Key Points

• Acute inflammation of the vermiform appendix, a common surgical emergency.
• Peak incidence in adolescents and young adults; lifetime risk ~7–8%.
• Pathogenesis usually involves luminal obstruction leading to bacterial overgrowth and ischemia.
• Classic presentation: peri-umbilical pain migrating to right lower quadrant, anorexia, nausea, low-grade fever, leukocytosis.
• Definitive treatment is appendectomy (laparoscopic preferred), with antibiotics for uncomplicated cases in select patients.

Introduction

Appendicitis is acute inflammation of the vermiform appendix. It is among the most common causes of acute abdominal pain requiring surgery. Early recognition and prompt management are essential to prevent complications such as perforation, abscess formation, and peritonitis.

Epidemiology

• Incidence: approximately 100 per 100,000 person-years.
• Age: highest incidence between 10 and 30 years.
• Gender: slight male predominance.
• Seasonal peaks in summer and autumn in some regions.

Anatomy and Pathophysiology

• The appendix is a blind-ended tube arising from the cecum.
• Rich lymphoid tissue in the submucosa predisposes to lymphoid hyperplasia.
• Common causes of luminal obstruction:
• Lymphoid hyperplasia (children/young adults)
• Fecaliths (adults)
• Foreign bodies, parasites, or neoplasms (rare)
• Obstruction leads to increased intraluminal pressure, venous congestion, and bacterial invasion, resulting in mucosal ischemia, necrosis, and eventual perforation if untreated.

Clinical Presentation

History

• Early symptoms: vague, colicky peri-umbilical or epigastric pain.
• Migration of pain to right lower quadrant (RLQ) within 12–24 hours.
• Anorexia, nausea, sometimes vomiting; low-grade fever.
• Pain exacerbated by movement, coughing, or percussion.

Physical Examination

• Tenderness at McBurney’s point.
• Rebound tenderness and guarding.
• Rovsing’s sign: RLQ pain on left-sided palpation.
• Psoas sign: RLQ pain on right hip extension.
• Obturator sign: RLQ pain on internal rotation of flexed hip.

Diagnostic Evaluation

Laboratory Studies

• Complete blood count: leukocytosis with left shift.
• C-reactive protein: often elevated.
• Urinalysis to exclude urinary tract pathology.

Imaging

• Ultrasound: initial choice in children and pregnant patients; may show noncompressible, blind-ended tubular structure >6 mm.
• Computed tomography (CT): high sensitivity and specificity; demonstrates appendiceal diameter, wall thickening, periappendiceal fat stranding, and complications.
• MRI: alternative in pregnancy or when CT contraindicated.

Differential Diagnosis

• Mesenteric adenitis
• Gastroenteritis
• Crohn’s disease (terminal ileitis)
• Meckel’s diverticulitis
• Ureteral colic
• Gynecologic causes (e.g., ovarian torsion, ectopic pregnancy)
• Diverticulitis (older adults)

Management

Preoperative Care

• NPO (nil per os) and IV fluid resuscitation.
• Broad-spectrum IV antibiotics covering gram-negative and anaerobic organisms (e.g., ceftriaxone plus metronidazole or piperacillin–tazobactam).
• Analgesia and antiemetics as needed.

Surgical Treatment

• Laparoscopic appendectomy: preferred method; shorter hospital stay and faster recovery.
• Open appendectomy: indicated in complicated cases or when laparoscopy is contraindicated.
• In cases of contained abscess, percutaneous drainage followed by interval appendectomy may be considered.

Nonoperative Management

• Selected patients with uncomplicated appendicitis may be managed with antibiotics alone.
• Requires close follow-up; risk of recurrence ~20–30%.

Nursing Considerations

• Monitor vital signs, pain level, and abdominal examination findings.
• Ensure IV access for fluids and antibiotics.
• Prepare patient for surgery (consent, skin preparation).
• Postoperative care: wound assessment, pain control, early ambulation, and advance diet as tolerated.
• Educate patient on signs of complications (fever, increasing pain, wound discharge).

Complications and Prognosis

• Perforation: risk increases after 36–48 hours of symptom onset; leads to peritonitis and abscess.
• Postoperative wound infection, intra-abdominal abscess, and ileus.
• Overall prognosis excellent with timely intervention; mortality <1% in uncomplicated cases.

Patient Education

• Encourage early medical evaluation for abdominal pain.
• Discuss postoperative care: wound hygiene, activity level, diet progression.
• Advise on follow-up appointments and when to seek care for complications.

References

1. Addiss DG, Shaffer N, Fowler BS, Tauxe RV. The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol. 1990;132(5):910–925.
2. Bickell NA, Federman AD, Aufses AH Jr. How time affects the risk of rupture in appendicitis. J Am Coll Surg. 2006;202(3):401–406.
3. Flum DR, Koepsell T. The clinical and economic correlates of misdiagnosed appendicitis: nationwide analysis. Arch Surg. 2002;137(7):799–804.
4. Andersson RE. Meta-analysis of the clinical and laboratory diagnosis of appendicitis. Br J Surg. 2004;91(1):28–37.