20.1 Genitourinary Infections: Cystitis & Pyelonephritis, Urine Diagnostics, Urethritis, Balanoposthitis, Pelvic Inflammatory Disease and Genital Ulcers

Why this area matters

The TOS genitourinary area lists:

• urinary tract infection, pyelonephritis and cystitis;
• urethritis and balanoposthitis;
• pelvic inflammatory disease;
• genital ulcers.

UTIs are among the most common bacterial infections in outpatient practice and pregnancy. Sexually transmitted infections are increasing among young Filipinos alongside the HIV epidemic. Board questions test the organism from a urinalysis or Gram stain, the meaning of nitrite and leukocyte esterase, which bacteriuria to treat, and how to tell the causes of genital ulcer apart.

Pathogenesis and organisms of urinary tract infection

• Route: most UTIs ascend from the periurethral area. Women are at higher risk because of the short urethra.
• Risk factors:
  • sexual activity and spermicides;
  • pregnancy, in which progesterone dilates the ureters;
  • obstruction from stones or an enlarged prostate;
  • vesicoureteral reflux in children;
  • diabetes;
  • urinary catheters.
• Hematogenous infection of the kidney is uncommon. It is seen with S. aureus bacteremia and with tuberculosis.

Clinical syndromes and diagnosis

• Cystitis: dysuria, frequency, urgency, suprapubic pain and sometimes hematuria, usually without fever.
• Acute pyelonephritis: fever and chills, flank pain, costovertebral angle tenderness, nausea and vomiting, with or without cystitis symptoms. Complications include renal abscess, emphysematous pyelonephritis in diabetics, and sepsis.
• Urinalysis:
  • Leukocyte esterase and pyuria indicate inflammation.
  • A positive nitrite test needs organisms that reduce nitrate (Enterobacterales) and urine that stayed in the bladder for some hours. Enterococcus, S. saprophyticus and Pseudomonas may be nitrite negative.
  • White cell casts localize infection to the kidney.
• Urine culture:
  • In a clean-catch midstream sample, 10^5 colony-forming units per mL or more of one organism is the classic threshold. Lower counts can be significant in symptomatic women and in catheter specimens.
  • Any growth from a suprapubic aspirate is significant.
  • Mixed growth of skin organisms suggests contamination.
• Asymptomatic bacteriuria: screen for and treat it in pregnancy, where it can progress to pyelonephritis and preterm birth, and before urologic procedures that injure the mucosa. Do not treat it in nonpregnant women, older adults or patients with catheters.
• Sterile pyuria (pyuria with negative routine culture) suggests:
  • renal tuberculosis;
  • chlamydial or gonococcal urethritis;
  • recent antibiotics;
  • stones or interstitial nephritis.
• Treatment follows local resistance:
  • Uncomplicated cystitis: nitrofurantoin for 5 days or single-dose fosfomycin. TMP-SMX is suitable only where resistance is low.
  • Pyelonephritis: an oral fluoroquinolone where susceptible, or ceftriaxone, then adjusted to culture.
  • Complicated UTI: look for and relieve obstruction.

Urethritis

• Gonococcal urethritis:
  • Neisseria gonorrhoeae causes purulent discharge and dysuria a few days after exposure;
  • a urethral Gram stain shows Gram-negative intracellular diplococci in neutrophils;
  • nucleic acid amplification tests are most sensitive.
• Nongonococcal urethritis: Chlamydia trachomatis (serovars D to K) is the most common cause, followed by Mycoplasma genitalium, Ureaplasma and Trichomonas. Discharge is scant and mucoid.
• Treatment (CDC 2020 and 2021):
  • ceftriaxone 500 mg IM once for gonorrhea, plus doxycycline if chlamydia has not been excluded;
  • doxycycline 100 mg twice daily for 7 days for chlamydia, or azithromycin when doxycycline cannot be used.
  • Sex partners are treated, and patients are tested for HIV and syphilis.

Balanoposthitis

• Balanoposthitis is inflammation of the glans and foreskin. It is most common in uncircumcised men and in men with diabetes or poor hygiene.
• Causes:
  • Candida: red, itchy patches with satellite lesions, often the first sign of diabetes;
  • anaerobes: foul discharge;
  • group A streptococcus;
  • irritant dermatitis.
• Recurrent balanoposthitis and phimosis are indications for circumcision.

Pelvic inflammatory disease (PID)

• PID is an ascending infection of the endometrium, tubes and ovaries. It is caused by N. gonorrhoeae, C. trachomatis and vaginal anaerobes and other organisms of bacterial vaginosis.
• Minimum clinical criteria: in a sexually active woman with pelvic pain, find cervical motion tenderness, uterine tenderness or adnexal tenderness. Fever, cervical discharge and raised inflammatory markers support the diagnosis.
• Complications:
  • tubo-ovarian abscess;
  • infertility and ectopic pregnancy from tubal scarring;
  • chronic pelvic pain;
  • Fitz-Hugh-Curtis syndrome, a perihepatitis with "violin-string" adhesions.
• Outpatient regimen (CDC 2021): ceftriaxone 500 mg IM once plus doxycycline and metronidazole for 14 days. Hospitalize for abscess, pregnancy, severe illness or failed oral therapy.

Genital ulcers

All patients with genital ulcers should be tested for syphilis and HIV, because ulcers increase HIV transmission.