CHAPTER 2 Abdominal pain

Abdominal pain is a subjective feeling of discomfort in the abdomen that can be caused by a variety of problems. The goal of initial clinical assessment is to distinguish acute life-threatening conditions from chronic/recurrent or acute mild, self-limiting conditions. Assessment is complicated by the dynamic rather than static nature of acute abdominal pain, which can produce a changing clinical picture, often over a short period of time. In addition, both children and older adults tend to deviate from the usual and anticipated clinical pattern of abdominal pain.

The following three processes can produce abdominal pain: (1) tension in the gastrointestinal (GI) tract wall from muscle contraction or distention; (2) ischemia; and (3) inflammation of the peritoneum. Pain can also be referred from within or outside the abdomen.

Colic is a type of tension pain. It is associated with forceful peristaltic contractions and is the most characteristic type of pain arising from the viscera. Colicky pain can be produced by an irritant substance, from infection with a virus or bacteria, or by the body’s attempt to force its luminal contents through an obstruction. Another type of tension pain is caused by acute stretching of the capsule of an organ, such as the liver, spleen, or kidney. The patient with this visceral pain is restless, moves about, and has difficulty getting comfortable.

Ischemia produces an intense, continuous pain. The most common cause of intestinal ischemic pain is strangulation of the bowel from obstruction.

Inflammation of the peritoneum usually begins at the serosa covering the affected and inflamed organ, causing visceral peritonitis. The pain is a poorly localized aching. As the inflammatory process spreads to the adjacent parietal peritoneum, it produces localized parietal peritonitis. The pain of parietal peritonitis is more severe and is perceived in the area of the abdomen corresponding to the inflammation. The patient with parietal pain usually lies still and does not want to move.

Pain can be referred from within the abdomen or from other parts of the body (Box 2-1).

Box 2-1 Some Causes of Pain Perceived in Anatomical Regions

Right Upper Quadrant	Periumbilical Intestinal obstruction Acute pancreatitis Early appendicitis Mesenteric thrombosis Aortic aneurysm Diverticulitis	Left Upper Quadrant
Duodenal ulcer		Ruptured spleen
Hepatitis		Gastric ulcer
Hepatomegaly		Aortic aneurysm
Pneumonia		Perforated colon
Cholecystitis		Pneumonia
Right Lower Quadrant		Left Lower Quadrant
Appendicitis		Sigmoid diverticulitis
Salpingitis		Salpingitis
Ovarian cyst		Ovarian cyst
Ruptured ectopic pregnancy		Ruptured ectopic pregnancy
Renal/ureteral stone		Renal/ureteral stone
Strangulated hernia		Strangulated hernia
Meckel diverticulitis		Perforated colon
Regional ileitis		Regional ileitis
Perforated cecum		Ulcerative colitis

Modified from Judge R, Zuidema G, Fitzgerald F: Clinical diagnosis, ed 5, Boston, 1988, Little Brown.

Referral of pain occurs because tissues supplied by the same or adjacent neural segments have the same common pathways inside the central nervous system. Thus stimulation of these neural segments produces the sensation of pain. For example, nerves that supply the appendix are derived from the same source as those that supply the small intestine, resulting in the onset of appendicitis pain in the epigastric area.

Abdominal pain in adults can be classified as acute, chronic, or recurrent. The term acute abdomen refers to any acute condition within the abdomen that requires immediate surgical attention. Not all acute abdominal pain, however, requires surgical intervention. Acute abdominal pain refers to a relatively sudden onset of pain that is severe or increasing in severity and has been present for a short duration. Chronic pain is characterized by its persistent duration or recurrence. Recurrent episodes of pain can be either acute or chronic in nature.

In adults, acute pain requiring surgical intervention is commonly caused by appendicitis, perforated peptic ulcer, intestinal obstruction, peritonitis, perforate diverticulitis, ectopic pregnancy, or dissection of aortic aneurysm. Common causes of acute pain not requiring surgical intervention include cholelithiasis, gastroenteritis, peptic gastroduodenal syndrome, pancreatitis, pelvic inflammatory disease (PID), or urinary tract infection (UTI). Chronic or recurrent pain can be caused by GI disorders, such as irritable bowel syndrome (IBS), diverticulitis, or esophagitis; pelvic disorders, such as dysmenorrhea or uterine fibroids; genitourinary disorders, such as recurrent UTI or chronic prostatitis; or conditions outside the abdomen, such as costochondritis, hip disease, or hernia.

