Deltoids are usually spared and may appear enlarged due to severe atrophy of upper arm muscles. Pelvic girdle musculature usually becomes affected at

dystrophy - Either sex. Onset usually in third decade. (i) Pelvifemoral form - Weakness begins in pelvic girdle musculature (psoas, glutei and quadriceps) and results in waddling lordotic gait with difficulty in climbing stairs. Winging of scapulae. (ii) Scapulohumeral form- Weakness confined initially to shoulder girdle and upper arm muscles. Deltoids are usually spared and may appear enlarged due to severe atrophy of upper arm muscles. Pelvic girdle musculature usually becomes affected at a later stage. The disease runs a variable course leading to severe disability in fourth or fifth decade. CPK is elevated and muscle biopsy shows non-specific dystrophic changes. (b) Scapuloperoneal muscular dystrophy - Presents in early adult life with foot drop due to weakness of anterior tibial and peroneal groups. Extensor digitorum muscle is characteristically spared and may be hypertrophied. The disease runs a benign course. Wasting and weakness in upper limbs is initially confined to scapular muscles but later spreacte to involve biceps, triceps, forearm extensors and sometimes small muscles of hand. (c) Congenital muscular dystrophy - One of the causes of the floppy infant. Myopathy manifests at birth or early life. Small, weak, hypotonic muscles, proximal usually more affected than distal. Both sexes (3) Autosomal dominant muscular dystrophy - (a) Facioscapulohumeral dystrophy - Either sex. Onset usually in adolescence. Initial involvement, sometimes symmetrical, of facial and shoulder-girdle muscles, soon followed by weakness of anterior tibial and peroneal muscles, usually with spread within 20 or 30 years to pelvic muscles. Profound facial weakness produces pouting of the lips and a transverse smile. Slow insidious progression with periods of long arrest of the disease. (b) Distal muscular dystrophy of Welander - Very rare Presents with slowly progressive, predominantly distal wasting and weakness. Muscle biopsy similar to myotonic dystrophy. (c) Ocular and oculopharyngeal muscular dystrophy - Presents in adult life with ptosis and extraocular weakness, usually without significant diplopia. Dysphagia is prominent in some families. Face and sternomastoicte are commonly affected and most patients develop weakness in the legs. Relatively benign course. Muscle biopsy shows vacuolar changes. Management - None specific. Principles are to treat complications such as respiratory and urinary infection if and when they occur, to avoid trauma which may easily result in fracture of limb bones and to keep the patient active as long as possible. II. Myotonic disorders -Failure of voluntary muscles to relax immediately innervation ceases. 1. MYOTONIC DYSTROPHY (Dystrophia myotonica) - (i) Onset - Most patients present in adult life with distal weakness and wasting in upper or lower limbs. (ii) Muscle weakness/wasting - (a) Myopathic facies - Ptosis, hanging jaw, haggard ap­pearance, temporal wasting. (b) Weakness of neck flexion, wasting of sternomastoicte. (c) Distal limb weakness with wasted brachioradialis. 3. Frontal baldness. Hyperostosis frontalis interna. 4. Cataracts (post. subcapsular) 5. Cardiac conduction defects (Heart block, at rial arrhythmias). Cardiomyopathy. 6. Hypoventilation, post-an aesthetic respiratory failure. 7. Hypersomnolence, mental retardation. 8. Hypogammaglobulinemia. 9. End-organ resistance to insulin (Impaired glucose tolerance). 10. Dysphagia, oesophageal dilatation. Investigations - (a) CPK - Normal or slightly elevated. (b) EMG - Characteristic myopathic picture with myotonic discharges. (c) Muscle biopsy - Chains of central nuclei, marked variation of