Pelvic and Abdominal Pain
Pelvic and abdominal pain is a common diagnostic and management dilemma that spans a wide diversity of clinical settings. One of the most significant challenges in the diagnosis and management of these conditions is the lack of consensus for diagnostic criteria.
Pelvic pain refers to pain primarily in the anatomic pelvis, anterior abdominal wall at or below the umbilicus. It is a common presenting symptom in women and, occasionally, in men, both as an acute or a chronic symptom. Chronic pelvic pain is noncyclic pain of a duration of at least 6 months in the pelvis, anterior abdominal wall at or below umbilicus, lumbosacral back, or buttock that is severe enough to cause functional disability requiring medical evaluation.
Abdominal pain is a generic term for focal or general discomfort localized to the abdominal region. Recurrent abdominal pain is defined as at least three separate episodes of abdominal pain that occur in a 3-month period. Despite recent technologic advances, the diagnosis and treatment of chronic, recurrent abdominal pain has remained a challenge.
Pain is a subjective sensation that patients often find difficult to describe. In contrast to other areas of the body, the abdominal and pelvic organs have a poorly developed sensory system, which contributes to the patients’ difficulty in describing and localizing the pain.
Both pelvic and abdominal pain can be of visceral or somatic etiology.
Visceral pain results from activation of visceral nociceptors. Visceral structures are highly sensitive to stretch, distension, ischemia, and inflammation but are relatively insensitive to other stimuli such as cutting or burning. Visceral pain is diffuse, poorly localized, often referred to other structures, and associated with autonomic and somatosensory reflexes and strong negative affective symptoms.
Visceral abdominal pain is transmitted from nociceptors found on the walls of the abdominal viscera via sympathetic (thoracic branches and lumbar splanchnic nerves synapsing in subsidiary plexuses: celiac, splenic, hepatic, aorticorenal, superior mesenteric, adrenal) and parasympathetic (vagus and nervi erigentes S2–4; motor and sensory) pathways. Visceral nociceptors are polymodal—activated by mechanical, thermal, and chemical stimuli—and sensitize after tissue insult. Some visceral nociceptors are silent, which can be recruited in certain disease states like inflammation. Visceral pain is nonspecific because of wide divergence and a relatively small number of afferent fibers innervating a large area with extensive ramifications. Patients usually have difficulty localizing the source of pain and will describe it as aching, cramping, or burning that fluctuates in intensity. Visceral pain usually is paroxysmal, colicky, deep, squeezing, and diffuse, and it may be referred to other structures. Functional visceral disorders like irritable bowel disorders and functional dyspepsia are characterized by hypersensitivity, often in the absence of pathological explanation for the discomfort and pain.