lNVESTlGATlON OF A CASE OF MUSCULAR WASTING

week improvement after till symptoms, thymectomy are controlled Ocular myasthenia or dose of 120 mg is reached, then reduced to minimum effective Ievel 4. immuno- suppression Pts reacting Azathioprine poorly to 2.5 mg/kg articholinesterase body wt. Failure to improvement MANAGEMENT OF CRISIS - Crisis is characterised by severe generalised weakness and respiratory failure. Crisis occurs most frequently in pts wrih savera bulkar wetness lollowlng upper respiratory Inluctiong, surgery, obsiairtc dshvy Also recenlly diagnosed pts or those with poorly controlled symptoms. (a) Myasthenic crisis - Disease worsening occurs with inadequate treatment and can be precipitated by infection, etc. Control of airway and ventilation. anticholinesterase medication. Plasma exchange or i.v immunoglabulin for excessive cholinesterase drugs. (b) Cholinergic crisis - due to excess anticholiesterase drugs (rare) Dilated pupils specific sign. Control of airway and assisted ventilation and temporary withdrawal of anticholinesterase drugs with later introduction at reduced does regimen. Immunosuppressive drug therapy and/or plasma exchange 24. MUSCULAR WASTING Causes: A. In reflex are -1. Primary muscular disease - (a) Mascular dystrophies. (b) Myotonia atrophica (c) Polymyositis 2. Cord lesions - (a) Motor naurone disease. (b) Cord compression (c) Syringomyelia. 3 Anterior horn cell lesion - (a) Poliomyelitis (b) Progressive mascular atrophy. (c) Infantile muscular atrophies - (i) Amyotonia congenita (Oppenheim's disease) (ii) Progressive spinal muscular atrophy (Wardnig Hoffmann's paralysis) 4. Root lesions - (a) Cervical spondylosis (b) injury or tumour or carvical enlargement of spinal cord (c) Hypertrophic cervical pachymeningitis. (d) Vertebral metastsis. 5. Brachial plexus or peripheral nerve lesions - e. g -(a) Thoracic inlet syndrome (b) inflammation of spinal nerve (neuralgic amyotrophy). (c) Carpal tunnel syndrome (d) Diphtheritic and lead paralysis (e) Leprosy (f) Neoplasm of vartebrae. (g) Trauma. (h) Peroneal muscular atrophy. 6. Myoneural function disorder - Myasthenia gravis (muscular wasting very rare). B. Disuse atrophy - (a) Arthritic -Rheumatoid arthritis (b) Post-paralytic -Hemiplegia and paraplegia.(c)Therapeutic immobilization-fracture. (d) Psychogenic lNVESTlGATlON OF A CASE OF MUSCULAR WASTING History-1. Family history - constant in muscular dystrophy and peroneal muscular atrophy. Absent in motor neurone desease. 2 Age of onset -Muscular dystrophyr poliomyelitis and diphtheritic paralysis in infancy and childhood. motor neurone disease in second half of lifer peroneal muscular atrophy and wasting of cervical rib pressure in early adult life, cervical spondylosis usually after 45. 3. Mode of onset -Rapid in poliomyelitis and acute radiculitis. More gradual in diphtheritic paralysis, cervical spondylosis or tumour, and infective polyneuritis. In spinal lesions, atrophy uaually precedes weakness, in polyneuritis. weakness precedea atrophy. 4 Symmetry -muscle weakness may be symmetrical which precedes weekness indicates myopathic disease, or asymmetrical, suggesting neurogenic disease. 5. Episodic or progressive -Progressive weakness is usually associated with one of the limit girdle, lasctoscapulohumeral or scapuloperoneal syndrome. Episodic weakness if accompanied by fatigue. suggests a disorder of neuromuscular transmission. Episodic weakness following exercise or heavy meal suggests periodic paralysis. 6. Associated discomfort- Muscle pain - at rest can occur in polymyositis, polymyalgia - rheumatica. acute myoglobinuric myopathy and in myopathies of metabolic bone disease. Episodic pain, which may at times be associated with weakness. suggests a metabolic disorder. Pain that develops during exercise is considered to be characteristic of McArdie's disease. though it can occur in other metabolic myopathies (e.g mitichondrial myopathies) Pain that follows exercise by a few hours usually occurs in disorders of UpKf meiaboiem n Examlnailon - 1 Dtoirlbuilon ol wasting - (a) PROXIMAL MUSCLE WASTING - Muscular dysi>opr>kesr syringomyelia, (in early stages). Inflammatory lesione such as neuralgic amyotrophy. old poliomyelitis. myositis, compressive lesions of lower cervical roots, rarely In motor neurone disease. Cauda aquina lesions cause wasting of buttocks. (b) PERIPHERAL MUSCLE WASTING - Forearm and small muscle of hand. Lower motor lesion affecting principally the segmental distribution C7-T1. This may occur at many levels - Anterior horn cells - Polimyelitis motor neurone disease. Syringomyelia, cervical card tumours. Anterior root - Cervical spondylosis or tumour Brachial plexus - Injuries, cervical rib, cervical glandular enlargement, traumatic lesions of radial. median and ulnar nerves, carpal tunnel syndrome. Muscular lesion such as dystrophia myotonica involvement of joints - Rheumatoid arthritis (ii) Lower leg - Wasting less common than in arm. Occurs as part of cauda eouina lesion, polyneuritis. peroneal muscular atrophy. injury to erternal popliteal nerve. (iii) Both upper and lower limbs -Peroneal muscular atrophy, chronic polyneuritis. distal myopathy NB - Myotonic dystrophy causes prominent forearm wasting but spares small hand muscles. (C) CRANIAL MUSCULATURE INVOLVEMENT - early in myotonic dystrophy.