Ann Rheum Dis 1996;55:921-923 921 CONCISE REPORTS Ann Rheum Dis: first published as 10.1136/ard.55.12.921 on 1 December 1996. Downloaded from Enthesopathy and tendinopathy in gout: computed tomographic assessment Jean-Charles Gerster, Michel Landry, Georges Rappoport, Gilles Rivier, Bertrand Duvoisin, Pierre Schnyder Abstract urate deposits in clinically involved tendons Objective-To establish if computed (Achilles tendon in two patients, patellar tendon tomography (CT) imaging, which has in one patient) was assessed. proved helpful in detecting intra-articular tophi in gout, can also be used to Case reports document gouty enthesopathy and tendin- PATIENT 1 opathy. A 70 year old man was admitted with acute Methods-Three patients with tophaceous arthritis of the left ankle joint. He had been gout and clinical involvement of the suffering from gout for 10 years, and had a his- Achilles tendon (two cases) or patellar tory of excessive alcohol consumption and of tendon (one case) were assessed with CT irregular medication consisting of non- examination and plain radiographs. steroidal anti-inflammatory drugs and allopu- Results-In the first two cases, CT images rinol. revealed linear or nodular high attenua- Upon admission, the patient was overweight tion opacities within the substance of the (body mass index 32.8 kg m-', normal < 25), Achilles tendons and their calcaneal and he had an effusion of the left knee, signs of insertion. In case 3, dense linear opacities acute arthritis of the left ankle, and nodules of were seen within the patellar tendon and both Achilles tendons, which were slightly ten- within its tibial insertion. No such der on palpation; he also had nodules next to opacities ofthe tendons and entheses were the olecranon processes. The arteries of both seen on standard radiographs of these feet were pulsatile; blood pressure was 170/80 http://ard.bmj.com/ patients. mm Hg. Synovial fluid aspirated from the left Conclusions-CT appears to be the imag- knee contained 1000 leucocytes mm-3 with ing method of choice for demonstrating intracellular negatively birefringent crystals. monosodium urate deposits in entheses Serum uric acid was 455 jmol litre-1 (normal < and tendons in tophaceous gout. 416); creatinine 80 jmol litre-' (normal < 106); fasting blood sugar 7.0 mmol litre-1; and (Ann Rheum Dis 1996;55:921-923) cholesterol 4.2 mmol litre-1 (normal < 5.2). on September 28, 2021 by guest. Protected copyright. Plain radiographs of both knees did not reveal Tendinopathy, particularly of the Achilles and chondrocalcinosis. The lateral radiographs of patellar tendons, is a fairly common present- both ankles were normal except for ation ofgout and can even lead to their rupture.' calcifications of the posterior tibial arteries (fig Clinical involvement of these tendons can 1A). A CT scan was achieved with a 9800 High precede any articular gouty manifestation, as Speed Advantage GE scanner, using 120 KV, CHUV, CH-1011 found in 12 out of 17 cases oftendinopathy ofthe Lausanne, 140 mAs, 1 mm collimation (table speed 1 Switzerland: Achilles tendon.2 More recently, gouty mmis, pitch 1). The CT sections revealed University enthesopathy-mainly of the heels-has been opacities in the posterior part of the Achilles Rheumatology and reported in some renal transplant recipients who tendon, undetected on the plain radiographs Rehabilitation Centre were receiving cyclosporin treatment, despite the J C Gerster (fig 1 B), and were considered to be mono- G Rappoport absence ofmicrocrystalline joint effusion.3 Inag- sodium urate deposits based on their density, G Rivier ing ofthe gouty Achilles tendon with plain radio- that is, 170 (15) HU. or a Department of graphs xeroradiographs reveals diffuse or Radiology nodular thickening that cannot be distinguished PATIENT 2 M Landry from xanthomata or nodular thickening due to A man aged 42 years who had had gout for 15 B Duvoisin partial rupture.4 We have previously shown that years presented articular pains of both elbows P Schnyder computed tomography (CT) was useful in docu- and right knee and inflammation of the poste- Correspondence to: menting tophaceous deposits of monosodium rior aspect of both feet. There was a history of Dr J C Gerster, urate within the knee the Rheumatology Centre, crystals joint: tophi are chronic excessive alcohol consumption and of CHUV, 1011 Lausanne, ofgreater attenuation than the muscles, and their hyperuricaemia treated irregularly. Switzerland. density is 170 (SD 15) Hounsfield Units (HU).' The patient was obese (body mass index 33 Accepted for publication In this study of three patients with tophaceous kg m-2), and upon examination an effusion of 9 September 1996 gout, the ability of CT to identify monosodium the knee joints, nodular thickening of both 922 Gerster, Landry, Rappoport, Rivier, Duvoisin, Schnyder tendon. In 1993, an arthroscopic examination of the knee revealed a thickened synovium and Ann Rheum Dis: first published as 10.1136/ard.55.12.921 on 1 December 1996. Downloaded from white crystal