Ruptured salpingitis isthmica nodosa: a rare cause for spontaneous haemoperitoneum.

Salpingitis isthmica nodosa (SIN) is the nodular swelling or diverticulum of the isthmus of the fallopian tube. It is most commonly identified when investigating female infertility or in association with ruptured ectopic pregnancies. We experienced a rare and atypical presentation of SIN. A 33-year-old woman presented with a 1-hour history of acute lower abdominal pain associated with nausea and vomiting. CT and pelvic ultrasound revealed haemoperitoneum with no radiological evidence for its aetiology. Initial beta-human chorionic gonadotropin excluded ectopic pregnancy. A diagnostic laparoscopy was performed following clinical deterioration of the patient. Active bleeding of the right fallopian tube was identified and managed with a right partial salpingectomy, with subsequent histopathology revealing ruptured SIN. There have been no reported cases of SIN being a primary cause for an acute abdomen or haemoperitoneum in the absence of an ectopic pregnancy, making this case a surgical novelty.

general surgery, obstetrics and gynaecology

Spontaneous haemoperitoneum in females of reproductive age is typically caused by a ruptured ovarian cyst or ectopic pregnancy.1 We report a novel case of spontaneous small-volume haemoperitoneum in a 33-year-old woman secondary to ruptured salpingitis isthmica nodosa (SIN). This report outlines an unexpected cause of acute abdominal pain and a rare complication of SIN. Case presentation A fit-and-well 33-year-old gravida 2, para 2 woman, with a history of cholecystectomy and bilateral tubal ligation, presented with a 1-hour history of acute onset of right iliac fossa (RIF) pain associated with anorexia and vomiting. She was menstruating at the time of presentation. Her bowels opened normally the day prior and was passing flatus. There was no other reported significant sexual or gynaecological history. She was not taking any antiplatelet or anticoagulant medication. On examination, she was haemodynamically stable and afebrile. Abdominal examination demonstrated tenderness at the right iliac fossa with localised peritonism. Investigations Blood tests showed initial haemoglobin of 152 g/L, normal inflammatory markers with a white cell count of 8.4 ×109/L and C reactive protein 5 mg/L. The urine pregnancy test was negative and serum beta-human chorionic gonadotropin (b-HCG) was <1 IU/L. The transabdominal and transvaginal ultrasonography showed free fluid in the right adnexa and pouch of Douglas. Both ovaries and uterus were unremarkable, and there was no evidence of obstruction of the urinary system. Contrast-enhanced CT of the abdomen and pelvis confirmed small-volume free fluid in the pelvis; however, no other intra-abdominal or pelvic pathology was identified. There was no CT evidence of vascular, bowel, liver, spleen, urinary tract, gynaecological or inflammatory pathology. It should be noted that the appendix was not able to be visualised on this scan. Over the course of 48 hours, the patient was closely monitored. She deteriorated clinically with worsening RIF pain associated with hypotensive episodes and a haemoglobin drop to 124 g/L. A repeated serum b-HCG remained <1 IU/L. Differential diagnosis The differential diagnoses for acute RIF pain associated with free fluid in a previously well 33-year-old woman are broad-ranging. The initial leading differentials were: Ruptured ectopic pregnancy with haemorrhage Despite the history of bilateral tubal ligation, ruptured ectopic pregnancy remained important to exclude on presentation. This differential was ruled out following a normal serum b-HCG level and transvaginal ultrasound with no evidence of extra-uterine pregnancy. Ruptured ovarian cyst with haemorrhage or ovarian torsion Ovarian pathologies were considered as other possible gynaecological causes. However, these were considered unlikely due to the unremarkable ultrasound findings of the ovaries. Appendicitis with inflammatory free fluid Appendicitis was considered given the RIF pain associated with vomiting, anorexia and localised peritonism. Factors not consistent with appendicitis were apyrexia, normal inflammatory markers and a radiologically unremarkable appendix. Bleeding or inflammation from an undifferentiated cause This was considered given the presence of free fluid in the absence of other intra-abdominal pathology. Renal colic This was considered unlikely due to the non-colicky nature of the pain, as well as the normal renal function, urine dipstick, urinary tract on CT. Complications of hernia There was no clinical or radiological evidence of incisional, inguinal or femoral hernia, thus this differential was also excluded. The two differentials that were unable to be excluded based on initial assessment included appendicitis and bleeding from an undifferentiated cause. The patient was admitted under the general surgery unit for further investigation. Treatment The patient was admitted under the general surgery unit for further management. Given the largely undifferentiated cause for this patient’s abdominal pain and her clinical deterioration, a decision was made to proceed with a diagnostic laparoscopy. The diagnostic laparoscopy revealed an actively bleeding right fallopian cornu associated with haemoperitoneum of approximately 100 mL (figures 1 and 2). The appendix appeared macroscopically normal. The clips from previous bilateral tubal ligation were visualised and noted to be in appropriate position. The atypical appearance of the right fallopian tube prompted a request for additional assistance from the gynaecology team. There was consensus agreement that the primary pathology of acute abdomen was ruptured right fallopian cornu of unknown cause, thus the decision was made to proceed with a right partial salpingectomy with diathermy. Although the appendix appeared macroscopically normal, an appendicectomy was performed as per preoperative discussion with the patient. Outcome and follow-up The right partial salpingectomy specimen containing the cornu and isthmus of the right fallopian tube was examined. Microscopic assessment showed SIN with focal acute interstitial haemorrhage predominantly in the adventitia tissues (figure 3), with no associated products of conception. The appendix showed mild lymphoid hyperplasia with no evidence of acute inflammation. She had an uncomplicated recovery and discharged day 2 postoperatively. At the 2-week post-operative follow-up, the patient was well with an unremarkable clinical review. She is pending a formal gynaecology outpatient review.

