The document discusses the acute abdomen, which refers to symptoms and signs of acute intra-abdominal disease that are usually best treated with surgery. It defines the different types of abdominal pain and covers the epidemiology, causes, diagnostic evaluation including history, exams, labs, and imaging. High risk patients are identified. The management of acute abdomen in the emergency department is outlined, including when surgery is indicated versus other conservative treatments.

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. Nonspecific abd. pain 39.5
Appendicitis 32.5
Cholecystitis 6.3
Obstruction 2.5
Pancreatitis 1.6
Diverticular disease <0.1
Cancer <0.1
Hernia <0.1
Vascular <0.1
Acute Abdominal Pain in Patients Under and
Over Age 50
Cholecystitis 20.5
Nonspecific abd. Pain 15.7
Appendicitis 15.2
Obstruction 12.5
Pancreatitis 7.3
Diverticular disease 5.5
Cancer 4.1
Hernia 3.1
Vascular 2.3
Under 50 (6317 cases), % Over 50 (2406 cases), %

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
1. 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
• “Free” air
• KUB
(kidney/ureter/bladder)
• 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
• 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