The role of ultrasound in the management of peritonsillar abscess.

A distinction between a peritonsillar abscess and peritonsillitis is useful clinically, as the former requires surgical drainage while the latter merely requires treatment with antibiotics. To evaluate the diagnostic implications of performing ultrasonography of the tonsils in patients with clinically diagnosed peritonsillar abscess, 27 patients underwent ultrasound examination before needle aspiration of the abscess was performed. Ultrasound was able to detect peritonsillar abscess in 91 per cent of the cases (sensitivity rate), with a false negative rate of nine per cent and a false positive rate of 20 per cent. The specificity of the test was 80 per cent, and was able to differentiate abscess from peritonsillitis in 88.9 per cent. On the basis of these results we conclude that ultrasonography of the tonsils in patients thought to have peritonsillar abscess is a useful adjunct, enhancing diagnostic accuracy and reducing unnecessary surgical drainage.