Chronic lower abdominal pain in an elderly female patient: a case report about sigmoid colon fistula and pelvic abdominal infection

Abstract

An elderly woman patient presented with a history of recurrent right lower abdominal pain accompanied by fever and abnormal vaginal discharge for 36 years worse for two weeks. Conservative medical treatment was ineffective, by laparoscopic exploration combined with intraoperative colonoscopy, the presence of a sigmoid colon fistula and pelvic abdominal infection with foreign bodies were confirmed. It was hypothesized that the occurrence of recurrent right lower abdominal pain and intestinal fistula may be potentially associated with tubal injection sterilization performed 36 years ago.

Introduction

Chronic abdominal pain is defined as pain persisting for over six months, presenting a significant diagnostic challenge due to its gradual onset, extended course, and potential overlap with acute abdominal pain. Notably, 24–35% of cases remain clinically undiagnosed [1]. In women, the etiology is particularly complex and diverse, making diagnosis even more difficult. Differential diagnosis should include conditions such as urinary system disorders, hernias, infections, neoplastic diseases, hematologic and lymphatic disorders, rheumatic immune diseases, and tuberculosis. Additionally, for women of childbearing age, ectopic pregnancy and pathological pregnancy must also be considered [2].

Case presentation

A 66-year-old female patient was admitted with a 36-year history of intermittent right lower abdominal pain, which had worsened over the past two weeks, accompanied by fever and abnormal vaginal discharge. Prior gynecological color Doppler ultrasound and abdominal CT scans at another hospital had identified a cervical cyst, diffuse gallbladder hyperdensity, and abnormal midabdominal bowel changes, with no notable abnormalities in the uterine adnexa. Initial anti-infection treatment reduced the fever, but her abdominal pain persisted and intensified beyond previous episodes.

Her reproductive history includes marriage at 23 years old, with three natural births. She began menstruating at 15 and reached menopause at 50, with regular cycles throughout. The patient reported a sensation of pelvic fullness and perineal bulging, accompanied by foul-smelling red and white vaginal discharge. On physical examination, the abdomen was soft but exhibited marked tenderness and rebound pain localized to the right lower quadrant, with no significant findings elsewhere.

Laboratory investigations revealed elevated C-reactive protein (CRP) levels at 58.9 mg/L (reference range: 0–6 mg/L), an erythrocyte sedimentation rate (ESR) of 79 mm/h (reference range: 0–15 mm/h), and a serum CA-125 level of 60.15 U/ml (reference range: 0–35 U/ml). The T-SPOT.TB test was negative at 0.2 pg/ml. Other gynecological tumor markers were within normal limits. Vaginal discharge analysis was negative for acid-fast bacilli, though fungi were detected on two occasions, with negative fungal cultures. The fungal D-glucan G test returned a result of 38.7 pg/ml (reference range: <60 pg/mL).

Contrast-enhanced CT imaging of the abdomen revealed an irregular cystic low-density lesion in the left adnexal region, suggestive of a benign etiology. A soft tissue mass in the right adnexal region raised suspicion of an infectious process involving the appendix and adjacent bowel (Fig. 1). Colonoscopy identified a 0.3 × 0.4 cm ulcer in the sigmoid colon, 15 cm from the anal verge, with white moss coverage, surrounding mucosal congestion, and a fistula at the ulcer’s base; no other abnormalities were observed. Biopsy of the ulcer margin revealed inflammatory changes (Fig. 2). Pelvic contrast-enhanced MRI showed cystic hyperintense T1 signals in the left iliac and right inguinal regions, with associated ileocecal bowel swelling and adjacent exudation (Fig. 3). A barium enema demonstrated localized narrowing of the sigmoid colon, consistent with inflammation but without evidence of contrast leakage (Fig. 4).

Fig. 1

Contrast-enhanced CT: Abdominal CT scan with contrast enhancement revealed suspicious soft tissue lesions in the appendiceal region (within the red circle), involving the right ovarian adnexal region, appendix and adjacent bowel

Fig. 2

Colonoscopy and result of pathology: A: Sigmoid ulcer and fistula were observed during colonoscopy; B: Pathological examination of the ulcer edge suggested inflammation. (at 100x magnification)

Fig. 3

Pelvic MRI with contrast enhancement results. The intestinal swelling in the ileocecal area and exudation signal around it were considered as inflammatory lesions

Fig. 4

Barium enema examination: It showed no significant extravasation of contrast agent

