There is a lot of foam in the urine. Is it really caused by proteinuria?

"Doctor, I noticed a lot of bubbles in my urine recently. Is this proteinuria? Are my kidneys damaged?"

Today we will introduce you to proteinuria and help you understand the clues about kidney health hidden in urine.

Urine protein physiological status

Urine protein refers to a common abnormal result of clinical urine test when the protein content in urine exceeds the normal range . The normal human body excretes very little protein in urine every day, mainly low molecular weight protein and a small amount of albumin. The 24-hour excretion is generally less than 150 mg, and the qualitative protein test of urine routine is negative.

Urine protein diagnosis criteria

If the urine protein test shows that the qualitative result is greater than or equal to positive, the 24-hour urine protein amount is greater than 150 mg, and the urine protein to urine creatinine ratio is greater than 0.2, any one of these is proteinuria.

Proteinuria is the most common clinical manifestation of kidney disease and can also be seen in certain non-renal diseases.

Causes of foamy urine

It is worth noting that proteinuria is not equal to foamy urine . The key reason for the generation of foam in urine lies in the surface tension of the liquid . There are many reasons for foamy urine, which are not necessarily related to the kidneys. Its appearance only means that the surface tension of urine has increased. For example, drinking too little water or sweating too much will increase the concentration of inorganic salts in the urine, which will increase the surface tension of urine. When the urine is still for a while, the foam will disappear by itself.

If this is the case, all you need to do is stay hydrated.

Types of proteinuria

There are also different types of proteinuria:

1. Physiological proteinuria: transient proteinuria occurs due to the stress of fever, cold, high-temperature work, sympathetic nerve excitement, and intense exercise, but there is no organic lesion in the kidneys.

2. Pseudoproteinuria: It is often caused by the presence of blood, pus, highly concentrated urine, or the use of contrast agents such as ceftriaxone. It may also indicate lower urinary tract disease.

3. Orthostatic proteinuria: A type of orthostatic proteinuria that often occurs in adolescents. It refers to an abnormal clinical urine test result in which urine protein appears when the body is standing upright and disappears when lying down. The cause of the disease is not yet clear.

4. Pathological proteinuria: Pathological proteinuria requires special attention. Its characteristics are persistence - mostly persistent proteinuria, associated symptoms - often accompanied by other manifestations of kidney disease, such as hypertension, edema, etc., and combined with other problems - often combined with other urine test abnormalities, such as hematuria, leukocyturia, and tubular urine.

The kidneys are like a sieve for the body, sifting out waste and garbage. Precious nutrients - protein are not allowed to pass through. If too much protein leaks out, it most likely means that the sieve is broken, that is, there is an organic problem with the kidneys. Various primary or secondary glomerular diseases, tubular interstitial diseases, hereditary kidney diseases, renal vascular diseases and other kidney diseases (gestational nephropathy, radiation nephropathy, transplant nephropathy), etc. may all lead to pathological proteinuria.

If foamy urine continues to appear, with oily substances floating in it, or even small bubbles that are difficult to dissipate like beer foam, it is very likely caused by increased protein content in the urine. At this time, you must be vigilant and go to the hospital for a routine urine test as soon as possible. The type of kidney damage can be determined by the random urine protein marker test. Therefore, long-term follow-up of these patients is very necessary.

Since different random urine protein markers vary greatly in different individuals and at different stages of the disease, combined detection of urine protein markers can help diagnose kidney damage at an early stage.

In addition, for the prevention and control of proteinuria, the general population can screen by having a routine urine test once a year , or doing a random urine protein quantitative monitoring, and urine protein marker testing.

Patients with hypertension, diabetes, obese people, the elderly, and those with a family history of kidney disease should pay closer attention and maintain regular review and long-term follow-up of urine protein.

Authors of this article: Ying Furong (Chief Technician of the Laboratory Department, the First Affiliated Hospital of Wenzhou Medical University), Ma Jun (Attending Physician of the Pathology Department, the First Affiliated Hospital of Wenzhou Medical University)

Other staff: Chen Chen, Lü Yujie, Tong Yuheng, Yang Qiuqin (Wenzhou Medical University)