A Case Report of 99mtc-Labelled Glucosamine [99mtc-ECDG] In The Evaluation of Myositis
Corresponding author: Dr. Yaseen Omran, Department of Rheumatology, Westmead Hospital. Sydney. NSW. Australia. 2145, Email: email@example.com
Key Words: Myositis; Glucosamine; Radionuclide Imaging; Nuclear Medicine
A 69-year-old man presented with upper and lower limb weakness progressing over several months, to the point of being unable to mobilise. His past medical history included type 2 diabetes mellitus, hypertension and hypercholesterolemia on simvastatin for over 5 years. Physical examination revealed symmetrical proximal upper and lower limb and axial weakness. Investigations comprised of an elevated serum creatine kinase (9900 U/L), negative antinuclear and extractable nuclear antibodies, and a negative screen for an underlying malignancy. Magnetic resonance imaging (MRI) of the thighs showed extensive abnormal oe- dematous signal in the musculature bilaterally, in keeping with myositis (Figure 1). Biopsy of the right vastus lateralis muscle demonstrated chronic active inflammatory myopathy, consistent with statin-induced myositis. A nuclear medicine scan using technetium-99m labelled glucosamine was performed as a comparator to the MRI. As shown in Figure 2, there was extensive uptake in the proximal thighs and upper arms, corresponding with areas of myositis noted clinically and on MRI. Simvastatin was ceased and the patient was treated with corticosteroids, oral methotrexate and intravenous immunoglobulins with im- provement in muscle power and return of serum creatine kinase to normal.
This is the first report of a novel imaging modality (99mTc-labelled glucosamine [99mTc-ECDG]) with the ability to image the entire patient for areas of inflammation, and as shown in this case, identify myositis. Glucosamine scans may be of clinical utility in other rheumatic situations where positron emission (PET) or MRI scans are very expensive or not readily available. This im- aging modality is currently being investigated in the role of inflammatory and degenerative arthritis. [ 1,2,3]
Figure 1: MRI – coronal STIR sequence of bilateral thighs showing extensive abnormal oedematous signal in the mus-
culature bilaterally, in keeping with myositis. Figure 2: Technetium-99m labelled glucosamine scan demon-
strating extensive uptake in the proximal thighs and upper arms, corresponding with areas of myositis noted clinically
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