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Most common extrauterine surgical emergency
No more common in pregnant versus nonpregnant women
Higher rate of perforation; more likely to present with peritonitis
ETIOLOGY AND PATHOPHYSIOLOGY
The cause is thought to be obstruction of the appendiceal lumen. This leads to distention, ischemia, and bacterial overgrowth. Without intervention, most cases of appendicitis will lead to perforation and subsequently abscess formation or generalized peritonitis. Causes of obstruction:
- Fecaliths (most common)
- Lymphoid tissue hyperplasia (in children)
- Vegetable, fruit seeds, and other foreign bodies
- Intestinal worms (ascarids)
- Strictures, fibrosis, neoplasms
Genetics
First-degree relative with history of appendicitis increases risk, although no direct genetic link has been found.
RISK FACTORS
Adolescent males, familial tendency, intra-abdominal tumors
DIAGNOSIS
- Diagnosis of acute appendicitis relies on the history and physical examination with supporting laboratory studies and imaging.
- Scoring systems
- Modified Alvarado Scoring System (MASS): The use of MASS in the diagnosis of acute appendicitis has been reported to improve the diagnostic accuracy and consequently reduces negative appendectomy and complication rates.
- Use of MASS in for acute appendicitis in female patients should be supplemented by additional investigations like abdominal ultrasound or laparoscopy.
- A MASS score above 7 should indicate appendectomy without the need for further imaging.
- A cutoff point of 6 for the MASS score will yield higher sensitivity and a better diagnosis of appendicitis but provides an increase in negative appendectomy.
- Pediatric Appendicitis Score-this has been developed to help predict the likelihood of acute appendicitis, although diagnosis is still considered a clinical decision.
HISTORY
- Classic history is vague periumbilical pain, followed by anorexia/nausea/vomiting. Over the next 4 to 48 hours, pain migrates to the RLQ.
- Only 50% of patients present with this classic history.
- Pain before vomiting (~100% sensitive), abdominal pain (~100%), pain migration (50%)
- Anorexia (~100%), nausea (90%), vomiting (75%), obstipation
- Atypical symptoms and pain associated with a retrocecal or pelvic appendix
PHYSICAL EXAM
- Fever; temperature >100.4 °F (may be absent); tachycardia
- RLQ tenderness; maximal tenderness at McBurney point (1/3 the distance from the anterior superior iliac spine to the umbilicus)
- Voluntary and involuntary guarding
- Rovsing sign: RLQ pain with palpation of left lower quadrant
- Psoas sign: pain with right thigh extension (retrocecal appendix)
- Obturator sign: pain with internal rotation of flexed right thigh (pelvic appendix); local and suprapubic pain on rectal exam (pelvic appendix)
- Pelvic and rectal exams are necessary to rule out other causes of lower abdominal pain (e.g., pelvic inflammatory disease, prostatitis).
- Serial exams can be useful in indeterminate cases.
DIFFERENTIAL DIAGNOSIS
- GI:
- Gastroenteritis, inflammatory bowel disease
- Diverticulitis, ileitis
- Cholecystitis, pancreatitis
- Intussusception, volvulus
- Gynecologic:
- Pelvic inflammatory disease, ectopic pregnancy
- Ovarian cyst, ovarian torsion, tubo-ovarian abscess
- Endometriosis
- Ruptured Graafian follicle
- Urologic:
- Testicular torsion, epididymitis
- Kidney stones, prostatitis, cystitis, pyelonephritis
- Systemic:
- Diabetic ketoacidosis
- Henoch-Sch ¶nlein purpura
- Sickle cell crisis
- Porphyria
- Other:
- Acute mesenteric lymphadenitis
- No organic pathologic condition
- Hernias
- Psoas abscess
- Rectus sheath hematoma
- Epiploic appendagitis
- Pneumonia (basilar)
Pediatric Considerations
Pregnancy Considerations
Geriatric Considerations
Decreased diagnostic accuracy, more likely to be atypical presentation
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
- Leukocytosis: WBC >10,000/mm3 (70%)
- Polymorphonuclear predominance or "left shift" (>90%)
- Human chorionic gonadotropin (hCG) (if negative, rule out ectopic pregnancy)
- Urinalysis: hematuria, pyuria (~30%)
- C-reactive protein: nonspecific inflammatory marker. When paired with an elevated WBC can increase the likelihood of appendicitis.
