Abdominal Pain

Numerous causes,ranging from acute, life-threatening emergencies to chronic

functional disease and disorders of several organ systems,can generate abdominal

pain. Evaluation of acute pain requires rapid assessment of likely causes

and early initiation of appropriate therapy (see Chap. 51). A more detailed and

time-consuming approach to diagnosis may be followed in less acute situations.

Table 33-1 lists the common causes of abdominal pain.

Common Etiologiesof Abdominal Pain

Mucosal or muscle inflammation in hollow viscera: Peptic disease (ulcers,

erosions,inflammation), hemorrhagic gastritis, gastroesophageal reflux, appendicitis, diverticulitis, cholecystitis,cholangitis,inflammatory bowel diseases

(Crohn’s,ulcerative colitis), infectious gastroenteritis, mesenteric lymphadenitis,

colitis,cystitis,or pyelonephritis

Visceral spasm or distention: Intestinal obstruction (adhesions,tumor, intussusception), appendiceal obstruction with appendicitis, strangulation of hernia, irritable bowel syndrome (muscle hypertrophy and spasm),acute biliary obstruction, pancreatic ductal obstruction (chronic pancreatitis,stone),ureteral

obstruction (kidney stone,blood clot), fallopian tubes (tubal pregnancy)

Vascular disorders: Mesenteric thromboembolic disease (arterial or venous),

arterial dissection or rupture (e.g.,aortic aneurysm), occlusion from external

pressure or torsion (e.g., volvulus,hernia,tumor, adhesions, intussusception),

hemoglobinopathy (esp. sickle cell disease)

Distention or inflammation of visceral surfaces: Hepatic capsule (hepatitis,

hemorrhage,tumor,Budd-Chiari syndrome, Fitz-Hugh-Curtis syndrome), renal

capsule (tumor,infection,infarction, venous occlusion), splenic capsule

(hemorrhage,abscess, infarction), pancreas (pancreatitis, pseudocyst, abscess,

tumor),ovary (hemorrhage into cyst, ectopic pregnancy, abscess)

Peritoneal inflammation: Bacterial infection (perforated viscus,pelvic inflammatory disease,infected ascites),intestinal infarction, chemical irritation, pancreatitis, perforated viscus (esp. stomach and duodenum), reactive inflammation (neighboring abscess,incl. diverticulitis,pleuropulmonary infection or

inflammation),serositis (collagen-vascular diseases, familial Mediterranean fever),

ovulation (mittelschmerz).

Abdominal wall disorders: Trauma,hernias, muscle inflammation or infection,

hematoma (trauma,anticoagulant therapy), traction from mesentery (e.g., adhesions)

Toxins: Lead poisoning,black widow spider bite

Metabolic disorders: Uremia,ketoacidosis (diabetic,alcoholic), Addisonian

crisis,porphyria,angioedema (C1 esterase deficiency), narcotic withdrawal

Neurologic disorders: Herpes zoster, tabes dorsalis,causalgia,compression or

inflammation of spinal roots,(e.g., arthritis,herniated disk, tumor, abscess),

psychogenic

Referred pain: From heart,lungs,esophagus, genitalia (e.g., cardiac ischemia,

pneumonia,pneumothorax, pulmonary embolism, esophagitis, esophageal

spasm,esophageal rupture)

Approach to the Patient

History

History is of critical diagnostic importance. Physical exam may be unrevealing

or misleading,and laboratory and radiologic exams delayed or unhelpful.

Characteristic Features of Abdominal Pain

Duration and Pattern These provide clues to nature and severity,although

acute abdominal crisis may occasionally present insidiously or on a

background of chronic pain.

Type and location provide a rough guide to nature of disease. Visceral pain

(due to distention of a hollow viscus) localizes poorly and is often perceived in

the midline. Intestinal pain tends to be crampy; when originating proximal to

the ileocecal valve,it usually localizes above and around the umbilicus. Pain

of colonic origin is perceived in the hypogastrium and lower quadrants. Pain

from biliary or ureteral obstruction often causes pts to writhe in discomfort.

