Outline • Definitions • What causes an “acute abdomen” • Differential Diagnosis • History and physical • Labs • Diagnostic imaging • High Risk Patients with Acute Abdomen
Acute Abdomen Symptoms and signs of acute intra- abdominal disease processes, usually treated best by surgical operation
The Epidemiology of Acute Abdominal Pain • 5-10% of all ED visits. • Among them, 14-40% patients need surgical intervention. • Challenge for emergency physician (EP): • About 1/3have an atypical presentation. • If misdiagnosis, mortality rate 2.5times higher than correct diagnosis in the elderly.
Three Types of Abdominal Pain • Visceral Pain • Somatic (Parietal) Pain • Referred Pain
The Physiology and Mechanisms of Abdominal Pain • Visceral Pain • Within the muscular walls of hollow organs and the capsules of solid organs. • Stimulated primarily by stretching, distension, and excessive contractions. • Characteristically deep, dull, aching or cramping, and poorly localized. • Usually felt in the midline, unaccompanied by tenderness.
The Physiology and Mechanisms of Abdominal Pain • Somatic (Parietal) Pain • Afferent fibers: from T6 to L1, more localized. • Characteristically sharper, aggravated by stimulation of the parietal peritoneum with movement, coughing, or walking. • True parietal pain surgical cause of abdominal pain.
The Physiology and Mechanisms of Abdominal Pain • Referred Pain • Pain felt a site other than that of the primary noxious stimulus. • Occurs in an area supplied by the same neurosegment as the involved organ. • Most visceral pain is of this type. • Usually intense and most often secondary to an inflammatory lesion. • Subdiaphragm disorder~shoulder pain • Biliary tract disorder~right shoulder pain • Small bowel disorder~back pain
Causes of Acute Abdomen (DDx) • Appendicitis • Peritonitis • Bowel Perforation • Pancreatitis • Diverticular disease • Cholecystitis • Perforating Gastric/Duodenal ulcer • Ruptured Ectopic Pregnancy • Ruptured or hemorrhagic ovarian cyst • Pelvic Inflammatory Disease • Abdominal Aortic Aneurysm • Tubo-ovarian abscess
Nonspecific abd. pain 39.5 Appendicitis32.5 Cholecystitis 6.3 Obstruction 2.5 Pancreatitis 1.6 Diverticular disease <0.1 Cancer <0.1 Hernia <0.1 Vascular <0.1 Cholecystitis 20.5 Nonspecific abd. Pain15.7 Appendicitis 15.2 Obstruction 12.5 Pancreatitis 7.3 Diverticular disease 5.5 Cancer 4.1 Hernia 3.1 Vascular 2.3 Acute Abdominal Pain in Patients Under and Over Age 50 Under 50 (6317 cases), % Over 50 (2406 cases), %
Systemic DKA Alcoholic ketoacidosis Uremia Sickle cell disease Porphyria SLE Vasculitis Glaucoma Hyperthyroidism Toxic Methanol poisoning Heavy metal toxicity Scorpion bite Black widow spider bite Thoracic Myocardial infarction/ Unstable angina Pneumonia Pulmonary embolism Herniated thoracic disc (neuralgia) Genitourinary Testicular torison Renal colic Infectious Strep pharyngitis (more often in children) Rocky Mountain Spotted Fever Monocucleosis Abdominal wall Muscle spasm Muscle hematoma Herpes zoster Important Extra-abdominal Causes of Abdominal Pain
History of Present Illness • Onset • Precipitating/ relieving • Quality • Radiation • Severity • Timing • Matched to clinical condition • Emerges over time and then concentrates (acute appy) • Sudden onset (perforated viscous)
High-Yield Historical Questions • How old are you? (Advanced age mean increased risk) 2. Describe the position, character,and migration of the pain sudden coupled with weakness or fainting, less acute but still abrupt onset ,or begin gradually and maximize slowly Is the pain constant or intermittent? (Constant pain is worse) Have you ever had this before? (No prior episodes is worse) Did the pain start centrally and migrate to the right lower quadrant? (High specificity for appendicitis) 3. Have you noticed specific aggravating or relieving factors? (Eating, defecation or flatus) 4. Have you ever had abdominal surgery? (Consider obstruction in patients who report previous abdominal surgery)
