Tubo-ovarian abscess (TOA)

A tubo-ovarian abscess is collection of pus in the adnexa which develops in about 15% of women with salpingitis. It can accompany with acute or chronic infection and is more likely if treatment is late or incomplete. Pain, fever, and peritoneal signs are usually present and may be severe. The abscess may rupture, causing progressively severe symptoms and lead to septic shock.

Pathophysiology of TOA

• Ascending bacterial infection originating in the uterus
• Extending to the fallopian tube and broad ligament
• Acute supprative salpingitis, salpingo-oophoritis, pyosalpinx
• Tuboovarian complex or tuboovarian abscess [7].

Ovarian abscess is an almost unheard entity during pregnancy. Maternal and fetal morbidity and mortality significantly increase if the tubo-ovarian abscess is not removed at an optimal time. In pregnancy, diagnosis and management are difficult than in non-pregnant state. Clinical data may not reveal the diagnosis until surgery is resorted to as an elective or emergency procedure [3].

Arora D, 2004, reported a case a women that pregnant a round 19 weeks have a laparotomy for removal the ovarian abscess. The patient discharge on 10th post operative day with ongoing pregnancy. And she delivered a healthy male baby. The author suggested that if there is a large sized ovarian cyst should be removed pre-conceptionally. If diagnosed in early pregnancy it should be removed during 2nd trimester to prevent complications of rupture, torsion or soft tissue obstruction during labor [8].

Tubo-ovarian abscess may require more prolonged IV antibiotics and hospitalization. Treatment with ultrasound- or CT-guided percutaneous or transvaginal drainage can be considered if response to antibiotics alone is incomplete. Laparoscopy or laparotomy is sometimes required for drainage. Suspicion of a ruptured tubo-ovarian abscess requires immediate laparotomy. In women of reproductive age, surgery should aim to preserve the pelvic organs (with the hope of preserving fertility).

DIAGNOSIS OF PID/ TOA WITH CONVENTIONAL MODALITIES: The exact incidence of PID is unclear because the disease cannot be diagnosed reliably from clinical symptoms and signs. Comparing with laparoscopy the positive predictive value of clinical diagnosis is 65-90% [4, 9] and from observational studies suggest that delaying treatment by 3 days can impair fertility [5, 10].

Ultrasonography is very useful aids in establishing the diagnosis of TOA, although the "gold standard" remains laparoscopy [10]. However, if the patient cannot tolerate a thorough palpation of the adnexa because of pain, pelvic ultrasonography may be needed. An ultrasonographic examination excludes the presence of a tubo-ovarian abscess (TOA). However, if a TOA is not present, ultrasonography will probably not be helpful [11].

Pelvic sonograms finding frequently appear normal in the early stages or in uncomplicated conditions. In severe or advanced conditions, sonographic findings include endometrial thickening with or without endometrial fluid and gas, ovarian enlargement with indistinct ovarian borders, uterine enlargement with indistinct uterine contours, and free intraperitoneal fluid. Ascending extrauterine disease may cause tuboovarian complexes (Fig. 2a), originating as a combination of dilated inflamed fallopian tubes and enlarged inflamed ovaries, or frank tuboovarian abscess (Fig. 2b). [12]

Fig. 2.— 24-year-old woman with pelvic inflammatory disease and tuboovarian complex. A, Sagittal endovaginal sonogram reveals complex free fluid (FF). U = uterus. B, Coronal image of left adnexa reveals dilated fallopian tube (T) with echogenic fluid. Findings are consistent with those of pyosalpinx [12].

Fig.3 CT scan imagine of tubo-ovarian abscess [13].

CT scan examination has been found to be superior than USG for the detection of abdominal abscess (78-100% sensitivity) as compared to ultrasound with a sensitivity of 75 - 82%[13].

Fig. 4. MR imaging of tubo-ovarian abscess with left hydrosalpinx in a 31 years old woman. Images show an about 5 x 4 cm sized thick walled cystic lesion (arrow) in the right adnexa. Also noted an elongated sausageshaped cystic lesion (arrows) in the left sided cul-de-sac. Both lesions have internal solid portions and pelvic LNs, mimicking malignancy. Note fluidfluid levels (arrows) in both adnexal lesions [7].

Timo A, et al, reported MR imaging diagnose PID with sensitivity 95% and specificity 89% and overall accuracy was 93% of the 21 patient which proved with laparoscopy. And for transvaginal US, the values were 81%, 78%, and 80% respectively [14].

Fig. 5. Laparoscopy umage and close-up image of same patient shoe sausage-shape dilated right fallopian tube (arrow) [7].

Differential diagnosis:

Always consider specifically ectopic pregnancy and appendicitis in the differential diagnosis

• Ectopic pregnancy
• Acute appendicitis
• Complications of an ovarian cyst
• Endometriosis
• Urinary tract infection
• Constipation and surgical causes of acute abdomen
• Functional pain
• Irritable bowel syndrome

Investigations

• Urine pregnancy Test to exclude ectopic
• Full STD screen
• Consider laparoscopy to confirm diagnosis (this is the gold standard for diagnosis)
• Consider blood tests, ESR may be raised as may WCC and CRP
• Negative microbiological tests do not exclude a diagnosis of PID [15].