The Acute AbdomenThe Acute Abdomen

OutlineOutline

• Definitions• What causes an “acute abdomen”• Differential Diagnosis

• History and physical• Labs• Diagnostic imaging

•High Risk Patients with Acute AbdomenHigh Risk Patients with Acute Abdomen

Acute AbdomenAcute Abdomen

Symptoms and signs of acute intra- abdominal disease processes, usually

treated best by surgical operation

The Epidemiology of Acute The Epidemiology of Acute Abdominal PainAbdominal 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.

Three Types of Three Types of Abdominal PainAbdominal Pain

• Visceral Pain

• Somatic (Parietal) Pain

• Referred Pain

The Physiology and The Physiology and Mechanisms of Abdominal Mechanisms of Abdominal

PainPain • 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 The Physiology and Mechanisms of Abdominal Mechanisms of Abdominal

PainPain• 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 The Physiology and Mechanisms of Abdominal Mechanisms of Abdominal

PainPain • 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 Causes of Acute Abdomen (DDx)(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

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 Acute Abdominal Pain in Patients Under and Over Age 50and 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), %

Important Extra-abdominal Causes of Important Extra-abdominal Causes of Abdominal PainAbdominal 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

History of Present IllnessHistory 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)

High-Yield Historical High-Yield Historical QuestionsQuestions

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)

High-Yield Historical High-Yield Historical QuestionsQuestions

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 ExaminationPhysical 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 ExaminationLaboratory 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 Five Major Categories of Acute Abdomen (BIOPI)Acute Abdomen (BIOPI)• Bleeding or rupture of vessels or

tumor

• Ischemia or Infarction

• Obstruction

• Perforation

• Inflammation

Emergency Department Emergency Department Evaluation of Acute AbdomenEvaluation 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.

Diagnostic ImagingDiagnostic Imaging

Important Imaging Studies Important Imaging Studies for Acute Abdomenfor 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 Indications for Abdominal Plain FilmsPlain Films

Suspected Diagnosis Clinical Findings

Perforated viscus Sudden-onset painRigid abdomenDecreased bowel sounds

Bowel obstruction Prior abdominal surgeryAbdominal distensionAbnormal bowel soundsHigh risk for obstruction or volvulus

Foreign body Mental retardationPsychosisSuspicion of rectal foreign body

Plain FilmsPlain Films

• Upright CXR• “Free” air

• KUB (kidney/ureter/bladder)• Calcifications• Air/ Fluid levels• Reactive bowel patterns• Foreign bodies

Lateral Decubitus FilmLateral Decubitus Film

UltrasoundUltrasound

• Rapid, safe, low cost– Operator dependent

• Fluid, inflammation, air in walls, masses

• Liver, GB, CBD, Spleen, Pancreas, Appendix, Kidney, Ovaries, Uterus

CT ScansCT 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 The Identification of High Risk Patients with Acute Risk Patients with Acute

AbdomenAbdomen• 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 Emergency Department Management of Acute Management of Acute

AbdomenAbdomen• 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 ?When to Operate ?

• Peritonitis• Excluding primary

peritonitis• Abdominal

pain/tenderness + sepsis

• Acute intestinal ischemia

• Pneumoperitoneum• Make sure pancreatitis

is excluded

When When NOT NOT to to Operate ?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