Obstruction-driven inflammation of the appendix; classic periumbilical-to-RLQ pain with peritoneal signs.
Also known as: appendicitis, acute appendicitis
Overview
Acute inflammation of the vermiform appendix, typically due to luminal obstruction (fecalith, lymphoid hyperplasia, tumor) with secondary bacterial overgrowth, distension, ischemia, and risk of perforation.
Epidemiology
Lifetime risk ~7-8%. Most common surgical abdominal emergency. Peak incidence age 10-30; can occur at any age. Slight male predominance.
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Question 1GastrointestinalEasy
A 28-year-old man has 12 hours of periumbilical pain that has migrated to the right lower quadrant. Temperature is 38.4 C, and he is tender at McBurney point with rebound tenderness. The examiner palpates the patient's left lower quadrant. Which of the following signs, if present, would further support acute appendicitis?
ARovsing sign
BMurphy sign
CCullen sign
DCarnett sign
Reveal answer & full explanation
Correct answer: A — Rovsing sign
ARovsing sign✓
BMurphy sign
CCullen sign
DCarnett sign
Why Rovsing sign is correct
This case presents with classic acute appendicitis: migratory periumbilical-to-right-lower-quadrant (RLQ) pain, fever, McBurney point tenderness, and rebound tenderness
Rovsing sign is RLQ pain produced when the examiner palpates the left lower quadrant, reflecting peritoneal irritation transmitted across the peritoneum to the inflamed appendix
The stem specifically cues the left lower quadrant palpation maneuver, so a positive Rovsing sign directly supports the diagnosis
Why the others are wrong
Murphy sign — Murphy sign is inspiratory arrest during palpation of the right upper quadrant and indicates acute cholecystitis, not appendicitis
Cullen sign — Cullen sign is periumbilical bruising from hemoperitoneum, seen in ruptured ectopic pregnancy or hemorrhagic pancreatitis; it is unrelated to the LLQ palpation maneuver described
Carnett sign — Carnett sign is increased tenderness when the abdominal wall is tensed (head lift), which localizes pain to the abdominal wall rather than the viscera and would argue against an intra-abdominal cause such as appendicitis
Additional high-yield points
Other appendicitis-specific signs: the psoas sign (pain on right hip extension, suggesting a retrocecal appendix) and the obturator sign (pain on internal rotation of the flexed right hip, suggesting a pelvic appendix)
Question 2GastrointestinalMedium
A 19-year-old man has 18 hours of periumbilical pain that migrates to the right lower quadrant with anorexia and nausea. Which of the following best explains the usual initiating event in this condition?
AMesenteric arterial embolic occlusion
BAppendiceal lumen obstruction by fecalith
CVenous congestion of the appendiceal wall
DBacterial invasion of the appendiceal wall
Reveal answer & full explanation
Correct answer: B — Appendiceal lumen obstruction by fecalith
AMesenteric arterial embolic occlusion
BAppendiceal lumen obstruction by fecalith✓
CVenous congestion of the appendiceal wall
DBacterial invasion of the appendiceal wall
Why Appendiceal lumen obstruction by fecalith is correct
Acute appendicitis almost always begins with obstruction of the appendiceal lumen by a fecalith or by lymphoid hyperplasia, common in this age group.
The obstruction raises intraluminal pressure, distends the appendix, and triggers vague visceral periumbilical pain.
As inflammation reaches the parietal peritoneum, pain localizes to the right lower quadrant, producing the classic migration described.
Why the others are wrong
Mesenteric arterial embolic occlusion — Wrong-vascular trap: mesenteric ischemia causes pain out of proportion to exam in older patients with emboli, not adolescent migratory RLQ pain.
Bacterial invasion of the appendiceal wall — Sequence trap: bacterial translocation into the wall follows obstruction and luminal stasis, driving suppuration and later perforation rather than starting the process.
Venous congestion of the appendiceal wall — Sequence trap: rising intraluminal pressure first impairs lymphatic and venous outflow, so mural congestion is a downstream consequence of the obstruction, not the initiating event.
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Clinical diagnosis supported by imaging. Histopathology confirms post-operatively.
