Cylinders are structures formed exclusively in the kidneys that are often not identified in the urine of healthy people. For example, when cylinders are seen in the urine test, it may indicate that there is some change in the kidneys, such as infection, inflammation or destruction of kidney structures.
The presence of cylinders is verified by urine examination, SAA or type I urine test, in which, by microscopic analysis, it is possible to observe the cylinders. Normally, when the presence of cylinders is checked, other aspects of the test, such as leukocytes, the number of epithelial cells and erythrocytes, for example, are also modified. Here’s how to understand the urine test.
- Depending on the place of formation and components.
- Cylinders may be considered normal.
- But when large quantities of cylinders are checked and other changes are identified in the urine test.
- It is important that research is conducted.
- As this may indicate further serious changes.
The main types of cylinders in urine and their possible meaning are
This type of cylinder is the most common and is essentially made up of the Tamm-Horsfall protein. When up to 2 cylinders of hyaline are found in the urine, this is normally considered normal and can occur due to intense physical activity, dehydration, excessive heat or stress. However, when several hyalin cylinders are observed, this may be a sign of glomerutonephritis, pyelonephritis or chronic kidney disease, for example.
This type of cylinder, in addition to the Tamm-Horsfall protein, is composed of red blood cells and usually indicates damage to any structure of the nephron, which is the functional unit of the kidneys responsible for the production of urine.
It is common that, in addition to the cylinders, the urine test may indicate the presence of proteins and many red blood cells. In addition to revealing kidney problems, hematic cylinders may also appear in the urine test of healthy people after playing contact sports.
The leukodate cylinder consists mainly of leukocytes and its presence usually indicates an infection or inflammation of the nephron, usually associated with pyelonephritis and acute interstitial nephritis, which is a non-bacterial inflammation of the nephron.
Although the leukodate cylinder indicates pyelonephritis, the presence of this structure should not be considered as a single diagnostic criterion and it is important to evaluate other test parameters.
The bacterial cylinder is difficult to see, however, it is common to appear in pyelonephritis and is made up of bacteria related to the Tamm-Horsfall protein.
The presence of epithelial cell cylinders in the urine usually indicates advanced destruction of the renal tubule, but may also be associated with drug toxicity, exposure to heavy metals and viral infections.
In addition to these, there are also granular, cerebral and fatty cylinders, the latter formed by fat cells and usually associated with nephrotic syndrome and diabetes mellitus. It is important for your doctor to evaluate the result of your urine test, especially if the report indicates the presence of cylinders. Thus, your doctor can look for the cause of the cylinder and start the most appropriate treatment.
The cylinders are formed inside the twisted distal tube and the collecting duct, which are structures related to the formation and removal of urine. One of the main components of the cylinders is the Tamm-Horsfall protein, which is a protein excreted by the renal tubular epithelium and is naturally eliminated in the urine.
When there is greater protein removal from stress, intense physical activity or kidney problems, proteins tend to stick to form a solid structure, the cylinders. Also during the formation process, elements present in tubular filtration (later called urine), such as epithelial cells, bacteria, pigments, red blood cells and leukocytes, for example, may also be incorporated.
After cylinder formation, constituent proteins are detached from the tubular epithelium and removed in the urine.
See more details about urine formation.