Abdominal Pain

   An acute abdomen is abdominal pain associated with findings on physical exam, such as guarding or rigidity, and generally implies that surgery will be required to manage the patient. Determining the exact cause of abdominal discomfort can be challenging, especially in the prehospital setting (see Table III). The following provides an overview of select causes of abdominal pain.³

APPENDICITIS

   Zachary Cope once said, "Acute appendicitis can mimic any intraabdominal process; therefore, to know acute appendicitis is to know well the diagnosis of acute abdominal pain."⁴ The appendix is a narrow tube attached to the colon. The lining of the appendix produces mucus that flows through the open center of the appendix and into the cecum. The wall of the appendix contains lymphatic tissue and a layer of muscle.^5-7

   Acute appendicitis develops when the appendix becomes inflamed as a result of obstruction of the lumen with subsequent bacterial invasion, distention and ultimately rupture. The incidence of appendicitis can be as high as 25% for males and 12% for females. Although appendicitis may occur at any age, adolescents and young adults account for a majority of the cases.^5-7

   The characteristic presentation of acute appendicitis is abdominal pain associated with anorexia, nausea and sometimes vomiting. The pain often begins in the periumbilical area and is described as vague and crampy. As the condition persists, the pain may become steady and sharp, localizing to the right lower quadrant.^5-7

   If the appendix ruptures, the patient may experience severe and diffuse abdominal pain, vomiting and a high-grade fever. Abdominal assessment may reveal a mass in the right lower quadrant that is tender to palpation, or signs of peritoneal irritation such as rebound, involuntary guarding and abdominal wall muscle spasms. Any movement of the patient (e.g., bumping the stretcher) may elicit severe pain. Patients may prefer to have their legs flexed and pulled up, similar to fetal position. If perforation occurs, hemodynamic compromise may develop.^5-7 Depending on when in the course of appendicitis the patient is encountered, any number of presentations are possible, so always be aware of the possibility of appendicitis in virtually any patient complaining of abdominal pain.

BILIARY COLIC

   The gallbladder is a pear-shaped organ that stores bile, which assists with digestion. The gallbladder is located in the upper right side of the abdomen, just below the liver. Gallbladder disease is a common problem, primarily because of the high prevalence of gallstones. About 25% of women and 15% of men over age 50 have gallstones, and more than one-half million cholecystectomies are performed every year in the United States.^8-12

   Biliary colic is the primary symptom of a majority of the patients who have gallstones and develop symptoms. The pain in biliary colic is most likely to occur when gallstones interrupt the normal flow of bile from the gallbladder into the bile ducts and down to the duodenum. The pain may initially develop in the epigastric area, or it may originate in the right upper quadrant of the abdomen. The pain may also extend under the right side of the rib cage. It is also possible for the pain to be poorly localized, and it may radiate to the right posterior shoulder. In rare cases, the pain may mimic that of substernal myocardial chest pain.^8-12

   The onset of pain tends to occur shortly after eating, especially meals that include fatty foods. Repeat episodes tend to involve a greater frequency and intensity of symptoms. Most episodes subside within a few hours; however, the patient may report abdominal aching that lasts for a few days following an episode of biliary colic. Nausea is often associated with biliary colic and vomiting may be present. Fever and chills are not common symptoms in uncomplicated biliary colic due to gallbladder stones.^8-12

CHOLECYSTITIS

   Acute cholecystitis occurs when there is a buildup of bile in the gallbladder. The accumulation of bile causes irritation and pressure in the gallbladder and can lead to inflammation, bacterial infection and perforation, any of which may cause pain. The primary cause of cholecystitis is gallstones. Other factors, such as alcohol abuse and tumors, can lead to gallstones as well. In general, cholecystitis tends to be more common in middle-aged women.^8,13,14