Background
Actinomycosis is a chronic granulomatous disease, caused by the genus Actinomyces species, which are obligate anaerobes. In the past, it was thought to be a fungal infection, but later the causative organisms of this disease were proved to be Gram-positive filamentous bacteria. Actinomycosis in humans is most commonly caused by the species Actinomyces israelii [1]. They are not considered remarkably virulent pathogens, but rather as opportunistic ones as the infection usually occurs only after the mucous membranes are disrupted. Actinomyces israelii is considered as a common commensal of the oropharynx, gastrointestinal tract, and the vagina [2,3].
The disease spreads by direct extension into surrounding tissues regardless of tissue planes through the formation of sinus tracts that can lead directly to the skin. There is no documented person-to-person transmission of this disease. Typically sulfur granules can drain from these tracts, but it is not a pathognomonic feature. This case of ours adds to the growing body of literature that actinomycosis should be considered in a list of differential diagnosis of abdominal pain, particularly in any women using an intra-uterine device and presenting to the clinic with abdominal pain or a pelvic mass.
Case Presentation
A 36-year-old single lady presented to King Edward Memorial Hospital, Mumbai, India with several episodes of abdominal pain, since July 2002, which had increased in severity for last 4 years. Physical examination elicited abdominal pain which was moderate-severe and not radiating to the legs. She had a past surgical history of tubectomy with no complications in 2002. USG abdomen and pelvis in 2006 showed an enlarged left ovary measuring 5 × 3 cm having a cyst of 3.5 × 3.5 cm s/o chocolate cyst. Laparoscopic removal of this ovarian cyst was done after a couple of months. Histopathology report was suggestive of fungal infection like Actinomyces. The patient was given IV broad antibiotic coverage followed by an oral course on discharge. The patient had subjective improvement, but the symptoms gradually returned in 2012 and she reported to the hospital by 2014. At that point, computerized tomography (CT) scan of the abdomen and pelvis showed a soft tissue mass of size 3.4 × 2.6 cm in left adnexa and another cystic lesion sized 5.5 × 3.2 cm was noted in the right iliac fossa Figures(1 – 3). The patient was again treated with broad antibiotic coverage for actinomycosis but failed to show any response. Ultimately, she underwent diagnostic laparoscopy followed by ovarian cystectomy, salpingectomy, and omental mass removal in February 2015. Slide preparation of the block dissection of pelvic adnexal mass was suggestive of an actinomycotic abscess. The patient was discharged from the hospital and was comfortable until August 2015. She returned with similar complaints as earlier soon, however, the gastrointestinal (GI) symptoms were mild. On physical exam, she had nodularity felt in the Pouch of Douglas. The CT scan abdomen & pelvis revealed an ill-defined, infiltrative plaque-like lesion, located in the recto-uterine pouch, bilateral adnexal regions, and also involving peritoneal surfaces of these regions. Furthermore, there was involvement of distal half of sigmoid colon and the recto-sigmoid junction with encasement of almost entire uterus. The patient again underwent an exploratory laparotomy in November 2015, but surgery was abandoned since the mass was proven through naked eyes, to be plastered to the various organs and peritoneum. Patient consent was taken for use of patient-related information for possible publication. Unfortunately, the patient was lost to further follow-up.
Discussion
The most common site of human actinomycosis is the cervicofacial region, which is known to be affected in about 40%–50% of cases. About 15% of the cases occur in the thorax [4]. Pelvic actinomycosis occurs almost always in women only. It may conceivably mimic pelvic malignancies or even retroperitoneal tumors [5] and therefore diagnosing it generally is problematic. Almost 85% of cases of pelvic actinomycosis occur in women, who have had an intra-uterine contraceptive device (IUCD) in situ for more than 3 years [6]. Actinomyces israelii infects 1.65%–11.6% of IUCD users [7]. Due to its invasion of surrounding tissues and the formation of masses, it is often confused with an ovarian neoplasm [8–10]. Usually, the symptoms include lower abdominal pain, cachexia, vaginal discharge, and nausea [11]. As the disease advances, tubo-ovarian abscess formation occurs. This may lead to a “frozen pelvis,” mimicking pelvic cancer [11].
The gold standard for diagnosis is culture from the tissue, pus, or IUCD itself. Actinomyces species is a slow-growing, anaerobic bacterium that requires 2–3 weeks to culture and with a failure rate of more than 50% [12]. Therefore, most diagnoses are made histologically with the presence of sulfur granules, which are yellowish particles with a mycelium-like structure containing clusters of neutrophils and Actinomyces. Sulfur granules may be scant or absent in some patients [13] and their presence is not pathognomonic of Actinomyces infection [12].
Peabody and Seabury [14] endorsed abscess drainage along with high-dose antibiotics as the principal therapy for actinomycosis. Actinomyces species are known to be susceptible to a broad range of beta-lactam agents and, when given with beta-lactamase inhibitors, they are deemed as the first choice [15]. Smith et al. [16] described that ciprofloxacin and tetracyclines showed inadequate performance against Actinomyces species.
Although there are contrasting opinions in the literature about dosage and duration of antibiotic treatment, antibiotics can medically treat uncomplicated actinomycosis [15]. The antibiotics have poor penetration into the fibrous tissues and so a long course of treatment is required. In advanced and complicated actinomycosis, there are abundant avascular spaces are present due to severe tissue reactions. In such cases, medical therapy may be less effective, resulting in a longer duration of antibiotic treatment, regardless of the site of actinomycosis. It was interestingly noted that two patients in one series (9.0%) who were treated with IV antibiotics after surgery for less than 4 weeks did not recur during the last 34 months of follow-up. Therefore, the clinical impact of surgical resection followed by short-term antibiotics merits, further study [15]. However, no complicated case like ours exists in the prior published literature.
Conclusion
Although intra-abdominal actinomycosis is very rare, it should be considered in the differential diagnosis of recurrent abdominal pain and pelvic mass particularly in women with a history of IUCD use. If actinomycosis is suspected preoperatively, appropriate handling of cultures will increase the diagnostic yield, which may obviate the need for an extensive surgery. Furthermore, early empirical treatment with appropriate antibiotic coverage for suspected actinomycosis is another practical solution.