- Drugs may alter lab results: antibiotics, steroids.
- Imaging used in cases of suspected appendicitis when the diagnosis is not clear; is helpful to detect complications (abscess, perforation)
- Plain films: little utility, nonspecific findings, may visualize fecalith
- CT scan with contrast: sensitivity ~91-98%; specificity 95-99%; imaging modality of choice However, growing concern regarding radiation dose, particularly in young patients (1)[A].
- Ultrasound: alternative in pregnant patients, children, and in women with suspected gynecologic pathology. Sensitivity and specificity vary by report and accuracy depends on the skill of the ultrasonographer. Can rule in appendicitis but cannot reliably exclude the diagnosis. Starting with an ultrasound and, if negative, obtaining a CT scan has been proposed as an effective workup strategy (2)[B].
- MRI: growing in popularity for diagnosing pregnant patients but also may be useful for patients with contrast allergies and/or patients with renal failure. Limitations include cost, availability, and time required to complete study.
- Radioisotope-labeled WBC scans: may be used in patients with indeterminate CT scans and suspected appendicitis as an alternative to observation or surgery. Limitations include availability and time required to complete study.
Diagnostic Procedures/Other
Exploratory laparotomy/laparoscopy: Acceptable nontherapeutic appendectomy rates vary based on age and gender and may be higher for females of childbearing age than males.
Test Interpretation
- Acute appendiceal inflammation, local vascular congestion, obstruction
- Gangrene, perforation with abscess (15-30%)
- Fecalith
TREATMENT
GENERAL MEASURES
Surgery (appendectomy) is the standard of care for acute, uncomplicated appendicitis.
MEDICATION
First Line
- Uncomplicated acute appendicitis: perioperative dose of antibiotic (3)[A]: single dose of cefoxitin or ampicillin/sulbactam (Unasyn) or cefazolin plus metronidazole
- Gangrenous or perforating appendicitis:
- Broadened antibiotic coverage for aerobic and anaerobic enteric pathogens
- Piperacillin and tazobactam (Zosyn) or ticarcillin and clavulanate (Timentin) or a 3rd-generation cephalosporin plus metronidazole are initial options.
- Adjust dosage and choice of antibiotic based on intraoperative cultures.
- Continue antibiotics for at least 7 days postoperatively or until patient becomes afebrile with normal WBC count.
Second Line
- Among patients with CT-proven, uncomplicated appendicitis, antibiotic treatment did not meet the prespecified criterion for noninferiority compared with appendectomy. Most patients randomized to antibiotic treatment for uncomplicated appendicitis did not require appendectomy during the 1-year follow-up period, and those who required appendectomy did not experience significant complications.
- In the case of acute appendicitis complicated by abscess formation or phlegmon in pediatric patients, some studies show initial conservative management with antibiotics alone to carry fewer risks and complications than emergent appendectomy (4)[A].
- Uncomplicated acute appendicitis: clindamycin plus one of the following: ciprofloxacin, levofloxacin, gentamicin, or aztreonam
- Gangrenous or perforated appendicitis: ciprofloxacin or levofloxacin plus metronidazole or monotherapy with a carbapenem (imipenem and cilastatin, meropenem, ertapenem)
ISSUES FOR REFERRAL
All cases of appendicitis require emergent surgical consultation.
SURGERY/OTHER PROCEDURES
- Inpatient surgery is indicated.
- Patients presenting within 72 hours of onset:
- Immediate appendectomy; laparoscopic favored unless perforation (5)[A]
- Drainage of abscess, if present
- Patients who present late (>4 to 5 days after symptom onset) may be treated initially with antibiotics, bowel rest, and drainage of any abscess. Later (4 to 10 weeks) appendectomy can then be performed in this subgroup only.
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
All patients with appendicitis should be admitted.
IV Fluids
Fluid resuscitation with normal saline (NS) or lactated Ringer (LR) solution. Correct fluid and electrolyte deficits.
Nursing
Preoperative preparation
Discharge Criteria
Tolerating PO; return of bowel function; afebrile; normal WBC
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
- Return to work is usually possible 1 to 2 weeks following most uncomplicated appendicitis.
- Restrict activity for 4 to 6 weeks after surgery: No heavy lifting (>10 lb) or strenuous physical activity.
