Scapular Winging In Patients With Anti-Hydroxy Methyl Glutaryl CoA Reductase (HMGCR) Antibody Positive Immune Mediated Necrotizing Myopathy (IMNM): A Case Series
Nakul Katyal1, Neelam Goyal2
1Stanford School of Medicine, 2Stanford University
Objective:
To report examination finding of scapular winging in two patients with Anti-hydroxymethylglutaryl CoA reductase (HMGCR) antibody positive immune mediated necrotizing myopathy (IMNM).  
Background:
IMNM is a disabling auto-immune myopathy characterized by severe proximal muscle weakness, markedly elevated creatine kinase (CK) and muscle necrosis. Diagnosis is made via muscle biopsy and antibody testing in a patient with a suggestive history, examination and laboratory abnormalities. 
Design/Methods:
Case Series
Results:

Patient 1, a 46 year old male presented for evaluation of muscular dystrophy. He had proximal lower extremity muscle weakness, dysphagia and 20 lbs weight loss over 1 year duration. He was on statin in the past which was discontinued after he was found to have elevated liver enzymes. Examination was notable for mild eye closure weakness, bilateral scapular winging, leg > arm, proximal > distal weakness and abdominal weakness. CK was elevated to 12, 000 u/L. HMCCoA Ab was positive with elevated titer to 435.8. He was started on methotrexate and IVIG Q2 weeks. CK level down trended to 2652 U/L. Patient had significant improvement in his symptoms.  

Patient 2, a 58 year-old male presented with proximal upper and lower extremity muscle weakness, dysphagia and 10 lbs weight loss of over 4 month duration. He was on atorvastatin for over 3 years which was discontinued 1 month after symptom onset. Examination was notable for proximal muscle weakness in bilateral upper and lower extremities, right scapular winging and neck flexion weakness. CK was elevated to 7500. HMG COA reductase antibody was positive with elevated titer to 169.4.  He was started on methotrexate and IVIG Q2 weeks. He also noted improvement in his symptoms.  

Conclusions:
Scapular winging can be seen with HMGCR Ab+ IMNM. Such patients can be misdiagnosed having muscular dystrophy. Neurologists should be aware of this clinical phenotype as these patients may respond favorably to immunotherapy. 
10.1212/WNL.0000000000203451