High-Yield Historical Questions 5. Do you have nausea, vomiting, diarrhea or bowel habit change? (D/D true diarrhea, overflow incontinence or tenesmus) 6. Do you have HIV? (Consider occult and unusual infection, 30% mortality of surgical treatment) 7. How much alcohol do you drink per day? (Consider pancreatitis, hepatitis, or cirrhosis) 8. Are you pregnant? (Test for pregnancy-consider ectopic pregnancy, menstrual history, sexual exposure history) 9. Are you taking antibiotics or steroids? (These may mask infection) 10. Do you have a history of vascular or heart disease, hypertension, or atrial fibrillation? (Consider mesenteric ischemia and abdominal aneurysm)
Physical Examination • Overall appearance ( Facial expression, diaphoresis, pallor, and degree of agitation) • Walking and recumbent • Vital signs • Temperature (T > 40 °C or < 35° C consider abdominal sepsis) • Tachycardia • Hypotension • Inspection: scars, hernias, masses • Auscultation (Hyperactive BS, hypoactive BS or silent BS, Pulsatile bruit) • Percussion • Palpation : The most critical step • Tenderness • Rigidity and guarding (Only 21% > 70 y patients with PPU present with epigastria rigidity) • “Board-like abdomen” • Rectal digital examination • rebounding pain
Laboratory Examination • CBC & differential • Serum electrolyte ( K, Bicarbonate ) • Urinalysis • ß-HCG – woman of childbearing age • Bilirubin, Alk-p, ALT, AST, G-GT – RUQ pain, jaundice • Amylase, lipase – epigastralgia • PT, APTT • EKG, CK – epigastralgia with aged patient
Five Major Categories of Acute Abdomen (BIOPI) • Bleeding or rupture of vessels or tumor • Ischemia or Infarction • Obstruction • Perforation • Inflammation
Emergency Department Evaluation of Acute Abdomen • History • Menstruation history(LMP, ovulation, sexual exposure) • Rapid pregnancy test: women of childbearing age. • Lab: CBC, liver panel, EKG for elderly. • Plain KUB: helpful in obstruction; 40% patients invisible free air. • Ultrasound and CT scan: aneurysm, cholelithiasis, ectopic pregnancy, and ureterolithiasis.
Important Imaging Studies for Acute Abdomen • Standing CXR and KUB • Ultrasound: for solid organs. • CT of abdomen for abscess, free air, vessel, tumor and ischemia bowel.( gold standard for finding acute appendicitis) • Angiography: Especially in non-diagnostic ischemia bowel.
Indications for Abdominal Plain Films Suspected Diagnosis Clinical Findings Perforated viscus Sudden-onset pain Rigid abdomen Decreased bowel sounds Bowel obstruction Prior abdominal surgery Abdominal distension Abnormal bowel sounds High risk for obstruction or volvulus Foreign body Mental retardation Psychosis Suspicion of rectal foreign body
Plain Films • Upright CXR • “Free” air • KUB (kidney/ureter/bladder) • Calcifications • Air/ Fluid levels • Reactive bowel patterns • Foreign bodies Lateral Decubitus Film
Ultrasound • Rapid, safe, low cost • Operator dependent • Fluid, inflammation, air in walls, masses • Liver, GB, CBD, Spleen, Pancreas, Appendix, Kidney, Ovaries, Uterus
CT Scans • Better than plain films and US for evaluation of solid and hollow organs • Intravenous contrast • Oral contrast • Per rectal contrast • High use in appendicitis, diverticulitis, abscess, pancreatitis
The Identification of High Risk Patients with Acute Abdomen • Elderly > 65 y • S/S of Shock • Peritoneal sign (+) • silent bowel sound • Pulsatile mass • Refractory pain post Tx • The immunocompromised. (e.g. HIV) • Women of childbearing age. • Elevation of Band WBC • Fever cause • Hypothermia • Acute renal failure • Not post-surgical obstruction
Emergency Department Management of Acute Abdomen • IV volume replacement and NG decompression • Antibiotics: indicated if infection is suspected. • Narcotic analgesia (?) Timing (?) • Pro: Permit a more accurate history and PE. Morphine (2-5 mg IV) • Con: Surgeon is hostile to this approach, consultation immediately.
When to Operate ? • Peritonitis • Excluding primary peritonitis • Abdominal pain/tenderness + sepsis • Acute intestinal ischemia • Pneumoperitoneum • Make sure pancreatitis is excluded
When NOT to Operate ? • Cholangitis • Appendiceal abscess • Acute diverticulitis + abscess • Acute pancreatitis or hepatitis • Ruptured ovarian cysts • Long standing perforated ulcers? • MI, Acute pericarditis • PN, pulmonary infarction • GE reflux, DKA, Adrenal Insufficiency • Acute Porphyria • Rectus muscle hematoma • Pyelonephritis, Sickle cell crisis