In children, abdominal pain can be classified as acute or recurrent. Common causes of acute pain include appendicitis, food poisoning, UTI, viral gastroenteritis, and bacterial enterocolitis. Recurrent abdominal pain (RAP) is defined as more than three episodes of pain in 3 months in children older than 3 years. It affects 10% to 15% of children between the ages of 3 and 14; of these children, 90% will not have an organic etiology.

Diagnostic reasoning: focused history

Is this an acute condition?

Key questions

How long ago did your pain start?

Was the onset sudden or gradual?

How severe is the pain (on a scale of 1 to 10)?

If a child: What is the child’s level of activity?

Does the pain wake you up from sleep?

What has been the course of the pain since it started? Is it getting worse or better?

When was your last bowel movement?

Have you ever had this pain before?

Onset/duration

Acute onset of pain that is getting progressively worse could signal a surgical emergency. In general, patients who present with severe pain 6 to 24 hours from the onset probably have an acute surgical condition. Acute abdominal pain can signal a few potentially life-threatening conditions that must be considered first. The following are possible surgical emergencies that require immediate evaluation and intervention:

Perforation: look for signs and symptoms of peritonitis (Box 2-2)

Ectopic pregnancy: in any woman of childbearing age

Obstruction: in the elderly

Ruptured abdominal aortic aneurysm: when back pain is present

Intussusception: in infants

Malrotation: in infants usually less than 1 month old

Box 2-2 Features of Peritonitis

Pain: front, back, sides, shoulders

Electrolytes fall; shock ensues

Rigidity or rebound of anterior abdominal wall

Immobile abdomen and patient

Tenderness with involuntary guarding

Obstruction

Nausea and vomiting

Increasing pulse rate, decreasing blood pressure

Temperature falls and then rises; tachypnea

Increasing girth of abdomen

Silent abdomen (no bowel sounds)

Modified from Shipman JJ: Mnemonics and tactics in surgery and medicine, ed 2, Chicago, 1984, Mosby.

Pain of sudden onset is more likely associated with colic, perforation, or acute ischemia (torsion, volvulus). Slower onset of pain generally is associated with inflammatory conditions, such as appendicitis, pancreatitis, and cholecystitis.

Acute pain that comes and goes can be related to intestinal peristalsis. The onset of pain in relation to food ingestion provides diagnostic clues: pain occurring several hours after a meal suggests a duodenal ulcer (pain with stomach empty), whereas pain immediately after eating occurs with esophagitis.

In children, RAP occurs in attacks usually lasting less than 1 hour and rarely longer than 3 hours and frequently interferes with daily routines. Between episodes, the pain resolves completely. When interviewing a child, remember that the child might not be old enough to have a clear sense of time.

Severity and progression

Severity is the most difficult symptom to evaluate because of its subjective quality. It is helpful to use a 1-to-10 scale in adults. Children often respond to the use of the pain faces or the Oucher Pain Scale (Figure 2-1).

FIGURE 2-1 The Oucher Pain Scale illustrated with African American, Caucasian, and Hispanic children to best fit the child’s cultural identity. The African American child version of the Oucher was developed and copyrighted in 1990 by Mary J. Denyes, PhD, RN, FAAN (Wayne State University), and Antonia Villarruel, PhD, RN, FAAN (University of Michigan), at the Children’s Hospital of Michigan. Cornelia P. Porter, PhD, RN, and Charlotta Marshall, MSN, RN, contributed to the development of this scale. The Caucasian child version of the Oucher was developed and copyrighted in 1983 by Judith E. Beyer, PhD, RN, currently at the University of Missouri—Kansas City School of Nursing. Photographs were taken by Lynn Julaino, RN, BSN, at Martha Jefferson Hospital in Charlottesville, Va. The Hispanic child version of the Oucher was developed and copyrighted in 1990 by Antonia M. Villarruel, PhD, RN (University of Michigan), and Mary J. Denyes, PhD, RN (Wayne State University). Photographs were taken at Children’s Hospital of Michigan in Detroit.

