Appendicitis in the Transplant Patient: A Common Problem in a Less Common Patient Population

Authors:
Michael Megaly, Todd Costantini, Qi Wang

Body of Abstract:
Background:
Acute appendicitis is an uncommon surgical emergency among solid organ transplant (SOT) recipients and may present atypically due to immunosuppression. Comparative data with non-transplant patients remain limited. We hypothesized that SOT recipients would demonstrate blunted inflammatory responses and atypical clinical presentations.

Methods:
We performed a retrospective review of adult SOT recipients diagnosed with appendicitis within a multi-center integrated health system from January 2011 to July 2025. SOT patients were compared with a contemporaneous cohort of non-transplant patients with appendicitis. Demographics, presenting vital signs, laboratory values, perforation rates, operative versus non-operative management, and antibiotic use were assessed.

Results:
Among 4,049 SOT recipients, 58 (1.4%) developed appendicitis. Median time from transplant to diagnosis was 889 days (IQR 116–3,399). SOT recipients were older (51.9 ± 16.6 vs 41.8 ± 18.2 years, p < 0.001) and had higher rates of hypertension (74% vs 20%) and diabetes (36% vs 8%) (p < 0.001 for both). Fever (>100.4 °F) occurred in 9.4% of SOT recipients versus 17.2% of non-transplant patients (p = 0.18), and leukocytosis (>11 × 10⁹/L) in 44.8% of SOT patients vs 68.6% non-transplant patients (p < 0.01). Non-operative management was more common in SOT recipients (14% vs 3%, p = 0.0028). Perforated appendicitis occurred more frequently (17% vs 8%, p = 0.04) in SOT patients. SOT patients had longer courses of antibiotics for all appendicitis management. Median length of stay was longer (2.9 vs 1.0 days, p = 0.02) in SOT recipients while no 30-day mortality occurred in either group. Conclusions: Appendicitis in SOT recipients is rare and frequently presents with attenuated inflammatory signs and increased risk of perforation.This underscores the need for a high index of suspicion for acute appendicitis in SOT recipients even in the absence of traditional diagnostic findings.