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| Image = Muscle wasting in HIV.jpg| | | Image = Muscle wasting in HIV.jpg| |
| Caption = Muscle wasting in HIV. <br> <small> [http://www.peir.net Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology] </small>| | | Caption = Muscle wasting in HIV. <br> <small> [http://www.peir.net Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology] </small>| |
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| }} | | }} |
| {{SI}} | | {{Muscle weakness}} |
| {{CMG}}; '''Associate Editor(s)-In-Chief:''' {{MUT}} | | {{CMG}}; '''Associate Editor(s)-In-Chief:''' {{MUT}} |
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| ==Overview== | | ==[[Muscle weakness overview|Overview]]== |
| Muscle weakness (or "lack of strength") is a direct term for the inability to exert force with ones [[muscle]]s to the degree that would be expected given the individual's general [[physical fitness]]. A test of strength is often used during a [[diagnosis]] of a muscular disorder before the [[etiology]] can be identified. Such etiology depends on the type of muscle weakness, which can be true or perceived as well as variable topically. True weakness is substantial, while perceived rather is a sensation of having to put more effort to do the same task. On the other hand, various topic locations for muscle weakness are central, neural and peripheral. Central muscle weakness is an overall exhaustion of the whole body, while peripheral weakness is an exhaustion of individual muscles. Neural weakness are somewhere between. | |
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| Muscle weakness can be a result of vigorous [[Physical exercise|exercise]] but abnormal fatigue may be caused by barriers to or interference with the different stages of [[muscle contraction]]. | | ==[[Muscle weakness historical perspective|Historical Perspective]]== |
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| In a broader sense, muscle weakness is the physical part of [[fatigue (medical)]].
| | ==[[Muscle weakness classification|Classification]]== |
|
| |
|
| ==Complete Differential Diagnosis of Causes of Muscle weakness== | | ==[[Muscle weakness pathophysiology|Pathophysiology]]== |
| (In alphabetical order)
| |
|
| |
|
| {{MultiCol}}
| | ==[[Muscle weakness causes|Causes]]== |
| *[[3-Methylglutaconic aciduria]]
| |
| *[[3-Quinuclidinyl benzilate]]
| |
| *[[Acamprosate ]]
| |
| *[[Accessory nerve disorder]]
| |
| *[[Acitretin ]]
| |
| *[[Acute intermittent porphyria]]
| |
| *Acute peripheral neuropathy
| |
| *[[Acute viral nasopharyngitis (common cold)]]
| |
| *[[Addison's disease]]
| |
| *[[Adrenal carcinoma]]
| |
| *[[Alcoholic polyneuropathy]]
| |
| *[[Aluminum Hydroxide ]]
| |
| *[[Amiloride and Hydrochlorothiazide ]]
| |
| *[[Amiodarone Oral ]]
| |
| *[[Amyotrophic lateral sclerosis]]
| |
| *[[Anorexia nervosa]]
| |
| *[[Arnold-Chiari malformation]]
| |
| *[[Arthrogryposis]]
| |
| *[[Autism]]
| |
| *[[Bassen-Kornzweig syndrome]]
| |
| *[[Becker's muscular dystrophy]]
| |
| *[[Beclomethasone Oral Inhalation ]]
| |
| *[[Benztropine Mesylate Oral ]]
| |
| *[[Bezafibrate ]]
| |
| *[[Botulism]]
| |
| *[[Brachial plexus injury]]
| |
| *[[Brompheniramine ]]
| |
