Characteristics of the pain may aid in determining the diagnosis.
Important characteristics include timing of onset, location, quality,
Pain of sudden onset suggests an acute event such as hemorrhage,
rupture, or torsion of an ovarian cyst, whereas pain that is more
gradual may be present in subacute or progressive conditions. The differential
diagnosis of lower abdominal pain grouped by time of onset is presented
in Table 5–1.
Table 5–1. Differential Diagnosis of Lower Abdominal Pain by Time of Onset. ||Download (.pdf)
Table 5–1. Differential Diagnosis of Lower Abdominal Pain by Time of Onset.
|Acute onset (seconds to minutes)|
|Abdominal aortic aneurysm|
|Gradual onset (hours to days)|
|Mittelschmerz (midcycle ovulatory pain)|
|Pelvic inflammatory disease (PID)|
|Slow onset (days to weeks)|
|Abdominal aortic aneurysm|
|Chronic onset (weeks to months)|
|Chronic pelvic pain|
|Domestic violence or sexual abuse|
|Inflammatory bowel disease|
|Irritable bowel syndrome|
The location of the pain may also be helpful, although different
disease processes can lead to pain in the same region. The uterus,
cervix, and adnexae share visceral innervation with the lower ileum,
sigmoid, and rectum (T10–L1), and pain from any of these
structures may be felt in the same place. This is one of the dilemmas
when trying to distinguish acute appendicitis from pelvic inflammatory
disease (PID), although typically the pain of appendicitis is localized
in the right lower quadrant whereas that of PID is more diffuse.
Diffuse and generalized pain should alert the clinician to the possibility
of peritonitis, which may be seen following intra-abdominal hemorrhage
Although pain quality and severity are nonspecific symptoms, they
may provide some clue to the etiology of the pain. Abrupt and severe
pain is typically associated with perforation (ectopic pregnancy),
strangulation (ovarian torsion), or hemorrhage (ovarian cysts).
Crampy pain is often seen with dysmenorrhea or spontaneous abortion.
Pain that is colicky in nature is typical of ovarian torsion or
nephrolithiasis. Burning or aching pain often occurs with inflammatory
processes such as appendicitis or PID.
Associated symptoms are often helpful when trying to narrow the
diagnosis. Pain with fever suggests an infectious or inflammatory
etiology, such as appendicitis, PID, or a tubo-ovarian abscess. Nausea,
vomiting, and anorexia are nonspecific symptoms of peritoneal irritation
that may be present in patients with inflammatory conditions and
hemoperitoneum. Vaginal discharge can occur with infectious conditions
of the female genital tract, such as cervicitis or PID. Vaginal bleeding
may be associated with pregnancy-related disorders, abnormalities
of the menstrual cycle, PID, or pathology of the uterus or cervix.
Aggravating and Alleviating Factors
Depending on the etiology, changes in pain may occur in relation
to menses, coitus, activity, diet, bowel movements, or voiding.
In women who present with lower abdominal pain, vital signs must
be obtained as part of the evaluation. The presence of fever is
a key feature that can help to identify an inflammatory process
but may not help to specify which one. One study, for example, found
no significant difference between oral temperatures in patients
with PID and appendicitis. Women with acute PID or tubo-ovarian
abscess may be afebrile; therefore, the absence of fever should
not exclude these conditions. In conditions that raise suspicion
of hemorrhage, such as ruptured ectopic pregnancy or hemorrhagic
ovarian cysts, orthostatic pulse and blood pressure should be measured
to evaluate for hypovolemia.
The important components of the abdominal examination include inspection,
auscultation, percussion, and palpation. Bowel sounds may be decreased
in the presence of peritoneal irritation. Percussion and palpation
can help to identify masses and peritoneal irritation. Peritoneal
irritation is confirmed by the presence of rebound tenderness, involuntary
guarding, and increased pain with motion or cough.
The pelvic examination is most easily organized to proceed from
external to internal structures.
The external genitalia should be carefully inspected for lesions.
The presence of inguinal adenopathy is suggestive of a local infectious
process such as genital ulcer disease. On speculum examination,
the vagina and cervix should be visualized. Lesions, blood, or discharge
should be noted. The presence of cervical discharge, erythema, or
friability should alert the clinician to the possibility of cervicitis
or PID. Grossly purulent cervical discharge (mucopus) reflects a
high concentration of polymorphonuclear leukocytes in the mucus,
but the presence of mucopus has not been shown to accurately predict
On internal pelvic examination, the first step should be an assessment
for cervical motion tenderness. Its presence is nonspecific and
may indicate PID, ectopic pregnancy, endometriosis, or appendicitis.
