28th July 2023

Genitourinary Infections

Urinary tract infections (UTIs)

UTIs can be classified as lower or upper. Lower urinary tract infection usually refers to cystitis, with symptoms of urinary frequency and dysuria. Upper urinary tract infection implies ascending infection in the kidneys, i.e. pyelonephritis, which typically presents with loin pain, fever, rigours, and nausea/vomiting.

Enteric bacteria are usually the cause of infection in the urinary tract, with Escherichia coli implicated in over 50% of cases. A wide range of antibiotics are used for UTIs, with choice depending on the patient’s microbiological history and local epidemiology, meaning local guidance should always be consulted.

Diagnosis is made through urinalysis, with urine samples sent for microscopy, culture and sensitivities to confirm infection and help tailor antibiotic choice. Urinalysis is not a reliable diagnostic tool in elderly patients, who should be treated based on symptoms and laboratory confirmation.

Pregnancy is a risk factor for urinary tract infections, and the antibiotic choice is limited by adverse effects on the foetus, with trimethoprim an important contraindicated antibiotic to know.

Bacteria are often found colonising the urinary tract without causing infection, known as asymptomatic bacteriuria. It is increasingly recognised that this finding does not require treatment, except in special populations such as pregnant women, men, and potentially renal transplant patients.

In men, prostatitis can cause exquisite pain on sitting or rectal examination. The same urinary pathogens cause it as UTIs but require extended treatment, usually for 14 days with ciprofloxacin.

Sexually transmitted infections (STIs)

Most STIs are caused by Chlamydia trachomatis or Neisseria gonorrhoeae. Both are Gram negative bacteria, and N. gonorrhoea is particularly notable for its diplococci morphology, which makes it distinctive in microscopy.

Both chlamydia and gonorrhoea cause a similar broad spectrum of disease, ranging from asymptomatic infection to pelvic inflammatory disease.

Diagnosis is either made on microscopy of swab smears or by a nucleic acid amplification test (NAAT).

Treatment of gonorrhoea has changed over the past few decades as resistance has emerged. Currently, ceftriaxone (1g, intramuscularly) is the treatment of choice. For chlamydia, a single dose treatment of azithromycin is the preferred treatment. Neonates may develop conjunctival disease after exposure to chlamydia in the birth canal, which is an important potential complication of chlamydia to be aware of.

Syphilis is caused by Treponema pallidum. It is one of medicine’s great mimickers and can be confused for many other diseases. It usually starts with a primary, painless ulcer (chancre) at the initial infection site, often the genitals. A secondary syphilis rash may occur a few weeks after inoculation before the bacteria enters the latent phase, which may last for decades.

If untreated, after this latency period, tertiary syphilis may develop, which can have life-threatening complications. Tertiary syphilis manifestations include aortic root disease, neurological disease, and gummatous disease of the skeleton.

Penicillin is the treatment of choice for syphilis. The dose and route depend on stage and organ involvement, summarised in the British Association for Sexual Health and HIV (BASHH) guidelines, which can be found in the References section.