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Urethral discharge and genital ulcers/warts

Medicine > Infection

Differential Diagnosis Schema 🧠

Urethral Discharge

  • Gonorrhoea: Presents with purulent discharge, dysuria, and possibly systemic symptoms; diagnosed with NAAT (nucleic acid amplification test).
  • Chlamydia: Often asymptomatic but may present with clear or mucoid discharge and dysuria; diagnosed with NAAT.
  • Non-gonococcal urethritis (NGU): Caused by organisms like Mycoplasma genitalium, Ureaplasma urealyticum, or Trichomonas vaginalis; presents with mild discharge and dysuria.
  • Trichomoniasis: Presents with frothy yellow-green discharge, pruritus, and dysuria; diagnosed with microscopy or NAAT.
  • Urethritis due to herpes simplex virus (HSV): May present with painful urination and clear discharge; associated with genital ulcers.
  • Chemical urethritis: Irritation from soaps, spermicides, or antiseptics leading to dysuria and discharge.
  • Traumatic urethritis: Resulting from catheterisation or sexual activity, presenting with minor discharge and discomfort.
  • Urinary tract infection (UTI): Less common in men but can present with urethral discharge, particularly in older men or those with underlying urological conditions.
  • Prostatitis: May present with urethral discharge, perineal pain, and urinary symptoms; diagnosed with urine culture and examination.

Genital Ulcers

  • Herpes simplex virus (HSV): Presents with painful, grouped vesicles or ulcers on erythematous base; primary infection may include systemic symptoms.
  • Syphilis: Caused by Treponema pallidum; primary syphilis presents with a single, painless ulcer (chancre) with indurated edges.
  • Chancroid: Caused by Haemophilus ducreyi; presents with painful, ragged-edged ulcers and tender inguinal lymphadenopathy.
  • Lymphogranuloma venereum (LGV): Caused by certain serovars of Chlamydia trachomatis; presents with small, painless ulcers followed by painful lymphadenopathy.
  • Granuloma inguinale (Donovanosis): Caused by Klebsiella granulomatis; presents with painless, beefy-red ulcers that bleed easily.
  • Behçet’s disease: An autoimmune condition presenting with recurrent oral and genital ulcers, along with other systemic manifestations.
  • Fixed drug eruption: Presents as a solitary, well-demarcated, erythematous or violaceous plaque or ulcer following drug exposure.
  • Traumatic ulcers: Result from physical injury, often during sexual activity; typically painful and associated with a history of trauma.
  • Malignancy: Rare, but squamous cell carcinoma can present as a persistent ulcer in the genital region, particularly in older adults.

Genital Warts

  • Human papillomavirus (HPV): Presents with flesh-coloured, cauliflower-like growths; subtypes 6 and 11 are most commonly involved in genital warts.
  • Condylomata lata: Secondary syphilis presenting with broad, moist, flat-topped papules in the genital or perianal region.
  • Molluscum contagiosum: Caused by a poxvirus; presents with pearly, umbilicated papules that can occur in the genital area.
  • Seborrheic keratosis: Benign skin lesions that may resemble warts, typically occurring in older individuals.
  • Skin tags (acrochordons): Benign, flesh-coloured growths that can appear in the genital area; usually soft and pedunculated.
  • Squamous cell carcinoma: A malignant lesion that can present as a wart-like growth in the genital region, particularly in immunocompromised patients.
  • Bowenoid papulosis: A premalignant condition associated with HPV, presenting as pigmented papules in the genital area.
  • Lichen planus: An inflammatory condition that can cause white or violaceous papules or plaques on the genital mucosa.

Key Points in History 🥼

Sexual History

  • Number of sexual partners: Recent and past, to assess risk of sexually transmitted infections (STIs).
  • Type of sexual contact: Vaginal, anal, or oral, which can influence the type of STI and site of symptoms.
  • Use of condoms: Consistent or inconsistent use can help assess the risk of STIs.
  • History of STIs: Previous diagnoses can predispose to recurrent infections or complications.
  • Symptoms in sexual partners: Whether current or recent partners have symptoms suggestive of an STI.
  • Travel history: Exposure to STIs or other infections that may be more prevalent in certain geographic regions.
  • Substance use: Alcohol or drug use that may increase risky sexual behaviour.
  • HIV status: Knowledge of the patient’s HIV status and whether they are on treatment, as this can affect STI risk and management.
  • Vaccination history: HPV and hepatitis B vaccinations, which can provide protection against some STIs.
  • Symptoms of systemic illness: Fever, malaise, or lymphadenopathy, which may suggest a more severe or systemic infection.
  • Pain and discomfort: Details about the nature, onset, and severity of pain or discomfort associated with ulcers, warts, or discharge.

