Increased fascial thickness of the deltoid muscle in dermatomyositis and polymyositis: An ultrasound study.

INTRODUCTION

We investigated the use of ultrasound to detect fascial thickening of the deltoid, vastus lateralis (VL), and rectus femoris (RF) muscles in dermatomyositis (DM) and polymyositis (PM).

METHODS

Fascial thickness of 7 DM and 5 PM patients was compared with that of healthy controls (n = 54).

RESULTS

The deltoid fascial thickness was 2-fold greater in the DM/PM group (1.15 mm vs. 0.54 mm; P < 0.001) compared with healthy controls. Eight patients had markedly thickened deltoid fascia (>5 SD). Only 1 patient with a mild clinical presentation had normal deltoid fascial thickness. Four patients also had fascial thickening of the VL and/or RF.

CONCLUSIONS

Deltoid fascial thickness was increased significantly in DM and PM patients, whereas the quadriceps muscle only showed thickened fascia in severely affected patients. This study suggests that a concomitant fasciitis may be present more often than previously believed.