Despite anti-infection and spasmolytic therapy in the Department of Gastroenterology, the patient’s abdominal pain became increasingly severe and intolerable. With informed consent, laparoscopic exploration and intraoperative colonoscopy were performed. Extensive adhesions were observed involving the uterus, bilateral adnexa, greater omentum, and adjacent intestinal loops. Severe adhesions were noted between the greater omentum and the ileocecal region, as well as the right adnexa. The appendix was markedly swollen and thickened, measuring approximately 5 × 1.2 cm, with mesenteric edema and hypertrophy. The right fallopian tube exhibited significant dilation (approximately 5 × 2 cm) with proximal empyema and severe inflammation. Adhesions between the ascending colon and terminal ileum required careful dissection. During the procedure, yellow pus and a foreign body (a cucumber seed) were expelled from the fimbriae of the fallopian tube. The patient underwent laparoscopic bilateral adnexectomy, appendectomy, cholecystectomy, adhesiolysis, and titanium clip closure of the sigmoid fistula under colonoscopy (Fig. 5).

Fig. 5

Intraoperative colonoscopy: A: The sigmoid fistula was identified under sigmoidoscopy; B: The sigmoid fistula was clipped using titanium clips

During laparoscopic exploration and intraoperative colonoscopy, extensive adhesions were observed involving the uterus, bilateral adnexa, greater omentum, and adjacent intestinal loops, which likely contributed to the chronic and recurrent nature of the patient’s symptoms. The appendix was markedly swollen and thickened, and the right fallopian tube exhibited significant dilation with proximal empyema and severe inflammation, consistent with a long-standing inflammatory process. Notably, a foreign body (a cucumber seed) was discovered in the fimbriae of the fallopian tube, which may have acted as a nidus for infection and contributed to the development of the sigmoid fistula.

The findings suggest a chronic pelvic inflammatory disease (PID) with extensive adhesions and fistula formation, likely exacerbated by the presence of the foreign body. The detection of the foreign body raises the possibility that it was introduced during the tubal sterilization procedure 36 years prior, resulting in a chronic inflammatory response that eventually led to the complications observed. The sigmoid colon fistula and severe adhesions between the bowel and adnexal structures further support the hypothesis that the recurrent abdominal pain was due to a combination of chronic PID and subsequent complications.

Postoperative pathology confirmed chronic suppurative inflammation of the right fallopian tube, chronic appendicitis with peri-appendicitis, and localized suppurative inflammation on the serosal surface. The left adnexa showed chronic inflammatory changes, consistent with pelvic inflammatory disease and associated internal sigmoid fistula formation (Fig. 6). One year postoperatively, a telephone follow-up revealed significant relief of abdominal pain, indicating a substantial recovery.

Fig. 6

Postoperative pathological findings: (at 100x magnification). A: Salpingitis; B: Suppurative appendicitis serosal surface

Discussion

The patient, a 66-year-old woman, presented with a 36-year history of recurrent, chronic, and tolerable abdominal pain, which had acutely worsened. The exacerbation was characterized by severe pain, fever, and malodorous red and white vaginal discharge. Despite initial anti-infective treatment, her abdominal pain expanded in scope and failed to improve. Physical examination suggested a possible infection localized to the right lower abdomen, corroborated by laboratory findings of elevated inflammatory markers. Abdominal CT and MRI revealed infectious lesions involving the appendix, adjacent bowel, and right adnexal region. Colonoscopy identified a sigmoid colon ulcer with a suspected fistula at its base.

Laparoscopic exploration uncovered significant bilateral fallopian tube edema, marked dilatation, and empyema in the right fallopian tube, with extensive adhesions to the ileocecal region and ascending colon. During surgical separation of these adhesions, purulent material and cucumber seeds were expelled from the fimbriae of the right fallopian tube, confirming the presence of a sigmoid colon fistula, as further validated by intraoperative endoscopy. Postoperative histopathology revealed chronic inflammation in the left adnexa, chronic suppurative inflammation in the right fallopian tube, appendicitis with peri-appendicitis, and localized suppurative inflammation of the appendix’s serosal surface.

