Myopathies presenting with head drop: Clinical spectrum and treatment outcomes

Abstract

Dropped-head syndrome can be the presenting feature of a wide spectrum of neurological conditions. However, little is known regarding myopathies presenting with head drop posing a major diagnostic and management challenge. We performed a retrospective chart review to identify patients with a myopathy evaluated between 2000 and 2018, where head drop was the presenting or predominant clinical feature of a myopathy. We identified 107 adult patients with a median age at presentation was 68 years, and median duration of the head drop was 12 months. A specific diagnosis was reached in 53% of patients and included the following: Inflammatory myopathy (n = 16), myopathy with rimmed vacuoles (n = 10), radiation-induced myopathy (n = 8), sporadic late-onset nemaline myopathy (n = 7), myofibrillar myopathy (n = 4), facioscapulohumeral dystrophy (n = 3), inclusion body myositis (n = 2), mitochondrial myopathy (n = 2), scleroderma-associated myopathy (n = 2), necrotizing autoimmune myopathy (n = 1), a drug-induced myopathy (Binimetinib, n = 1), and B-cell chronic lymphocytic leukemia-associated myopathy (n = 1). Splenius capitis had the highest diagnostic yield for a muscle biopsy (67%).When tested, 89% of patients had abnormal pulmonary function tests, 50% abnormal swallow evaluation, 37% abnormal electrocardiogram and 13% abnormal transthoracic echocardiogram. 23 out of 43 (53%) treated patients responded to treatment. Patient-reported limb weakness and neck flexion weakness on physical examination were associated with good response to treatment, while isolated neck extensor weakness was not associated with refractoriness to treatment. A wide spectrum of acquired and hereditary, treatable and non-treatable myopathies can present with head drop. Establishing a diagnosis in such patients is crucial for timely treatment administration.