Abdominal pain is the most common complaint in the emergency department (ED), accounting for one in nine patients who present.

Most causes are benign and self-limiting, but approximately one in six may be serious or life threatening.

Diagnosis is often difficult and may rely on elements from the patient demographics, history, past medical and surgical history, physical examination, laboratory tests, and imaging.

The use of advanced medical imaging has increased significantly in recent years for patients with abdominal pain.

In one-third of patients, a cause will not be found in the ED.

The vast majority of patients with undifferentiated abdominal pain will improve spontaneously.

Elderly patients are at high risk for serious and surgical pathologies.

Abdominal pain is often approached anatomically, using the approximate location of the pain as a starting point.

As innervation of organs and their capsules relates to their embryologic development or spinal nerve level, several organs may present with pain in similar areas.

Symptoms may range from hypotension or shock, to nausea and vomiting, diarrhea, diffuse pain, anxiety, or localized pain depending on the organ affected.

To differentiate the cause, it is essential to piece together elements from the history and physical examination to establish a pain pattern representative of more specific pathologies.

Visceral pain is often described as deep, dull, and poorly localized.

Parietal pain or somatic abdominal pain is produced by ischemia, inflammation, or stretching of the parietal peritoneum.

Referred pain is felt in an area distinct from the origin of pain.

Those patients who are assessed to have nonsurgical abdominal examinations and are diagnosed with “undifferentiated abdominal pain” or abdominal pain NYD include approximately one-third of all cases of abdominal pain in the ED.

The vast majority of patients leaving the ED will have complete resolution of pain within 2 weeks of discharge.

Analgesia should be given at the earliest in patients with abdominal pain, including in those patients without a confirmed diagnosis.

Withholding pain medication before diagnosis was based on antiquated methods, yet up to 76% of physicians fail to give appropriate analgesia for these patients prior to getting a surgical evaluation.

Many studies show improved diagnostic accuracy when the patient is given analgesics.

Those who receive opioids tend to have more severe disease and are associated with higher mortality, but no causal link has been established and analgesia should be viewed as an important aspect of care in the ED.

Hemodynamically unstable patients need to have early aggressive supportive and surgical care prior to definitive diagnosis or imaging in many cases.

Five percent of patients above 65 years have an abdominal aortic aneurysm (AAA).

It is associated with atherosclerosis, smoking, hypertension, and family history.

Ruptured AAA has a very high mortality. Early ED identification may decrease mortality from 75%–35%.

Patients with AAA may present with severe abdominal, flank or back pain. This may be accompanied by radiation to the groin or thigh.

Clinical examination may show hypotension, diffuse abdominal tenderness, pulsatile abdominal mass, abdominal bruits, abdominal or flank ecchymosis, or absent distal pulses.

The triad of abdominal pain, hypotension, and a palpable pulsatile mass are seen in approximately one-half of patients with ruptured AAA.

Clinical examination is of limited value and ultrasound (US) examination is recommended in the ED to rule in and rule out the disease.

Management:

Despite rapid management, patients have a high mortality from ruptured AAA, and 50% of those who survive to reach the operating room will die.

Appendicitis is the most common surgical cause of abdominal pain in adults.

Appendicitis remains a difficult diagnosis, and missed diagnosis is one of the most common reasons for malpractice.

It is challenging to diagnose in some cases, especially in pregnancy and elderly patients.

Typically presents as a poorly differentiated pain localizing to the periumbilical area, later localizing to the RLQ with peritoneal irritation. It is often associated with anorexia, fever, and nausea.

Clinical examination may reveal tenderness in the RLQ, but may extend to anywhere along the length of the appendix.

Laboratory findings:

Imaging:

Serial examination should be done within 12 hours or earlier if symptoms evolve as longer delays may result in an increase in perforation.

Management:

It is generally acceptable to operate within 12 hours of diagnosis.

Bowel obstruction is the second most common cause for surgical intervention in the elderly.

It may occur in small or large intestine.

Causes may include extrinsic, intrinsic, or intraluminal processes.

Typically, pain is described as diffuse, poorly localized cramping and is moderate to severe.

Symptoms usually include:

Fever, general abdominal tenderness, peritoneal signs, and increased or high-pitched bowel sounds may be seen on examination.

Plain radiographs may show obstruction and remains one of the few clinical settings where plain films are used in workup of abdominal pain.

If obstruction is seen, most patients will require CT evaluation.

Typically in patients older than age 50.

Colonic diverticuli may become obstructed by fecal matter, resulting in bacterial growth and subsequent inflammation and distension.

Occurs in ∼30% of patients with diverticulosis.

Typical presentation is fever, LLQ pain, and elevated WBC in a patient older than age 50.

Typically, pain is deep, unremitting, and may progress to severe diffuse pain if the patient has a perforation.

Palpation of a mass in the LLQ may be appreciated, and tenderness on rectal examination is common. A rigid abdomen with guarding may be present following perforation.

Imaging:

Management:

Ectopic pregnancy is the leading cause of pregnancy-related death.

Ectopic implantation most commonly occurs in the distal ampulla of the fallopian tube.

Forty percent are missed on the first ED visit.

Two percent of all pregnancies are ectopic and the incidence is rising.