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Evaluation of Abdominal Pain in the Emergency Department Hartmut Gross, M.D., FACEP
Abdominal pain complaints comprise about 5% of all Emergency Department visits. The etiology of the pain may be any of a large number of processes. Many of these causes will be benign and self-limited, while others are medical urgencies or even surgical emergencies. As with any complaint in the ED, the worst diagnosis is always entertained first. Therefore, there is one thought, which the ED practitioner must maintain in the foreground of his mind: “Is there a life threatening process?”
Etiology A breakdown of the most common diagnoses of abdominal pain presentations is listed below. Note that nearly half of the time, “unknown origin” is the diagnosis made. This is a perfectly acceptable conclusion, after a proper work-up has ruled out any life threatening illness.
Common Diagnoses of Non-traumatic Abdominal Pain in the ED 1 Abdominal pain of unknown origin 41.3% 2 Gastroenteritis 6.9% 3 Pelvic Inflammatory Disease 6.7% 4 Urinary Tract Infection 5.2% 5 Ureteral Stone 4.3% 6 Appendicitis 4.3% 7 Acute Cholecystitis 2.5% 8 Intestinal Obstruction 2.5% 9 Constipation 2.3% 10 Duodenal Ulcer 2.0% 11 Dysmenorrhea 1.8% 12 Simple Pregnancy 1.8% 13 Pyelonephritis 1.7% 14 Gastritis 1.4% 15 Other 12.8%
From Brewer, RJ., et al, Am J Surg 131: 219, 1976.
Two important factors modify the differential diagnosis in patients who present with abdominal pain: sex and age. Other common diagnoses of abdominal pain in men and women are as follows. Male Female Perforated ulcer Nonspecific Gastritis Diverticulitis Appendicitis Acute Cholecystitis
The other factor is age over 70 years. As you can see from the table below, the breakdown of causes varies significantly for this population.
Causes of Abdominal Pain in Patients Over 70 Years Old Acute Cholecystitis 26.0% Malignant Disease 13.2%
Ileus 10.7% Nonspecific Abdominal Pain 9.6% Gastroduodenal Ulcer 8.4% Acute Diverticular Disease of the Colon 7.0% Incarcerated Hernia 4.8% Acute Pancreatitis 4.1% Acute Appendicitis 3.5% Other Causes 12.7%
From Fenya, C, Am J Surg 143: 751, 1982.
Types of Pain A patient’s description of the pain is vital in assessing the problem. Careful questioning will allow the physician to discern the origin of the pain and formulate a good working differential diagnosis list. Visceral pain is described as crampy, dull and gaseous. It typically arises from the walls of hollow viscera and capsules of solid organs due to abnormal stretching or distention, ischemia, or inflammation. Localization is often vague and frequently midline. It is generally accompanied by autonomic responses causing nausea, pallor, and diaphoresis. Somatic pain on the other hand is well localized and sharp in quality. It arises from the parietal peritoneum, mesenteric roots, and anterior abdominal wall due to chemical or bacterial inflammation.
Visceral vs. Parietal pain
Type Location Time Activity (movement)
Vomiting Palpation
Visceral Central Intermittent or constant
Little or no change in pain
Decreases or no change in pain
Little or no change in pain
Parietal Peripheral or generalized
Constant Increases pain
Increases or no change in pain
Increases pain
Referred pain is due to fibers from different organs returning to the CNS overlapping with pathways from cutaneous sites which had similar embrylogic origin [e.g. diaphragmatic irritation refers pain to the shoulder via C4 (Kehr’s Sign)]
Obstipation Belching Flatus Dysuria Sputum SOB Chest Pain (acute myocardial infarction)
Physical Examination The physical exam serves several purposes: 1 To confirm suspicions from the history 2 To localize the area of disease 3 To avoid missing extra-abdominal causes of pain There are numerous components to the examination, all of which are important. These include careful consideration of each of the following items.
Vital Signs temperature, BP, pulse, respiratory rate. Check orthostatic vital signs Abdomen Observation general appearance: conscious, alert, upright, diaphoretic, pale, distressed, writhing, motionless, smiling. Inspection distended, ecchymosis, scars, hernias, caput Medusa Auscultation bowel sounds present (listen long enough), pitch, bruits Palpation Patient must be relaxed. Start gently. Guarding (voluntary and involuntary) Masses Tenderness (watch patients facial expression and use point 1 and 2 comparison method) Have patient tense abdominal wall and re-palpate –difference? Rebound (vs. startle) peritoneal signs Rebound without guarding is generally not true rebound Also shake pt., heel strike, have pt cough, have pt jump Some MD’s will kick or jar the stretcher Special maneuvers / signs Murphy’s sign-respiratory arrest on inspiration during palpation of the right upper quadrant of the abd. Rovsing’s sign-pain referred to the right lower quadrant on palpation of opposite side of the abd. Obturator sign-pain with internal rotation of flexed hip Iliopsoas sign-pain with hyperextension of the hip Turn pt on side and reexamine the abdomen in the lateral decubitus position Percussion liver size, tympany, localization of tenderness Rectal blood, masses, tenderness Pelvic blood, masses, tenderness, discharge
Do Not Forget Heart (including peripheral pulses) , Lungs, External Genitalia, and General Exam!
