Clinical Immunology & Rheumatology Service, Department of Medicine, All India Institute of Medical Sciences, New Delhi, India and
1 Department of Rheumatology, Royal Hampshire County Hospital, Winchester SO22 5DG, UK
SIR, Meralgia paraesthetica is caused by entrapment of the lateral cutaneous femoral nerve as it passes under the inguinal ligament. Direct pressure from belts and other tight-fitting garments may contribute to this entrapment. Several clinical conditions have been associated with the development of meralgia paraesthetica, including obesity, pregnancy, diabetes mellitus, ascites and trauma to the thigh or inguinal region [1, 2]. We describe a patient having meralgia paraesthetica caused by a left hip joint synovial cyst. A 70-yr-old male patient having chronic rheumatoid arthritis of 10 yr duration presented at our monitoring clinic with gradual onset of numbness over the lateral aspect of his left thigh. His rheumatoid activity was under control on combination DMARDs (disease-modifying anti-rheumatic drugs): methotrexate 15 mg/week, Sulphasalazine 3 g/day, hydroxychloroquine 200 mg/day and prednisolone 5 mg/day. Examination revealed various deformities of chronic rheumatoid arthritis in both hands, with no clinical evidence of ongoing active synovitis. There was no evidence of any cutaneous vasculitis or extra-articular manifestations. Neurological examination revealed mild sensory loss over dermatomes L2 and L3 on the left side. Other systemic examinations, including abdominal examination, were normal. On the basis of our clinical findings, meralgia paraesthetica was considered and an electrophysiological study was organized. Blood investigations were normal, with mildly elevated inflammatory markers (erythrocyte sedimentation rate 33 mm/h and C-reactive protein 11 mg/l). The patient was reviewed after 4 weeks in the rheumatology clinic. His symptoms were the same and nerve conduction study confirmed the diagnosis of meralgia paraesthetica. During this consultation he also complained of mild difficulty in passing urine and swelling in the left iliac fossa. Examination revealed a firm, non-tender swelling in the left iliac fossa. An urgent ultrasonographic examination revealed a cystic swelling, and a diagnostic aspiration was done. The aspirated fluid was thick brown in colour and examination of the fluid was unremarkable. A contrast-enhancing CT scan of the lower abdomen, including the hip joint, revealed a well-defined hypodense lesion communicating with the left hip joint, suggestive of hip-joint synovial cyst (Fig. 1) The patient was operated upon and histology confirmed the diagnosis of left hip synovial cyst. The patient's symptoms improved after the operation.
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Notes
Correspondence to: N. Cox. E-mail: nigelcox{at}tinyonline.co.uk
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