Dr Neelima Sibal and Dr Pallavi Latthe Consider Possible Causes of Pelvic Pain in Women—is it Ectopic Pregnancy, Endometriosis, Pelvic Inflammatory Disease, or Something Else?
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The pelvis is the lowest part of abdomen. Various organs are in the pelvis including the bowel, bladder, uterus, and ovaries and any of these organs can cause pelvic pain. Pelvic pain can also originate in the pelvic bones, muscles, nerves, joints, or blood vessels. Lower abdominal and pelvic pain can be diagnostically difficult and the differentiation between gynaecological and surgical causes is sometimes blurred.
Background
Pelvic pain is more common in women than men. It is a common presentation in primary care; between 1991 and 1995, 38 per 1000 women aged 12–70 years in the UK were affected annually.1,2 Common causes of acute pelvic pain include pelvic inflammatory disease (PID), urinary tract infection (UTI), miscarriage, ectopic pregnancy, and torsion or rupture of ovarian cysts. Chronic pelvic pain can be due to various aetiologies including endometriosis, PID, adenomyosis, and dense adhesions.
Pelvic pain can be classed as acute or chronic based on the onset and duration of symptoms. Chronic pelvic pain (CPP) is defined as: 'intermittent or constant pain in the lower abdomen or pelvis of a woman of at least 6 months in duration, not occurring exclusively with menstruation or intercourse, and not associated with pregnancy.’3 It is a symptom that presents in primary care as frequently as migraine or low back pain.2 It may significantly impact on a woman’s quality of life as well as carrying a heavy economic and social burden.
Patients with chronic inflammatory condition of the bladder (characterised by urination urgency, frequency, and pain on holding too long), in absence of another cause or irritable bowel syndrome, often present with CPP.3
In addition, past pelvic or abdominal surgery, or trauma during childbirth may contribute to the genesis of CPP. Social and psychological factors are strongly associated with chronic pelvic pain. History of social issues and psychological issues (such as physical or sexual abuse) should also be investigated during the assessment of CPP.1
Acute pelvic pain in younger women may indicate problems with pregnancy, such as ectopic pregnancy. In the acute setting, PID and lower genital tract infections (e.g. cervicitis, candidiasis, Bartholin’s abscess) account for almost half of all diagnoses for women with pain caused by gynaecologic disorders. Other common diagnoses include menstrual disorders, non-inflammatory ovarian and tubal pathology (including cysts and torsion), and ectopic pregnancy.4
Aiming for accurate diagnosis and effective management from the first presentation will help to reduce the disruption of the woman’s life and may avoid an endless succession of referrals, investigations, and operations.
History Taking
A careful history (focusing on pain characteristics, a review of symptoms, as well as taking a gynaecological, sexual, and social history) and physical examination helps to narrow the differential diagnoses. The patient should be asked to describe the pain they are experiencing, for example:
- location
- intensity
- radiation
- timing (in relation to menses, food, micturition, defaecation, and sexual intercourse)
- duration
- any exacerbating and mitigating factors.
The example case studies presented below discuss different presentations of pathologies causing acute and chronic pelvic pain.
Case 1
A 25-year-old woman presents with persistent lower abdominal pain of 1-week duration and smelly vaginal discharge. She has been in a new relationship for the past 4 months. Her past medical history is unremarkable with the exception of a ruptured appendix 1 year ago, which required surgery. On examination, she was febrile with lower abdominal tenderness. She had cervical motion tenderness on bimanual vaginal examination with some adnexal tenderness. A urine dipstick test gave unremarkable results.
Diagnosis
Pelvic inflammatory disease (PID) is a likely diagnosis in this case. Typical symptoms, new sexual relationship, and the findings of the physical examination support the clinical diagnosis of PID.5
Clinicians should consider PID in young women who are sexually active and in other women at risk of sexually transmitted infections (STIs) when they experience pelvic or lower abdominal pain and no other cause is apparent. This is especially true if the patient has cervical motion, uterine, or adnexal tenderness.5
The exact incidence of PID is unknown because of the difficulty in making a clinical diagnosis, and because it is often unrecognised if it presents atypically or is asymptomatic. An Office of Population Censuses Survey (1991–1992) of 60 general practices in England and Wales showed that PID was diagnosed in 1.7% of GP attendances by women 16–46 years of age.6
Management
All women presenting with pelvic pain should be offered a pregnancy test (where appropriate) to exclude pregnancy, and screening for sexually transmitted infections. Referral of the index case woman and her partner to a genitourinary medicine (GUM) or sexual health clinic to facilitate contact tracing and infection screening should be encouraged.5
If clinical diagnosis of PID is suspected then antibiotic treatment should be prescribed promptly, based on local guidelines. It is likely that delaying treatment increases the risk of long-term sequelae such as ectopic pregnancy, infertility, and pelvic pain.7
Because of the risk of complications and the lack of definitive diagnostic criteria, a low threshold for empiric treatment of PID is recommended. Appropriate analgesia should be provided. Antibiotic regimens commonly used for outpatients are:5
- oral ofloxacin 400 mg twice daily plus metronidazole 400 mg twice daily for 14 days
- intramuscular ceftriaxone 500 mg single dose, followed by oral doxycycline 100 mg twice daily plus metronidazole 400 mg twice daily for 14 days.
