Orthostatic proteinuria

Introduction Postural or orthostatic urinary protein refers to an increase in urinary protein excretion only in the upright position or in the position of the anterior spine, while urinary protein excretion is normal in the supine position. It can be divided into temporary (or intermittent) and fixed according to whether the urinary protein in the erect position often appears. The former refers to the urine protein not necessarily increasing every time in the upright position, and the latter refers to the urinary protein displacement in the upright position. More than normal. Orthostatic urine protein is more common, seen in 2% to 5% of prepubertal adolescents, rare after 30 years of age. Asymptomatic urine proteins found in population censuses are mostly of this type. Among them, 70% to 80% are temporary, and 15% to 20% are fixed.

Cause

At present, the pathogenesis of the disease is unknown. It is generally considered to be due to changes in renal hemodynamics during the upright position, renal venous reflux disorder or excessive renal artery contraction. Quantitative examination results in 24-hour urine protein quantitation of 20-80 mg (including Albumin accounted for 40%, globulin accounted for 15%, and urinary tract tissue protein accounted for 40%. If the 24-hour urine protein is more than 150mg, some experts believe that it is caused by a change in the renin-angiotensin system in the upright position. In recent years, some experts believe that such children often have a basis for mild immune damage of the glomerulus plus an erect kidney. Caused by changes in hemodynamics.

an examination

Related inspection

Urine protein quantitative protein index (SPI)

Because of the temporary renal urinary protein, renal biopsy is rarely performed, so little is known about its pathological changes. Fixed erectile urinary protein also has few specific lesions. Sinniah et al reported that 30% of cases had normal renal tissue or only mild glomerular changes, 70% showed mild mesangial hyperplasia, and occasionally Ig or C3 deposition. Robinson et al reported that 47% had no abnormalities, 45% had mild glomerular changes but no clear glomerular basement changes, and 8% had clearer primary glomerular lesions.

Clinically, such patients have occasionally found in the physical examination or urine screening, the child has no exact history of kidney, and a positive family history, renal function, blood biochemistry, B-mode ultrasound, intravenous pyelography, etc. The inspections are all within the normal range. Its main performance is that the erect protein is over-represented in the upright position, but it is normal in the lying position and can be confirmed by an upright test. The method is as follows: urinating before going to bed at night, and getting up in the morning to urinate for examination, the urine protein qualitative test formed at night is negative and quantitative.

Differential diagnosis

(1) Temporary or transient urine protein: refers to normal kidney, but transient urine protein occurs during fever, heart failure or dehydration. After exercise, there may be an increase in temporary urinary protein excretion, especially after adolescent long-distance running, swimming, football, basketball and other sports, the protein in the urine is transiently increased.

(2) Intermittent proteinuria: Repeated infection of cystitis, pyelonephritis, urine protein will appear, once the infection is controlled, proteinuria will disappear. And high blood pressure, heart failure and other diseases will appear intermittent urine eggs with the condition.

(3) Persistent (pathological) proteinuria: Usually when the kidney spheroid or tubular irreversible damage occurs, there will be persistent proteinuria. Glomerular disease is the most common cause of pathological proteinuria.

(4) Obesity: If the patient is overweight, overweight will increase the kidney load and will cause proteinuria.

(5) Standing proteinuria: The young man's spine will have proteinuria when it bends forward and bends into the kidneys. If left untreated, it will disappear automatically around the age of thirty.

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