Somatic pain (due to peritoneal inflammation) is usually sharper and more precisely localized to the diseased region (e.g.,acute appendicitis; capsular distention of liver,kidney,or spleen),exacerbated by movement, causing pts to remain still. Pattern of radiation may be helpful: right shoulder (hepatobiliary origin), left shoulder (splenic),midback (pancreatic), flank (proximal urinary tract),

groin (genital or distal urinary tract).

Factors that Precipitate or Relieve Pain Ask about its relationship to

eating (e.g.,upper GI,biliary,pancreatic, ischemic bowel disease), defecation

(colorectal),urination (genitourinary or colorectal), respiratory (pleuropulmonary,

hepatobiliary), position (pancreatic, gastroesophageal reflux, musculoskeletal),

menstrual cycle/menarche (tuboovarian,endometrial,including endometriosis),

exertion (coronary/intestinal ischemia, musculoskeletal), medication/

specific foods (motility disorders,food intolerance, gastroesophageal reflux,

porphyria,adrenal insufficiency,ketoacidosis, toxins), and stress (motility disorders,

nonulcer dyspepsia,irritable bowel syndrome).

Associated Symptoms Look for fevers/chills (infection,inflammatory disease,

infarction),weight loss (tumor,inflammatory diseases, malabsorption, ischemia),

nausea/vomiting (obstruction,infection,inflammatory disease, metabolic

disease),dysphagia/odynophagia (esophageal),early satiety (gastric),

hematemesis (esophageal, gastric,duodenal),constipation (colorectal, perianal,

genitourinary),jaundice (hepatobiliary, hemolytic), diarrhea (inflammatory disease,

infection,malabsorption, secretory tumors, ischemia, genitourinary), dysuria/

hematuria/vaginal or penile discharge (genitourinary),hematochezia (colorectal

or, rarely,urinary),skin/joint/eye disorders (inflammatory disease,

bacterial or viral infection).

Predisposing Factors Inquire about family history (inflammatory disease,

tumors,pancreatitis),hypertension and atherosclerotic disease (ischemia), diabetes

mellitus (motility disorders,ketoacidosis),connective tissue disease (motility

disorders,serositis),depression (motility disorders, tumors), smoking (ischemia),

recent smoking cessation (inflammatory disease), ethanol use (motility

disorders, hepatobiliary,pancreatic,gastritis, peptic ulcer disease).

Physical Examination

Evaluate abdomen for prior trauma or surgery,current trauma; abdominal distention, fluid, or air; direct,rebound, and referred tenderness; liver and spleen

size; masses, bruits,altered bowel sounds,hernias, arterial masses. Rectal examination for presence and location of tenderness,masses, blood (gross or occult). Pelvic examination in women is essential. General examination: evaluate

for evidence of hemodynamic instability,acid-base disturbances, nutritional deficiency, coagulopathy, arterial occlusive disease, stigmata of liver disease, cardiac dysfunction,lymphadenopathy, and skin lesions.

Routine Laboratory and Radiologic Studies

Choices depend on clinical setting (esp. severity of pain,rapidity of onset): may

include CBC,serum electrolytes,coagulation parameters, serum glucose, and

biochemical tests of liver,kidney, and pancreatic function; CXR to determine

the presence of diseases involving heart, lung,mediastinum,and pleura; ECG

is helpful to exclude referred pain from cardiac disease; plain abdominal radiographs to evaluate bowel displacement,intestinal distention, fluid and gas pattern,free peritoneal air, liver size, and abdominal calcifications (e.g., gallstones,

renal stones,chronic pancreatitis).

Special Studies

These include abdominal ultrasonography (to visualize biliary ducts,gallbladder,

liver,pancreas,and kidneys); CT to identify masses, abscesses, evidence

of inflammation (bowel wall thickening,mesenteric “stranding,” lymphadenopathy), aortic aneurysm; barium contrast radiographs (barium swallow, upper GI series,small-bowel follow-through,barium enema); upper GI endoscopy, sigmoidoscopy, or colonoscopy; cholangiography (endoscopic, percutaneous, or

via MRI),angiography (direct or via CT or MRI),and radionuclide scanning.

In selected cases,percutaneous biopsy,laparoscopy, and exploratory laparotomy

may be required.