Pathology of Acute Appendicitis – Its Etiology, Morphology, Gross Appearance & Microscopic view

Aims of the Practical

Pathological Process: Acute Inflammation

Model : Appendix

Specimen Provided : Acute Appendicitis Slide

What is Acute Appendicitis?

Histopathological Definition

Acute Appendicitis is defined as an acute inflammation of the inner lining (glandular epithelium) of the vermiform appendix that spreads to its other layers

Who gets it?

1.Mostly young people (age 10-20) but can present at any age

2.M>F : (1.4:1)

3.A common surgical disease : 7-9% lifetime risk

How does Acute Appendicitis Develop ?

• Obstruction of opening
• Distention
• Perforation

Cyclic Changes Causing Appendicitis

Pictorial Explanation

Etiology

1.Fecalith

2.Gallstone

3.Ball of Intestinal Worms

4.Tumors

“Typical” Presentation

• Dull, crampy central abdominal pain
• Malaise/vomiting/anorexia/low grade fevers
• Pain worsens & localises to RIF with cough/movement tenderness
• Systemic symptoms

Morphology

Normal Vermiform Appendix

Gross Pathology

• Grossly inflamed, swollen & red.
• Prominent vessels visible on the surface
• May be covered by phlegmatic eroded tissue

Acutely Inflamed Appendix

Gangrenous Appendix ( a )

Microscopic Appearance

Normal Appendix Histology

• Similar histologically to the rest of the colon.

Few differences which make the appendix identifiable.

• Shorter glands (and no villi – like the colon)
• Large lymphoid nodules deep to the outer muscular wall
• Absence of the tenia coli

Histology Normal Appendix

Normal Appendix Histology

 

Histology Normal Appendix

Histology of Normal Appendix

Microscopy of Acute Appendicitis

• Infiltration of PMN Cells in mucosa Infiltrating into muscularis
• Splitting of muscularis due to edema
• Edema of all layers
• Ulceration of outer layers
• Vasodilation
• Perivascular infiltration of inflammatory cells
• Intraluminal inflammatory exudates

Identification Points

• Presence of acute inflammatory cells

( Eosinophils and polymorphonuclear   Neutrophils )

• Separation of muscles fibers due to edema
• Loss of mucosal lining due to bacterial overgrowth

Summary

• A common surgical emergency with high mortality if not treated well in time
• Any pain in RIF should be thoroughly investigated
• One of the commonest reason of Acute Abdomen

If you have any question regarding acute appendicitis, write it in the below comment box.