1. The Acute Abdomen

2. Outline Definitions What causes an “acute abdomen”
Differential Diagnosis
History and physical
Labs
Diagnostic imaging
High Risk Patients with Acute Abdomen

3. Acute Abdomen
Symptoms and signs of acute intra- abdominal disease processes, usually treated best by surgical operation

4. 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 1/3 have an atypical presentation.
If misdiagnosis, mortality rate 2.5 times higher than correct diagnosis in the elderly.

5. Three Types of Abdominal Pain
Visceral Pain
Somatic (Parietal) Pain
Referred Pain

6. 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.

7. 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.

8. 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

9. 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

10. Acute Abdominal Pain in Patients Under and Over Age 50
Under 50 (6317 cases), % Over 50 (2406 cases), %
Nonspecific abd. pain
Appendicitis
Cholecystitis
Obstruction
Pancreatitis
Diverticular disease <0.1
Cancer <0.1
Hernia <0.1
Vascular <0.1
Cholecystitis
Nonspecific abd. Pain
Appendicitis
Obstruction
Pancreatitis
Diverticular disease
Cancer
Hernia
Vascular

11. Important Extra-abdominal Causes of Abdominal Pain
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

12. History of Present Illness
O nset
P recipitating/ relieving
Q uality
R adiation
S everity
T iming
Matched to clinical condition
Emerges over time and then concentrates (acute appy)
Sudden onset (perforated viscous)

13. 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)

14. 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)

15. 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

16. 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

17. Five Major Categories of Acute Abdomen (BIOPI)
Bleeding or rupture of vessels or tumor
Ischemia or Infarction
Obstruction
Perforation
Inflammation

18. 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.

19. Diagnostic Imaging

20. 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.

21. 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

22. Plain Films Upright CXR KUB (kidney/ureter/bladder) “Free” air
Calcifications
Air/ Fluid levels
Reactive bowel patterns
Foreign bodies
Lateral Decubitus Film

23. Ultrasound Rapid, safe, low cost
Operator dependent
Fluid, inflammation, air in walls, masses
Liver, GB, CBD, Spleen, Pancreas, Appendix, Kidney, Ovaries, Uterus

24. 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

25. 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

26. 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.

27. When to Operate ? Peritonitis Abdominal pain/tenderness + sepsis
Excluding primary peritonitis
Abdominal pain/tenderness + sepsis
Acute intestinal ischemia
Pneumoperitoneum
Make sure pancreatitis is excluded

28. 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

29. Thank you