Can vaginitis cause white blood cells (WBCs) in urine?

Can Vaginitis Cause White Blood Cells in Urine?

Yes, vaginitis can cause white blood cells (WBCs) to appear in urine samples, particularly when inflammatory forms of vaginitis are present. This occurs primarily due to contamination of the urine sample with vaginal discharge containing WBCs during collection.

Types of Vaginitis and Their Relationship to WBCs

Inflammatory Vaginitis

• Inflammatory forms of vaginitis are characterized by the presence of leukorrhea (>10 WBCs per high power field on microscopic examination of vaginal fluid) 1
• This inflammatory exudate can contaminate urine samples during collection, leading to the appearance of WBCs in urinalysis results 1

Common Types of Vaginitis Associated with WBCs:

Trichomoniasis

• Caused by Trichomonas vaginalis, a protozoan that triggers an inflammatory response
• Features include more leukocytes than epithelial cells in vaginal secretions 2
• When present, can lead to WBCs in urine through contamination during sample collection 2

Cervicitis (Often Co-occurring with Vaginitis)

• Characterized by purulent or mucopurulent endocervical exudate
• A finding of leukorrhea has been associated with chlamydial and gonococcal infection of the cervix 1
• In the absence of inflammatory vaginitis, leukorrhea might be a sensitive indicator of cervical inflammation 1
• NAAT for C. trachomatis and N. gonorrhoeae are preferred for diagnostic evaluation of cervicitis 1

Diagnostic Considerations

Distinguishing Urinary Tract Infection from Vaginitis

• A finding of >10 WBC in vaginal fluid, in the absence of trichomoniasis, might indicate endocervical inflammation caused specifically by C. trachomatis or N. gonorrhoeae 1
• When evaluating WBCs in urine, it's important to determine if they originate from the urinary tract or from vaginal contamination 1

Proper Diagnostic Approach

• Microscopic examination of vaginal discharge can help identify the cause of vaginitis 1
• For bacterial vaginosis: pH >4.5, clue cells, homogeneous discharge, and positive whiff test 1
• For trichomoniasis: motile trichomonads on wet mount, pH >4.5, and often WBCs in discharge 3
• For vulvovaginal candidiasis: normal pH (3.8-4.2), hyphae or budding yeast on microscopy 3

Clinical Implications

When to Consider Vaginitis as Source of WBCs in Urine

• When urinalysis shows WBCs but patient has concurrent vaginal symptoms (discharge, odor, irritation) 4
• When proper clean-catch technique was not used during urine collection 1
• When microscopic examination of vaginal fluid confirms inflammatory vaginitis 1, 2

Treatment Considerations

• Treatment should target the specific cause of vaginitis to resolve the inflammatory response 4
• For bacterial vaginosis: metronidazole (oral or intravaginal) or clindamycin 4
• For trichomoniasis: oral metronidazole or tinidazole, with treatment of sex partners 4
• For vulvovaginal candidiasis: oral fluconazole or topical azoles 4

Practical Tips for Accurate Diagnosis

• Obtain a clean-catch midstream urine sample to minimize vaginal contamination 1
• Consider vaginal examination with microscopy when WBCs are found in urine but symptoms suggest vaginitis 2
• Use pH testing of vaginal fluid to help differentiate between types of vaginitis 1
• When both urinary and vaginal symptoms are present, evaluate for both conditions as they can coexist 5

By properly identifying the source of WBCs in urine, clinicians can provide appropriate targeted therapy and avoid unnecessary antibiotic treatment for presumed urinary tract infections when the actual cause is vaginitis.