Determine whether the pain is an acute episode or a chronic or recurrent episode. Acute abdominal pain requires immediate attention, because it can signal an acute surgical condition in the abdomen. Chronic or recurrent episodes of pain can be handled in a more temperate manner.

Pain that is steady, severe, and progressive is worrisome. Pain that causes one to awake from sleep is serious. A sudden pain severe enough to cause fainting suggests perforated ulcer, ruptured aneurysm, or ectopic pregnancy. A severe knifelike pain usually indicates an emergency. Tearing pain is characteristic of an aortic aneurysm. Appendicitis is often described as an ache. Colicky pain that becomes steady can indicate appendicitis or strangulating intestinal obstruction.

Children are poor historians regarding the severity of pain. The caregiver should indicate how severe the child’s pain is by a description of the activity level of the child. In general, avoidance of favorite activities or motion indicates an organic problem. Organic disease awakens the child from sleep.

Last bowel movement

Obstipation (the absence of stools) occurs with complete obstruction, but diarrhea can be present with partial obstruction. Lack of a bowel movement for 3 days could signal constipation. Children can have sudden onset of constipation that can cause severe abdominal pain.

Previous pain

Chronic pain could result when a potential surgical event is partially controlled but is not totally resolved. Chronic pain that has been present for longer than 1 year generally is not caused by a neoplasm; consider instead IBS or colorectal, endometrial, or inflammatory causes.

Recurrent attacks of acute pain could be caused by inflammation and exacerbation of a chronic condition, such as functional colonic pain, IBS, cholecystitis, chronic pancreatitis, diverticulitis, or ulcer disease. Acute pain can also be caused by recurrent infection, such as pyelonephritis or cystitis. Urinary tract stones can also cause acute attacks of recurrent pain.

Will the location of pain give me any clues?

Key questions

Where is the pain? Can you point to it?

Does it travel (radiate) anywhere?

Location of the pain

The viscera is innervated bilaterally so that pain is perceived in the midline. It is often described as a deep, dull, diffuse pain. Visceral pain originates from epigastric, periumbilical, and hypogastric causes; from intraabdominal extraperitoneal organs (pancreas, kidneys, ureters, great vessels, pelvic organs); or from a referred source.

Parietal (also known as peritoneal or somatic) pain is more localized and is described as a sharp pain. Peritoneal pain originates from intraabdominal and intraperitoneal organs.

Inflammation (for example, with appendicitis) can produce either visceral or parietal peritonitis. Initially the inflammation is limited to the serosa covering an inflamed organ. The pain is visceral and is felt diffusely. As the inflammation progresses to the adjacent parietal peritoneum, it produces a more severe localized pain that is perceived in the corresponding area of the abdomen. Children have a poor ability to localize pain and are not helpful in the majority of cases.

The Apley rule states that the further the localization of pain from the umbilicus, the more likely it is that there is an underlying organic disorder.

When blood, pus, or gastric fluid suddenly floods the peritoneal cavity, the pain is frequently reported as “all over the abdomen” at first. However, the maximum intensity of pain at the onset is likely to be in the upper abdomen with gastric problems and in the lower abdomen with tubal and appendix rupture. Irritating fluid from a perforated duodenal ulcer produces pain in the right hypochondrium, lumbar, and iliac regions.

Pain arising from the small intestine is always felt in the epigastric and umbilical areas of the abdomen. The ninth and eleventh thoracic nerves supply the small intestine via the common mesentery nerve. Appendicular nerves are derived from the same source as those that supply the small intestine, resulting in onset of pain in the epigastric area with appendicitis.

Table 2-1 describes the structures involved in specific pain locations.

Table 2-1 Pain Location and Involved Structures

PAIN LOCATION	INVOLVED STRUCTURES
Epigastric	Esophagus, stomach, duodenum, liver, gallbladder, pancreas, spleen
Upper abdominal	Esophagus, stomach, duodenum, pancreas, liver, gallbladder, or thorax
Right upper quadrant	Usually esophagus, stomach, duodenum, pancreas, liver, gallbladder, or thorax; often indicates acute cholecystitis
Left upper quadrant	Spleen
Periumbilical	Jejunum, midgut, ileum, appendix, ascending colon; pain caused by inflammation, ischemic spasm, or abnormal distention
Lower abdominal	Colon, sigmoid colon, rectum, and genitourinary structures—bladder, uterus, prostate
Right lower quadrant	Appendix, fallopian tube, ovary
Left lower quadrant	Sigmoid colon, fallopian tube, ovary
Flanks	Kidney(s)
Localized	Occurs from local inflammation of skin or peritoneum, as with appendicitis; lateralized pain occurs in paired organs—kidneys, ureters, fallopian tubes, gonads
Generalized	Produced by diffuse inflammation of gastrointestinal tract, peritoneum, or abdomen wall

