Chronic appendicitis is recurrent or ongoing low-grade inflammation of the appendix. Unlike acute appendicitis, symptoms are mild, vague, and intermittent. Pathologically characterized by fibrosis, mucosal atrophy, and chronic inflammatory infiltrate. CT findings are subtle, presenting as appendiceal wall thickening, mild periappendiceal stranding, and partial luminal obliteration.
Age Range
15-60
Peak Age
30
Gender
Equal
Prevalence
Uncommon
Chronic appendicitis develops following recurrent partial luminal obstructions or prior acute episodes. Each episode leads to mucosal damage and fibrosis during the healing process. Chronic inflammation causes wall thickening, lymphoid follicle proliferation, and transmural fibrosis. Fibrotic changes narrow the lumen, predisposing to partial obstruction and recurrent symptoms. On CT, the appendiceal wall is thickened due to fibrosis, but periappendiceal inflammatory changes are much milder compared to the acute form because chronic remodeling rather than active transmural inflammation is occurring.
On CT, the appendiceal wall is thickened but surrounding inflammatory changes (fat stranding, free fluid) are minimal or absent. This 'disproportion' (wall thickening vs minimal surrounding reaction) is the diagnostic clue for chronic appendicitis and supports the diagnosis when evaluated together with recurrent right lower quadrant pain.
The appendiceal wall is mildly thickened (3-5 mm) but unlike the prominent edematous thickening in acute appendicitis, it is fibrotic and smooth-margined. Wall enhancement is homogeneous and moderate.
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The appendiceal wall is mildly thickened with a fibrotic appearance, which may be consistent with chronic appendicitis.
Minimal or absent periappendiceal fat stranding is a distinguishing feature of chronic appendicitis. Since active inflammation is minimal, surrounding fat tissue appears nearly normal.
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No significant periappendiceal fat stranding is identified, consistent with a chronic process.
The appendiceal lumen may be partially or completely obliterated. Luminal narrowing due to fibrosis is a characteristic finding of chronic appendicitis. Calcified fecalith or mucus accumulation may be seen within the lumen.
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Luminal narrowing/obliteration of the appendix due to fibrosis is identified.
Calcified appendicolith is detected in the appendiceal lumen in 30-50% of chronic appendicitis cases. Appendicolith may be both the cause and result of chronic obstruction. An isolated appendicolith without significant surrounding inflammatory findings suggests a chronic process.
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Calcified appendicolith is noted in the appendiceal lumen, consistent with a chronic obstructive process.
On ultrasound, the appendiceal wall is thickened (>3 mm) but the lumen is not significantly dilated (outer diameter usually 6-9 mm). Wall echogenicity is increased reflecting fibrotic changes. The appendix may be partially compressible with graded compression.
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The appendiceal wall is thickened without significant luminal dilatation; chronic appendicitis should be considered.
On MRI, the fibrotic wall of chronic appendicitis shows low-to-intermediate signal intensity on T2-weighted sequences, unlike the bright edematous wall in acute appendicitis. Periappendiceal T2 hyperintensity (edema) is minimal or absent.
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The appendiceal wall shows low-to-intermediate signal intensity on T2-weighted sequences, consistent with fibrotic change/chronic appendicitis.
Criteria
Recurrent symptoms after spontaneous resolution of acute episodes; transient inflammatory changes seen on CT during each episode
Distinct Features
CT may be completely normal or show only mild wall thickening between acute episodes. Acute appendicitis findings are seen during episodes but resolve spontaneously.
Criteria
Appendiceal lumen completely obliterated, wall shows fibrotic thickening; may be associated with neurogenic appendicopathy
Distinct Features
On CT, the appendix appears completely solid, lumen cannot be discerned. Pathologically, the lumen is completely closed by fibrosis with possible neural hyperplasia.
Distinguishing Feature
Acute appendicitis shows prominent periappendiceal fat stranding, dilated lumen (>10 mm), and marked wall enhancement; chronic form shows mild or absent findings
Distinguishing Feature
Carcinoid tumor shows a focal mass lesion (typically at apex or tip location) with enhancing solid nodule appearance; chronic appendicitis lacks a focal mass
Distinguishing Feature
Appendiceal diverticulitis shows focal outpouching (diverticulum) and localized periappendiceal inflammation; chronic appendicitis lacks diverticulum and inflammation is diffuse
Urgency
routineManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralChronic appendicitis diagnosis is usually made by exclusion and should be considered in recurrent right lower quadrant pain. Treatment is typically elective laparoscopic appendectomy, which completely resolves symptoms in 80-90% of patients. The excised specimen should be pathologically evaluated to exclude malignancy. Conservative approach (surveillance + symptomatic treatment) is an alternative in mild cases.
Treatment of chronic appendicitis is elective appendectomy. Symptoms usually resolve completely after surgery. It should be considered in cases of unexplained recurrent RLQ pain. Pathological examination reveals chronic inflammation, fibrosis, and wall thickening.