A fresh look at the correlation between timing of histological changes in acute cholecystitis and difficulty of cholecystectomy

Abstract

Presenter: Roheena Panni MD, MPHS | Washington University, St. Louis Background: Difficulty of gallbladder surgery in Acute Cholecystitis (AC) increases with time after the onset of symptoms due to evolving inflammation. Clinical/pathological correlation has been confounded by timing findings from the date of admission to hospital rather than date of onset of symptoms and by inclusion of patients who had prior attacks of AC. The purpose of this study was to determine histologic changes for 10 days from onset of symptoms in a first attack of AC and correlate these changes to 3 time periods known to be associated with increasing difficulty of surgery. Methods: We identified patients with calculous AC who underwent cholecystectomy from 2005-2018 at our hospital. Initial review (n=7171) included selection of ICD-9 codes for AC followed by review of pathology to confirm the diagnosis. To confine the study to first attack of AC, patients were excluded if they had prior admissions for AC, biliary colic requiring ER visit or admission or choledocholithiasis. A blinded pathologic review was performed on stored specimens by a GI pathologist to define histological changes in the gallbladder wall. Statistical analysis was performed using SAS to determine the association between pathologic changes and duration of symptoms prior to surgery. Results: We identified 150 patients who were diagnosed with calculous AC and underwent cholecystectomy within ten days of onset of symptoms. 68 patients (45.3%) were males and 82 (54.7%) were females. Patients were divided into three groups; “Early” who underwent cholecystectomy between 1-3 days after onset of symptoms 61 patients (41%), “Intermediate” between 4-6 days, 63 patients (42%), and “Late” who had cholecystectomy between 7-10 days after onset of symptoms 26 patients (17%). Necrosis of the inner gallbladder wall layers (mucosa and muscularis) was found in 58% of Early specimens and rose to 88% in Late specimens (p=0.019). Both hyaline and liquefactive forms of necrosis were present. The latter type was infiltrated with neutrophils. The outer perimuscular layer of the wall (adventitia/subserosa) became necrotic infrequently. Mural hemorrhage in all layers was abundant in 56% of Early specimens which rose to 86% in Late specimens (p = 0.031). Fibrinous exudate was abundantly present on the surface of the peritonealized outer layer (serosa) in 38% of Early specimens and 65% pf Late ones (p = 0.013). The perimuscular layer (adventitia/subserosa) demonstrated edema, cellular infiltrate, predominately with lymphocytes and eosinophils, and early fibrosis in which myofibroblasts were prominent. Conclusion: Multiple inflammatory changes occur rapidly in the Early stage of AC. Large and significant increases from Early to Late periods in necrosis of the mucosa and muscularis, , mural hemorrhage and accumulation of serosal fibrinous exudate parallel increases in surgical difficulty in performing cholecystectomy for acute cholecystitis. Early fibrosis was already present in some specimens on days 1-3.