Beyond Acute Appendicitis: Probably first noted by Fascinating - PowerPoint PPT Presentation

5/23/2014 The Appendix: historical perspectives Beyond Acute Appendicitis: • Probably first noted by Fascinating Lesions of the Vermiform Egyptians around 3000 B.C. Appendix • First sketched by da Vinci around 1500 – Used term “orecchio,” or “ear,” to describe Laura W. Lamps, M.D. • Formally described by University of Arkansas for Medical da Capri (1521) and Sciences Vesalius (1543) da Vinci, 1504-6 Little Rock, AR The Misunderstood Appendix The Appendix: historical perspectives Wikipedia-quoting The Story of Evolution • “ The vermiform appendage-in which • Phillippe Verheyen, a Belgian anatomist/surge some recent medical writers have vainly on, coined the endeavored to find a utility-is the normal intestine of a remote ancestor. ” term “appendix shrunken remainder of a large and vermiformis” in 1710. 1

5/23/2014 The Naked Scientists ’ Forum The Misunderstood Appendix The Misunderstood Appendix- Perspectives • “ What does the appendix do? Lots of from the Internet operations and don ’ t seem to miss it. ” people have them removed in “Its major importance would appear to – “ The appendix is a supplementary be financial support of the surgical don ’ t know why people have them profession.” explanatory section at the end of books. I removed. ” - Alfred Sherwood Romer and Thomas S. Parsons The Vertebrate Body (1986) The First Appendectomy The Misunderstood Appendix “ Instead of regarding the appendix as a vestigial • Performed by Claudius Amyand, surgeon to King George II, December 6, 1735, at organ, useless to man and not worthy of close attention by pathologists, it would perhaps be St. George’s Hospital in London more useful to view the appendix as a miniature – “Not a man of genius, but one of solid worth” of the colon, reflecting the spectrum of pathology • Patient was Hanvil Anderson, age 11 seen in the large bowel together with several interest. ” organ-specific conditions which are of undoubted • Presented with inguinal hernia and fecal fistula tract draining in the groin - Williams and Myers, Pathology of the Appendix 2

5/23/2014 The First Appendectomy Most Famous Appendectomy • No anesthesia • Prince Edward VII, son of Queen – “Tis easy to conceive that this operation Victoria was as painful to the patient as laborious to • Became ill two weeks before coronation me.” in 1902 • Philosophical Transactions of the Royal Society, 1736 • Perforated appendix was found within a • Treves finally convinced him to undergo hernia sac (Amyand’s hernia) the operation, which lasted less than an • Supposedly caused by ingested pin that hour and was successful lodged in the appendix Handling of Appendectomy Handling of Appendectomy Specimens Specimens • General guidelines: • If grossly dilated and neoplasm – Measurements suspected: – External examination • Hyperemia, exudate, perforation, mucin – Take margin – Transverse sections of margin, midportion – Bisect longitudinally – Longitudinal section of tip (2 cm) – Representative sections – Section remainder and examine • Invasion, perforation, extra-appendiceal • Lesions, masses, fecaliths, foreign bodies mucin 3

5/23/2014 Acute “ nonspecific ” appendicitis Inflammatory Processes in the Appendix • Acute “ nonspecific ” appendicitis – Granulomatous appendicitis • Most common intra-abdominal surgical – ?Chronic appendicitis emergency • Infections of the appendix • Peak incidence 2nd-3rd decades – Viral – Bacterial • Perforation more common in children – Parasitic and very elderly • Miscellaneous lesions • Tumors associated with appendicitis in – Malakoplakia – Appendiceal diverticula older adults – Tumors frequently associated with appendicitis Earliest changes: serosal dullness, injection of vessels Increased serosal dullness and early hyperemia/exudate 4

5/23/2014 ……..and purulent exudate. Over time, increasing hyperemia develops….. Edema and extension of the neutrophilic infiltrate across the muscularis mucosa into the submucosa 5

5/23/2014 Gangrenous appendix with green-gray mural discoloration Eventual progression to transmural neutrophilic inflammation and necrosis 6

