Corticosteroid-Induced Myopathy Clinical Presentation

Updated: Sep 10, 2019
  • Author: Patrick M Foye, MD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Presentation

History

Chronic (classic) steroid myopathy history findings are as follows:

  • This form is the classic presentation of steroid myopathy.

  • This condition can develop after prolonged administration of prednisone at a dose of 40-60 mg/d. [5, 6] Although there is no clear length of time, onset of weakness has been found to occur within weeks to years following initiation of corticosteroid administration.

  • Several studies have suggested that the risk for steroid-induced myopathy is greater in severely asthmatic patients who use oral steroids. [12] One study, however, found no significant difference in the prevalence of myopathy in oral steroid users and inhaled steroid users.

  • A report by Stanton et al indicated that in 43 patients with asthma, a statistically significant association existed between inhaled corticosteroid dose and patient voice scores obtained using the GRBAS (grade-roughness-breathiness-asthenicity-strain) system. [13] Despite this apparent relationship, however, evidence of steroid-induced myopathy was found in only 2 of the 43 patients.

  • Fluorinated steroids seem to produce weakness and myopathy more frequently than do nonfluorinated ones.

  • The insidious onset of proximal muscle weakness of the upper and lower limbs is a prominent clinical feature.

  • Progressive proximal muscle weakness of the upper and lower limbs is reported.

  • Patients typically complain of a progressive inability to rise from chairs, climb stairs, and perform overhead activities.

  • Patients initially note little difficulty with hand strength.

  • The facial and sphincter muscles usually are spared.

  • Myalgias can become a prominent feature with time.

  • Contrary to previous beliefs, several studies have shown involvement of the respiratory muscles (eg, the diaphragm); thus, pulmonary symptoms may be present. [11]

Acute steroid myopathy history findings are as follows:

  • This form is encountered less frequently than is the chronic type.

  • Acute, generalized weakness, including weakness of the respiratory muscles, typically occurs 5-7 days after the onset of treatment with high-dose corticosteroids. [11] Some case reports describe the development of muscle weakness after the administration of a single dose of corticosteroid.

  • One study indicates a possible correlation between the occurrence of acute steroid myopathy and the total dose of steroid administered; acute atrophy was encountered with total doses of greater than 5.4 g of hydrocortisone in 6 days, whereas no signs of myopathy were noted with total doses of less than 4 g.

  • Previous systemic corticosteroid use does not appear to contribute to the development of myopathy.

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Physical

Chronic (classic) steroid myopathy physical findings are as follows:

  • Proximal muscle weakness is more pronounced than is distal muscle weakness; however, severe relative weakness of the anterior tibialis muscle can be found.

  • Pelvic girdle muscles usually are affected more severely and earlier than are pectoral girdle muscles.

  • Muscle bulk typically is normal, but muscle atrophy can occur.

  • Muscle stretch reflexes typically are normal.

  • Sensory examination should be normal.

Acute steroid myopathy physical findings are as follows:

  • Generalized muscle weakness, not limited to a more proximal distribution, is noted.

  • Muscle stretch reflexes typically are normal.

  • Sensory examination should be normal.

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