Intravenous therapy and hospitalisation is recommended for patients with more severe clinical disease, for example, pyrexia >38 °C, clinical signs of tubo-ovarian abscess, or signs of pelvic peritonitis.5
Consideration should also be given to removing an intrauterine contraceptive device in women presenting with PID, especially if symptoms have not resolved within 72 hours.8
Clinical Outcome
This patient was offered triple swabs in the surgery and was commenced on combination antibiotic treatment. Her swabs confirmed Neisseria gonorrhoea. She was informed regarding the diagnosis and advised to visit the local GUM clinic with her partner for treatment. She was advised to avoid unprotected intercourse until she and her partner(s) had completed treatment and follow up.
Case 2
A 36-year-old woman presents with a history of left-sided lower abdominal pain for 2 days, which started suddenly and was followed by reddish-brown bleeding. Her periods have been delayed by 3 weeks. She also complains of feeling nauseous and dizzy. She has no previous history of miscarriage but her patient record shows a history of suspected pelvic infections. On examination, she has a pulse rate of 132 bpm and blood pressure is found to be 92/67 mmHg. Urine pregnancy test is positive. Abdominal examination reveals left lower abdominal tenderness with guarding.
Diagnosis
Ectopic pregnancy is the most likely diagnosis until otherwise ruled out.
An ectopic pregnancy is any pregnancy implanted outside of the endometrial cavity. In the UK, the incidence is approximately 11 per 1000 pregnancies, with an estimated 11,000 ectopic pregnancies diagnosed each year.9
Due to its life-threatening nature, ectopic pregnancy must be ruled out when a woman of reproductive age presents with acute pelvic pain and a positive pregnancy test. An unruptured ectopic pregnancy produces localised pain due to dilatation of the fallopian tube. Once the ectopic pregnancy is ruptured, the pain tends to be generalised due to peritoneal irritation from the blood and this includes shoulder-tip pain.10
Risk factors for ectopic pregnancy include tubal damage following surgery or infection, smoking, previous ectopic pregnancy, and in vitro fertilisation; however, the majority of women with an ectopic pregnancy have no identifiable risk factor.9 Transvaginal ultrasound (TVS) and serum human chorionic gonadotrophin (hCG) levels are commonly used investigations.
Management
Emergency referral to the local gynaecology unit should be made following a discussion with the on-call specialist.9
Laparoscopic management is the norm if:
- the patient is haemodynamically stable, or
- a high index of suspicion remains, or
- the patient complains of increasing pain despite adequate analgesia.
Surgical treatment options for an ectopic pregnancy in the fallopian tube include salpingectomy and salpingotomy. These may be performed laparoscopically or by open procedure.9
Methotrexate is a possible pharmacological option for unruptured ectopic pregnancy and works well if the serum hCG is <1500 IU/litre.11 It can only be given in the hospital setting with proper follow up. If hCG levels are <1000 IU/litre and have fallen on a repeat test 48 hours later, a conservative approach can be adopted; watch and wait—monitor hCG levels to ensure they are falling as the ectopic pregnancy can resolve spontaneously.
Caesarean scar ectopic pregnancy and ovarian or cervical pregnancy are rarer ectopic pregnancies and should ideally be managed in centres with expertise in these conditions.
Outcome
In this patient, ultrasound examination confirmed an empty uterus and a significant amount of free fluid. She was offered emergency laparoscopy and left salpingectomy was undertaken for leaking left tubal ectopic pregnancy.
Case 3
A 20-year-old woman presents with a 2-year history of worsening secondary dysmenorrhoea. Her periods are regular but she usually has 2–3 days of spotting with severe pain before her periods are due. She also complains of pain during intercourse and post-coital ache. Abdominal examination is normal. Pelvic examination reveals some nodularity in the uterosacral area.
Diagnosis
The likely diagnosis in this case is endometriosis.