Labs
CBC — mild to moderate leukocytosis (10-18,000) with left shift; very high WBC suggests perforation
BMP, CRP
Urinalysis — exclude UTI; mild pyuria/hematuria possible from inflamed appendix adjacent to ureter
Pregnancy test in women of childbearing age (CRITICAL before imaging or surgery)
Lactate if septic
Imaging
CT abdomen/pelvis with contrast — modality of choice in adults; sensitivity and specificity >95%; findings: dilated appendix >6 mm, wall thickening, periappendiceal fat stranding, fluid, abscess, fecalith
Ultrasound — first-line in children and pregnant women to avoid radiation; operator-dependent
MRI — alternative in pregnancy if ultrasound non-diagnostic
Alvarado score (MANTRELS) ≥7 supports appendicitis; useful for risk stratification but does not replace imaging
Diagnostic algorithm
flowchart TD
A[Suspected appendicitis<br/>RLQ pain + anorexia + fever] --> B[Labs: CBC, CRP<br/>BHCG in women]
B --> C{Pregnant?}
C -->|No| D[CT abd/pelvis<br/>with contrast]
C -->|Yes| E[Ultrasound first<br/>MRI if equivocal]
D --> F{Appendicitis<br/>confirmed?}
E --> F
F -->|Uncomplicated| G[IV antibiotics +<br/>laparoscopic appendectomy]
F -->|Complicated:<br/>perforation/abscess| H{Abscess<br/>drainable?}
H -->|Yes| I[Percutaneous drain<br/>+ IV antibiotics<br/>+ interval appendectomy]
H -->|No - peritonitis| J[Emergent surgery]
F -->|Equivocal| K[Observation +<br/>serial exams<br/>± repeat imaging]
Acute appendicitis diagnostic and treatment pathway.
Treatment
First-line
NPO, IV fluids, analgesia, antiemetics
IV antibiotics covering Gram-negative and anaerobic flora — piperacillin-tazobactam, ceftriaxone + metronidazole, or ertapenem; administer pre-operatively
Laparoscopic appendectomy — standard of care; lower wound infection rate and faster recovery vs open
Open appendectomy — alternative when laparoscopy contraindicated
Second-line / adjunct
Nonoperative management with antibiotics alone — emerging option for uncomplicated appendicitis without fecalith (CODA trial); failure/recurrence ~40% at 5 yr; appropriate for selected patients who decline or cannot undergo surgery
Percutaneous drainage of abscess + interval appendectomy 6-12 weeks later — for contained perforation with abscess (Hinchey-like approach)
Open laparotomy if diffuse peritonitis, perforation with diffuse contamination, or hemodynamic instability
Appendiceal tumor management depends on histology (carcinoid, mucinous, adenocarcinoma) — may require right hemicolectomy
Complications
Perforation (especially in delayed diagnosis — elderly, pregnant, immunocompromised)
Periappendiceal abscess
Diffuse peritonitis, sepsis
Wound infection, intra-abdominal abscess after surgery
Stump appendicitis (rare)
Adhesive small bowel obstruction (years later)
Pylephlebitis (septic portal vein thrombosis) — rare but life-threatening
PANCE pearls
Anorexia is highly sensitive — appendicitis is unlikely if the patient is hungry.
Vomiting BEFORE pain suggests gastroenteritis; vomiting AFTER pain suggests appendicitis.
Always obtain pregnancy test in women of childbearing age BEFORE imaging.
Ultrasound is first-line in children and pregnant women to avoid radiation.
Pregnancy shifts appendix cephalad and laterally — third-trimester appendicitis can present with RUQ or right flank pain.
Atypical presentations (elderly, immunocompromised) lead to higher perforation rates — maintain low threshold for imaging.
Carcinoid is the most common appendiceal tumor; usually incidental at appendectomy; tumors >2 cm or with mesenteric invasion require right hemicolectomy.
Nonoperative management with antibiotics (CODA trial, NEJM 2020) is a reasonable alternative for uncomplicated appendicitis without fecalith — counsel about ~40% recurrence at 5 yr.
Appendectomy WITHOUT a clinical or imaging diagnosis is no longer standard — image first when possible.
Pylephlebitis: persistent fever and bacteremia after appendicitis — CT shows portal vein thrombosis; treat with prolonged antibiotics ± anticoagulation.
References
WSES 2020 — Di Saverio S et al. Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines. World J Emerg Surg 2020;15:27
CODA Trial — Flum DR et al. A Randomized Trial Comparing Antibiotics with Appendectomy for Appendicitis. NEJM 2020;383:1907-1919
EAST 2017 — Rao A et al. Eastern Association for the Surgery of Trauma Guidelines on the Management of Acute Appendicitis. J Trauma Acute Care Surg 2017
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