| *[[Budesonide Inhalation Powder ]]
| |
| *[[Bulimia nervosa]]
| |
| *[[Cadmium poisoning]]
| |
| *[[Carnitine palmitoyltransferase I deficiency]]
| |
| *[[Chloroquine Phosphate Oral ]]
| |
| *[[Chlorothiazide ]]
| |
| *[[Chlorpheniramine ]]
| |
| *[[Chlorthalidone ]]
| |
| *[[Chronic fatigue syndrome]]
| |
| *[[Chronic inflammatory demyelinating polyneuropathy]]
| |
| *[[Ciclesonide Nasal Spray ]]
| |
| *[[Cirrhosis]]
| |
| *[[Clofibrate ]]
| |
| *[[Colistimethate Injection ]]
| |
| *[[Congenital muscular dystrophy]]
| |
| *[[Congenital myasthenic syndrome]]
| |
| *[[Congenital myopathy]]
| |
| *[[Connective tissue disease]]
| |
| *[[Cushing's syndrome]]
| |
| *[[Cyanocobalamin Injection ]]
| |
| *[[Cyproheptadine ]]
| |
| *[[Cytarabine ]]
| |
| *[[Daptomycin]]
| |
| *[[Decompression sickness]]
| |
| *[[Dejerine Sottas syndrome]]
| |
| *[[Dermatomyositis]]
| |
| *[[Desipramine ]]
| |
| *[[Devic's disease]]
| |
| *[[Dexamethasone Oral ]]
| |
| *[[Dextroamphetamine and Amphetamine ]]
| |
| *[[Diabetic amyotrophy]]
| |
| *[[Diabetic neuropathy]]
| |
| *[[Dicamba]]
| |
| *[[Dicyclomine ]]
| |
| *[[Diphenhydramine Oral ]]
| |
| *[[Donepezil ]]
| |
| *[[Dorzolamide and Timolol Ophthalmic ]]
| |
| *[[Doxazosin ]]
| |
| *[[Doxylamine ]]
| |
| *[[Duchenne muscular dystrophy]]
| |
| *[[Emery-Dreifuss Muscular Dystrophy]]
| |
| *[[Engelmann syndrome]]
| |
| *[[Epidural hematoma]]
| |
| *[[Exercise intolerance]]
| |
| *[[Ezetimibe ]]
| |
| *[[Facioscapulohumeral muscular dystrophy]]
| |
| *[[Fexofenadine and Pseudoephedrine ]]
| |
| *[[Fludrocortisone Acetate ]]
| |
| *[[Flunisolide Nasal Inhalation ]]
| |
| *[[Fluoride poisoning]]
| |
| *[[Fluticasone and Salmeterol Oral Inhalation ]]
| |
| *[[Fluvastatin ]]
| |
| *[[Frailty syndrome]]
| |
| *[[Friedreich's ataxia]]
| |
| *[[Galantamine ]]
| |
| *[[Gemeprost]]
| |
| *[[Glucocorticoids]]
| |
| *[[Glutaric aciduria type 1]]
| |
| *[[Glycogen storage disease type II]]
| |
| *[[GM1 gangliosidoses]]
| |
| *[[Graves' Disease]]
| |
| *[[Group A streptococcal infection]]
| |
| *[[Guanidinoacetate methyltransferase deficiency]]
| |
| *[[Guillain-Barre syndrome]]
| |
| *[[Hereditary inclusion body myopathy]]
| |
| *[[Hereditary spastic paraplegia]]
| |
| *[[Herpes zoster]]
| |
| *[[Hexane-2,5-dione]]
| |
| *[[HIV]]
| |
| *[[Hopkins syndrome]]
| |
| *[[Hydrochlorothiazide ]]
| |
| *[[Hydrocortisone Injection ]]
| |
| *[[Hydrocortisone Oral ]]
| |
| *[[Hydroxychloroquine ]]
| |
| *[[Hydroxyzine ]]
| |
| *[[Hyperaldosteronism]]
| |
| *[[Hypercalcemia]]
| |
| *[[Hyperkalaemic periodic paralysis]]
| |
| {{ColBreak}}
| |
| *[[Hyperkalemia]]
| |
| *[[Hypermagnesemia]]
| |
| *[[Hypermethioninemia]]
| |
| *[[Hyperpituitarism]]
| |
| *[[Hyperthyroidism]]
| |
| *[[Hypoglycemia]]
| |
| *[[Hypokalemic periodic paralysis]]
| |
| *[[Hypomagnesemia]]
| |
| *[[Hypophosphatemia]]
| |
| *[[Hypothyroidism]]
| |
| *[[Imiquimod ]]
| |
| *[[Inclusion body myositis]]
| |
| *[[Influenza]]
| |
| *[[Interferon Beta-1b Injection ]]
| |
| *[[Juvenile dermatomyositis]]
| |
| *[[Juvenile primary lateral sclerosis]]
| |
| *[[Kennedy disease]]
| |
| *[[Krabbe disease]]
| |
| *[[Lambert-Eaton myasthenic syndrome]]
| |
| *[[Leflunomide ]]
| |
| *[[Letrozole ]]
| |
| *[[Levalbuterol Oral Inhalation ]]
