Determining the cause of acute abdominal pain is often complex due to the many organs in the abdomen and the fact that pain may be nonspecific. Acute abdomen is a general diagnosis, typically referring to severe abdominal pain that occurs suddenly over a short period (usually no longer than 7 days) and often requires surgical intervention. Symptoms may be severe and progress rapidly, indicating a life-threatening process, so fast and accurate assessment is essential.
In this article, I'll describe how to assess a patient with acute abdominal pain and intervene appropriately.
What a pain!!
Acute abdominal pain is one of the top three symptoms of patients presenting in the ED. Reasons for acute abdominal pain fall into six broad categories:
* inflammatory-may be a bacterial cause, such as acute appendicitis, diverticulitis, or pelvic inflammatory disease, or a chemical cause, such as perforation of a peptic ulcer in which gastric contents cause a peritoneal infection or abscess
* mechanical-such as an ileus or obstruction
* neoplastic-such as a tumor causing obstruction or impinging on nerves or vessels
* vascular-such as a superior mesenteric clot or atherosclerosis
* congenital-such as esophageal atresia (the esophagus doesn't connect normally with the stomach), hernia, or malrotation of the bowel
* traumatic-such as blunt trauma, liver laceration, or major organ damage sustained in a motor vehicle accident.
The four most common causes of acute abdominal pain requiring surgery are acute appendicitis, acute cholecystitis, small bowel obstruction, and gynecologic disorders (see Some causes of acute abdominal pain). However, over 30% of patients with acute abdomen have nonspecific abdominal pain, or pain for which no cause or source can be identified. It's also possible that the patient is pain free or has minimal pain, which occurs more often in older patients, children, and women in the third trimester of pregnancy.
Presentation may be confusing and difficult for the patient to describe. For instance, a hepatic abscess may radiate to the diaphragm and shoulder area, whereas appendicitis may present with pain in the psoas muscle, and cholecystitis with pain in the low and mid back (see Common sites of referred abdominal pain). The pain may be localized or more generalized and deeper (visceral), sharp and constant or dull and intermittent, or any combination of these.
Visceral pain can be divided into three subtypes:
* tension pain. This type of pain is caused by organ distension, such as in bowel obstruction or constipation. Blood accumulation from trauma and pus or fluid accumulation from infection may also cause tension pain. Tension pain that's described as colicky may be caused by increased peristaltic contractile force, such as when the bowel tries to eliminate irritating substances. Patients with tension pain may have trouble getting comfortable.
* inflammatory pain. This type of pain may arise from inflammation of either the visceral or parietal peritoneum, such as in acute appendicitis. It may be described as deep and like a boring sensation. Initially, if the visceral peritoneum is involved, the pain may be poorly localized; as the parietal peritoneum becomes involved, the pain may become localized. Most patients with inflammatory abdominal pain want to lie still.
* ischemic pain. This type of pain is the most serious. Sudden in onset, ischemic pain is extremely intense, progressive in severity, and not relieved by analgesics. Like patients with inflammatory pain, patients with ischemic pain won't want to move or change positions. The most common cause of ischemic abdominal pain is a strangulated bowel.
Narrowing things down
So where do you start when a patient has abdominal pain? Besides identifying the kind of pain the patient is experiencing, the pain's location can provide clues to its cause. So it's imperative that you know the anatomy and physiology of the abdominal area. The abdomen is divided into four areas, or quadrants: the upper left quadrant, the upper right quadrant, the lower left quadrant, and the lower right quadrant (see Where does it hurt?). It can further be divided into nine regions (see Understanding the abdominal regions).
The patient's age may also help narrow the diagnosis. For example, appendicitis is more common in the younger adolescent, whereas an obstruction of the large intestine is more common in patients over age 40. Acute pancreatitis or a perforated ulcer is more often seen in the adult patient. Cholecystitis may be seen in a younger patient, but is more commonly seen in adults. Acute abdominal pain caused by vascular reasons is more common in patients over age 70.
Take a health history, gynecologic history for a female patient, and family history of abdominal conditions, such as gastroesophageal reflux disease (GERD), gallbladder disease, renal calculi, colon cancer, or inflammatory bowel disease. Patients can often provide clues to guide you to the correct diagnosis; for example, a patient with a history of diabetes may have bowel ischemia or renal dysfunction. A patient with alcoholism may have pancreatitis, liver disease, or poor renal functioning.
Ask the patient when the pain began, where it's located, and how he'd describe its quality and intensity. Ask if the pain is constant or intermittent, if it wakes him at night, and if anything aggravates it or relieves it. Remember to ask open-ended questions, such as "What makes the pain better?," rather than "Does laying down make the pain better?" Determine where the pain was when it began because it may be different from where it is now. Also, ask the patient what he was doing when the pain began. For example, if he indicates that the pain began after eating, ask him what kind of food he ate.
