Subphrenic Abscess and Empyema Due to Migrating Appendicolith

Document Type

Article

Abstract

INTRODUCTION: Acute appendicitis is one of the most common acute abdominal conditions where first line surgical approach is via. laparoscopic appendectomy with lower rates of surgical site infections, shorter length of stay and better cosmetic appearance. A rare complication post-appendectomy is the formation of abdominal/retroperitoneal abscesses at unusual locations. We present an unusual case of a migrating appendicolith leading to a subphrenic abscess accompanied by an empyema several months later in an immunosuppressed patient.

CASE PRESENTATION: A 57-year-old male presented to an outside hospital with fever of 102.2F and shortness of breath. His past medical history was significant for rheumatoid arthritis on methotrexate and surgical history of appendectomy for acute gangrenous appendicitis 7 months prior to presentation. An outpatient chest x-ray and CT showed a loculated right pleural effusion. Following admission, he was administered broad spectrum antibiotics with vancomycin and cefepime due to concern for sepsis related to right sided pneumonia and complicated parapneumonic effusion. A chest tube was placed which revealed culture negative exudative effusion. He received tPA/dornase instillation with significant improvement in his effusion on repeat CT chest with now visible subdiaphragmatic abscess. He was transferred to our hospital for further evaluation. On physical examination, the patient's temperature was 97.6 °F, his blood pressure 126/70 mmHg, heart rate 67 beats/minute, and respiratory rate 18 breaths/minute. His abdomen was flat and soft, with no tenderness and normal bowel sounds. Laboratory values were significant for leukocytosis 12.8, hemoglobin 10.7, mildly elevated AST 52, ALT 115, Cr 0.7, negative MRSA and negative blood cultures. Chest CT with intravenous contrast showed a large partially loculated right pleural effusion with severe lower lobe atelectasis and 4.5 x 3.8 cm fluid collection inferior to the right hemidiaphragm. A clinical diagnosis of right subdiaphragmatic abscess due to post-appendectomy migration of appendicolith or fecalith complicated by right sided effusion was made. Antibiotics were broadened to include metronidazole. He underwent abscess tube placement at the peri-diaphragmatic collection. Purulent material and several small dark fragments were aspirated that could represent presumed appendicolith. A follow up CT scan showed interval improvement in fluid collection up to 2.9 cm followed by removal of drainage catheter. Post-procedure cultures were negative. He was discharged on a six-week course of antibiotics.

DISCUSSION: An appendicolith or fecalith is a calcified fecal mass present in 15-20% cases of acute appendicitis. An incarcerated appendicolith can act as a nidus of infection due to the surrounding bacteria and contribute to abscess formation particularly among immunosuppressed hosts. Infrequently, pre-procedure and intraprocedural expulsion of the fecalith may form a nidus of infection with subsequent intra-abdominal abscess formation typically in the pelvis or Morrison's pouch. Occasionally, unusual sites like retroperitoneum, perihepatic, psoas and gluteal regions have been described.

CONCLUSIONS: Identification and retrieval of the infective nidus is important to decrease morbidity and risk of recurrent abscesses which can be achieved with CT guided percutaneous drainage. We recommend that a migrating fecalith should be considered in a patient with empyema and subphrenic abscess following a laparoscopic appendectomy.

First Page

A1331

Last Page

A1332

DOI

10.1016/j.chest.2023.07.934

Publication Date

10-1-2023

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