section name header

Basics ⬇

[Section Outline]

Author:

Colleen N.Hickey


Description!!navigator!!

Pediatric Considerations
  • 28-57% misdiagnosis in patients <12 yr (nearly 100% in patients <2 yr)
  • 60-86% perforation rate in children <4 yr
  • Perforation correlates strongly with delayed diagnosis

Geriatric Considerations
  • Decreased inflammatory response
  • Up to 3 times more likely to have perforation owing to anatomic changes
  • Diagnosis often delayed owing to atypical presentations

Pregnancy Prophylaxis
  • Slightly higher rate in second trimester compared to first/third/postpartum periods
  • Increased perforation rate (25-40%), highest in third trimester
  • RLQ pain remains the most common symptom
  • 5-10% fetal loss, up to 24% in perforated appendicitis

Etiology!!navigator!!

Diagnosis ⬆ ⬇

[Section Outline]

Signs and Symptoms!!navigator!!

History

  • Abdominal pain: Primary symptom
    • Normal location:
      • RLQ pain
      • 35% of patients have appendix located within 5 cm of “normal” location
    • Retrocecal appendix (28-68%):
      • Back pain
      • Flank pain
      • Testicular pain
    • Pelvic appendix (27-53%):
      • Suprapubic pain
      • Urinary or rectal symptoms
    • Long appendix (<0.2%):
      • Inflamed tip may cause pain in RUQ or LLQ
      • Anorexia
      • Vomiting
  • Change in bowel habits: Diarrhea (33%), constipation (9-33%)
  • Classic presentation (<75% adults):
    • Initially periumbilical pain
    • Anorexia (first symptom in 95%) and nausea
    • Pain localizes to RLQ (1-12 hr after onset)
    • Finally, vomiting and fever
Pediatric Considerations
  • Presentations often nonspecific and difficult to localize (<50% have classic presentation)
  • Anorexia, vomiting, and diarrhea more common (half-eaten meal hours before complaints of pain may more accurately indicate duration of symptoms)
  • Observe child before exam for subtle indicators of local inflammation:
    • Limping gait
    • Hesitation to move, climb, or jump
    • Flexed right hip

Physical Exam

  • Vital signs:
    • Often normal
    • Fever: Normal to mild elevation (<1°F) initially, increases with perforation
  • Abdominal exam:
    • Tenderness at McBurney point (1/3 of distance from right anterior iliac spine to umbilicus)
    • Guarding:
      • Voluntary guarding early owing to muscular resistance to palpation
      • Involuntary guarding (rigidity) later as inflammation progresses and perforation occurs
    • Rebound:
      • Pain with any rapid movement of peritoneum (e.g., bumping stretcher)
    • Specific signs (less useful in pediatrics):
      • Rovsing sign: Pain in RLQ when palpating LLQ
      • Psoas sign: Increased pain on extension of right hip with patient lying on her or his left side, owing to inflamed appendix touching iliopsoas muscle
      • Obturator sign: Pain with passive internal rotation and flexion of right hip
  • Rectal exam:
    • Limited value: May localize tenderness/mass
  • Pelvic exam:
    • Important to differentiate gynecologic disease
    • Vaginal discharge and /or adnexal tenderness or mass suggests gynecologic disease
    • Cervical motion tenderness when present suggests PID, but can be seen in up to 25% of women with appendicitis
  • Patient position:
    • Supine or decubitus with legs (particularly the right) drawn up
    • Prefer not to move
  • Shuffling gait—known as “appy walk”
Pediatric Considerations
Almost all children have generalized abdominal tenderness with some rigidity

Pregnancy Prophylaxis
  • Enlarging uterus displaces appendix upward and laterally
  • Hyperemesis gravidarum and other nonsurgical causes of vomiting should not cause abdominal tenderness

Geriatric Considerations
Typical signs of peritonitis may be absent in elderly

Essential Workup!!navigator!!

Diagnostic Tests & Interpretation!!navigator!!

Lab

  • CBC:
    • WBC >10,000, with left shift (80%)
    • Normal WBC does not exclude diagnosis
  • C-reactive protein:
    • Overall sensitivity 65-85%, specificity 35-85%
    • May not be elevated early (<12 hr)
    • Increased sensitivity with serial measurements
  • Urinalysis:
    • Generally normal
    • Mild pyuria, bacteriuria, or hematuria (25-30%)
    • Pyuria present if inflamed appendix lies near ureter or bladder
  • Pregnancy test for females of child-bearing age

Imaging

  • Unnecessary when diagnosis is clear
  • Most helpful in female patients of childbearing age where diagnosis is often unclear
  • Abdominal radiographs—not recommended
  • US: Sensitivity 86-90%; specificity 85-95%:
    • Noncompressible appendix 6 mm anteroposterior (AP) diameter
    • Presence of appendicolith
    • Periappendiceal fluid/mass
    • Limited by obesity, bowel gas, retrocecal appendix, and operator
    • Negative study of limited use
  • CT: Sensitivity 94-100%; specificity 91-99%:
    • Highest yield using oral contrast with focused appendiceal technique (5 mm cuts from 3 cm above cecum extending distally 12-15 cm)
    • Fat strand ing (100%)
    • Appendix 6 mm in diameter (93%)
    • Focal cecal apical thickening
    • Defines appendiceal masses (phlegmon vs. abscess)
    • Best study for finding alternative diagnoses
    • Nonvisualized appendix does not rule out appendicitis
  • MRI: Sensitivity 90-100%, specificity 92-94%:
    • Appendix 7 mm in diameter
    • Periappendiceal fat strand ing
    • Advantages: Lack of ionizing radiation, excellent safety profile of gadolinium contrast agents
    • Disadvantages: High cost, limited availability, lengthy exam, lack of radiologist familiarity in appendicitis
    • No gadolinium in early pregnancy (class C drug)
Pediatric Considerations
American College of Radiology recommends US followed by CT as needed for suspected appendicitis

Diagnostic Procedures/Surgery

  • Laparoscopy:
    • Diagnostic and therapeutic use
    • Gross pathology may be absent with positive microscopic findings
    • Decreased risk of wound infections, decreased hospital LOS
  • Open appendectomy
  • Percutaneous drainage

Differential Diagnosis!!navigator!!

Treatment ⬆ ⬇

[Section Outline]

Initial Stabilization/Therapy!!navigator!!

ED Treatment/Procedures!!navigator!!

Medication!!navigator!!

Follow-Up ⬆ ⬇

[Section Outline]

Disposition!!navigator!!

Admission Criteria

  • Surgical intervention of acute appendicitis
  • Observation or further diagnostic workup if diagnosis is uncertain

Discharge Criteria

Patients with abdominal pain thought not to be appendicitis may be discharged if they meet the following criteria:

  • Resolved or resolving symptoms
  • Minimal or no abdominal tenderness
  • No lab/radiologic abnormalities
  • Able to tolerate PO intake
  • Adequate social support and able to return if symptoms worsen

Follow-up Recommendations!!navigator!!

24-48 hr recheck for patients discharged from the ED with abdominal pain of unclear etiology

Pearls and Pitfalls ⬆ ⬇

  • Pediatric and geriatric patients present atypically and have increased perforation rates
  • Imaging is not required in a classic presentation of acute appendicitis
  • Appendicitis cannot be ruled out on any imaging modality if the appendix is not visualized

Additional Reading ⬆ ⬇

See Also (Topic, Algorithm, Electronic Media Element)

The authors gratefully acknowledge Jennifer L. Kolodchak for his contribution to the previous edition of this chapter.

Codes ⬆

ICD9

ICD10

SNOMED