Mucus is a protein made up of fibers. Grossly, it is a slimy substance that is brought about by glands and mucous membranes. It can be normally present in our urine in very small amounts.
However, it can be a sign of an underlying pathology. Moreover, the mucus can give the urine a cloudy appearance wherein the degree of turbidity depends on the amount of the mucus and other factors that may be causing this opacity. Normal urine is supposed to be clear which can be amber or straw-colored.
Picture 1: Normal urine is clear which can be amber or straw-colored.
Picture 2: Mucus threads in the urine give off this cloudy appearance. What could this mean?
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Mucus in Laboratory Urinalysis
Picture 3: Mucus Thread in the Urine
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Two forms of mucus appear in the urine: mucus threads and mucus corpuscles. Mucus threads are groups of mucus fibers bundled together forming a pale, irregular, longitudinal fragments that are narrowed on one end. If there is too much mucus, mucus casts will be formed.
The second form of mucus in the urine is called mucus corpuscles which is similar with pus cells in appearance. This is because mucus corpuscles are the crooked version of mucus cells .
Reporting of the presence of mucus in the urine is based on its number. It is written as “rare,” “few,” “moderate,” or “many” in the urinalysis laboratory result. It can also be stated according to the power field, i.e. “per low power field (LPF)” or “per high power field (HPF)” .
Picture 4: Sample of Urinalysis Laboratory Result
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Sources of Mucus in Urine
Picture 5: The Genitourinary Tract of Female and Male
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Most of the mucus in our urine comes from the linings of urinary bladder and urethra. The linings are made up of epithelial cells. These epithelial cells, in turn, make up the mucous membrane that secretes mucus for protection .
When a person urinates, a part of mucus comes along with urine and flows from the bladder to the urethra and out of your body. The mucus in the urine is not always visible by the naked eye because the refractive power of mucus and urine are almost the same .
Another source of mucus in urine is the source of the urine itself, the kidneys. Mucus contains a protein called Tamm-Horsfall protein or uromodulin. This protein is produced by the kidneys and it goes down with the urine through the ureter towards the urinary bladder into the urethra and out of the body .
For females, ovulation can also be a factor for you to see mucus threads in your urine. During ovulation, there is increased cervical and vaginal secretions that may flow together with the urine.
Picture 6: Cervical Mucus in the Urine
Image Source: wikihow.com
During menstruation, you may also notice that along with blood and endometrial fragments are mucus threads in the urine. This is normal.
Pathologic Causes of Mucus in Urine
Picture 7: Common Causes of Mucus in Urine
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A. Urinary Tract Infection (UTI)
UTI is a common disease wherein foreign bacteria invade your genitourinary tract. More often than not, the bacteria love multiplying in the bladder because this is where the urine is stored. This gives you cystitis. If left untreated and becomes severe, it can advance up to the kidneys, resulting to pyelonephritis.
The bacteria disrupt the epithelium of the linings of your genitourinary organs, causing epithelial cells to shed off, hence the presence of mucus in the urine.
Because of this, the person suffering from UTI experiences pain upon urination, urinary frequency, urinary urgency, dribbling of urine, hypogastric pain, and/or lower back pain.
UTI predisposes women in pregnancy because the uterus compresses the bladder, giving less room for extra urine. The bladder becomes filled easily and the epithelium becomes more irritated. Moreover, pregnant women have more active secretions on their reproductive tract so the mucus comes along with the urine.
B. Sexually Transmitted Diseases (STD)
STD/STI associated with the presence of mucus in the urine most commonly involves Gonorrhea and Chlamydia. Gonorrhea gives off a yellowish genital discharge while Chlamydia expresses a rather whitish discharge. Either ways, both make you shed off mucus in the urine.
Gonorrhea, Chlamydia, and other STDs/STIs are acquired if one does not practice safe sex. One simple way to prevent this is to wear condoms, or better yet, sexual abstinence is the key, especially if you do not know your sexual partner very well.
C. Irritable Bowel Syndrome (IBS)
IBS is an idiopathic (with unknown cause) disease wherein your bowel habits have been deviated from normal for 6 months or more. Aside from changes in the bowel habits, passage of mucus is also a manifestation of this syndrome .
The mucus comes from the intestine in this disease, not from any organs in the genitourinary tract.
The mixing of mucus does not occur inside the body because normally, there is no conduit between the genitourinary and gastrointestinal tracts that could make it possible for the mucus in the intestine to go directly into the urinary tract.
There is mucus in urine of IBS patients probably because the excess mucus from the stool gets mixed up with urine as it being passed out, especially if the person urinates and defecates at the same time. Considering the altered bowel habits of the patient, this is possible.
D. Ulcerative Colitis
Ulcerative colitis is an inflammatory bowel disease wherein there are patches of ulcers and erosions in the colon. This is where the excess mucus comes from and the disseminated ulcers cause the hallmark feature of this disease which is bloody diarrhea. Patients experience fecal urgency and pain in the lower quadrants of the abdomen.
There is mucus in urine in patients with ulcerative colitis probably because the excess mucus from the anus gets mixed up with urine as it being passed out, considering the fact that these patients have fecal urgency.
E. Urachal Cancer or Bladder Cancer
Urachal cancer refers to the presence of rapidly multiplying malignant cells in the urinary bladder. Several cases have revealed the presence of mucus in the urine. That is why physicians consider this as a differential diagnosis when there is persistent mucus in the urine.
F. Urinary Stone Disease
Like in urachal cancer, presence of mucus in urine is associated with urinary stone disease, especially nephrolithiasis (kidney stones). Other signs and symptoms include severe abdominal pain, back pain, and dark-colored and malodorous urine [6-10].
- For normal or physiologic causes of the presence of mucus in urine, there is no need to worry unless you have other manifestations that may be due to an underlying condition. If this is the case, it is better if you consult your doctor.
- For pathologic causes of mucus in the urine, the following treatment and remedies may help you have that clear urine once again.
- For UTI and STD/STI, have your doctor prescribe you with appropriate antibiotics.
- For IBS, antispasmodics, antidiarrheals, anticonstipation, psychotropics, serotonin receptor agonists and antagonists, non-absorbable antibiotics, and probiotics may be prescribed by the gastroenterologist.
- For mild to moderate ulcerative colitis, 5-ASA agents, corticosteroids, immunomodulators, and probiotics can be considered.
- For severe ulcerative colitis, corticosteroids, anti-TNF therapy, cyclosporines, and surgery are the options for treatment.
- For urachal cancer, chemotherapy, radiation therapy, or surgery may be necessary to get rid of the cancer.
- For urinary stone disease, medications that can dissolve the stones will be useful. If this does not help, surgery will be the final option .
- Das Gupta B, Urine Analysis, Butterworth
- Berzelius JJ, The Kidneys and Urine, Lea & Blanchard, 1843
- Brunzel NA, Fundamentals of Urine and Body Fluid Analysis, 3rd edition, Elsevier Health Sciences, 2013
- Papadakis MA & McPhee SJ, Current Medical Diagnosis and Treatment 2013, McGraw-Hill Lange, 2013