QuestionSBA
QuestionChoice
Mycoplasma genitalium is a bacterium without a cell wall that can cause urethritis. While it is intracellular, it is less common than Chlamydia trachomatis and typically associated with persistent or recurrent urethritis rather than acute symptoms as seen in this case.
10017213
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Mycoplasma genitalium
QuestionChoice
Chlamydia trachomatis is the most common cause of sexually transmitted urethritis in young men. It is an obligate intracellular bacterium, which fits the NAAT findings. It typically presents with dysuria and a clear or white urethral discharge.
10017211
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Chlamydia trachomatis
QuestionChoice
Treponema pallidum is the causative organism of syphilis, a sexually transmitted infection that can cause painless genital ulcers (primary syphilis) or systemic symptoms (secondary syphilis). It is a spirochete, not an obligate intracellular bacterium, and is not associated with urethritis.
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Treponema pallidum
QuestionChoice
Trichomonas vaginalis is a motile protozoan, not a bacterium. It is a rare cause of urethritis in men and is typically associated with frothy discharge and irritation, not the white discharge and dysuria seen here.
10017214
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Trichomonas vaginalis
QuestionChoice
Although Neisseria gonorrhoeae is another common cause of sexually transmitted urethritis, it is a Gram-negative diplococcus, not an obligate intracellular bacterium. Gonorrhoea typically causes a more severe presentation with purulent (yellow or green) urethral discharge and more pronounced dysuria.
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Neisseria gonorrhoeae
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# Summary
 

Urethral discharge is a common symptom often associated with sexually transmitted infections (STIs) such as gonorrhoea and chlamydia, or non-specific/non-gonococcal urethritis. Less common causes include infections by Ureaplasma urealyticum, Trichomoniasis, herpes simplex, and E.coli, as well as conditions like cystitis and pyelonephritis. Trauma or a foreign body in the urethra can also be responsible. Key signs and symptoms, in addition to urethral discharge, can include dysuria, pruritis, or haematuria. Investigations typically involve laboratory tests such as urinalysis and cultures, alongside polymerase chain reaction (PCR) for detecting specific pathogens. Management primarily revolves around antimicrobial therapy, symptom relief, and partner notification and treatment.
 

# Definition
 

Urethral discharge refers to any abnormal fluid that is expelled from the urethra, aside from urine and semen. This discharge can be the result of an infection, inflammation, or other conditions affecting the urinary tract.

# Epidemiology

Urethral discharge is a common presenting symptom of urethritis, of which the most common causes are sexually transmitted infections including chlamydia and gonorrhoea.
 

# Aetiology
 

Causes of urethral discharge include:
 

- *Neisseria gonorrhoeae*, or gonococcal urethritis, which typically presents 2-5 days after exposure
- Non-gonococcal urethritis (NGU) - common causes include*Chlamydia trachomatis* and *Mycoplasma genitalium*. Other causes of NGU include:
 - Infections: *Ureaplasma urealyticum, Trichomonas vaginalis*, herpes simplex virus, adenovirus, lower & upper urinary tract infections
 - Non-infectious: trauma to the urethra, irritants, foreign body


# Signs and Symptoms
 

Common symptoms associated with urethral discharge and urethritis include:
 

- Mucoid and/or purulent urethral discharge
- Dysuria, haematuria
- Pruritis, erythema and irritation
- Associated lymphadenopathy in groin/inguinal region
 

# Differential Diagnosis
 

- **Gonorrhoea**: Characterised by a purulent, often copious urethral discharge, dysuria, and less commonly, testicular discomfort.
- **Chlamydia**: Presents with a mucoid or watery discharge, dysuria, testicular discomfort, and possibly conjunctivitis.
- **Non-specific urethritis** (NSU) or non-gonococcal urethritis (NGU): Discharge, dysuria, and occasionally urethral pruritus.
- **Ureaplasma urealyticum**: Causes dysuria and urethral discharge, less commonly associated with testicular discomfort.
- **Trichomoniasis**: Causes pruritus, dysuria, and a frothy, yellow-green discharge with a foul smell.
- **Herpes simplex virus**: Painful vesicles or ulcers, possible urethral discharge, and systemic symptoms like fever.
- **E.coli**: Typically presents as a urinary tract infection (UTI) with dysuria, frequency, urgency, and occasionally haematuria.
- **Cystitis**: Lower urinary tract infection causing dysuria, frequency, urgency, and suprapubic pain.
- **Pyelonephritis**: An upper urinary tract infection causing flank pain, fever, nausea/vomiting, dysuria, frequency, and urgency.
- **Trauma**: Painful urination, possible blood in the urine or at the urethral meatus, and history of trauma.
- **Foreign body**: Pain, possible blood at the urethral meatus, history of foreign body insertion.
 

# Investigations
 
Clinical assessment of urethral discharge should include:

- **History** including symptoms, sexual history and past medical history
- **Examination** including genitalia, lymph node palpation and digital rectal examination to assess for prostatitis
- Bedside tests including **urinalysis** and **observations**

Laboratory tests to consider include:

- Nucleic acid amplification testing (**NAAT**) for *N. gonorrhoea*, *C. trachomatis* and *M. genitalium*.
- Swabs/first-void urine sample for **microscopy and culture** for *Trichomonas*
- **HIV** testing
- **Urine microscopy and culture** for urinary tract infection
- **Blood tests** including FBC, U&Es & CRP, especially if systemic symptoms are present
 

# Management

If a sexually transmitted infection is suspected or diagnosed, patients should be referred to a genito-urinary medicine (GUM) clinic. Management involves:
 

- Antibiotic therapy targeting the suspected pathogen based on clinical presentation, or following cultures and sensitivities
 - Empirical treatment usually involves doxycycline 100mg twice daily for seven days. Alternatives include azithromycin or ofloxacin.
 - If gonococcal urethritis is suspected, ceftriaxone is usually first-line
 - If Trichomoniasis is suspected, this should be treated with oral metronidazole
- Symptom management (for example, pain relief)
- Partner notification and treatment to prevent reinfection
 

# NICE guidelines
 

[NICE CKS: Urethritis](https://cks.nice.org.uk/topics/urethritis-male/)

[NICE CKS: Gonorrhoea](https://cks.nice.org.uk/topics/gonorrhoea/)

[NICE CKS: Trichomoniasis](https://cks.nice.org.uk/topics/trichomoniasis/)

 
# References


[BASHH guideline: Non-gonococcal urethritis](https://www.bashhguidelines.org/media/1051/ngu-2015.pdf)

[BMJ Best Practice: Urethritis](https://bestpractice.bmj.com/topics/en-gb/54)
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Urethral discharge
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Genitourinary medicine
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Concept
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Urethral discharge
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Common genito-urinary infections 1
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Chlamydia trachomatis is an intracellular gram-negative bacterium that causes a range of infections, including sexually transmitted diseases, pelvic inflammatory disease, and eye infections such as trachoma.
A 21-year-old man presents to his GP with a 3-day history of white urethral discharge and dysuria. He is sexually active and recently began a casual relationship. Nucleic acid amplification testing (NAAT) confirms that his condition is caused by an obligate intracellular bacterium.

What is the most likely causative organism?
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