Differential Diagnosis

• Single most likely diagnosis
  • Gonococcal urethritis is less likely due to the absence of intercellular diplococci on Gram stain, but Non-Gonococcal Urethritis (NGU): This condition is characterized by the presence of white blood cells (WBCs) in the urethral discharge without the presence of gonococci. Given the patient's history of unprotected sex, NGU caused by pathogens like Chlamydia trachomatis or Mycoplasma genitalium is a strong consideration.
• Other Likely diagnoses
  • Herpes Simplex Virus (HSV) infection: Although HSV typically presents with vesicular lesions, it can also cause urethritis. The patient's history of unprotected sex increases the risk of sexually transmitted infections (STIs), including HSV.
  • Trichomonas vaginalis infection: This is another STI that can cause urethritis. It's less common in men but should be considered, especially in the context of unprotected sex and a diabetic patient who may be more susceptible to infections.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Disseminated Gonococcal Infection (DGI): Although the Gram stain does not show intercellular diplococci, it's crucial not to miss DGI, which can present with systemic symptoms and may not always have a positive Gram stain. DGI can lead to severe complications, including septic arthritis and endocarditis.
  • Human Immunodeficiency Virus (HIV) infection: Given the patient's history of unprotected sex, HIV testing is essential. Early diagnosis and treatment of HIV can significantly improve outcomes.
• Rare diagnoses
  • Urethral candidiasis: Although more common in women, especially those with diabetes, urethral candidiasis can occur in men, particularly those with diabetes or immunocompromised states. It would be an unusual cause of urethritis in a male but should be considered in the context of the patient's diabetes.
  • Ureaplasma urealyticum infection: This bacterium can cause NGU and is often considered in the differential diagnosis of urethritis, especially when other common causes are ruled out.