Unexplained Muscle Weakness - From 50 Pushups Per Day To Zero

HISTORY: A 76 y/o male with T2DM, BPH, hypercholesterolemia on rosuvastatin presented with progressive proximal muscle weakness. Two months prior, he noticed a significant decline in performance during morning exercise. He could no longer perform daily push-ups, play golf, or hike—citing decreased strength in his upper and lower extremities. Following the onset of these symptoms, he presented to his PCP where his rosuvastatin was discontinued and he was diagnosed with Parkinson's disease and started on Carbidopa-Levodopa. One month later he returned to his PCP with difficulty swallowing, inability to ambulate, climb stairs, or brush his hair and teeth. Due to the severity, he was sent to the emergency room and transferred to a tertiary care hospital for evaluation. PHYSICAL EXAMINATION MSK: Negative TTP over UE and LE bilaterally. Decreased passive ROM to hip flexion, leg raise, UE abduction and forward flexion. 2/5 strength to shoulder abduction and forward flexion bilaterally. 4/5 strength to elbow flexion and extension bilaterally. 5/5 hand grip strength bilaterally. 2/5 strength to hip flexion. 4/5 strength to knee flexion and extension bilaterally. 4/5 strength to ankle dorsiflexion and plantarflexion. Positive Gower’s Sign. Neuro: Sensation intact. Patellar, achilles, & biceps reflexes absent bilaterally. CNII-XII intact. Finger-to-nose intact. Slight intention tremor present. No resting tremor. DIFFERENTIAL DIAGNOSIS: 1. Idiopathic Inflammatory Myopathy 2. NMJ Disorder 3. ALS 4. Parkinson's Disease TESTS & RESULTS: ALP: 76 AST: 13391 ALT: 749 GGT: 25 CK: 13391 CRP: 10.8 ESR: 20 LDH: 1087 Troponin 1: 0.122 Vitamin B12: low Anti-HMG CoA Reductase Ab: Positive Muscle Biopsy: Consistent with acute necrotic myopathy XR Swallow Study: No evidence of laryngeal penetration or aspiration Echo: Normal, LVEF 60-65%CT Head: Negative for mass or hemorrhage FINAL WORKING DIAGNOSIS: Necrotizing autoimmune myopathy with positive Anti-HMG CoA Reductase Ab TREATMENT & OUTCOMES High dose IV solumedrol x3 days, IVIG x5 days, taper to 70 mg daily prednisone.Taper off steroids, start mycophenolate mofetil and bactrim. Admit to inpatient rehab, remain off statin. Discharged 1 month later able to perform all ADLs independently with assistance while climbing stairs and entering/exiting a vehicle.