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Washington University Experience | MUSCLE | Autophagic myopathy | 11W Case 11 Denouement
The findings are compatible with an HCQ-associated neuromyopathy syndrome, which likely contributed to the patient’s weakness. Nerve biopsy demonstrated chronic, severe, large and small myelinated axon loss; however, severe nerve injury is not fully explained by HCQ-induced injury but potentially could have been driven by his severe kidney disease and diabetes. An exhaustively comprehensive evaluation, including extensive serological testing showed no evidence for hATTR amyloidosis, neuromuscular autoimmune antibodies, paraneoplastic auto-antibodies or VEGF. This patient showed elevated serum neurofilament light chain levels, consistent with his severe peripheral neuropathy. Muscle fiber vacuoles with lysosomal, basal lamina and sarcolemmal membranous components is part of a spectrum of Autophagic Vacuoles with Sarcolemmal Features (AVSF). This muscle fiber pathology can occur with hydroxychloroquine-related myopathies, particularly hydroxychloroquine. Only a few fibers were involved by markedly abnormal mitochondria, likely paralleling the minimal changes in COX and SDH stains.