PATIENT EDUCATION
Contact physician for postoperative development of:
- Anorexia, nausea, vomiting
- Abdominal pain, fever, chills
- Signs/symptoms of wound infection
PROGNOSIS
- Generally uncomplicated course in young adults with unruptured appendicitis
- Factors increasing morbidity and mortality: extremes of age, presence of appendiceal rupture
- Morbidity rates:
- Nonperforated appendicitis: 3%
- Perforated appendicitis: 47%
- Mortality rates:
- Unruptured appendicitis: 0.1%
- Ruptured appendicitis: 3%
- Patients >60 years of age make up 50% of total deaths from appendicitis.
- Older patients with ruptured appendix: 15%
Pediatric Considerations
Rupture earlier
Rupture rate: 15-60%
Pregnancy Considerations
Geriatric Considerations
Rupture rate: 67-90%
COMPLICATIONS
- Wound infection, intra-abdominal abscess; lower rate with antibiotic prophylaxis (6)[A], intestinal fistulas
- Intestinal obstruction, paralytic ileus, incisional hernia
- Liver abscess (rare), pyelophlebitis
REFERENCES
11 Hlibczuk V, Dattaro JA, Jin Z, et al. Diagnostic accuracy of noncontrast computed tomography for appendicitis in adults: a systematic review. Ann Emerg Med. 2010;55(1):51.e1-59.e1.22 Poortman P, Oostvogel HJ, Bosma E, et al. Improving diagnosis of acute appendicitis: results of a diagnostic pathway with standard use of ultrasonography followed by selective use of CT. J Am Coll Surg. 2009;208(3):434-441.33 Andersen BR, Kallehave FL, Andersen HK. Antibiotics versus placebo for prevention of postoperative infection after appendicectomy. Cochrane Database Syst Rev. 2005;(3):CD001439.44 Simillis C, Symeonides P, Shorthouse AJ, et al. A meta-analysis comparing conservative treatment versus acute appendectomy for complicated appendicitis (abscess or phlegmon). Surgery. 2010;147(6):818-829.55 Sauerland S, Lefering R, Neugebauer EA. Laparoscopic versus open surgery for suspected appendicitis. Cochrane Database Syst Rev. 2004;(4):CD001546.66 Wilms IM, de Hoog DE, de Visser DC, et al. Appendectomy versus antibiotic treatment for acute appendicitis. Cochrane Database Syst Rev. 2011;(11):CD008359.
ADDITIONAL READING
- Kanumba ES, Mabula JB, Rambau P, et al. Modified Alvarado Scoring System as a diagnostic tool for acute appendicitis at Bugando Medical Centre, Mwanza, Tanzania. BMC Surg. 2011;11:4.
- Nasiri S, Mohebbi F, Sodagari N, et al. Diagnostic values of ultrasound and the Modified Alvarado Scoring System in acute appendicitis. Int J Emerg Med. 2012;5(1):26.
- Salminen P, Paajanen H, Rautio T, et al. Antibiotic therapy vs appendectomy for treatment of uncomplicated acute appendicitis: the APPAC randomized clinical trial. JAMA. 2015;313(23):2340-2348.
SEE ALSO
Algorithm: Abdominal Rigidity
CODES
ICD10
- K35.80 Unspecified acute appendicitis
- K35.2 Acute appendicitis with generalized peritonitis
- K35.3 Acute appendicitis with localized peritonitis
- K35.89 Other acute appendicitis
- K35 Acute appendicitis
- K35.8 Other and unspecified acute appendicitis
ICD9
- 540 Acute appendicitis
- 540.0 Acute appendicitis with generalized peritonitis
- 540.1 Acute appendicitis with peritoneal abscess
- 540.9 Acute appendicitis without mention of peritonitis
- 541 Appendicitis, unqualified
SNOMED
- 85189001 Acute appendicitis (disorder)
- 196781001 Acute appendicitis with peritonitis
- 51036000 Acute appendicitis with peritoneal abscess (disorder)
CLINICAL PEARLS
- Classic history of anorexia with periumbilical pain localizing to RLQ is the cornerstone of diagnosis for acute appendicitis.
- Diagnosis is much more challenging in children, pregnant patients, and the elderly due to varying symptoms and signs.
- In equivocal cases, CT of abdomen and pelvis is the diagnostic test of choice, although ultrasound and MRI are useful alternatives.
- Acute appendicitis is the most common surgical emergency during pregnancy.