Pelvic Abscesses

A pelvic abscess most commonly follows acute appendicitis, or gynaecological infections or procedures. It can also occur as a complication of Crohn’s disease, diverticulitis or following abdominal surgery. An abscess contains infected pus or fluid, and is walled off by inflammatory tissue. A pelvic abscess may grow quite large before making a patient ill, or causing obvious signs, and so may be easily missed.

In males the abscess is usually located between the bladder and the rectum.

In females the abscess usually lies between the uterus and the posterior fornix of the vagina, and the rectum posteriorly.

A tubo-ovarian abscess is one type of pelvic abscess, which is found in women of reproductive age, and may be a complication of pelvic inflammatory disease. In this case it is an inflammatory mass, which involves the ovary and Fallopian tube.

Prevalence

Uncommon.

Predisposing factors include Crohn’s disease, diabetes mellitus, immunodeficiency and pregnancy. In Crohn’s disease, abscesses may occur either spontaneously or as a complication of surgery.

Appearance

Systemic features of toxicity: fever, malaise, anorexia, nausea, vomiting, pyrexia. Local effects: eg, pain, deep tenderness in one or both lower quadrants, diarrhoea, tenesmus, mucous discharge per rectum, urinary frequency, dysuria, vaginal bleeding or discharge.

Rectal or vaginal examination: may reveal tenderness of the pelvic peritoneum and bulging of the anterior rectal wall.

Partial obstruction of the small intestine: this may sometimes occur.

Distinguished interpretation

·Pelvic inflammatory disease

·Appendicitis

·Diverticular disease

Generalised peritonitis-eg, from a perforated peptic uler

Sepsis following termination of pregnancy or miscarriage

investigations

FBC: raised white cell count often but not invariably.

Ultrasound.

CT/MRI scanning may be more effective at identifying the origin of the abscess.

Wellness program

Urgent admission to hospital.

Management is usually by drainage of the abscess along with antibiotic treatment. Antibiotics used alone are occasionally effective for very early, small abscesses.

Antibiotic choice is guided by the likely cause and local resistance patterns and guidelines, but usually needs to be broad-spectrum until the pathogens are determined.

Procedures used for drainage of the abscess include:

Ultrasound-guided aspiration and drainage: usually the abscess would be rectally drained in men, and in females it would be drained vaginally.

CT-guided aspiration and drainage. Percutaneous drainage often uses a trans-gluteal approach.

Endoscopic ultrasound-guided drainage (EUS-guided drainage). Evidence supporting this as an effective, minimally invasive option is growing.

Laparotomy or laparoscopy with drainage of abscess may be required in some cases.

An abscess which is enlarging suprapubically needs draining urgently.

In females the abscess is more difficult to diagnose if coils of bowel lie between the abscess and the posterior fornix and it may have to be drained suprapubically.

Abscess drainage with adjuvant thrombolytic treatment, such as tissue plasminogen activator (tPA), has been used to aid drainage.

Definitive surgery may be required after initial drainage for some causes of pelvic abscess, such as appendicectomy for abscesses due to appendicitis, or salpingo-oophorectomy for tubo-ovarian abscess.

Outlook

The prognosis will depend on the aetiology of the abscess, underlying well-being of the patient and the speed of diagnosis and effective management.