Definition

Appendicitis Overview

• Definition: Inflammation of the vermiform appendix, a small pouch attached to the large intestine.
• Cause: Obstruction of the appendix lumen.
• Result: Invasion by gut flora, leading to inflammation and infection.
• Consequences:
  • If untreated, can progress to local ischemia, perforation, and abscess formation.
  • Rupture leads to peritonitis.
• Causes an acute abdomen: often requires emergency abdominal surgery.

Aetiology

Causes of Appendicitis

• Common Causes:
  • Obstruction of the appendix lumen:
    • Fecal matter accumulation.
    • Swollen lymphoid tissue.
    • Foreign body (rare).

Mechanism

• Obstruction Effects:
  • Elevated pressure within the appendix.
  • Reduced blood flow.
  • Bacterial overgrowth.
  • Inflammation and infection.

Risk Factors

Risk Factors for Appendicitis

• Age and Gender:
  • More common in children, young adults (10 – 30 years old).
  • Slightly higher prevalence in males.
• Family History:
  • Genetic predisposition increases risk.
• Underlying Conditions:
  • Conditions like Crohn’s disease.
  • Conditions causing fecal matter accumulation or lymphoid hyperplasia, e.g., cystic fibrosis, inflammatory bowel disease.

Pathophysiology

Appendicitis Pathophysiology

1. Obstruction and Pressure Increase:
   • Obstruction of the appendix lumen.
   • Leads to distension and increased intraluminal pressure.
2. Blood Flow Compromise:
   • Elevated pressure compromises blood flow.
   • Results in ischemia and inflammation.
3. Infection and Inflammation:
   • Persistent obstruction allows gut organisms to invade the appendix wall.
   • Infection and bacterial overgrowth occur.
4. Progression to Tissue Damage:
   • Uncontrolled inflammation leads to tissue necrosis.
5. Potential Rupture:
   • If not treated promptly, tissue damage can result in perforation.
   • Rupture releases infected material into the peritoneal cavity.

Consequences

• Perforation Risk:
  • Untreated appendicitis can lead to perforation.
• Peritonitis Risk:
  • Ruptured appendix can cause peritonitis (inflammation of the peritoneum).
  • Peritonitis is a serious, potentially life-threatening condition.

Differential Diagnosis

Differential Diagnosis of Acute Appendicitis

• Gastrointestinal Causes
  • Obstruction
  • Intussusception
  • Hernia
  • Cholecystitis
  • Peptic Ulcer Perforation
  • Diverticulitis
  • Mesenteric Adenitis
  • Crohn’s Disease
  • Pancreatitis
  • Gastroenteritis
  • Colon carcinoma.

• Urological Causes
  • Testicular Torsion
  • Renal Calculi
  • Urinary Tract Infection

• Gynecological Causes
  • Ectopic Pregnancy
  • Ovarian Torsion or Rupture
  • Ovarian cysts
  • Pelvic Inflammatory Disease

• Other Causes
  • Diabetic Ketoacidosis
  • Pneumonia
  • Immune Modulation Therapy Effects
  • Psoas abscess

Epidemiology

Appendicitis Incidence and Epidemiology

• Common Surgical Emergency
  • Peak Incidence: 10 – 30 years old
  • Affects Both Genders
  • Slightly Higher Risk in Males

Appendicitis Incidence and Statistics

• Incidence in the UK: 70 to 80 cases per 100,000 population per year
• Common Cause of Acute Abdomen
• Approximately 10% of Population Develop Acute Appendicitis
• Most Common in Adolescents and Young Adults
• More Common in Males
• Normal Appendix Removed in 10-20% of Appendectomies

Clinical Presentation (Signs and Symptoms)

Clinical Presentation of Appendicitis:

• Abdominal Pain: Gradual onset around the umbilicus, migrating to the right lower quadrant, worsened by movement.
• Other Symptoms: Loss of appetite, nausea, vomiting, low-grade fever, tenderness in the right lower abdomen.

Diagnosis:

• Incidence: Around 223 cases per 100,000 people.
• Common Symptoms: Right anterior iliac fossa abdominal pain, anorexia, nausea/vomiting.
• Atypical Presentations: Indigestion, flatulence, bowel irregularity, diarrhea, generalized malaise.
• Physical Signs: Tenderness at McBurney’s point, Rovsing’s sign, Psoas sign, Obturator sign.
• Alvarado Score: Score of 0-3 makes appendicitis less likely.

Epidemiology and Age:

• Most common in 2nd and 3rd decades of life, peak in ages 10-20.

Additional Presentation Details:

• Abdominal pain shifts from umbilicus to right iliac fossa, worsened by movement.
• Other features: mild pyrexia, vomiting (usually not marked), anorexia.
• Examination: localized tenderness, guarding, rebound tenderness, and classical signs like Rovsing’s sign.

Scoring Systems for Diagnosis:

• Alvarado score, AIR score, and others help determine further investigation and treatment.
• A score of 0-4 on Alvarado score makes appendicitis less likely, while 9-12 suggests surgical exploration.

Appendicitis may have atypical presentations in different age groups, but scoring systems aid in accurate diagnosis and decision-making.