Next, a bimanual examination should be performed, with assessment
of the uterus and adnexae. An enlarged uterus may indicate fibroids
or pregnancy. A uterus that is fixed and immobile may occur as a
result of adhesions from endometriosis or PID. Adnexal enlargement may
be seen with ovarian cysts, torsion, tubo-ovarian abscess, or ectopic
pregnancy. Pain on bimanual examination may occur with endometritis,
degenerating uterine fibroids, endometriosis, PID, ovarian cysts
or torsion, ectopic pregnancy, or appendicitis. Finally, digital
rectal and rectovaginal examinations should be performed. These
parts of the examination can be especially useful when abdominal
examination is unremarkable. Nodularity in the cul-de-sac or on
the uterosacral ligaments as a result of endometriosis may be appreciated
this way. Also, a tender mass may be palpated in certain gastrointestinal
disorders, such as appendicitis or diverticulitis.
When interpreting the pelvic examination, it is important to
remember that movement of the pelvic organs will be painful if peritoneal
irritation is present, regardless of the cause. Therefore, cervical
motion tenderness and adnexal tenderness may be found with a variety
of disorders, not only pelvic infection. In one study that compared
findings in patients with PID and appendicitis, cervical motion
tenderness was found significantly more often in patients with PID,
but was still found in 28% of patients with appendicitis.
Adnexal tenderness was found with equal frequency in both groups
but was usually limited to the right side in patients with appendicitis
and was usually, but not always, bilateral in patients with PID.
Laboratory and diagnostic imaging tests may help in the differential
diagnosis of acute pelvic pain but should be interpreted cautiously.
Baseline tests should include at least a complete blood count (CBC)
and pregnancy test. The white blood cell (WBC) count may be elevated
in inflammatory conditions, and the hematocrit may be low in the
setting of hemorrhage. In one study, the total WBC count was significantly
higher in patients with appendicitis than in those with PID (15.3 cells/ mm3 vs
12.7 cells/mm3, P < .01).
It is important to note, however, that the CBC has a low sensitivity
and specificity. The hematocrit is low in roughly one third of patients
with ectopic pregnancy but normal in the remainder. In studies,
a normal WBC count has been found in over half of patients with
PID and in one third of patients with acute appendicitis, whereas
an elevated WBC count is commonly seen in patients with ectopic
pregnancies and bleeding corpus luteum cysts. The erythrocyte sedimentation
rate is another nonspecific sign of inflammation. It is classically
elevated in PID, but can be normal in up to 25% of patients.
A urinalysis should be performed on every patient with acute
pelvic pain to rule out the presence of a urinary tract infection
or kidney stone. Care must be taken with specimen collection to
avoid contamination by vaginal or cervical discharge. Cervical specimens
should be obtained to test for Neisseria gonorrhoeae and Chlamydia
trachomatis. Vaginal fluid should be collected for saline (wet mount)
and potassium hydroxide (KOH) preparation, for the diagnosis of
bacterial vaginosis, Trichomonas vaginalis, and yeast infection.
The finding of leukocytes on wet mount is very useful for making
the diagnosis of PID, and the presence of 3 or more leukocytes per
high-power field has a high sensitivity. Furthermore, the absence
of leukocytes has a high negative predictive value for excluding
PID as a diagnosis.
Imaging studies, especially ultrasound, may be very useful in
making the diagnosis. Ultrasound is invaluable in the evaluation
of ovarian cysts and their complications. Ultrasound, especially
when performed transvaginally, is often the most useful imaging
modality for the gynecologic organs. Nonetheless, computed tomography
and magnetic resonance imaging scanning may also be helpful in the
evaluation of women presenting with lower abdominal pain, especially
when a nongynecologic cause is higher up on the differential diagnosis.
Diagnostic laparoscopy is perhaps the most definitive way to
arrive at a diagnosis in a patient with acute pelvic pain. It is
the best and most reliable method to achieve a complete evaluation
of the pelvic structures, and allows direct visual access to the
peritoneal cavity. It must be remembered, however, that although
laparoscopy is minimally invasive, it carries with it some risks.
Vascular injuries, as well as injuries to the gastrointestinal and
urinary tracts, have been reported. The overall risk of injury to
a vital structure has been estimated at between 2 and 3 per 1000.
The high cost associated with diagnostic laparoscopy limits its
utility in many cases of abdominal pain. Finally, although laparoscopy
can be helpful, it requires the involvement of a gynecologist. Consultation may
be useful in cases where the diagnosis remains unclear after investigation,
or where the chosen treatment regimen is not resulting in the patient’s