deposits on the synovium and in the internal meniscus. There was also a history of chronic alcohol abuse and poor observance of the antihyperuricaemic treatment. In 1995, the patient was overweight (body mass index 32.9 kg m-'). Upon examination, he had tophi of the right wrist and of the second left finger joint. The left knee was swollen with an enlarged prepatellar bursa and the patellar tendon diffusely swollen and tender at its tibial insertion. Laboratory results showed birefrin- gent negative monosodium urate crystals in a paucicellular synovial fluid aspirated from the left knee joint. Serum uric acid was 577 gmol litre-'; creatinine 109 ,umol litre-'; fasting glucose 12.4 mmol litre'1; and cholesterol 6.4 Figure 1 (A) Lateral radiograph ofthe left heel (case 1) showing vascular calcifications. mmol litre-1. The Achilles tendon is slightly enlarged. (B) Same heel. CT axial image; vascular Anteroposterior radiographs of the left calcifications are seen (white arrows) as well as opacities of the posteriorpart ofthe Achilles knee tendon [mean density 170 (SD 15) HU], considered to represent monosodium urate crystal joint revealed discrete signs of osteoarthritis deposits (black arrow). but no chondrocalcinosis. On the lateral view, there were no opacities of the soft tissues (fig Achilles tendons, and a tender and swollen cal- 3A). In contrast CT imaging showed irregular caneal insertion were noted. The blood pressure was 120/90 mm Hg. Laboratory results revealed negatively birefringent crystals in a paucicellular synovial fluid aspirated from the right knee joint; serum uric acid was 609 pmol litre'; creatinine 76 jmol litre-'; glucose 5.5 mmol litre'. Lateral radiographs of the heels did not reveal opacities of the soft tissues, but CT imaging showed opacities within the Achilles tendon, in the subcutaneous tissue, and at the calcaneal insertion, clearly demonstrated on a sagittal cross sectional reconstruction (fig 2). PATIENT 3 http://ard.bmj.com/ A 69 year old man with gout of 20 years' dura- tion had some years previously undergone an excision of the right olecranon bursa for chronic gouty bursitis as well as a decompression of the right carpal tunnel. At that time, macroscopic tophaceous deposits were observed in the flexor tendons. He on September 28, 2021 by guest. Protected copyright. suffered occasionally from inflammatory bouts of the left prepatellar bursa and patellar Figure 3 (A) Lateral radiograph of the left knee (case 3). A periosteal reaction along the anterior part ofthe patella is Figure 2 Computerised tomographic cross sectional sagittal seen. The patellar tendon is slightly enlarged. No opacity is image reconstruction of the right heel (case 2). The Achilles identified. (B) Computerised tomographic cross sectional tendon is thickened. There are linear opacities within the sagittal image reconstruction (same knee) showing opacities tendon (large arrow), in the subcutaneous tissue and at the within the tendon and infront of its tibial insertion. Two calcaneal insertion (preachilles bursa) (small arrow) [mean subcutaneous bursae are seen (arrows) and contain round density 170 (SD 15) HU]. opacities. Enthesopathy and tendinopathy in gout 923 round and oval opaque masses within the pre- deposits, distinctly seen on radiographs,'0 and patellar bursa, the patellar tendon, and at its finally from ossifications near the insertion of Ann Rheum Dis: first published as 10.1136/ard.55.12.921 on 1 December 1996. Downloaded from tibial insertion, clearly visible on a sagittal cross the Achilles tendon which may occur in diffuse sectional reconstruction (fig 3B). idiopathic skeletal hyperostosis (DISH)," well shown on conventional x ray films. Discussion CT should not be done routinely but it Symptomatic Achilles tendon and patellar ten- could become a method of choice for assessing don were selected for this study. These tendons certain cases of tendinous thickening of possi- are commonly involved in gout6 ; since they bly gouty origin. It can characterise the crystal are devoid of a synovial sheath, synovial fluid deposits by their shape and their density, cannot be obtained and the documentation of providing different information from magnetic the microcrystalline pathology is not easy. resonance imaging, which has recently been However, as we have shown previously,5 CT shown to have a place in the evaluation of techniques reveal monosodium urate deposits tophaceous gout of the hands.'2 in vitro as well as within the knee joint, while Long term studies are needed to determine such deposits are not visible on plain if CT could be helpful in monitoring antihype- radiographs.5 Increased attenuation ofthe x ray ruricaemic treatment and whether the abnorm- beam of the CT scanner, as reflected by an alities are reversible. increased HU value [170 (SD 15) HU], could be due to a concentration of sodium high 1 Mahoney PG, James PD, Howell CJ, Swannell AJ. Sponta- nuclei in the monosodium urate crystals. It is neous rupture ofthe Achilles tendon in a patient with gout.