Obstetric fistula

Obstetric Fistula

An obstetric fistula is an abnormal opening between the woman’s genital tract and the urinary tract or rectum. It is commonly a result of neglected or prolonged obstructed labor.

• Risk factors for obstetric fistulaThe 3 delays
  • First delay: delayed decision to seek care
    • Low socio-economic status
    • Early marriage
    • Illiteracy and lack of formal education
    • Low social status
    • Harmful traditional practices e.g. FGM
    • Inadequate family planning +/- short inter-delivery interval
    • Labor onset at home
  • Second delay: delayed arrival at the health facility
    • Poor road conditions
    • Poor transportation
    • Poor communication
    • Insecurity
  • Third delay: delayed access to adequate care
    • Insufficient skilled staff
    • Lack of emergency obstetric services (e.g. C-section)
• Causes of obstetric fistula
  • Prolonged and Obstructed labour (MCC)
  • Instrumental delivery
  • Caesarean Section (with or without hysterectomy)
  • Defibulation in women who have had FGM
  • Symphysiotomy
  • Episiotomy
• Types of obstetric fistula
  • Vesicovaginal
  • Vesiouterine
  • Vesicocervical
  • Ureterouterine
  • Ureterocervical
  • Ureterovaginal
  • Urethrovaginal
  • Rectovaginal
  Types of fistulas. Courtesy of Slideshare.Types of fistulas. Courtesy of Slideshare.

The obstetric labour injury complex

• Pathogenesis of obstetric fistula in obstructed labor
  • During obstructed labour there is prolonged pressure exerted on the anterior vaginal wall and bladder neck by the foetal head and posterior pubic symphysis
  • This causes ischemia and reduced venous outlfow ultimately causing pressure necrosis
  • After delivery the necrotic tissue sloughs off leaving a direct communication between the genital tract (uterus, cervix, vagina) and the urinary tract (ureters, bladder, urethra), and/or the rectum.
  • Ischemia can also involve other pelvic tissue resulting in a spectrum of injuries known as the obstetric labour injury complex

Waaldijik Classification of obstetric fistula

Type I: Fistulae ≥5 cm from the EUO and therefore not involving the closing mechanism. These have an excellent prognosis, because the all-important urethra and bladder neck are intact.

Type II: Fistulae that involve the closing mechanism (<5cm from the EUO):

A. Without (sub)total involvement of the urethra:

(a) without a circumferential defect

(b) with a circumferential defect

B. With (sub)total involvement of the urethra:

(a) without a circumferential defect

(b) with a circumferential defect.

Type III: Miscellaneous fistulae, e.g. uretero-vaginal and other exceptional fistulae.

NOTE:

• Circumferential defect – complete separation of the urethra from the bladder.
• Note there are other classification systems such as Goh’s system.
• Patient history
  • History of female genital mutilation
  • History stillbirth, cephalopelvic disproportion or obstructed labour
  • Operative vaginal delivery – episiotomy, symphysiotomy or destructive surgery
  • Caeserean section
• Signs and symptoms
  • Urinary incontinence
    • Constant leak
    • Not dependent on activity
    • Onset directly after labour and delivery
  • Fecal incontinence
  • Other problems with mobility and walking
• Physical exam
  • Speculum exam
    • Genital lacerations
    • Urine draining through the anterior vaginal wall
    • Site and number of fistula
• Investigations
  • Double dye test: pack the vagina with sterile gauze and give dye intravesical via foley or Per Oral
    • Instillation of methylene blue into the bladder: identifies vesicovaginal fistula
      • Methyleneblue crosses from the bladder and into the vagina staining the gauze blue
    • PO Phenazopydidine (Pyridium): identifies ureterovaginal fistula
      • Pyridium crosses the uterus into the vagina staining the tampon orange
  • 3 swab test: pack the vagina with 3 separate gauzes and fill the bladder with methylene blue die
    • Ureterovaginal fistula: wetting of the uppermost swab
    • Vulvovaginal fistula: discoloration of the uppermost swab (do you mean vesicovaginal)
    • Urethrovaginal fistula: discoloration of the bottom-most swab
  • CT KUBor IV pyelographyCystoscopyRetrograde pyelogram
    • Retrograde pyelography is the most definitive test to diagnose a ureterovaginal fistula
  • Urinalysis and culture: r/o concurrent UTI
  • U/E/C: evaluate kidney function
• Treatment
  • Surgical repair
• Prevention
  • Educate communities on the cultural, social and physiological factors that increase the incidence of obstetric fistulas such a delaying child bearing and improving nutrition.
  • Improve the social status of women by promoting education for young girls.
  • Ensuring their is easy access to health facilities which are well equipped and staffed with professionals.