What are leukocytes?
Surviving in any environment, for any organism, requires adaptability to the surrounding environment, this includes defence mechanisms. Fortunately, some defence mechanisms are inherited while others are acquired through our life journey. The first line of our defence mechanisms in the body is the immune system, which consists of physical barriers such as hair and skin and internal factors including white blood cells. These cells, regardless of their stage of maturation, are called white blood cells, or leukocytes. White blood cells are part of the innate immune system and protect the body against disease and infection, so raised levels can be a marker of poor health. Leukocytes normally range in number between four thousand to eleven thousand in each microlitre of blood.
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Causes of leukocytes in urine
It is worth noting that leukocytes` existence means more protection which reflects an abnormal exposure to external invaders such as bacterial or viral infections, or abnormal cellular growth as mentioned in the listed causes of leukocyte rise and presence in urine listed below.
Urinary tract infections can be caused by bacterial, viral or parasitic organisms, including:
- Sexually transmitted infections such as Neisseria gonorrhoea and Chlamydia that first attack the urinary system and urethra1
- Hospital-acquired infections, known as nosocomial infections, can result from surgery or catheterization. Such bacteria as Pseudomonas and Staphylococcus aureus are among the causes of hospital-acquired urinary tract infections
Urinary tract stones can cause an increase in urine leukocyte count, either directly by their chemical components` irrational inflammation or by the subsequent infection on top of their blockage of the urine pathways.2
Cancer, especially urinary tract ones, and immunologic diseases of the kidney such as systemic lupus may contribute to the rise in the white blood cells.3
Inflammation such as chronic prostatitis in people assigned male at birth (AMAB) and vulvovaginitis in people assigned female at birth (AFAB) can cause an increased leukocyte count in urine.4,5
The clinical picture of symptoms is considered as informative, rather than exclusive diagnostic criteria, of the process of rise in urinary leukocyte number. Among these are: 5
- Rise in the body temperature, either a low-grade or high-grade fever
- Shivering as a reflex mechanism of the brain centre to the fever
- Increased frequency of urination
- Pain or stinging sensation when passing urine
- Turbid urine with or without offensive odour
- Lower abdominal, deep-seated, pain
- Urinary discharge, especially in people AFAB due to the ascending infection from the genital tract. This discharge may be coloured and have an offensive odour
- Hematuria (blood in urine) in case of severe infection, urinary tract stones or genitourinary tract cancers
Who is at an increased risk?
People who are considered at high risk are those who have higher exposure to the causes and risk factors such as:
- Sexually active persons, particularly those who have unprotected sex
- People with low immunity such as those who are comatose, have diabetes mellitus or cancer
- People who depend on high-salt-containing water, such as that from wells
- People who are admitted to hospitals, especially those having urinary-related surgical or diagnostic tests such as endoscopy or catheterisation
- Cross-contamination between individuals using the same personal items including towels or underwear
The diagnosis of leukocytes in urine starts with the analysis of an early morning sample of the mid-stream urine. The mid-stream sample aims to avoid collecting such contaminants as surface-dwelling bacteria and skin cells. Urine culture and sensitivity testing can be useful in determining the response of the infective causative agent to antibiotic medications.
Imaging of the urinary tract may be needed to exclude any potential stones or tumours. This can include such tests as an ultrasonographic scan of the abdomen, plain X-ray filming of the urinary tract, computerized tomography scan (CT) and magnetic resonance imaging (MRI). The use of contrast images can contribute to a better vision of the lining of the urinary tract or any urinary tract obstructions.
Diagnostic endoscopy for the urinary bladder (cystoscopy) and ureters (ureteroscopy) can be of great value in case of suspected masses or even for taking a further tissue sample (biopsy). Such methods can be used in the treatment of obstructions in the urinary tract as well.
In the case of genital tract-based infections, a swab of the region can be taken for further molecular, microbiological and biochemical analyses.
The management of raised levels of leukocytes in the urinary tract is based on both prophylaxis (prevention) and treatment.
Various hygiene precautions can help prevent the condition:
- Personal hygiene and effective domicile cleaning can help to prevent inflammation, urinary tract infections and leukocytes in the urine
- Practising safe sex. The person who has a urinary tract infection should avoid having unprotected sex due to the possibility of having a sexually-transmitted disease
- Regular follow-up for diabetics with blood glucose level control
- Immune support supplements may also help
- Over-the-counter painkillers and anti-inflammatory agents can be taken
- Cold compresses can be applied to reduce fever
- Bathing may help to relieve the pain of inflamed areas
- Various botanic remedies have been suggested6
According to the NHS, antibiotics, painkillers, vaginal cream suppositories and douching can be prescribed according to the severity of the infection. In case of the persistence of the infection for more than 2 days, broad-spectrum antibiotics are prescribed such as trimethoprim-sulfamethoxazole, doxycycline and cefotaxime.
When to seek medical attention
Medical advice should be sought if you experience symptoms for more than 2 days, or if symptoms occur more than twice within 6 months. Additionally, if there is blood in the urine or severe pain, you should seek medical attention.
Urine is the filtrate of the kidney out of the blood, so the composition of urine can tell us a lot about the state of the urinary tract. White blood cells (leukocytes) in the urine can help to detect and diagnose a range of conditions including infection (bacterial and viral) and obstructions (e.g., kidney stones, cancer).
Reference range values (4-11 thousand per microlitre of blood) indicate how healthy the tract is. Although elevated levels of leukocytes can be indicative of several illnesses, most causes are not serious. If the pain or inflammation in the abdominal region persists for more than 2 days, or you notice red blood in your urine, seek advice medical advice.
- Wiggins RC, Holmes CH, Andersson M, Ibrahim F, Low N, Horner PJ. Quantifying leukocytes in first catch urine provides new insights into our understanding of symptomatic and asymptomatic urethritis. Int J STD AIDS. 2006 May;17(5):289–95.
- Crockett-Torabi E, Ward PA. The role of leukocytes in tissue injury. Eur J Anaesthesiol. 1996 May;13(3):235–46.
- De Boer EC, De Jong WH, Steerenberg PA, Van der Meijden AP, Aarden LA, Debruyne FM, et al. Leukocytes and cytokines in the urine of superficial bladder cancer patients after intravesical immunotherapy with bacillus Calmette-Guerin. In Vivo. 1991;5(6):671–7.
- Nickel JC, Alexander RB, Schaeffer AJ, Landis JR, Knauss JS, Propert KJ, et al. Leukocytes and bacteria in men with chronic prostatitis/chronic pelvic pain syndrome compared to asymptomatic controls. J Urol. 2003 Sep;170(3):818–22.
- Huppert JS, Biro F, Lan D, Mortensen JE, Reed J, Slap GB. Urinary symptoms in adolescent females: STI or UTI? J Adolesc Health. 2007 May;40(5):418–24.
- Das S. Natural therapeutics for urinary tract infections—a review. Future Journal of Pharmaceutical Sciences [Internet]. 2020 [cited 2023 Aug 21]; 6(1):64. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7498302/.