Is it normal for a child to urinate less?

If a child has little urine, it is definitely not a normal phenomenon. Under normal circumstances, the amount of urine will be at an average level and will not be very small. If this is the case, it will cause disease symptoms due to the impact on their original urethral system, or kidney disease. In fact, the cause of this disease is quite complicated and needs to be clarified.

1. Prerenal

(1) Decreased effective blood volume. Shock, severe water loss, massive bleeding, nephrotic syndrome, and hepatorenal syndrome caused by various reasons cause a large amount of water to infiltrate the tissue spaces and serosal cavities, resulting in decreased blood volume and reduced renal blood flow.

(2) Heart failure due to various reasons caused by decreased cardiac pumping function, severe arrhythmia, and unstable systemic circulation function after cardiopulmonary resuscitation. A decrease in blood pressure causes a decrease in renal blood flow.

(3) Renal vascular disease: renal vascular stenosis or inflammation, nephrotic syndrome, lupus nephritis, and renal artery embolism and thrombosis caused by long-term bed rest; hypertensive crisis, pregnancy-induced hypertension, etc. cause persistent spasm of the renal artery and renal ischemia leading to acute renal failure.

2. Renal

(1) Glomerular disease Rapidly progressive nephritis and chronic nephritis can cause a sharp deterioration in renal function due to severe infection, persistently high blood pressure, or the effects of nephrotoxic drugs.

(2) Renal tubular disease Acute interstitial nephritis includes drug-induced and infectious interstitial nephritis; acute tubular necrosis caused by biological toxins or heavy metal and chemical toxins; severe pyelonephritis complicated by renal papillary necrosis.

3. Postrenal

(1) Mechanical urinary tract obstruction such as stones, blood clots, necrotic tissue blocking the ureter, bladder inlet and outlet, or posterior urethra.

(2) External pressure on the urinary tract, such as tumors, retroperitoneal lymphoma, idiopathic retroperitoneal fibrosis, and prostatic hypertrophy.

(3) Other ureteral surgeries, scar contracture after healing of tuberculosis or ulcers, renal torsion caused by severe kidney ptosis or wandering kidney, neurogenic bladder, etc.

1. Physical examination

Pay attention to dehydration, blood pressure and peripheral circulation perfusion. For lower urinary tract obstruction, focus on checking the prostate, bladder urine volume and kidney palpation, etc.

2. Laboratory examination

Urine volume should be recorded daily, and relative urine density should be checked repeatedly in urinalysis, which is helpful for diagnosing renal parenchymal damage, renal failure and judging dehydration status; hematocrit in blood routine is effective in judging blood volume, and subclavian puncture to measure central venous pressure is more reliable for judging blood volume when necessary; blood biochemical examination includes renal function, acid-base balance, and electrolyte examination. When disseminated intravascular coagulation is suspected, routine DIC examination should be performed.

3. Instrumental examination: B-ultrasound, CT, MRI examination

It is very helpful in identifying stones, tumors, prostatic hypertrophy, hydronephrosis and tuberculosis.