Abdominal Pain
Patients presenting to the emergency department (ED) with abdominal symptoms represent a substantial challenge to the physician. There are several critical diagnoses which cannot be missed. Several groups of patients may have atypical presentations and findings are not apparent: children, geriatric patients, the chronically debilitated, the depressed, and those patients on steroids. A conservative approach to the evaluation and disposition of these patients is recommended.
COMMON CAUSES OF ABDOMINAL PAIN
Gastroenteritis*
Peptic ulcer disease*
Gastroesophageal reflux disease/erosive gastritis*
Appendicitis*
Biliary tract disease*
Acute pancreatitis*
Acute intestinal obstruction*
Renal colic*
Diverticulitis*
Ectopic pregnancy*
Ruptured ovarian cyst
Mittelschmerz (ovarian follicular rupture)*
Urinary tract infection*
Premenstrual syndrome
Pelvic inflammatory disease*
Incarcerated hernia*
Medications*
LESS COMMON CAUSES OF ABDOMINAL PAIN NOT TO BE MISSED
Myocardial infarction or ischemia
Pneumonitis or pleuritis*
Enterocolitis
Inflammatory bowel disease
Diabetic ketoacidosis*
Ovarian torsion*
Streptococcal pharyngitis*
Ischemic bowel disease*
Acute (narrow-angle) glaucoma
Abdominal aortic aneurysm*
Spontaneous bacterial peritonitis*
Testicular torsion*
Perforated viscus
Rectus sheath hematoma*
Volvulus
OTHER CAUSES OF ABDOMINAL PAIN
Mesenteric lymphadenitis
Hepatitis or perihepatitis*
Acute intermittent porphyria*
Familial Mediterranean fever*
Black widow spider bite*
Diabetic gastroparesis
Perforated Meckel diverticulum
Sickle cell disease
Intussusception*
HISTORY
To differentiate among the various causes of abdominal pain, several key features of the history must be explored in depth. These include the patient’s previous medical and surgical histories; any current medications (e.g., aspirin, erythromycin); the onset, location and referral of pain; and any associated symptoms.
Onset of Pain
Abdominal pain that is maximally severe at the onset and begins abruptly–to the extent that the patient recalls the exact time of onset or the specific activity occurring when the pain began–or pain that awakens the patient from sleep must generally be regarded as serious. Conditions which may begin explosively include ureteral colic, perforated ulcer, ruptured ectopic pregnancy, ruptured corpus luteum, and, occasionally, vascular phenomena such as leaking or dissecting abdominal aortic aneurysm and mesenteric artery obstruction. Conversely, patients with acute cholecystitis, acute appendicitis, pancreatitis, and acute diverticulitis more often report the gradual onset of increasing discomfort.
Location of Pain
In general, pain that is initially well localized to one area of the abdomen but then becomes generalized is suggestive of rupture or perforation of a viscus with resulting peritonitis. Immediately after rupture or perforation, many patients will report a relatively pain-free period followed by gradually increasing abdominal discomfort; this history is particularly ominous and is reported by patients with a ruptured appendix or diverticulum or perforated ulcer, as well. As pain becomes generalized, patients with evolving peritonitis have clinical evidence of peritoneal inflammation. Conversely, patients with classic appendicitis initially report vague, poorly localized, periumbilical pain, which may then localize to the right lower quadrant (RLQ) as the overlying parietal peritoneum becomes inflamed and irritated.
Location of abdominal processes by quadrant.
Right upper quadrant (RUQ) pain is frequently reported in patients with duodenal ulcer, acute pancreatitis, cardiac ischemia, peritonitis, acute cholecystitis, retrocecal appendicitis, acute pancreatitis, acute hepatitis, acute right-sided heart failure, and right lower lobe pleuritis from any cause.
Left upper quadrant (LUQ) pain is often reported in patients with gastritis, gastric ulcer, acute pancreatitis, cardiac ischemia, peritonitis, splenic infarction or rupture, left lower lobe pneumonitis, and colonic processes involving the area of the splenic flexure (perforation, ischemia, carcinoma).
Right lower quadrant (RLQ) discomfort is frequently noted in patients with appendicitis, salpingitis, diverticulitis, mittelschmerz, ruptured ectopic pregnancy, testicular or ovarian torsion, perforated cecum, strangulated right inguinal hernia, regional enteritis, intestinal obstruction, and psoas abscess.
Left lower quadrant (LLQ) discomfort may result from any of the aforementioned conditions, with the exceptions of the pain of acute appendicitis being appreciably less common in this location and that of acute diverticulitis being more common. Patients with renal or ureteral colic may present with pain in any quadrant.
