Steroid Myopathy

Steroid-Induced Myopathy
Steroid Induced Myopathy

1. Steroid Myopathy Ade Wijaya, MD

2. Introduction Non inflammatory toxic myopathy F irst described by Harvey Cushing in 1932 Postural > non postural muscles Proximal > distal Fluorinated glucocorticoids (dexamethasone, betamethasone, triamcinolone) Both endogen and exogen steroids M.A. Minetto, F. Lanfranco, G. Motta, S. Allasia, E. Arvat, G . D ’ Antona , Steroid myopathy: some unresolved issues. J. Endocrinol . Invest . 34 , 370 – 375 (2011) Schakman , S. Kalista, C. Barbé, A. Loumaye, J.P . Thisse, Glucocorticoid-induced skeletal muscle atrophy. Int . J. Biochem. Cell Biol. 45 , 2163 – 2172 (2013) R.M . Pereira, J. Freire de Carvalho , Glucocorticoid induced myopathy . Joint Bone Spine 78 , 41 – 44 (2011)   Cushing H. The basophil adenoma of the pituitary body and their clinical manifestation. Johns Hopkins Med J. 1932;50:137 .

3. Pathophysiology Indian J Endocrinol Metab . 2013 Sep-Oct; 17(5): 913–916.

4. Clinical Manifestation M.A. Minetto, F. Lanfranco, G. Motta, S. Allasia, E. Arvat, G . D ’ Antona , Steroid myopathy: some unresolved issues. J. Endocrinol . Invest . 34 , 370 – 375 (2011) Schakman , S. Kalista, C. Barbé, A. Loumaye, J.P . Thisse, Glucocorticoid-induced skeletal muscle atrophy. Int . J. Biochem. Cell Biol. 45 , 2163 – 2172 ( 2013 )

5. Clinical Manifestation Acute form: ICU Rapidly progressing weakness Proximal and distal weakness Chronic form: Proximal Pelvic girdle muscles > arm muscles Cranial nerve innervated muscles and sphincters are spared Indian J Endocrinol Metab . 2013 Sep-Oct; 17(5): 913–916.

6. Predisposing Factors Individuals Elderly Cancer Physically inactive Patients with diseases that affectiong respiratory muscles Patients with negative nitrogen balance before initiating glucocorticoid treatments Conditions Immobility Curare-like agents for neuromuscular blockade High dose of steroid Nutritional deficiencies Conccurent sepsis Indian J Endocrinol Metab . 2013 Sep-Oct; 17(5): 913–916.

7. Diagnosis History and physical examination Electromyography Laboratory assays Imaging Biopsy

8. Electromyography Mostly normal Mild reduction of the amplitude of the motor unit action potentials with low-grade spontaneous activity can be observed in few patients Motor and sensory nerve conduction studies are typically normal and also repetitive stimulation studies do not reveal significant changes in steroid myopathy patients D. Dumitru. Myopathies. in Electrodiagnostic Medicine , ed. by D. Dumitru (Hanley & Belfus: Philadelphia, 1995), pp. 1031 – 1129 P. Hanson, A. Dive, J.M. Brucher, M. Bisteau , M. Dangoisse , T. Deltombe , Acute corticosteroid myopathy in intensive care patients . Muscle Nerve 20 , 1371 – 1380 (1997)

9. Laboratory Assays Normal urinary 3-methyl histidine ( 3-MH ) to creatinine ratio in Cushing disease Increased urinary 3-methyl histidine (3-MH) to creatinine ratio in glucocorticoid-treated patients & ectopic ACTH production Decrease CK and myoglobin M. Elia, A. Carter, S. Bacon, C.G. Winearls, R. Smith , Clinical usefulness of urinary 3-methylhistidine excretion in indicating muscle protein breakdown. Br. Med. J. (Clin. Res. Ed .). 282 , 351 – 354 (1981) N . Aranibar, J.D. Vassallo, J. Rathmacher, S. Stryker, Y. Zhang, J . Dai , E.B. Janovitz, D. Robertson, M. Reily, L. Lowe-Krentz, L . Lehman-McKeeman , Identi fi cation of 1- and 3-methylhistidine as biomarkers of skeletal muscle toxicity by nuclear magnetic resonance-based metabolic pro fi ling. Anal. Biochem. 410 , 84 – 91 ( 2011)

10. Imaging (Muscle Mass Assestment) CT / MRI D ual-energy X-ray absorptiometry and bioelectrical impedance analysis Minetto MA, D’Angelo V, Arvat E, Kesari S. Diagnostic work-up in steroid myopathy. Endocrine. 2018 May 1;60(2):219-23.

11. Biopsy A trophy of type 2 muscle fibers A distinct lack of necrosis or regeneration Atrophy of Type 1 muscle fibers (rare) Minetto MA, D’Angelo V, Arvat E, Kesari S. Diagnostic work-up in steroid myopathy. Endocrine. 2018 May 1;60(2):219-23.

12. Treatment Reducing steroid dose, alternate dose, switch to non-fluorinated glucocorticoids Good protein diet and physical activity Experimental treatments: IGF-1, BCAA, creatines, adrogens, glutamine

13. Summary Non inflammatory toxic myopathy Fluorinated steroids Endogen vs exogen Muscle weakness, wasting, fatiqability Acute vs chronic form Atrophy of type 2 muscle fibers Reducing steroid dose, alternate dose, switch to non-fluorinated glucocorticoids

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