Comparison of ultrasound, radiography, and clinical examination in the diagnosis of acute maxillary sinusitis

Abstract

The objective of this study was to assess the discriminative properties of the methods for diagnosing acute maxillary sinusitis (AMS) in unselected patients. The study design was a systematic review of evaluation studies identified by using Medline, by searching reference lists, by hand searches, and by contacting investigators. Evaluation studies were conducted anywhere in the world. Subjects were adults with suspected AMS. Main outcome measures were: sensitivity, specificity, positive and negative likelihood ratios of the primary studies, weighted means of these parameters in each comparison (clinical examination, radiography, and ultrasound compared to a reference standard in diagnosing AMS), and summary ROC curves and their Q* points where sensitivity equals specificity. For the years from 1962 to present, 49 study reports were found; 11 articles on studies that included a total of 1144 patients were eligible. Compared to sinus puncture, radiography was the most accurate method for diagnosing AMS: the Q* point on the summary ROC curve was 0.82 (95% confidence interval, CI, 0.78–0.85). Ultrasound was slightly less accurate than radiography compared to sinus puncture (Q* 0.80, 95% CI 0.76–0.83). Only two articles reported clinical examination compared to sinus puncture and the Q* for them was 0.75 (95% 0.58–0.86). Clinical examination is a rather unreliable method for diagnosing AMS, even in the hands of experienced specialists. Using radiography or ultrasound improves the accuracy of diagnosis. The diagnosis of AMS is rarely studied in primary care settings. Future comparative trials should preferably combine diagnosis and treatment, evaluating the two aspects of clinical management as unit.

Introduction

Acute maxillary sinusitis (AMS) is one of the most frequent diagnoses in primary health care. Nasal complaints, allergy, and rhinitis are common, and distinguishing between rhinitis and sinusitis is not always simple. Most often the diagnosis of AMS is based on symptoms and clinical examination alone. In Northern Europe and in the Netherlands the sinus ultrasound performed by clinicians has gained wide acceptance in the diagnosis of AMS and in part displaced sinus radiographs. In the United States computed tomography has also been used in the diagnosis of AMS, while in Europe it is used only in secondary care.

The diagnostic criteria for AMS are not well established. Most often it is defined as inflammation of the paranasal sinus mucosa with retention in the sinuses [1]. Sinus puncture is considered as the gold standard in the diagnosis of sinusitis. However, it is invasive and not easily accepted by the patients. Radiography and computed tomography (CT) have also been used as reference standards. The problem with both of them is that they may produce a number of false-positive results (mucosal thickening or polyps, cysts, or anomalies). To our knowledge, there are no studies in which CT had been compared to sinus puncture. However, there is evidence that patients with the common cold and even nonsymptomatic patients may have pathological findings in the CT of sinuses 1, 2, 3.

The difficulties in indicating the retention in maxillary sinuses have led to the overdiagnosing of AMS and to overtreatment with antibiotics. In most countries the current practice is to treat suspected AMS with antibiotics [4]. In Finland, more than 90% of patients with symptoms of suspected sinusitis receive a course of antibiotics at their first visit to a general practitioner when the diagnosis is based on clinical examination only [5].

The aim of our study was to evaluate through a systematic review of the research literature the efficacy of clinical examination, ultrasound, and radiography as diagnostic measures for AMS in unselected populations. A second aim was to put some proposed meta-analytical approaches to test.