OVERVIEW
Tubular forms are cylindrical protein aggregates formed by the coagulation of proteins, cells, and cellular debris in the renal tubules and collecting ducts. Tubular urine (cylinderuria) refers to an increase in the number of tubular forms in the urine. Tubular patterns are an important component of the urinary sediment, and the presence of tubular urine suggests substantial renal damage, representing glomerular or tubular damage.
Etiology
Under pathological conditions, due to increased permeability of the glomerular filtration membrane, a large amount of protein passes from the glomerulus into the renal tubules. In the distal tubules and collecting ducts of the kidneys, proteins coalesce and precipitate in the lumen of the tubules due to condensation (water uptake), acidification (increase in acidity), and the presence of chondroitin sulfate to form the tubular pattern.
Cellular tubular patterns are common in acute glomerulonephritis, acute pyelonephritis, interstitial nephritis, and acute renal failure; granular tubular patterns are seen in a variety of glomerular disorders and toxic injuries to the renal tubules; waxy and fatty tubular patterns are most often seen in chronic renal disease with decreased urinary output or in nephrotic syndromes when steaturia is present.
It is common in the following diseases:
1. malignant hypertension proteinuria, azotemia, nausea, tinnitus, tubular urine, acute hypertension, etc.
2. Radiation nephritis proteinuria, tubular urine, fatigue, nephrotic syndrome, etc.
3. Pediatric chronic glomerulonephritis proteinuria, tubular urine, vitreous changes in the small arteries of the entry glomeruli, oliguria, etc.
4. Nail-patella syndrome with patellar defect or dysplasia, joint effusion, joint deformity, tubular urine, angular nail arc shadow, etc.
5. Pediatric polyarteritis nodosa convulsions, proteinuria, polyneuritis, malaise, abdominal pain, tubular urine, jaundice, etc.
Examination
Due to the different components, morphology and nature of tubular pattern, tubular pattern can be categorized into the following types:
(1) Cellular Tubular Cellular tubular is divided into the following three categories: ① epithelial cell tubular; ② erythrocyte tubular; ③ leukocyte tubular.
(2) Transparent tubular pattern Transparent tubular pattern can be seen occasionally in the morning urine of normal people, which can be increased during strenuous exercise, heavy physical labor, fever and anesthesia, and can be increased during acute pyelonephritis, acute and chronic glomerulonephritis, malignant hypertension and heart failure.
(3) Granular tubular pattern Coarse granular tubular pattern is seen in chronic glomerulonephritis or drug intoxication and other causes of tubular damage. Fine granular tubular pattern is seen in chronic glomerulonephritis or acute glomerulonephritis.
(4) Wax-like tubular pattern Wax-like tubular pattern is seen in the advanced stage of renal insufficiency or renal amyloidosis, and occasionally seen in acute or chronic rejection reaction after renal transplantation.
(5) Fatty tubular pattern When the tubular mechanism contains most of the fat droplets or embedded in the renal tubular cortical cells containing fat droplets, it is called fatty tubular pattern. The fat droplets are of different sizes, ovoid in shape and highly refractive. Fatty tubular pattern is seen in nephrotic syndrome, chronic glomerulonephritis and lipoid nephropathy.
Differential Diagnosis
Tubular urine requires a clear etiology, and clinical manifestations, laboratory tests and imaging tests help in the differential diagnosis.
1. Malignant hypertension: proteinuria, azotemia, nausea, tinnitus, tubulointerstitial urine, acute hypertension.
2. Radiation nephritis: proteinuria, tubular urine, fatigue, nephrotic syndrome, etc.
3. Pediatric chronic glomerulonephritis: proteinuria, tubular urine, vitreous changes of small arteries in the globe, oliguria, etc.
4. Nail-patella syndrome: patellar defect or dysplasia, joint effusion, joint deformity, tubular urine, angular nail arc shadow, etc.
5. Pediatric polyarteritis nodosa: convulsions, proteinuria, polyneuritis, malaise, abdominal pain, tubular urine, jaundice, etc.
Treatment principle
Tubular urine is a clinical manifestation of renal disease and does not represent the severity of renal disease. Early diagnosis and treatment should be actively carried out after discovery.