<prompt> Which of the following causes distal myopathy:Myotonic dystrophyDuchenne Muscular DystrophyBecker Muscular DystrophyPolymyositits  <response>: Ans: A Myotonic dystrophy Ref: Harrisons Principles of Internal Medicine. 18th ed, pg 3499.3500Explanation See the following tableMyotonic Dystrophy:Facial muscle hatchet face, neck.palatal, pharyngeal, distal muscle of hands and feet weaknessFrontal baldnessMyotonia of thenar muscle, tongue, wrist extensorCardiac conduction defects, cataract, insulin resistanceMyotonia treated with phenytoinmexilitineDrug induced proximal weaknessAmiodaroneChloroquineHCQColchicineLipid lowering drugsGlucocorticoidsZidovudineAlcoholAmphetamined-PenicillamincClofibratteVincristineEndocrine causes:HypohyperthyroidismHyperhypoparathyroidismCushings syndromeOsteomalaciaRenal osteodystrophyAdrenal insufficiencyConns syndromeAcromegalyDMChannelopathies:Malignant hyperthermia- Calcium channelHypokalemic periodic paralysis- Calcium sodium channelHyperkalemic periodic paralysis- Sodium channelParamyotonia congenita-Sodium channelMyotonia congenita! Thompsons disease- Chloride channelAnderson-Tawil syndrome- Potassium channelMitochondrial myopathies: MERFF, MELAS.CPEO, MNGIE. Kearns-Sayre syndromeDisorders of carbohydrate lipid metabolism: Me Ardle disease, CPT deficiency- In general, myopathies follow a proximal distribution of weakness and muscle wasting with the notable exception of myotonic muscular dystrophy- Neuropathies are generally distal in distribution with the notable exception of juvenile spinal muscular atrophy 