Formulation of the differential diagnoses
Based on the information obtained from the history and physical examination, a good working list of possible diagnoses to be ruled out should be formulated. This should be based on a keen knowledge of gross anatomy, embryology, neuroantomy, and physiology. Various lists suggesting causes of pain based on the localization of pain are available and one such list is presented below and it is not exhaustive. It should not be memorized, but rather should be understood. The history and physical will help narrow the possibilities further.
Differential Diagnoses of Acute Abdominal Pain by Location
Right Upper Quadrant Left Upper Quadrant Appendicitis Aortic Dissection Cholangitis Gastritis Cholecystitis Duodenal Ulcer Choledocholithiasis Gastric Ulcer Fitz-Hugh & Curtis Syndrome Herpes Zoster Hepatic Abscess Intestinal Obstruction Hepatitis Ischemic Colitis Hepatomegaly Left Lower Lobe Effusion/Empyema Myocardial Infarction Myocardial Infarction Pancreatitis Pancreatitis Peptic Ulcer Disease Pericarditis Pericarditis Pleurisy (diaphragmatic) Pleurisy (diaphragmatic) Pneumonia (basal) Pneumonia (basal) Pulmonary Embolism Pulmonary Embolism Pyelonephritis Pyelonephritis Renal Colic Renal Colic Splenic Infarction Rupture Subphrenic Abcess Subphrenic abcess Thoracic Aneurysm (dissecting) Thoracic Aneurysm (dissecting)
Differential Diagnoses of Acute Abdominal Pain by Location (continued)
Right Lower Quadrant Left Lower Quadrant Appendicitis Diverticulosis Cholecystitis (acute, perforated) Ectopic Pregnacy (ruptured) Diverticulitis Endometriosis Ectopic Pregnacy (ruptured) Epididymitis Endometriosis Fecal Impaction Epididymitis Hip Pain Gastroenteritis Incarcerated/ Inguinal Hernia Hip Pain Intestinal Obstruction
Pregnancy test β subunit, either urine or serum Obtain arterial blood gas
Laboratory Tests Specific tests to be ordered should be selected to confirm or rule out specific diagnoses on the working differential.
Liver enzymes –SGOT (AST), SGPT (ALT), GGT, Bilirubin (direct and indirect) Amylase [non specific (sources include pancreas, salivary glands, small bowel and fallopian tubes), rises early and falls early] Lipase (specific for pancreatic injury, rises later and stays elevated longer) CBC H/H WBC and diff. Electrolytes Glucose BUN & Creatinine UA Most useful if normal since nonspecific: PT/PTT & INR Lactic Acid
Other Tests
EKG
Radiographic Tests CXR or Upright Chest X-ray 1 Pulmonary disease 2 Free air under diaphragm 3 Air filled viscera in chest 4 Mediastinal air
KUB or Plain Film of Abdomen 1 Fluid filled loops 2 Abdominal densities 3 Renal calculi 4 Gallstones 5 Pancreatic or splenic calcifications 6 Air in biliary tree 7 Obscured psoas shadow 8 Displaced stomach bubble 9 Displaced kidney 10 Enlarged splenic shadow 11 Displaced splenic flexure Upright Abdominal x-ray (If patient can stand, obtain and upright abdomen)
1 Air-fluid levels 2 Air in stomach, intestine, colon 3 Massive dilation of colon
Left Lateral Decubitus (If patient is bedridden, obtain a left lateral decubitus film) 1 Free air 2 Air fluid levels
Clinical Findings Associated With a Statically Significant Likelihood of an Abnormal Abdominal Radiograph
Clinical Finding Likelihood Ratios* Likelihood predictive of abnormality (>1) Increased, high pitched bowel sounds 57. Distention 9. History of abdominal surgery 7. Blood in urine 6. History of renal-ureteral calculi 5. Flank pain, tenderness 5. History of abdominal tumor 4. History of gallbladder disease 4. Severe abdominal pain and tenderness 3. Generalized abdominal pain and tenderness 1. Abdominal pain for less than 1 day 1.8 † Vomiting 1.8 †
Likelihood predictive of abnormality (<1) History of ulcer disease 0. Mild abdominal pain 0. Abdominal pain for more than one week 0.5 †
_Modified from Eisenberg, R, et al.: Ann Surg 197:464, 1983
- Defined as the prevalence of each clinical variable in patients with abnormal abdominal radiographs divided by the number of patients who have abdominal radiographs. P<.001 unless otherwise noted._ † p<.
Don’t leave ill patients alone in x-ray!
Sonography
Indications for ultrasound scanning in patients with acute abdominal pain Right upper quadrant pain or possible cholelithiasis Potential abdominal aortic aneurysm Detection of ascitic fluid
Decision Tree of Evaluation of Abdominal Pain
Abdominal Pain
Shock (^) Resuscitation
Diagnosis Not Apparent
No Shock
Diagnosis Apparent
History/PE Simple Lab Tests
Routine X-Rays
Admit To Hospital
Minor Problem
Home WithTreatment Surgery
Complete In-Hos pital E valuation
Conclusion
A lesson frequently relearned by everyone is that if one listens carefully, the patient will tell the physician the diagnosis. The history and physical should yield the diagnosis some 90-95% of the time. Additional testing should be used to confirm the presumptive diagnosis. It is rare that “fishing” with laboratory tests will yield a diagnosis when the H&P does not and this practice should be condemned. This cannot be stressed enough. It will keep the physician from “shotgunning” unnecessary laboratory and X-ray tests, wasting time and patient’s money. When in doubt, go back and talk with and re-examine the patient.
