History
Chronic (classic) steroid myopathy history findings are as follows:
-
This form is the classic presentation of steroid myopathy.
-
Several studies have suggested that the risk for steroid-induced myopathy is greater in severely asthmatic patients who use oral steroids. [18] 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-asthenia-strain) system. [19] 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. [6]
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. [6] 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.
-
An unexpectedly short time may pass from initial steroid administration to the onset of clinical myopathy. A study performed by Haran et al reviewed published reports of myopathy developing within 14 days of initiating corticosteroid treatment, as well as their own experiences with four patients. There were cases that began within just 1 hour of administration and other cases that began within just 1-3 days. The study also reported cases in which comparatively low doses, or even a single dose, of corticosteroid led to the onset of myopathic signs and symptoms. In addition, acute myopathy was reported to occur after various administration routes for the steroids, including intravenous, oral, intramuscular, epidural, and inhalation. [5]
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.
-
Involvement of bulbar and respiratory muscles can occur [5]
-
Muscle stretch reflexes typically are normal.
-
Sensory examination should be normal.
