Oropharyngeal Dysphagia: Rare Presenting Symptom of Statin-induced HMG CoA Reductase Necrotizing Autoimmune Myopathy

Abstract

LEARNING OBJECTIVE #1: To recognize an atypical presenting symptom of Statin Induced Necrotizing Autoimmune Myopathy. LEARNING OBJECTIVE #2: To distinguish a rare case of treatment refractory disease process. CASE: A 79 year old male presented with four weeks of progressive dysphagia to solids and liquids, a 25lb weight loss and fatigue. He denied odynophagia, vomiting, dyspnea, fevers, skin changes, or arthralgias. No recent vaccinations were administered. Over time he reported pain with weakness in bilateral lower extremity proximal muscle groups. Increased effort was needed to rise from the sitting position. Once upright, he could ambulate. He denied tobacco or alcohol use. He had diabetes treated with metformin, hypertension controlled with medications and hyperlipidemia treated with daily atorvastatin 40 mg for the past 2 years. Age appropriate cancer screening was completed. On exam HR was 96, BP was 137/65 and RR was 18 without hypoxia. He was thin with notable temporal wasting and gargled speech. No neck masses were detected. Cardiopulmonary and abdominal exam were normal. Rashes were absent. Neurological exam revealed intact cranial nerves, no tremors, fasciculations or muscle wasting, no difficulty in raising arms above his head but visible difficulty rising from a chair with a subsequent normal gait and sensory testing. Labs included CPK of 8185, aldolase of 346 (normal < 8), AST/ALT of 176/395 (subsequently normalized), normal renal function, and a hemoglobin of 10. TSH and B12 levels were normal. HIV, T-SPOT, Hepatitis B/C were negative. Vitamin D levels were low. A barium swallow confirmed cricopharyngeal paralysis. MRI brain was normal. Atorvastatin was discontinued for a suspicion of statin induced myopathy but CPK levels remained elevated. Myopathy workup was pursued. Myositis panel antibodies including Jo- 1, MI-2, SRP, U2-snRNP, U1-RNP, NXP-2, and TIF1 were all negative. Anti-HMGCR antibodies were markedly elevated at > 200 (normal < 20). Biopsy revealed muscle fiber necrosis, phagocytosis, macrophages with minimal inflammation. Despite steroids, IVIG and Rituximab, the patient's clinical condition deteriorated with inability to ambulate and continued need for PEG feeding. IMPACT: This was a unique presentation of statin induced Necrotizing Autoimmune Myopathy that required a thorough investigation before reaching the diagnosis. Because patient presented with dysphagia as the primary symptom with no initial muscle weakness, myopathy was not initially high on our differential. However, this case highlights that in individuals with statin exposure and elevated CPK levels, oropharyngeal dysphagia should warrant a myopathy workup. DISCUSSION: We highlight two variations to descriptions of statin-induced HMGCR NAM: oropharyngeal dysphagia replacing the classic presentation of proximal muscle weakness and progression of disease despite immunosuppression. It is imperative to exercise early recognition of statin induced NAM to allow for prompt immunosupressive therapy, leading to better clinical outcomes.