Diffuse abdominal pain may be associated with peritonitis, acute pancreatitis, early appendicitis, small bowel obstruction, mesenteric thrombosis, gastroenteritis, streptococcal pharyngitis in children, and leaking abdominal aortic aneurysm. Metabolic causes of abdominal pain may also produce a diffuse picture.
Pattern of Pain Referral
The particular pattern of pain referral may provide valuable information. Acute cholecystitis pain may radiate laterally around the back and toward the inferior aspect of the right scapula. Acute pancreatitis most often radiates to the middle of the back. Processes that irritate the diaphragm may radiate to the ipsilateral shoulder. Mid back discomfort occurs with penetrating duodenal ulcer. Renal colic may radiate to the ipsilateral groin, testicle, or labia. In assessing patients with these patterns of pain referral, it is important to demonstrate that referral areas are not tender to palpation.
Associated Historical or Physical Features
Associated historical or physical features may provide the only clue to a diagnosis not previously considered.
Fever is relatively nonspecific but may be associated with a perforated viscus, peritonitis, gangrenous bowel, cholangitis, acute salpingitis, abscess, or pneumonia.
Jaundice is a relatively specific finding suggesting acute hepatitis, biliary obstruction or, in patients with high fever and rigors, acute cholangitis.
Polydipsia, polyphagia, polyuria, and Kussmaul respirations suggest diabetic ketoacidosis.
Discomfort precipitated by or fluctuating with food intake is often noted in acute cholecystitis or peptic ulcer disease, respectively.
A recent history of excessive alcohol or NSAID use may occur with acute pancreatitis or acute gastritis.
Diarrhea associated with nausea, vomiting, and epigastric or poorly localized pain occurs with acute gastroenteritis. A finding of other family members having similar symptoms further supports this diagnosis. Coryza, cough, and pharyngitis suggest a viral syndrome. With acute gastroenteritis, an episode of diarrhea may be associated with temporary relief from abdominal discomfort.
Diarrhea, occurring after the completion of a course of antibiotics (typically within 2-10 days), suggests (C. difficile) pseudomembranous enterocolitis.
Severe vomiting, a history of previous abdominal surgery, and diffuse pain suggest small bowel obstruction. Feculent or bilious vomitus occurs with mechanical obstruction. Vomiting of undigested food immediately after eating occurs with gastric outlet obstruction, which may be caused by ulcer disease or neoplasia.
Patients who vomit blood after retching or after an initial episode of nonbloody vomitus may have gastroesophageal junction laceration (Mallory-Weiss tear). Hematemesis suggests bleeding lesions proximal to the mid duodenum: esophagitis, bleeding varices, gastritis, ulcer, Mallory-Weiss syndrome. Ingestion of bismuth, licorice, or beets may produce a black but non-tarlike stool negative for occult blood.
In women with lower pelvic discomfort, a relatively normal appetite, and minimal or absent nausea or vomiting, a gynecologic cause should be considered. Associated vaginal discharge suggests acute salpingitis. Acute unilateral pelvic pain with an abnormal menstrual period and vaginal spotting is suggestive of ectopic pregnancy. The acute onset of unilateral pelvic pain at midmenstrual cycle (days 12-16 patients) associated with minimal gastrointestinal symptoms suggests mittelschmerz. This diagnosis should be made with caution in patients using hormonal birth control because ovulation is presumably prevented.
Testicular pain associated with lower quadrant discomfort suggests torsion or ureteral colic. Because patients will not often volunteer this information, specific inquiry should be made. Examination of the genitourinary system in men should be performed in all cases of acute abdominal pain.
Rectus sheath hematoma is a relatively uncommon diagnosis that may simulate a number of intra-abdominal processes and may also produce nausea, abdominal pain, low-grade fever, leukocytosis, referred and rebound tenderness, and local spasm. Many patients with rectus sheath hematomas have a history of anticoagulation therapy or abdominal wall trauma that may have been considered trivial.
Metabolic Conditions
A number of metabolic conditions may cause abdominal pain, and a high degree of suspicion must be maintained if these are to be recognized. Diabetic ketoacidosis, streptococcal pharyngitis (particularly in the child), basilar pleuritis secondary to infection, pulmonary embolus, porphyria, familial Mediterranean fever, C1 esterase inhibitor deficiency, and black widow spider bites may all produce major abdominal symptoms and signs.
Previous Abdominal Procedures
Previous abdominal procedures increase the likelihood of intestinal obstruction secondary to adhesions.
