Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

Appendix

Appendicitis

Acute appendicitis


Reviewer: Jaleh Mansouri, M.D. (see Reviewers page)
Revised: 19 October 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General
=========================================================================

● Formerly called typhilitis (typhlitis) (inflammation of cecum)
● Associated with obstruction in 50-80% of cases, usually due to a fecalith (Hum Pathol 1981;12:870)
● Also gallstone, tumor, Enterobius vermicularis (pinworm), diffuse lymphoid hyperplasia (children)
● However, not all cases show clear evidence of lumen obstruction

Clinical features
=========================================================================

● Common in US and Great Britain (Western world); rare in Asia and Africa
● Usually teenagers or young adults who present with periumbilical to right lower quadrant pain, nausea, vomiting, abdominal tenderness, mild fever, leukocytosis (15-20,000), elevated C reactive protein, elevated sedimentation rate
● May have right flank pain or pelvic pain with retrocecal appendix
● Pain in left upper quadrant if malrotated colon
● Nonclassic presentations occur in very young or very old
● Associated with reduced bulk / high protein diet
● Patients with clinical symptoms but histologically normal appendices often have neuronal hypertrophy (Arch Pathol Lab Med 2003;127:573), and increased levels of inflammatory mediators (Arch Pathol Lab Med 2001;125:759)
● Normal false positive rate for appendectomy is 20% (high false positive rate in women of reproductive age, J Gastroenterol 2006;41:745)
● Diagnosis: acute inflammation (neutrophils) within appendix
● Treatment: excision (appendectomy)

Pathophysiology
=========================================================================

● Obstruction causes increased intraluminal pressure, collapse of draining veins, ischemia, mucosal injury and ulceration, bacterial overgrowth, more edema, more ischemia
● Not associated with Helicobacter pylori infection (Arch Pathol Lab Med 2000;124:941)

Case reports
=========================================================================

● Associated with Kaposiís sarcoma of appendix (Arch Pathol Lab Med 1991;115:1157)

Complications
=========================================================================

● Wall abscess and perforation (2% mortality, higher rate in older populatoin)
● Rupture, peritonitis, pylephlebitis with thrombosis of portal venous drainage
● Also liver abscess, bacteremia, formation of sinus tract (often due to Actinomyces)

Gross description
=========================================================================

● Fibrinopurulent exudate on serosa, prominent vessels
● Lumen may contain blood-tinged pus
● Variable perforation, mucosal ulceration, fecalith or other obstructing agent

Gross images
=========================================================================


       
Exudate and hyperemia


Fecalith

Micro description
=========================================================================

● Mucosal ulceration
● Minimal (if early) to dense neutrophils in muscularis propria with necrosis, congestion, perivascular neutrophilic infiltrate
● Late: absent mucosa, necrotic wall, prominent fibrosis, granulation tissue, marked chronic inflammatory infiltrate in wall, thrombosed vessels

Micro images
=========================================================================


   
Mucosal inflammation and necrosis


Neutrophils within muscularis propria

Vitual slides
=========================================================================



Periappendiceal abscess

   
Acute appendicitis

Differential diagnosis
=========================================================================

● Drainage of exudate (Campylobacter) into appendix with neutrophils in mucosa, but not wall
● Mesenteric lymphadenitis due to Yersinia or viral enterocolitis
● Systemic viral infection, acute salpingitis, ectopic pregnancy, mittelschmerz, cystic fibrosis, Meckelís diverticulitis, acute diverticulitis, infarction of greater omentum, chemotherapy induced typhilitis (typhlitis)
● Appendiceal or colonic neoplasms may sometimes present as appendicitis

End of Appendix > Appendicitis > Acute appendicitis


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).