Background

  • Past medical history: Include previous episodes of similar symptoms, chronic conditions, and immunosuppression.
  • Medication history: Review current medications, particularly antibiotics, antivirals, and immunosuppressants.
  • Family history: Document any family history of conditions like herpes, HPV-related cancers, or autoimmune diseases.
  • Social history: Assess lifestyle factors such as smoking, alcohol use, and recreational drug use, which can impact immune function.
  • Surgical history: Any previous urological or gynaecological procedures that might influence symptoms.
  • Allergies: Document any allergies, especially to medications that might be used in treatment.
  • Occupational history: Consider occupations that might increase exposure to infectious agents.
  • Psychological history: Impact of symptoms on mental health, including anxiety or depression related to STI diagnosis or stigma.
  • Functional status: Assess the impact of symptoms on daily activities, including work and sexual relationships.
  • Recent treatments: Recent courses of antibiotics or other treatments that could influence current symptoms.

Possible Investigations 🌡️

Laboratory Tests

  • Nucleic acid amplification tests (NAATs): The gold standard for diagnosing gonorrhoea, chlamydia, and trichomoniasis.
  • Gram stain and culture: Used for diagnosing gonorrhoea; gram-negative diplococci are indicative.
  • Serology: Syphilis serology includes tests like RPR or VDRL for screening, and TPPA for confirmation.
  • PCR for herpes simplex virus (HSV): Highly sensitive for diagnosing genital herpes, particularly in the presence of ulcers.
  • HIV test: Routine testing in the context of STIs to assess for co-infection and guide management.
  • Hepatitis B and C serology: Important in patients with risk factors for blood-borne viruses.
  • HPV typing: Can be done in certain cases to identify high-risk strains, particularly in the context of genital warts or abnormal cytology.
  • Biopsy of ulcers or warts: May be necessary if there is suspicion of malignancy or atypical presentation.
  • Urinalysis and urine culture: To rule out UTI in patients presenting with urethral discharge or dysuria.
  • Darkfield microscopy: Used for direct detection of Treponema pallidum in suspected primary syphilis (chancre).
  • Wet mount microscopy: For diagnosing trichomoniasis, showing motile trichomonads, or bacterial vaginosis, showing clue cells.
  • Liver function tests: Particularly in the context of systemic illness or to assess for potential drug hepatotoxicity.
  • Full blood count (FBC): To assess for signs of systemic infection or underlying immunosuppression.
  • CD4 count and viral load (if HIV positive): To assess immune function and guide STI management.
  • Blood glucose: To rule out diabetes, which can predispose to recurrent infections.

Imaging and Specialist Investigations

  • Pelvic ultrasound: Useful in female patients presenting with pelvic pain, to rule out complications such as tubo-ovarian abscess or pelvic inflammatory disease.
  • Colposcopy: May be indicated for the evaluation of genital warts, particularly if there is suspicion of high-risk HPV or dysplasia.
  • Cystoscopy: Indicated in cases of persistent or recurrent urethritis to rule out structural abnormalities.
  • Chest X-ray: If there is concern for disseminated gonococcal infection, particularly in the presence of a systemic illness.
  • Anoscopy: Useful in evaluating anorectal symptoms or warts in men who have sex with men (MSM) or in cases of suspected syphilitic proctitis.
  • MRI pelvis: May be required in complex cases of suspected deep tissue involvement or when malignancy is suspected.
  • Electrocardiogram (ECG): If the patient is on certain medications (e.g., macrolides) that can cause QT prolongation.
  • Skin swab for viral culture: Particularly for HSV, though PCR is more commonly used due to higher sensitivity.
  • Transrectal ultrasound: For assessing prostate involvement in men with suspected prostatitis presenting with urethral discharge.

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Infection