| Title : case 249 |
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Age / Sex : 77 / F Chief complaint: Right shoulder swelling with tenderness for 2 days Courtesy : In Sook Lee(이인숙), Pusan National University Hospital(부산대학교병원) Diagnosis: Rhabdomyolysis Discussion
CT findings Diffuse low attenuation with swelling of right supraspinatus muscle. MR findings Right supraspinatus muscle shows heterogeneously high signal intensity on axial and coronal fat-suppressed T2WIs. Also, partial portion of left supraspinatus muscle shows abnormally high signal intensity. The posterior portion of corresponding muscle shows heterogeneously high signal intensity on axial T1WI. Coronal fat-suppressed, contrast enhanced T1WIs show suboptimal enhancement of most portion of the supraspinatus muscle except posterior portion. Hematoma formation might be suggested at posterior portion of right supraspinatus muscle. Bone scan Abnormally diffuse increased uptake at soft tissue areas of both upper extremities Differential Diagnosis: Myonecrosis, Myositis, subacute denervation,
Myoglobin : 1984.2 ng/mL, CK : 42760 U/L, CK-MB : 89.69 ug/L Excision biopsy of right supraspinatus muscle - Myonecrosis on pathologic report. Final diagnosis - Rhabdomyolysis of supraspinatous muscle Discussion: l Definition; Striated muscle dissolution or disintegration leading to muscle necrosis l Potentially life-threatening disease, may result from a large variety of causes, congenital or acquired l Etiology Congenital causes consist of enzyme defects ; Disorders of carboohydrate metabolism, mitochondrial lipid metabolism and other disorders Acquired causes ; Toxic (alcohol, drugs and toxins, such as heroin, morphine, methadone) ; Excessive muscle exercise (long training, convulsions) ; Direct muscle injury (crush, freezing, burning) ; Ischemic injury (compression, vascular occlusion) ; Metabolic disorders (diabetic ketoacidosis, hypothyroidism) ; Infections, heat stroke, inflammatory myopathies l Myoglobinemia, myoglobinuria; most important manifestation l Markedly increased serum CK; most important laboratory finding l CT findings Diffuse areas of low attenuation in the muscle Muscular swelling due to edema Fatty degeneration and abnormal patchy hyperdensity consistent with muscle calcification Intravenous contrast ; provides better demarcation of the lesions and confirms the avascularity of the necrotic areas l MR findings High SI on T2WI/ Low SI on T1WI STIR images ; display good contrast between normal and abnormal muscles better differentiation of the damaged muscles from the adjacent fat due to its fat suppression In the acute stage ; Abnormal signal is associated with an increase in the cross-sectional diameter of the affected muscle In long standing disease ; Hemorrhagic transformation l Bone scan ; valuable for visualizing the site and extent of damaged muscle ; inferior to MRI with regard to spatial resolution References: 1. European Journal of Radiology 65 (2008) 311–315 ; Importance of MRI in the diagnosis and treatment of rhabdomyolysis 2. RadioGraphics 2000; 20:S295–S315 ; Abnormal Signal Intensity in Skeletal Muscle at MR Imaging: Patterns, Pearls, and Pitfalls 3. AJR 2009; 192:1708–1716; MRI Findings in Inflammatory Muscle Diseases and Their Noninflammatory Mimics |
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| Name | Institution |
| 이름:소속병원 | |
| Total applicants: 13 | |
| Correct answer: 1 | |
| 윤민아: 예손병원 | |
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