Radiation of pain

Radiation of pain can help in diagnosis. Pain that radiates will do so to the area of distribution of the nerves coming from that segment of the spinal cord that supplies the affected area. Biliary colic pain is frequently referred to the region just under the right scapula (eighth dorsal segment), whereas renal colic in males is frequently felt in the testicle of the same side. Pain from a ruptured spleen is often referred to the top of the left shoulder.

What do the pain characteristics tell me?

Key questions

Can you describe the pain (e.g., burning, sharp, achy, crampy)?

What makes it worse or better?

Character of pain

Colicky or cramping pain occurs with obstruction of a hollow viscus that produces distention. Generally there are pain-free intervals when the pain is much less intense but still present, although it is subtle. During the painful episodes, the patient is exceedingly agitated and restless, and often pale and diaphoretic. The pain from obstruction of the small intestine is rhythmic, peristaltic pain with intermittent cramping. When the obstruction site is in the proximal small intestine rather than in the more distal portion, the paroxysms of cramping occur with greater frequency.

Steady pain is associated with perforation, ischemia, inflammation, and blood in the peritoneal cavity. Burning pain is characteristic of esophagitis. Pain from a duodenal ulcer has been described as burning or “gnawing.” Pain of pancreatic origin is steady, epigastric, and prostrating. Pricking, itching, or burning pain comes from superficial causes such as herpes zoster. Dull, aching pain indicates deeper pain. In children, abdominal pain is generally characterized as colicky or inflammatory.

Remember, however, that despite descriptions of characteristic or typical abdominal pain, presentation in children and the elderly is often atypical and might not fit any pattern.

Precipitating or aggravating factors

Lying down or bending forward often produces pain from esophagitis. Alcohol can aggravate gastritis or an ulcer.

Pain that is made worse by deep inspiration and is stopped or diminished by a respiratory pause indicates pleuritic origin. If the cause is peritonitis, intraperitoneal abscess, or abdominal distention from intestinal obstruction, pain will increase on deep inspiration. Biliary colic is made worse by forced inspiration. The pain from biliary colic often causes inhibition of movement of the diaphragm.

The patient with visceral pain is restless, moves about, and has difficulty getting comfortable. The patient with parietal pain usually lies still and does not want to move. Children with inflammatory pain secondary to peritoneal irritation usually appear quiet and motionless because movement exacerbates the pain.

Relieving factors

Food or antacids can relieve pain caused by an ulcer or gastritis. Both colicky pain and inflammatory pain are alleviated significantly with analgesics. However, the pain of a vascular accident will not respond to analgesics.

Are there any precipitating events that will help narrow my diagnosis?

Key questions

Is the pain related to any other activity (e.g., eating, lying down)?

Can you identify any trigger?

Relation to other events

Pain that is relieved by defecation, flatus, laxatives, or diet changes implicates the intestine. Pain associated with meals implicates the GI tract.

Pain with sexual activity (dyspareunia) suggests a pelvic origin. Pain that occurs with position changes can be referred from the spine, hips, sacroiliac joint, pelvic bones, or abdominal musculature. Exertional pain can be of cardiac origin.

What does the presence of vomiting or diarrhea tell me?

Key questions

Are you vomiting? What does the vomitus look like?

What do your stools look like?

How frequent are your stools?

Vomiting

Vomiting that precedes the onset of abdominal pain is unlikely to signal a problem requiring surgery. Vomiting suggests that the pain is visceral in origin. Anorexia is a nonspecific symptom, but its absence makes serious disease less likely.

Vomiting associated with an acute condition of the abdomen may be from one of the following three causes:

Severe irritation of the nerves of the peritoneum or mesentery. Sudden stimulation of many sympathetic nerves causes vomiting to occur early and to be persistent.

