Role of Ultrasonography in the Diagnosis of Chronic Appendicitis: An Observational Study of 400 Cases.

BACKGROUND: Chronic appendicitis is an uncommon clinical entity. Unlike acute appendicitis, the presence of nonspecific clinical features makes it a challenging diagnosis. Imaging modalities such as ultrasonography and computed tomography (CT) scans aid in the diagnosis of chronic appendicitis. CT scan has been widely described as the investigation of choice in previous studies. However, ultrasonography of the abdomen is a readily available and cheap alternative which provides comparable results and protects from radiation hazards. The aim of this study was to identify the core imaging features of chronic appendicitis on ultrasonography, their correlation with histopathology findings and to establish the most sensitive parameters for radiological diagnosis of chronic appendicitis.

METHODS: This was an observational research study which employed a descriptive study design. All patients suffering from chronic/recurrent abdominal pain in the epigastric, periumbilical region or right lower quadrant were included in the study. The patients were subjected to history taking and clinical examination. Ultrasonography was performed by graded compression technique with high-frequency linear transducer. The specimens of the patients undergoing open or laparoscopic appendectomy were sent for histopathology. The preoperative ultrasonography diagnosis was confirmed on histopathology examination.

RESULTS: Based on the statistical analysis of various major and minor criteria that were described in this study, the presence of localized pain in the right iliac fossa coupled with the ultrasonography features of irregularity of appendiceal lumen (sensitivity = 84.2%) and loss of wall stratification (sensitivity = 96.5%), showed a combined sensitivity of more than 99%, which were determined to be the most sensitive parameters for clinicoradiological diagnosis of chronic appendicitis.

CONCLUSION: Chronic appendicitis has often been misdiagnosed due to atypical symptoms at the time of presentation. Radiological investigations are used in the evaluation of patients with a high degree of clinical suspicion. This article has demonstrated the superiority of ultrasonography over CT scan for imaging of chronic appendicitis due to its advantages such as similar efficacy rates, higher spatial resolution in identifying features of chronic appendicitis, lack of ionizing radiation, cost-effectiveness, and easy availability. However, a definitive diagnosis is achieved by demonstrating evidence of chronic inflammation in the appendectomy specimen at histopathology.