Differential Diagnosis for Pyuria with No Growth on Urine Cultures
- Single Most Likely Diagnosis
- Contamination with antibiotics: The patient may have taken antibiotics recently, which can suppress bacterial growth in urine cultures, leading to a false-negative result despite the presence of pyuria.
- Other Likely Diagnoses
- Viral cystitis: Some viruses, such as adenovirus or BK virus, can cause cystitis and pyuria without bacterial growth on urine cultures.
- Fungal infections: Fungal infections, such as candidiasis, can cause pyuria, especially in immunocompromised patients or those with indwelling catheters.
- Tuberculosis: Genitourinary tuberculosis can cause pyuria and sterile urine cultures, as the bacteria may not be detected by standard culture methods.
- Interstitial cystitis: This chronic condition can cause pyuria, frequency, and urgency, without bacterial growth on urine cultures.
- Do Not Miss Diagnoses
- Gonorrhea or chlamydia: These sexually transmitted infections can cause pyuria and may not be detected by standard urine cultures, requiring specific testing (e.g., NAAT).
- Malignancy: Bladder or renal cancer can cause pyuria, and it is essential to rule out these conditions, especially in older adults or those with risk factors.
- Rare Diagnoses
- Schistosomiasis: This parasitic infection can cause pyuria, especially in patients who have traveled to or lived in endemic areas.
- Malakoplakia: A rare condition characterized by the formation of granulomatous lesions in the bladder, which can cause pyuria and sterile urine cultures.
- Sarcoidosis: This systemic disease can cause granulomatous inflammation in the bladder, leading to pyuria without bacterial growth on urine cultures.