Obstruction of an involuntary muscular tube. Obstruction of any of the muscular tubes causes peristaltic contraction and consequent stretching of the muscle wall, which results in vomiting. The area behind the obstruction becomes dilated, and, as each peristaltic wave occurs, the tension and stretching of the muscular fibers are temporarily increased; therefore the pain of colic usually occurs in spasms. Vomiting usually occurs at the height of the pain.

The action of absorbed toxins on the medullary centers. The chemoreceptor trigger zone is stimulated by drugs such as cardiac glycosides, ergot alkaloids, and morphine or by uremia, diabetic ketoacidosis, or general anesthetics. Impulses to the medullary vomiting center then activate the vomiting process.

Pain with vomiting

In sudden and severe stimulation of the peritoneum or mesentery, vomiting comes soon after the pain. In acute obstruction of the urethra or bile duct, vomiting is early, sudden, and intense. In intestinal obstruction, the timing of the vomiting indicates how high in the gut the obstruction is. If the duodenum is obstructed, vomiting occurs with the onset of pain. Obstruction of the large bowel causes very late or infrequent vomiting.

Vomiting is not usually seen in ectopic pregnancy, gastric or duodenal perforation, or intussusception. Vomiting occurring before pain indicates gastroenteritis. With appendicitis, pain almost always precedes the vomiting.

Vomitus appearance

Clear vomitus suggests gastric fluid; bile-colored vomitus is from upper GI contents. Feculent vomitus occurs with distal intestinal obstruction. Patients with gastric outlet obstruction vomit fluid that contains food particles if the patient has eaten recently, but later the vomitus becomes clear. Infants with duodenal atresia will vomit bilious fluid, but in pyloric stenosis no bile is seen.

Stool characteristics

Diarrhea is associated with inflammatory bowel disease, diverticulitis, or early obstruction. The presence of blood in the stool suggests that the pain originates in the intestinal tract. Blood can indicate neoplasm, intussusception, or inflammatory lesions.

Diarrhea can precede perforation of the appendix as a result of irritation of the sigmoid colon, by an inflammatory mass. Some patients will report gas stoppage symptoms: the sensation of fullness that suggests the need for a bowel movement. With appendicitis, the patient often attempts to defecate but without relief.

In children, mild diarrhea associated with the onset of pain suggests acute gastroenteritis but can also occur with early appendicitis. A low-lying appendix, close to the sigmoid colon and rectum, can induce an inflammatory process of the muscle wall of the sigmoid colon. Any distention of the sigmoid by fluid or gas signals the child to pass gas and small amounts of stool. The cycle repeats a few minutes later. In gastroenteritis, typically the child will have large liquid stools. Children can also have abdominal pain from chronic constipation. Constipation that precedes pain suggests disease of the colon or rectum.

Are there any clues to implicate a particular organ system?

If the patient gives a positive response to the following history questions, refer to the topic or chapter indicated for additional discussion. Pain that is not abdominal in origin could be referred to, or perceived to be in, the abdomen. Accompanying symptoms of headache, sore throat, and general aches and pains suggest a viral, flulike cause.

Key questions

Cardiovascular system (Chapter 7):

Does the pain occur with exertion or at rest?

Do you have any chest pain, palpitations, fast heartbeat, or pain that goes to the arm or jaw?

Referred pain from the chest is not uncommon. Pain on exertion signals coronary artery disease (CAD) and angina. Right upper quadrant (RUQ) pain can be caused by congestive heart failure. Myocardial infarction and pericarditis can also cause abdominal pain.

Key questions

Gastrointestinal system (Chapters 9 and 11):

Do you have any GI symptoms (e.g., gas, diarrhea, constipation, vomiting, heartburn)?

Have you had any changes in your bowel habits, stools, or eating pattern?

Is the pain relieved by defecation or burping?

Gas, bloating, diarrhea, constipation, and rectal bleeding can occur with pain that is intestinal in origin. Heartburn and dysphagia are characteristic of esophagitis. Changes in bowel habits can signal obstruction or neoplasm. Constipation alternating with diarrhea is characteristic of IBS. The patient often also reports distention, bloating, belching, gas, and mucus in the stools.

Pain relieved by defecation or the passage of gas suggests IBS or gas entrapment in the large intestine. Pain relieved by burping suggests distention of the stomach by gas.

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