Differential Diagnosis for a 17-year-old Male with Green Penile Discharge and Positive Nitrites

• Single most likely diagnosis:
  • Gonorrhea: This is the most likely diagnosis due to the presence of green penile discharge, which is a classic symptom of gonococcal urethritis. The positive nitrites test also supports this diagnosis, as gonococci can reduce nitrates to nitrites.
• Other Likely diagnoses:
  • Chlamydia: Chlamydial urethritis can also present with discharge, although it is typically clear or white. However, the presence of green discharge does not rule out chlamydia, and it is often co-infected with gonorrhea.
  • Urethritis due to other bacteria (e.g., Mycoplasma genitalium, Ureaplasma urealyticum): These organisms can cause urethritis with discharge, although the discharge is typically less purulent than in gonorrhea.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Sepsis due to disseminated gonococcal infection: Although rare, gonococcal infection can disseminate and cause life-threatening sepsis. It is crucial to consider this possibility, especially if the patient has systemic symptoms such as fever, chills, or joint pain.
• Rare diagnoses:
  • Herpes simplex virus (HSV) infection: HSV can cause genital ulcers, but it can also cause urethritis with discharge. However, this is less common and typically associated with other symptoms such as dysuria, genital pain, or ulcers.
  • Trichomoniasis: This is a sexually transmitted infection caused by the protozoan Trichomonas vaginalis. It can cause urethritis with discharge, but it is less common in men and typically associated with other symptoms such as dysuria or genital irritation.