5/23/2014 “ minimal diagnostic criteria ” Acute Appendicitis – Remain controversial – Two camps: • Those who require neutrophils in submucosa/muscularis propria • Those who accept mucosal ulceration/acute inflammation as enough Is the latter enough to explain the patient ’ s symptoms? for diagnosis “ minimal diagnostic criteria ” The Centrist Resolution Acute Appendicitis • Patients with symptoms and signs of AA may – Williams and Myers study show only mucosal/submucosal acute inflammation • More than 1000 appendectomies • However, enteric infections and trauma from • Detailed correlation of clinical, surgical, • Therefore, “ acute suppurative appendicitis ” fecaliths may produce similar histologic and pathological information changes • Found that mucosal neutrophilic infiltrates (usually with cryptitis or reserved for specimens with mural ulceration) represented the early stage neutrophilic infiltrate of acute suppurative appendicitis, and that more sections usually led to finding • Acute mucosal/submucosal appendicitis for neutrophils in wall those cases, with a comment 7

5/23/2014 Acute Appendicitis-pathogenesis • Rarely foreign bodies • Obstruction • Infection • Vascular compromise • No single theory can explain all cases Campylobacter infection involving appendix 8

5/23/2014 “ Chronic Appendicitis ” The Negative Appendectomy • There are chronic appendiceal infections (e.g. • A certain percentage will be histologically tuberculosis) normal, regardless of patient symptoms • Some patients have recurrent AA before • Submit the entire specimen resection • Molecular and retrospective histologic studies • Appendix with scarring, plasmacytic infiltrate- inconclusive probably resolving or ongoing AA • Symptoms usually still resolve after resection • Primary chronic appendicitis should not be used • Luminal fibrosis with mild chronic inflammation is not chronic appendicitis Selected Infectious Agents Affecting the Appendix Adenovirus in the Appendix Parasites Bacteria Viruses • Associated with ileal and cecal Pinworms Yersinia Adenovirus intussusception Amoeba Campylobacter EBV • Most often in children Schistosomes Actinomyces CMV • Patients usually do not have signs and Strongyloides Tb/MOTT Measles symptoms of acute appendicitis stercoralis Other helminths Salmonella Shigella 9

5/23/2014 Marked lymphoid hyperplasia in Adenovirus infection Warthin-Finkeldy giant cells in the appendix Adenovirus immunostain highlights intra-epithelial inclusions 10

5/23/2014 Yersinia Appendicitis Granulomatous Appendicitis • Fastidious, Gram negative bacilli cause wide • Infection range of GI diseases – Yersinia • Present in many food sources – Actinomycosis • Invasive Yersinia ( enterocolitica and – Tb/MOTT pseudotuberculosis ) responsible for about – Parasites 25% of granulomatous appendicitis cases • Interval appendectomy • Crohn ’ s disease less than 10% of the time • Usually self limited • Sarcoidosis Yersinia - Diagnosis • DDx: Crohn ’ s, other infectious causes • Not usually detectable with Gram stain or immunostains • Diagnosis: – Culture (fastidious organism) – Serologies (false negatives) – PCR – High index of suspicion Nodular mucosa overlying thickened wall 11

5/23/2014 Lymphoid hyperplasia and epithelioid granulomas Linear array of lymphoid aggregates mimics Crohn ’ s Disease 12

5/23/2014 Actinomycosis: Actinomyces israelii • Normal commensal • Any level of GI tract • Usually solitary mass, invading adjacent structures – Sometimes associated with diverticulosis • Symptoms: – Acute appendicitis – Fever, abdominal pain – +/- palpable mass Granulomas with central microabscesses in Y. pseudotuberculosis 13

5/23/2014 • Gram, GMS, Steiner positive • DDx: – Nocardia (partially acid fast) – Other bacteria that form clusters or chains, but are not truly filamentous, e.g. Pseudomonas, E. coli Splendore-Hoeppli Phenomenon 14

5/23/2014 Enterobius vermicularis - Pinworms Pinworms The appendicitis controversy • One of the most common human parasites • Present in 0.6-13% of appendectomies – Most common appendiceal parasite • Ability to actually cause mucosal damage and • Prevalent in developed countries inflammation is hotly debated • Generally infect children and adolescents • Some believe they invade peri- “ “ “ At any socioeconomic level, families with two or “ appendectomy enterobiasis. ” ” ” - Leopairut et al, Pathology of ” • Rarely observed to cause invasion, more children can expect at least one bout of ulceration, inflammation in appendix, colon, female genital tract, and peritoneum Infectious Diseases 15

5/23/2014 • Can often appreciate intestine, uterus • Eggs are ovoid with one flat side, two layered refractile shell 16