Continue your assessment by determining the presence of nausea or vomiting, diarrhea or constipation, anorexia, recent travel, or changes in medications (such as taking nonsteroidal anti-inflammatory drugs [NSAIDs], which may cause abdominal pain). Vomiting that precedes abdominal pain, or is associated with the onset of abdominal pain, may suggest infection as a possible cause of pain. Abdominal pain that began before vomiting may indicate appendicitis or, more rarely, cholecystitis. If he reports diarrhea, ask if the diarrhea is liquid, loose, or a combination and whether he has noticed blood in the stool. If he has had a change in bowel habits without diarrhea, ask about the color and consistency of the stool, whether it floats or sinks, and if it's associated with mucus or change in odor. If he reports recent travel, he may have drank contaminated water or gone swimming in lakes or public pools.
Assess for jaundice, melena (black, tarry stool), hematochezia (maroon-colored stool), hematemesis (vomiting blood), and hematuria (blood in the urine). Look at the patient's hemodynamic status. Does he have a fever, rigors, hypotension, tachycardia, or pallor? Has he had a change in mental status? Often the patient's position can give clues as to the etiology of the pain: Writhing in pain is more representative of colicky pain, whereas knees pulled up and flexed is more diagnostic of peritonitis. For signs and symptoms specific to common abdominal problems, see Some causes of acute abdominal pain.
Let's get physical
Next, conduct a physical assessment in this order: inspection, auscultation, percussion, and palpation (see Assessing the abdomen).
Inspect the abdomen for movement, such as fluid waves or increased peristalsis. Look for scars from past surgeries; the patient may have adhesions that could lead to bowel obstruction. Note the contour of the abdomen: Generalized distension may indicate increased gas, but local bulges may indicate a distended bladder or a hernia.
Auscultate the abdomen for bowel sounds or additional sounds such as bruits. Normal bowel sounds consist of peristaltic clicks and gurgles occurring at a rate of 5 to 34 per minute. Hypoactive bowel sounds may indicate an ileus. Hyperactive bowel sounds may indicate early intestinal obstruction. Arterial bruits with both systolic and diastolic components are abnormal sounds made by blood traveling through narrowed arteries such as the aorta or renal, iliac, or femoral arteries.
Percuss to identify the borders of organs and to determine the presence of air or solid masses such as tumors. Normally you'll hear tympany (a drumlike sound) over the stomach and intestines-areas that are normally filled with air. You'll hear dullness over solid areas such as the liver, spleen, tumors, or other masses. If you think the patient's abdominal pain may be related to pyelonephritis or renal calculi, assess for costovertebral angle tenderness. Place the palm of one hand in the right costovertebral angle and strike it with the ulnar surface of your fist. Repeat in the left costovertebral angle. Pain with percussion suggests pyelonephritis.
Palpate to assess local versus generalized areas of tenderness, as well as to check for masses and enlarged organs. Palpation can go from light to deep, but keep in mind that a patient with abdominal pain may not tolerate abdominal palpation at all. He may tighten his abdominal muscles, preventing you from assessing the abdomen adequately via palpation. If this happens, flexing his knees may relax the abdomen so you can palpate it. If the presence of a bruit leads you to suspect that the patient has an aortic aneurysm, palpation may be contraindicated or best left to the healthcare provider.
To assess for specific areas of tenderness, use specific palpation techniques. Murphy sign evaluates gallbladder tenderness and inflammation. Hook your fingers under the patient's right lower ribs or press them under his ribs, then ask him to take a deep breath. A sharp increase in tenderness with a sudden stop in inspiratory effort constitutes a positive Murphy sign, indicating acute cholecystitis.
If you suspect that your patient has appendicitis, check for Rovsing sign and for referred rebound tenderness. Press deeply and evenly in the patient's left lower quadrant, then quickly withdraw your fingers. Pain in the right lower quadrant during left-sided pressure (a positive Rovsing sign) suggests appendicitis, as does right lower quadrant pain on quick withdrawal (referred rebound tenderness).
Other techniques to assess for appendicitis include looking for a psoas or obturator sign. Place your hand just above the patient's right knee and ask him to raise his thigh against your resistance. Alternatively, ask him to turn onto his left side and then extend his right leg at the hip. Flexing the leg at the hip makes the psoas muscle contract; extension stretches it. Increased abdominal pain on either maneuver (a positive psoas sign) suggests that the psoas muscle is irritated by an inflamed appendix. To elicit the obturator sign, ask the patient to bend his right knee, then flex his right thigh at the hip and rotate the leg internally at the hip to stretch the internal obturator muscle. Right hypogastric pain (a positive obturator sign) suggests irritation of the obturator muscle by an inflamed appendix.
Diagnostic tools of the trade
After a complete history and physical are obtained, imaging studies may not be necessary for all acute abdomen patients. If diagnostic testing is indicated, a computed tomography (CT) scan, an abdominal/pelvic ultrasound, or an abdominal X-ray may be ordered.
A CT scan is the most frequently used tool for diagnosing acute abdominal pain because it's more specific, sensitive, and accurate than an X-ray. For acute abdomen, the CT scan may include an I.V. or oral contrast medium and possibly a rectal contrast medium. However, some patients will be unable to tolerate oral contrast, such as a patient who's vomiting, unable to swallow, or is suspected of having a bowel obstruction. With any kind of contrast medium, it must be determined if the patient has adequate renal functioning to clear it and that he isn't allergic to it.
