49 MUSCLE WEAKNESS General Discussion The first step in the evaluation of muscle weakness is differentiating true muscle weakness from fatigue and asthenia. Fatigue is the inability to continue performing a task after multiple repetitions while asthenia is a sense of exhaustion in the absence of actual muscle weakness. Peripheral nerve lesions must be distinguished from CNS disease. Peripheral neuropathies and myopathies usually follow a gradual progressive deterioration while central lesions are more commonly acute or subacute. The history and physical examination represent an important part of the evaluation of muscle weakness. Details of the history and physical examination are outlined below. Disease onset and progression as well as the pattern of muscle weakness are key historical features. During the physical examination, the muscle weakness must be objectively confirmed, quantified, and localized if possible. The laboratory and radiographic evaluation should be guided by findings from the history and physical examination. In the absence of features suggesting a particular diagnosis, the evaluation may proceed in a stepwise fashion, beginning with a general laboratory evaluation as outlined below. Medications Associated with Muscle Weakness Amiodarone Chemotherapeutic agents Cimetidine Corticosteroids Gemfibrozil Interferon Lamivudine Leuprolide acetate Methimazole NSAIDs Penicillin Propylthiouracil Statins (HMG-CoA reductase inhibitors) Sulfonamides Zidovudine Causes of Muscle Weakness Cocaine use Electrolyte imbalance • Hypercalcemia • Hyperkalemia • Hypermagnesemia • Hypokalemia • Hypomagnesemia Endocrine causes • Acromegaly • Hyperparathyroidism • Hyperthyroidism • Hypopituitarism • Hypothyroidism • Vitamin D deficiency Genetic causes • Distal myopathies • Muscular dystrophy • Myotonic dystrophy type 2 Infectious causes • Diphtheria • Epstein–Barr virus • HIV • Influenza • Lyme disease • Meningitis • Polio • Rabies • Syphilis • Tetanus • Tick paralysis • Toxoplasmosis Metabolic causes • Acid maltase deficiency • Aldolase A deficiency • Brancher enzyme deficiency • Carnitine deficiency Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS HYPOTHYROIDISM SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on MUSCLE WEAKNESS Full access? Get Clinical Tree
49 MUSCLE WEAKNESS General Discussion The first step in the evaluation of muscle weakness is differentiating true muscle weakness from fatigue and asthenia. Fatigue is the inability to continue performing a task after multiple repetitions while asthenia is a sense of exhaustion in the absence of actual muscle weakness. Peripheral nerve lesions must be distinguished from CNS disease. Peripheral neuropathies and myopathies usually follow a gradual progressive deterioration while central lesions are more commonly acute or subacute. The history and physical examination represent an important part of the evaluation of muscle weakness. Details of the history and physical examination are outlined below. Disease onset and progression as well as the pattern of muscle weakness are key historical features. During the physical examination, the muscle weakness must be objectively confirmed, quantified, and localized if possible. The laboratory and radiographic evaluation should be guided by findings from the history and physical examination. In the absence of features suggesting a particular diagnosis, the evaluation may proceed in a stepwise fashion, beginning with a general laboratory evaluation as outlined below. Medications Associated with Muscle Weakness Amiodarone Chemotherapeutic agents Cimetidine Corticosteroids Gemfibrozil Interferon Lamivudine Leuprolide acetate Methimazole NSAIDs Penicillin Propylthiouracil Statins (HMG-CoA reductase inhibitors) Sulfonamides Zidovudine Causes of Muscle Weakness Cocaine use Electrolyte imbalance • Hypercalcemia • Hyperkalemia • Hypermagnesemia • Hypokalemia • Hypomagnesemia Endocrine causes • Acromegaly • Hyperparathyroidism • Hyperthyroidism • Hypopituitarism • Hypothyroidism • Vitamin D deficiency Genetic causes • Distal myopathies • Muscular dystrophy • Myotonic dystrophy type 2 Infectious causes • Diphtheria • Epstein–Barr virus • HIV • Influenza • Lyme disease • Meningitis • Polio • Rabies • Syphilis • Tetanus • Tick paralysis • Toxoplasmosis Metabolic causes • Acid maltase deficiency • Aldolase A deficiency • Brancher enzyme deficiency • Carnitine deficiency Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS HYPOTHYROIDISM SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on MUSCLE WEAKNESS Full access? Get Clinical Tree