Analgesics
Improved diagnostic imaging has resulted in less reliance on serial exams. Studies suggest that narcotic analgesics can safely be given to patients while their evaluation progresses.
Antiemetics
Ondansetron (Zofran) is safe and effective.
PHYSICAL EXAMINATION
Note the patient’s position and behavior before initiating the formal examination. Patients with peritonitis generally will prefer to remain supine and motionless; any movement that stimulates the peritoneum, such as moving in bed, coughing, or sitting up will precipitate or worsen pain. Many patients with peritonitis will prefer to keep their hips and knees flexed in an attempt to reduce peritoneal traction-related discomfort.
In contrast, patients with ureteral colic frequently are standing or walking around the examination room holding the affected side, unable to rest in bed.
Patients with inflammatory processes in the area of the psoas (pancreatitis, perinephric abscess, retrocecal appendicitis, ruptured sigmoid diverticulitis) may attempt to assume positions that minimize stress on adjacent or overlying muscles. Patients with pancreatitis often prefer the “fetal” position. Patients with unilateral processes prefer a position with the ipsilateral hip and knee flexed.
A complete examination includes the pharynx, chest, back (noting the presence of costovertebral angle tenderness), genitalia, pelvis, and rectum. Stool for occult blood testing should be obtained as indicated.
Examination of the abdomen begins with the patient positioned supine and appropriately disrobed. Ask the patient to point with one finger to the area of maximal discomfort. It is useful to determine whether cough increases the patient’s discomfort, indicating peritoneal irritation.
Inspection. The abdomen is inspected for evidence of previous surgical scars, distention associated with obstruction or ileus, and the presence of abnormal pulsations.
Auscultation should be performed to determine the presence and character of bowel sounds.
Palpation of the abdomen must be gentle to minimize anxiety and guarding. Begin palpation distant to areas of pain. Two signs suggest localized peritoneal inflammation: (1) localized abdominal pain that is worsened by palpation at a site distant and (2) elicitation of referred rebound tenderness. Voluntary or involuntary resistance to gentle palpation should be noted and the patient’s area of maximal discomfort determined. Rebound tenderness is elicited by palpation over this site. When evidence of generalized peritoneal irritation exists, immediate surgical consultation is recommended.
With intussusception, an abdominal mass may be palpable, often on rectal examination. Passage of mucus and blood in the stool supports the diagnosis.
RLQ pain on rectal examination suggests retrocecal appendicitis.
The inguinal and genital regions should be carefully examined to exclude incarcerated hernia. This diagnosis remains a commonly overlooked cause of vomiting, abdominal pain, bowel obstruction, and sepsis, particularly in the elderly or debilitated patient with a vague history.
The pelvic examination evaluates the presence of endocervical discharge and whether lateral movement of the cervix intensifies the patient’s discomfort. An adnexal mass should suggest ectopic pregnancy, cyst, or abscess. Bleeding may occur with ectopic pregnancy or spontaneous abortion.
DIAGNOSTIC TESTS
Anemia suggests chronic or acute blood loss.
The white blood cell (WBC) is neither sensitive nor specific. A low WBC count with lymphocytosis suggests viral gastroenteritis. A WBC count greater than 18,000 to 20,000/μL with a predominant polymorphonuclear leukocytosis with bands should be further evaluated. AIDS and immunosuppressed patients may fail to develop an increased number of WBCs even with serious bacterial infection.
The urinalysis may demonstrate hematuria in ureteral colic, glycosuria and ketonuria in the patient with unsuspected diabetic ketoacidosis, bilirubinuria in the patient with hepatic or biliary disease, or WBCs with infectious processes.
The serum lipase, when elevated twice the normal value, has greater sensitivity and specificity (both ∽95%) than the serum amylase and is therefore the preferred test in pancreatitis. The serum amylase may be elevated in patients with acute pancreatitis as well as a variety of both extra-abdominal and intra-abdominal conditions; these include mumps, salivary duct stones, diabetic ketoacidosis, burns, renal insufficiency, a number of carcinomas, pregnancy, penetrating or perforating peptic ulcer, biliary tract disease, ruptured ectopic pregnancy, intestinal obstruction and infarction, peritonitis, and chronic liver disease.
A serum or urinary determination of the β-subunit of human chorionic gonadotropin (HCG) should be obtained in all women unless post-menopausal.
An electrocardiogram (ECG) should be considered in patients with upper abdominal discomfort.
Radiographs of the chest may demonstrate thoracic diagnoses or free air. Abdominal films may be useful for demonstrating bowel obstruction or paralytic ileus, but have limited utility.
