Ultrasonography of Non-Traumatic Rupture of the Achilles Tendon Secondary to Levofloxacin

INTRODUCTION

Secondary effects of fluoroquinolones are less than 1%, and consist of arthromyalgias, arthritis and tendinosis. The last especially affects the AT, and several cases of rupture have been described in the literature. ^13,12

In this case report we describe a case of bilateral tendinosis and rupture of the AT associated with levofloxacin with analysis of this entity from an ultrasonographic point of view.

Case Report

A 41-year-old male, previously diagnosed with psoriasis and Crohn's disease was under treatment with 5-ASA and prednisone.

He began levofloxacin treatment (500 mg/day) for acquired pneumonia. Two weeks later he developed pain in the right foot. Pain progressed and extended to the left foot and gait impairment started. Treatment with levofloxacin was subsequently discontinued after four weeks. Three weeks later the patient noted a pop in the right AT region while he was walking. Attempts at limping were thwarted by severe pain. With the patient in the prone position and hanging the feet over the end of the examination table, inspection showed less natural plantar flexion on the right side, and a gap was felt in the right Achilles tendon. Thompson test was positive. This test consist of squeezing the calf muscles transversely: a normal or partial rupture will produce plantar flexion, but in our case (complete rupture) the motion was absent in the right side. With this strong clinical suspicion of tendon rupture ultrasonography was performed with a Toshiba Eccocee.

A 7.5 MHz electronic lineal probe was used, and showed typical findings of tendinosis (thickening and hypoecogenicity) in the left AT (Figs. 1a, 1b) and right Achilles tendon rupture (complete rupture at the middle third with wide separation of both fragments) (Fig. 2).

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Fig. 1:

Longitudinal (a) and transversal (b) ecographic sections of the left AT show fusiform thickening and hypoecogenicity of the posterior half of the tendon (between marks).

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Fig. 2:

Longitudinal section of the right AT (composed image). The proximal fragment is on the left, the gap (23 mm, between marks) in the middle, and the distal fragment on the right. Thickening of hypoecogenicity and tendon rupture are shown. A small accumulation of fluid around the proximal segment is shown (arrow).

Mainly because the patient initially refused surgical repair and also because of an active episode of inflammatory bowel disease, surgery was delayed for 2.5 months. At that time, separation between tendon stumps was 7 cm. Surgical repair was performed following Lund's procedure. ^7,10 This consist of augmentation of the suture with two turned down fascial strips from the gastrocnemius. In this particular case the plantaris tendon was also used to reinforce the reconstruction.

At the time of surgery, both Achilles tendon fragments showed a distal area of necrosis which gave an aspect of irregular discontinuity. This area was surrounded by a proximal zone of greyish appearance and poorly defined tissue (tendinosis).

DISCUSSION

Pathogenesis of tendinosis secondary to fluoroquinolones (such as olprofloxacin, pefloxacin, ofloxacin (the risk is highest with ofloxacin), ¹⁴ norfloxacin, temafloxacin, etc.) ¹¹ , ¹ is unknown, but several hypotheses have been proposed: immunoallergic mechanism (mediated by cytokines), toxic effect (directly to the tendon), ischemic mechanism (infarction of the less vascularized area), mechanical stress (this would explain why AT rupture is more frequent). ⁸

Tendinosis secondary to fluoroquinolones is a rapidly progressive process, that usually disappears after treatment when the drug is discontinued. Rupture of the tendon generally develops at least three weeks after the quinolone is stopped. Some of the risk factors associated with this complication are advanced age, prolonged treatment with glucocorticoids (as in the patient we describe here), renal failure, hemodialysis, peripheral vasculopathy, associated rheumatic disease, ^3,5 and strenuous physical activity in previously healthy people. ⁶

Other tendons that may be affected after treatment with fluoroquinolones are: longus tendon of the biceps, extensor pollicis longus, rotator cuff, flexor and extensor digitorum and tendon of tibialis anterior. ^2,4

Ultrasonography is a well known diagnostic method for tendinous disorders particularly the AT due to its size and accessibility. ⁹

High frequency linear array transducers are usually used (7 to 12 MHz). The normal sonographic appearance of a tendon is a fibrilar pattern of hyperechoic lines. Contralateral comparison is important. ⁵ Tendinosis presents as thickening and hypoecogenicity of the tendon (Fig. 1) and partial or complete rupture presents as a gap between tendinous fibers and can be accompanied by fluid collections (hematoma) depending on time since rupture.