Haemoperitoneum is defined by the presence of blood within the peritoneal cavity. Its broad aetiological classifications are listed below, alongside some of their most common culprits: Gynaecological: endometriosis; ruptured ovarian cyst, ectopic pregnancy or uterus. Trauma: blunt or penetrating. Hepatobiliary: hepatoma; acute haemorrhagic pancreatitis. Splenic: splenic rupture. Vascular: aneurysm and pseudoaneurysm rupture. Other neoplasm rupture. Coagulopathic: spontaneous bleeding in patients with coagulopathy or anticoagulant therapy. Patients with spontaneous haemoperitoneum usually present with acute abdominal pain possibly with referred shoulder tip pain, haemodynamic instability and/or signs of peritonism. After initial resuscitation, baseline pathology including serum b-HCG in females is paramount. Imaging aids in the detection of haemoperitoneum as well as identifying its cause. Although a majority of patients who present with acute abdominal pain undergo a CT abdomen/pelvis, transvaginal and transabdominal ultrasonography may be the initial imaging performed in the emergency department if pelvic pathology is suspected.2–4 Management is variable and highly dependent on the aetiology suspected. As detailed in our case, no cause for haemoperitoneum was readily identifiable following initial investigations. Thus, her further clinical deterioration prompted a diagnostic laparoscopy and then the eventual, unexpected discovery of ruptured SIN on histopathology after resection. Salpingitis isthmica nodosa Salpingitis isthmica nodosa (SIN), as the name suggests, is a nodular swelling of the isthmic segment of the fallopian tube.5 The isthmus makes up only 2.5–4 cm of the 10–14 cm fallopian tube and connects directly to the uterus. Subsequently, it has a relatively thick, three-layered muscle wall. SIN is characterised by invasion of tubal epithelium through this muscle wall, forming an outpouching which can communicate with the isthmic lumen.6 This can best be understood by the analogy of ‘diverticulosis of the fallopian tube’, with a similar disease process to adenomyosis. This invasion of epithelium into the smooth muscle causes secondary hypertrophy, forming the nodular swellings which define SIN’s morphology. It is often bilateral in presentation.7 It should be noted that though the name suggests inflammation, there is sparse evidence that SIN is primarily an inflammatory process.5 There is no consensus on aetiology; however, theories of it having acquired, non-inflammatory origin are the most popular.5 7 Some have argued that SIN is synonymous with tubal adenomyosis.6 Secondary inflammation can result from muscle hypertrophy occluding the opening of the diverticulum, causing dilatation and, often, secondary infection.6 The vast majority of research into SIN has been in the context of infertility or ectopic pregnancy, neither of which were present in this patient. One study showed SIN to be present in 43% of tubal ectopic pregnancies7 and it has a strong correlation with infertility.5 SIN is a histological diagnosis, and there is limited data on its prevalence in the healthy population as it is primarily an incidental diagnosis associated with investigation of pelvic pathologies. SIN is not known to be associated with haemorrhage in the absence of a ruptured ectopic pregnancy.5 6 There have been no reported cases of SIN being a primary cause for an acute abdomen or haemoperitoneum in the absence of an ectopic pregnancy, making this case a surgical novelty. Learning points. Salpingitis isthmica nodosa (SIN) is a poorly understood disease process. Although SIN typically presents with complications of infertility or ruptured ectopic pregnancy, a potentially rare, but life-threatening sequelae is rupture. A breadth of differentials of haemoperitoneum should be considered in females. Imaging may be helpful in identifying the presence of haemoperitoneum; however, accurate localisation may not be possible. In these patients, a diagnostic laparoscopy may be required. Acknowledgments We would like to acknowledge Dr John Roberts for providing the histopathology slides and to Mr James Roberts-Thomson for managing the patient. Footnotes Contributors: The report was written by DH, SL and PK. DH and SL conducted the literature search. KTC supervised and proof-read. Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Competing interests: None declared. Patient consent for publication: Obtained. Provenance and peer review: Not commissioned; externally peer reviewed.

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