Investigations

Investigations for Appendicitis

• Diagnosis involves medical history, physical examination, and imaging studies.
• Blood tests:
  • Complete blood count (CBC).
  • Inflammatory markers (e.g., C-reactive protein).
• Imaging studies:
  • Ultrasound (US) and computed tomography (CT) scans.
  • CT is preferred in adults due to high diagnostic accuracy.
  • US and magnetic resonance imaging (MRI) used in children or pregnant women.
  • Plain x-ray usually not helpful.

Diagnosis

• Clinical diagnosis based on:
  • Raised inflammatory markers.
  • Compatible history and examination findings.
  • Neutrophil-predominant leucocytosis in 80-90%.
• Urine analysis:
  • Used to exclude pregnancy in women.
  • May show mild leucocytosis but no nitrites.
• Imaging usage determined by:
  • Patient’s gender, age, body habitus.
  • Likelihood of appendicitis.
• Thin, male patients with high likelihood may be diagnosed clinically.
• Ultrasound useful in females with suspected pelvic pathology.
  • Presence of free fluid raises suspicion.
• CT scans widely used in the US but not UK due to radiation concerns.

Additional Details on Investigations

• Appendicitis as a clinical diagnosis can be unreliable, especially in atypical presentations (e.g., pregnant women, older adults, infants).
• Investigations requested to exclude other differential diagnoses.
• Useful in intermediate-risk patients with moderate suspicion.
• Additional tests:
  • Urinalysis to exclude urinary tract infection.
  • Pregnancy test to exclude ectopic pregnancy in women.
  • FBC: Mild leukocytosis usually present, but normal count does not rule out appendicitis.
  • Raised CRP: Not always elevated in appendicitis.
• Imaging:
  • Ultrasound preferred in children, young people, and pregnant patients.
    • Better for diagnosing gynecological causes of right iliac fossa pain.
  • CT scanning more sensitive and specific than ultrasound.
    • Controversial due to radiation exposure, especially in children and young adults.
  • Low-dose CT imaging may offer equivalent diagnostic information with lower radiation.
  • MRI reserved for pregnant women after non-diagnostic ultrasound.
• Diagnostic laparoscopy may be considered for diagnosis.

Management

Appendicitis Treatment and Management

• Standard Treatment: Appendectomy (surgical removal of the appendix)
  • Approaches: Open or Laparoscopic
  • Choice: Laparoscopic appendectomy preferred
• Prevention: Prophylactic IV antibiotics to reduce wound infection rates
• Perforated Appendicitis:
  • Stable Perforation: IV antibiotics and drainage or delayed appendectomy
  • Unstable Perforation: Immediate appendectomy and IV antibiotics
• Medical Treatment with Antibiotics:
  • Controversial: Considered as an alternative to surgery
  • Research: Studies show mixed results
  • Drawback: Higher recurrence rate (up to 39% at five years)
• COVID-19 Pandemic: Antibiotic-first approach used due to concerns over surgery during the pandemic
• Observation: Diagnostic doubt can warrant a period of active observation
• Fluids and Analgesia: Intravenous fluids and proper analgesia required
• Antibiotics: Pre-operative antibiotics reduce surgical site infections
• Laparoscopic Appendicectomy:
  • Advantages: Reduced hospital stay, faster recovery
  • Applicable: Uncomplicated and complicated appendicitis

Appendicitis Management Considerations

• Age Group: Peak incidence in individuals aged 10 – 30 years
• Emergency Cases:
  • Admit suspected cases to hospital
  • Surgical intervention (appendectomy) is the primary treatment
  • Supportive care without antibiotics or surgery can be considered in some cases
  • Medical treatment with antibiotics under ongoing research
• COVID-19 Impact: Antibiotic-first approach used during pandemic due to surgery concerns
• Observation: Consider active observation in cases of diagnostic uncertainty
• Fluids and Pain Relief: Intravenous fluids and proper pain relief are essential
• Antibiotics: Pre-operative antibiotics reduce post-surgical infections
• Laparoscopic Appendicectomy: Preferred over open approach for quicker recovery

Prognosis

Prognosis and Complications of Appendicitis

• Prompt Treatment: Generally excellent prognosis
• Complications of Untreated Appendicitis:
  • Appendix Rupture
  • Peritonitis
  • Abscess Formation

Prognosis Considerations

• Appendicectomy Safety:
  • Mortality Rate for Non-Perforated Appendicitis: 0.8 per 1,000
  • Mortality After Perforation: 5.1 per 1,000
• Age Impact: Mortality >20% in patients >70 years
  • Subtle Symptoms, Rapid Progression
  • Delayed Diagnosis and Treatment
  • Comorbidities and Differential Diagnoses contribute

Complications

Complications of Appendicitis and Acute Appendicitis

• Complications of Appendicitis:
  • Appendix Rupture
  • Infection Spread (Peritonitis)
  • Appendix mass
  • Abscess Formation
  • Paralytic ileus
  • Rare Cases: Intestinal Obstruction, Sepsis

References

https://www.uptodate.com/contents/management-of-acute-appendicitis-in-adults?search=appendicitis%20adult&topicRef=1386&source=see_link#H4048700510