Diseases of the urethra
- Lesion
The urethra is inflamed mainly by sexually transmitted infections; caruncles and rare carcinomas complete its pathology.
What it is
Urethritis is classified as gonococcal (Neisseria gonorrhoeae) or non-gonococcal, mostly Chlamydia trachomatis, with Mycoplasma genitalium and Trichomonas vaginalis less often. Urethritis can accompany reactive arthritis with conjunctivitis. The urethral caruncle is a small, painful, red inflammatory polyp at the meatus of older women. Urethral carcinoma is rare; it is squamous in the distal urethra and urothelial in the proximal part, and adenocarcinoma can arise in women.
Structure
- Acute urethritis: neutrophils in the mucosa and periurethral glands; chronic forms cause strictures.
- Caruncle: friable red mass of vascular, inflamed stroma at the meatus.
- Carcinoma: infiltrative mass, often advanced at diagnosis.
Clinical notes
- Dysuria and urethral discharge in a sexually active man: test for both gonorrhea and chlamydia.
- Untreated urethritis can spread to the epididymis and prostate.
Test yourself
Think of the answer, then tap the question to see it.
What is the commonest cause of non-gonococcal urethritis?
Chlamydia trachomatis.
What is a urethral caruncle?
A small, painful inflammatory polyp of the urethral meatus, usually in older women.
What triad defines reactive arthritis?
Arthritis, urethritis and conjunctivitis, following a genitourinary or enteric infection.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Gonorrhea (MedlinePlus, US National Library of Medicine, 2025); Urethral Cancer Treatment (PDQ®)–Patient Version (National Cancer Institute, 2025).
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Representative model, for educational purposes only.