Ultrasound is often used to evaluate the kidneys, liver, gallbladder, pancreas, spleen, and abdominal aorta or other blood vessels. It can help identify renal stones, gallstones, appendicitis, and gynecologic problems. Because images are in real time, they can show movement of an organ and blood flow. It's fast, safe, and doesn't always require any preliminary preparation or N.P.O. status. Although ultrasound may not be the only test needed, it can help narrow the differential diagnoses and assist in determining the next step.
The abdominal X-ray is also of use. It may reveal fluid levels indicating bowel obstruction, ileus, and stool and gas patterns. It can also be used to identify problems with the urinary system such as kidney stones, ascites, abdominal masses, foreign objects, and injury to the abdominal tissues.
In addition to imaging studies, lab studies that may help narrow the cause of acute abdominal pain include:
* complete blood cell count for signs of infection, cancer, and inflammation
* complete metabolic profile for blood glucose levels, renal or hepatic dysfunction, electrolyte imbalances, or problems related to low albumin level
* stool sample to look for infection or parasites
* urinalysis to look for infection or evidence of renal calculi
* amylase and lipase levels, which will be elevated in a patient with pancreatic problems
* Helicobacter pylori level to check for peptic ulcer disease
* pregnancy test and microscopic examination of vaginal secretions in women to rule out ectopic pregnancy and infections such as bacterial vaginosis or vulvovaginal candidiasis
* sexually transmitted disease testing in sexually active men and women.
Did someone say surgery?
One of the primary goals when diagnosing a patient with acute abdomen is to determine if surgery is necessary and the timing of surgery. A patient presenting as toxic and unstable may need time in the CCU before surgery is performed. However, the patient may also need immediate surgery if the risk of waiting could be life-threatening. The balance of risk versus benefit must be weighed in treating the critically ill patient with acute abdominal pain.
Generally, surgery is indicated for bowel obstruction, acute appendicitis, a ruptured ovarian cyst, and aortic aneurysm. Antibiotics will be prescribed if the cause of pain is an infection such as pyelonephritis or a lower urinary tract infection. If the infection is due to an abscess, surgical drainage may also be performed. Abdominal pain due to viral gastroenteritis will be treated with fluids, bowel rest, and antiemetics if the patient is over age 12.
Treatment is, of course, based on the diagnosis. Surgery isn't always necessary.
Interventions galore
Triaging patients quickly and accurately is crucial because some causes of abdominal pain are life-threatening. Other nursing interventions include ongoing assessments, managing the patient's pain, restoring fluid and electrolyte balance, specific interventions to treat the pain's underlying cause, and providing emotional support.
Immediately report to the healthcare provider any symptoms that indicate shock or instability. If the acute abdomen symptoms occur while the patient is hospitalized for another illness, reviewing all previous care may shed light on the etiology of the pain. Assess previous lab results, changes in medications, dye administration during testing, and treatment outcomes.
Manage your patient's pain with medications as ordered and nonpharmacologic interventions, including positioning, back rubs, and heating pads (if not contraindicated). It was previously thought that providing pain medication to a patient with acute abdomen would mask the pain and make it more difficult to diagnose; however, this is an unfounded belief. Pain management will depend on the severity of the pain. If opioid management is needed, morphine is the drug of choice. If the patient is allergic to morphine, meperidine or ketorolac may be ordered instead.
To protect your patient against complications, such as cardiac dysrhythmias and seizures, you must maintain his fluid and electrolyte balance. Patients with diarrhea, vomiting, or fever are the most prone to such imbalances. Make sure electrolyte levels are evaluated before electrolyte replacement begins and periodically reassessed during replacement. Maintain accurate intake and output records.
If your patient's abdominal pain was caused by GERD, hiatal hernia, peptic ulcer disease, or diverticulitis, teach him about foods to avoid and how to time meals in relation to activities and bedtime. He should avoid overeating in general and stay away from fats, fried foods, spices, coffee, tea, tomato products, and alcohol. Tell him not to eat within 2 to 3 hours of bedtime and not to lie down or exercise immediately after eating. Advise him to try to maintain a normal weight and to lose weight if he's overweight or obese because the risk of GERD and gallbladder disease increases with weight. He should reduce stress, quit smoking, decrease or eliminate alcohol consumption, and reduce his use of medications that can damage the esophagus, such as corticosteroids and NSAIDs (including aspirin).
Provide emotional support for the patient and his family. Let them know the plan for diagnosing the pain and the results of any diagnostic testing. Provide instruction on pain management and positions of comfort. Instruct the patient on the use of the pain medication, how often he can receive it, and to report ineffectiveness or a reaction such as itching. After a diagnosis is made, provide the patient with information on treatment options and how his hospital stay may proceed. If surgery is indicated, discuss with the patient and his family what will happen and when he can anticipate going to the OR. Allow family members to visit before surgery and keep them updated.
Follow the clues
Although acute abdominal pain can be difficult to diagnose, knowing the anatomy and physiology of the abdomen and understanding the different types of abdominal pain can help you uncover clues to the cause of your patient's pain so he can receive the most timely treatment possible.
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