Differential Diagnosis for Painful Urination and Discharge in a Homosexual Male
Single Most Likely Diagnosis
- Urethritis due to Mycoplasma genitalium or Trichomonas vaginalis: These pathogens can cause urethritis, which presents with symptoms of painful urination and discharge. They are sexually transmitted and might not be detected by standard STI testing or urine cultures, which often focus on more common pathogens like Chlamydia and Gonorrhea.
Other Likely Diagnoses
- Prostatitis: Inflammation of the prostate gland can cause painful urination, discharge, and other symptoms. It can be acute or chronic and may not always be associated with positive STI tests or urine cultures.
- Urethral stricture: This condition, which can result from trauma, infection, or inflammation, leads to narrowing of the urethra and can cause obstructive and irritative urinary symptoms, including painful urination and discharge.
- Reiter's syndrome (Reactive Arthritis): A form of arthritis that occurs as a reaction to an infection elsewhere in the body, often in the gastrointestinal tract or the urethra. It can cause symptoms including urethritis, which might not be captured by standard STI testing.
Do Not Miss Diagnoses
- Gonorrhea or Chlamydia with resistant strains: Although the patient has negative STI testing, the possibility of infection with antibiotic-resistant strains of these common STIs should not be overlooked, as they can have serious consequences if not treated properly.
- HIV: Human Immunodeficiency Virus infection can increase susceptibility to other infections and can itself cause symptoms that might mimic those of other STIs. Early diagnosis is crucial for effective management.
Rare Diagnoses
- Urethral cancer: Although extremely rare, cancer of the urethra can cause symptoms of painful urination and discharge. It is more common in older individuals but should be considered in the differential diagnosis to ensure timely intervention if present.
- Foreign body in the urethra: Insertion of foreign objects into the urethra can lead to infection, inflammation, and symptoms of painful urination and discharge. This is a rare but possible cause that should be considered, especially in patients with a history suggestive of such behavior.