The etiology of lower abdominal pain is multifactorial and complex. When considering chronic right lower abdominal pain, potential causes to be considered include inflammatory infections and tumor diseases affecting the ileocecal region, appendix, and adnexa, as well as reversible external abdominal hernias. In this case, it is important to differentiate the right lower abdominal pain from conditions such as Crohn’s disease, intestinal tuberculosis or adnexal tuberculosis, \chronic appendicitis, and pelvic inflammatory disease [1]. Concomitant pulmonary tuberculosis, ascites, night sweats, involvement of fewer than four segments of the bowel, patulous ileocecal valve, transverse ulcers, scars or pseudopolyps strongly indicate ITB. Bloody stools, perianal signs, chronic diarrhea, extraintestinal manifestations, anorectal lesions, longitudinal ulcers and a cobblestone appearance are all suggestive of Crohn’s disease [3]. People with chronic appendicitis usually have mild to moderate pain on the lower right side of the abdomen. It may spread to the belly button and can feel dull or sharp. Other symptoms may include: abdominal swelling, fatigue or feeling generally unwell, gastrointestinal symptoms such as diarrhea or nausea, fever. Radiological imaging with US and/or CT scan can be useful, and further examination must be made in patients who present with similar clinical conditions [4]. There is a wide variation in PID clinical features; the type and severity of symptoms vary by microbiologic etiology [5]. The diagnosis is made primarily on clinical suspicion, and empiric treatment is recommended in sexually active young women or women at risk for sexually transmitted infections who have unexplained lower abdominal or pelvic pain and cervical motion, uterine, or adnexal tenderness on examination [6]. Despite the chronic right lower abdominal pain and fever, the likelihood of extrapulmonary tuberculosis was considered low, given the absence of a history of tuberculosis, night sweats, or manifestations of tuberculosis in other anatomical sites. The T-SPOT.TB test and vaginal secretion smear were negative for tuberculosis, and colonoscopy did not reveal ulcerative lesions in the terminal ileum or ileocecal valve. Notably, intestinal ulcers accompanied by internal fistulae and abdominal abscesses are more commonly associated with Crohn’s disease [7]. The typical clinical manifestations of Crohn’s disease include abdominal pain, diarrhea, and weight loss. Ulceration can affect the entire gastrointestinal tract, with the ileocolonic region being the most commonly involved. Intestinal lesions are usually segmental, displaying a characteristic cobblestone appearance due to longitudinal ulcers and submucosal edema. Extraintestinal manifestations, such as arthritis, skin and mucous membrane lesions, ocular involvement, and hepatobiliary diseases, can further complicate the condition. Colonoscopy may reveal non-caseating granulomas [7]. However, in this case, no significant abnormalities were observed in the stool, and comprehensive evaluations through digestive endoscopy, imaging studies, and surgical exploration failed to identify transmural lesions such as edema, thickening, stenosis, or exudation throughout the gastrointestinal tract. Additionally, the absence of perianal lesions or extraintestinal manifestations further diminishes the likelihood of a Crohn’s disease diagnosis.

The patient presented with recurrent and persistent lower abdominal pain, which remained unexplained despite multidisciplinary consultations. Imaging examinations revealed pelvic inflammation and adhesions, raising suspicion of an intestinal fistula. A thorough review of the patient’s medical history uncovered a temporal correlation between the onset of abdominal pain and tubal injection sterilization; however, further investigation is needed to establish causality. This association may be linked to the patient’s history of drug injections and tubal occlusion performed 36 years ago, potentially leading to chronic perforation of the fallopian tube post-surgery. Adhesive leakage into the pelvic cavity likely resulted in extensive chemical-induced inflammation, with repeated episodes of infection contributing to the formation of an internal fistula involving the sigmoid colon and severe inflammation affecting both fallopian tubes.

Tubal injection was a widely used sterilization method in China from the 1970s to the 1990s [8]. In this procedure, adhesive agents such as compound phenol sterilization paste were injected into the fallopian tubes via intubation to corrode and destroy the mucosa. The resulting necrosis and exfoliation of the mucosal epithelium were followed by granulation tissue proliferation, fibrosis, and eventual lumen occlusion, thereby achieving contraception. Postoperative complications included fever, bleeding and hematoma formation, infection, lower abdominal and back pain, and even drug leakage, which could lead to damage to abdominal and pelvic organs, as well as pelvic adhesions [9]. Although tubal sterilization is now considered outdated, its complications may continue to affect older women in China for generations [8]. For elderly female patients with chronic, unexplained abdominal pain, it is crucial to thoroughly investigate their medical and surgical histories. This case also underscores the significant role of laparoscopic exploration in identifying the etiology of chronic abdominal pain.

Conclusions

We can confirmed the presence of a sigmoid colon fistula and pelvic abdominal infection. However, the primary cause for it was unclear. The medical history unveiled a temporal correlation between abdominal pain and tubal injection sterilization. The potential occurrence of chronic inflammation and other complications following tubal sterilization should be taken into consideration in elderly Chinese women experiencing recurrent and persistent abdominal pain. In cases where surgical intervention is indicated for chronic abdominal pain, timely laparoscopic exploration should be conducted to ascertain the underlying cause.