to the extent of 50 per cent in this group. These are called 'iatrogenic' cases, i.e. when the disease has been induced in the body by the person himself, for example, by the unnecessary use of drugs, etc.

How to suspect a case of ARF?

The most important step in the clinical diagnosis of the disease is that, as a result of the acute involvement of the kidneys, both of them become badly affected and their function becomes markedly deranged, to the extent that the kidneys are not able to excrete urine in sufficient/normal quantities. Thus, the patient starts passing less urine, and slowly the excretion of urine becomes so little, that on measuring it in 24 hours, it will be hardly 400 ml, while an individual is expected to pass about 1500-2000 ml of urine per day.

Serum creatinine and blood urea also rise. Serum creatinine is a more sensitive index of kidney function than blood urea, which varies with the intake of food by the patient. Both the levels of these tests rise daily, if timely treatment is not initiated. Levels of serum creatinine have already been mentioned, and to repeat, normal levels of serum creatinine are 0.8 mg/ dl to 1.4 mg/ dl, with an average 1.00 mg/ dl. If the levels of serum creatinine rise more than 8.00 mg/ dl, urgent dialysis is required to save the kidneys/life of the patient.