Why is there so little urine?

Under normal circumstances, people urinate about 5-6 times a day. urinating once or less does not have much impact, but if you urinate very little, you should pay attention. From clinical examination, it may be due to insufficient blood volume, shock, decreased cardiac output, hepatorenal syndrome, renal parenchymal damage, renal interstitial disease, renal vascular disease, etc., which can cause this symptom, so you must check and treat it in time.

(1) Insufficient blood volume: It starts with functional oliguria and anuria. Once the blood volume is replenished, the urine volume will recover immediately. If it is not diagnosed and treated in time, it may cause organic kidney damage. Acute renal failure, manifested by oliguria or anuria, is seen in severe dehydration, massive bleeding, extensive burns, etc.

(2) Shock: Shock due to various reasons causes a decrease in renal perfusion pressure and a serious deficiency in glomerular filtration rate, which is seen in anaphylactic shock, hemorrhagic shock, cardiogenic shock, infectious toxic shock, etc.

(3) Decreased cardiac output : At this time, the blood supply to the kidneys decreases significantly, which is seen in left heart failure, severe arrhythmias, cardiac tamponade and constrictive pericarditis.

(4) Hepatorenal syndrome: In the late stage of cirrhosis, there is severe ascites and severe renal hypoperfusion, which manifests as oliguria or anuria. Once the ascites from cirrhosis is relieved, the kidneys will recover and the urine volume will increase. In hepatorenal syndrome, pathological examination of the kidneys is normal.

(5) Renal parenchymal damage: Whether it is primary glomerulonephritis or secondary to systemic lupus erythematosus, polyarteritis nodosa, infective endocarditis, dermatomyositis, etc., it can cause renal parenchymal damage and even renal function damage or failure, leading to oliguria and anuria.

In the late stage of chronic renal failure, the kidneys atrophy, the glomerular filtration rate decreases, and the urine volume may be significantly reduced or even anuria; in the oliguria and anuria stage of acute renal failure, the symptoms are oliguria and anuria.

(6) Renal interstitial disease: The most common drug allergies such as penicillin, sulfonamides, rifampicin, aminoglycosides, etc. cause renal interstitial damage. It is also seen in the late stage of renal damage in chronic pyelonephritis.

(7) Renal vascular diseases: renal cortical vasospasm or embolism, reduced renal blood supply leading to oliguria or anuria, seen in disseminated intravascular coagulation (DIC), pregnancy-induced hypertension syndrome, large-area burns, etc.