Endometriosis is defined as the growth of endometrial-like tissue outside the uterus.12 It is often associated with dysmenorrhea, pelvic pain, subfertility, and mainly affects women of reproductive age.13 Dysuria and haematuria can be presenting features in cases where there is bladder involvement; painful defecation and blood in stools sometimes occur in cases where there is bowel involvement. Population based studies report a prevalence of around 1.5% compared with 6–15% in hospital-based studies.12,13 There is a hereditary element to endometriosis as the condition tends to run in families.
Management
To confirm a diagnosis of endometriosis, laparoscopy or transvaginal ultrasound should be considered in women who do not respond to conservative treatment or have subfertility. Abdominal ultrasound, magnetic resonance imaging, and computed tomography are only useful in presence of pelvic or adnexal masses—a diagnosis of endometriosis should not be excluded if the abdominal or pelvic examination, ultrasound, or MRI are normal.12,13
The primary treatment goal for endometriosis is essentially pain relief and/or improving fertility.13
Management can be medical or surgical. Medical management involves:12
- pain management—
- NSAIDS, paracetamol (alone or in combination), or codeine-based analgesics
- hormonal treatment—
- the oral contraceptive pill, progestins/progesterone, gonadotrophin-releasing hormone (GnRH) analogues, danazol, or levonorgestrel-releasing intrauterine system.
Hormonal therapies have varying degrees of side-effects and, unfortunately, for many patients, pain relief may be only temporary. If medical management is tried, review the woman after 3–6 months (earlier if symptoms are troublesome) and refer to a gynaecologist if there is no improvement in symptoms during this period.14
Laparoscopic surgery is the only definitive way to diagnose endometriosis, and in most cases the disease can be diagnosed and treated in the same procedure. Pelvic clearance (abdominal hysterectomy and bilateral salpingo-oophorectomy) can be offered to women for whom fertility is not a priority.15
Clinical Outcome
The patient was initiated on a 21-week trial of the combined oral contraceptive pill, but had little improvement in her symptoms. The patient had laparoscopic excision of endometriosis and insertion of levonorgestrel-releasing intrauterine system. At a follow-up appointment after 4 months the patient had become amenorrhoeic and pain during intercourse had improved significantly.
Case 4
A 17-year-old woman presents as an emergency with sudden-onset pain in the left side of her lower abdomen following exercise, progressively getting worse in last 10 hours. Pain was radiating to her pelvis and left thigh. The patient had associated nausea and two episodes of vomiting. On further questioning, the patient admitted having similar but less severe episodes in last few months. Abdominal examination showed tenderness in the left lower quadrant. Urine dipstick analysis was clear and pregnancy test was negative. Pelvic examination revealed fullness in left adnexa. Ultrasound revealed left adnexal pelvic mass.
Diagnosis
The likely diagnosis of this patient is ovarian cyst torsion.
Changes in ovarian axial morphology, which are typically secondary to ovarian cysts (most commonly dermoids), can undergo torsion around the ovarian pedicle. Persistent torsion progresses to occlusion of the venous drainage of the ovary, which leads to congestion, ovarian enlargement, thickening of the ovarian capsule, and subsequent infarction. Pain is typically colicky and eventually becomes severe and is accompanied by nausea, vomiting, and restlessness. Infarction also leads to fever and mild leukocytosis. On pelvic exam, a tender unilateral mass in the anterior pelvis may be palpable.16
Conservative management with laparoscopic detorsion with or without cystectomy and oophoropexy is recommended.16 In older and postmenopausal women, salpingo-oophorectomy is the treatment of choice to completely remove the risk of re-torsion.
Outcome
The patient had a pelvic ultrasound, which confirmed a 7 cm ovarian cyst. She underwent laparoscopic de-torsion, ovarian cystectomy, and made a good recovery.
Conclusion
Pelvic pain is a common presentation in primary care. Full history and detailed examination is required to establish possible causes of the pain. Further investigations in the form of urine examination, blood tests, and imaging are undertaken based on history in order to establish the diagnosis and plan treatment and management. Depending on the diagnosis, patients can be managed in primary care but some may require referral to secondary care if there is doubt about the diagnosis, pain is unresponsive to conservative management, or if the cause of pelvic pain merits surgical intervention.
Even if no explanation for the pain can be found initially, attempts should be made to treat the pain empirically and to develop a management plan in partnership with the woman. Women can also be directed to organisations and websites for further information and/or support (see Box 1).3
| Box 1: Organisations and Websites for Women with Pelvic Pain |
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| UK charity dedicated to providing information and support to people with endometriosis. The UK’s national charity for IBS, offering information, advice and support to patients with IBS and working with healthcare professionals to facilitate IBS self management. The Pelvic Pain Support Network supports those with pelvic pain whether they have a diagnosed condition or not. |