Acute Appendicitis
Definition
- Acute appendicitis: Inflammation of the vermiform appendix, usually due to luminal obstruction leading to bacterial overgrowth and ischemia.
- Most common cause of acute abdomen requiring emergency surgery.
Epidemiology
- Incidence: ~7–10 % of all surgical admissions worldwide.
- Peak age: 10–30 years; second peak in 50–60 years.
- Male predominance (M:F ≈ 1.5:1).
- In India: ~1.5 % of all emergency surgical cases; higher in urban tertiary centres.
- Mortality: < 1 % with timely surgery; rises to 10–20 % with perforation or delayed treatment.
Aetiology
- Luminal obstruction (most common): fecalith (≈ 60 %), lymphoid hyperplasia (≈ 20 %), foreign body, tumour, or anatomical variants.
- Infection: viral (adenovirus, rotavirus) → lymphoid hyperplasia.
- Trauma: blunt abdominal injury.
- Congenital: duplicated appendix, appendiceal diverticula.
- Other: Crohn’s disease, tuberculosis, parasites.
Pathophysiology
- Obstruction → ↑ intraluminal pressure.
- Ischemia of mucosa → bacterial translocation.
- Inflammatory cascade: neutrophil infiltration, cytokine release (IL‑1, TNF‑α).
- Perforation if pressure > 50 mm Hg persists > 24 h.
- Systemic response: fever, leukocytosis, SIRS.
Clinical Features
- Pain: starts periumbilical, migrates to RLQ (McBurney’s point).
- Associated symptoms: anorexia, nausea/vomiting, low‑grade fever.
- Physical signs: RLQ tenderness, rebound, guarding, Rovsing’s sign, Psoas sign, Obturator sign.
- Laboratory: leukocytosis (↑ WBC, neutrophilia), ↑ CRP, ESR.
- Imaging clues: enlarged appendix (> 6 mm), peri‑appendiceal fat stranding, appendicolith, free fluid.
- Special populations: atypical presentation in pregnancy, elderly (fever may be absent), children (pain may be diffuse).
Investigations
| Modality | Utility | Typical Findings |
|---|---|---|
| CBC, CRP, ESR | Inflammatory markers | ↑ WBC, ↑ CRP |
| Urinalysis | Rule out UTI | Normal |
| Ultrasound (US) | First‑line in children, pregnancy | Appendiceal diameter > 6 mm, non‑compressible, peri‑appendiceal fluid |
| CT‑abdomen/pelvis (contrast) | Gold standard in adults | Appendiceal diameter > 6 mm, wall thickening, peri‑appendiceal fat stranding, abscess |
| MRI | Pregnancy, children | Same as CT without radiation |
| Laparoscopy | Diagnostic/therapeutic | Direct visualization, perforation, abscess |
Management
Current Guideline (2023)
American College of Surgeons (ACS) & SAGES 2023:
- Early laparoscopic appendectomy (within 24 h of diagnosis).
- Antibiotic prophylaxis: single dose of cefazolin 1 g IV + metronidazole 500 mg IV.
- Post‑op antibiotics: 24 h for uncomplicated; 48–72 h for perforated/peritonitis.
- Enhanced Recovery After Surgery (ERAS) protocols: early feeding, multimodal analgesia, early mobilization.
Indian Association of Surgeons (IAS) 2022:
- Same early laparoscopic approach.
- Emphasis on “watchful waiting” only for selected cases with low Alvarado score (< 5) and normal imaging.
- Non‑operative management (antibiotics alone) reserved for uncomplicated cases in low‑resource settings.
Surgical Technique
- Laparoscopic appendectomy: 3‑port technique, mobilize mesoappendix, divide base with endoloop or stapler, remove specimen in bag.
- Open appendectomy: McBurney’s incision if laparoscopy unavailable or contraindicated.
Post‑operative Care
- Pain control: multimodal (acetaminophen, NSAIDs, opioid sparingly).
- Early ambulation (within 6 h).
- Oral fluids 4–6 h post‑op; advance diet as tolerated.
- Discharge: 24–48 h for uncomplicated, 48–72 h for complicated.
Complications
- Perforation: 10–20 % if untreated > 48 h.
- Abscess/Phlegmon: 5–10 %.
- Sepsis: 1–2 %.
- Post‑op wound infection: 2–5 %.
- Intestinal obstruction: adhesive, 1–2 %.
- Recurrence: rare (< 1 %) if appendectomy incomplete.
High‑Yield Exam Points
- Alvarado Score: ≥ 7 → high probability; < 5 → low probability.
- Appendicolith on imaging → higher risk of perforation.
- Psoas sign: indicates retrocecal appendix.
- Obturator sign: indicates pelvic appendix.
- Non‑operative management: only for uncomplicated, low‑risk patients; not recommended in India per IAS 2022.
- Early laparoscopic appendectomy reduces hospital stay, wound infection, and postoperative ileus.
- ERAS improves recovery; key components: early feeding, multimodal analgesia, early mobilization.
- Perforated appendicitis: requires broad‑spectrum antibiotics (piperacillin‑tazobactam + metronidazole) and possible drainage.
- Pregnancy: right‑sided pain, use US first, consider MRI if US inconclusive.
Practice Questions
A 28‑year‑old woman presents with 12 h of periumbilical pain that has migrated to the right lower quadrant. Her Alvarado score is 8. Which of the following is the most appropriate next step?
- A) Start oral antibiotics and observe for 24 h
- B) Perform an abdominal ultrasound
- C) Proceed to laparoscopic appendectomy
- D) Order a CT scan with contrast
Answer: C – An Alvarado score ≥ 7 warrants immediate surgical intervention; early laparoscopy is recommended.
Which of the following is the least likely cause of luminal obstruction in acute appendicitis?
- A) Fecalith
- B) Lymphoid hyperplasia
- C) Appendiceal diverticulum
- D) Appendiceal carcinoma
Answer: C – Appendiceal diverticulum is a congenital anomaly, not a common obstructive cause.
In a patient with perforated appendicitis, the recommended duration of postoperative antibiotics is:
- A) 24 h
- B) 48–72 h
- C) 5–7 days
- D) 10–14 days
Answer: B – For perforated or peritonitis, 48–72 h of broad‑spectrum antibiotics is guideline‑recommended.
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