| |
| *[[Limb-girdle muscular dystrophy]]
| |
| *[[Lisinopril and Hydrochlorothiazide ]]
| |
| *[[Lithium ]]
| |
| *[[Loprazolam]]
| |
| *[[Lormetazepam]]
| |
| *[[Lovastatin ]]
| |
| *[[Low-carbohydrate diet]]
| |
| *[[Machado-Joseph disease]]
| |
| *[[Marinesco-Sjogren syndrome]]
| |
| *[[Mepyramine]]
| |
| *[[Metabolic acidosis]]
| |
| *[[Metachromatic leukodystrophy]]
| |
| *[[Methyclothiazide ]]
| |
| *[[Methyldopa and Hydrochlorothiazide ]]
| |
| *[[Methylprednisolone Oral ]]
| |
| *[[Metolazone ]]
| |
| *[[Mitochondrial trifunctional protein deficiency]]
| |
| *[[Motor neurone disease]]
| |
| *[[Multiple sclerosis]]
| |
| *[[Myasthenia gravis]]
| |
| *[[Nelson's syndrome]]
| |
| *[[Nemaline myopathy]]
| |
| *[[Nitrazepam]]
| |
| *[[Nitrofurantoin ]]
| |
| *[[Oxcarbazepine ]]
| |
| *[[Peripheral Arterial Disease]]
| |
| *[[Peripheral neuropathy]]
| |
| *[[Phosphofructokinase deficiency]]
| |
| *[[Poliomyelitis]]
| |
| *[[Polymyositis]]
| |
| *[[Postherpetic neuralgia]]
| |
| *[[Post-polio syndrome]]
| |
| *[[Pott's disease]]
| |
| *[[Pramipexole ]]
| |
| *[[Pravastatin ]]
| |
| *[[Prazosin and polythiazide ]]
| |
| *[[Prednisone]]
| |
| *[[Primary carnitine deficiency]]
| |
| *[[Primary hyperparathyroidism]]
| |
| *[[Primary lateral sclerosis]]
| |
| *[[Procyclidine ]]
| |
| *[[Pseudoephedrine and triprolidine ]]
| |
| *[[Pyridostigmine ]]
| |
| *[[Pyruvate carboxylase deficiency]]
| |
| *[[Reserpine, hydralazine, and hydrochlorothiazide ]]
| |
| *[[Rhabdomyolysis]]
| |
| *[[Rhabdomyolysis]]
| |
| *[[Rheumatoid Arthritis]]
| |
| *[[Rhinovirus]]
| |
| *[[Riluzole ]]
| |
| *[[Rosuvastatin ]]
| |
| *[[Salmeterol oral inhalation ]]
| |
| *[[Sandhoff disease]]
| |
| *[[Schilder's disease]]
| |
| *[[Scleroderma]]
| |
| *[[Selegiline ]]
| |
| *[[Sjogren's Syndrome]]
| |
| *[[Small fiber peripheral neuropathy]]
| |
| *[[Somatization disorder]]
| |
| *[[Spinal cord injury]]
| |
| *[[Spinal disc herniation]]
| |
| *[[Spinal stenosis]]
| |
| *[[Spironolactone ]]
| |
| *[[Spondylosis]]
| |
| *[[Sturge-Weber syndrome]]
| |
| *[[Tabes dorsalis]]
| |
| *[[Tamoxifen ]]
| |
| *[[Telbivudine ]]
| |
| *[[Temik]]
| |
| *[[Tension myositis syndrome]]
| |
| *[[Teriparatide (rDNA origin) Injection ]]
| |
| *[[Thyrotoxicosis]]
| |
| *[[Tocopherol]]
| |
| *[[Topiramate]]
| |
| *[[Trastuzumab ]]
| |
| *[[Triamcinolone Nasal Inhalation ]]
| |
| *[[Triamterene ]]
| |
| *[[Trimeprazine ]]
| |
| *[[Uremia]]
| |
| *[[Variegate porphyria]]
| |
| *[[Vitamin D deficiency]]
| |
| *[[Walker-Warburg syndrome]]
| |
| *[[Zoledronic Acid Injection ]]
| |
| {{EndMultiCol}}
| |
|
| |
|
| ===Complete Differential Diagnosis of the Causes of Muscle weakness=== | | ==[[Muscle weakness differential diagnosis|Differentiating Muscle Weakness from other Diseases]]== |
| (By organ system)
| |
| {|style="width:80%; height:100px" border="1"
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| |style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
| |
| |style="height:100px"; style="width:75%" border="1" bgcolor="Beige" |
| |
| [[Peripheral Arterial Disease]],
| |
|
| |
|
| |-
| | ==[[Muscle weakness epidemiology and demographics|Epidemiology and Demographics]]== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Chemical / poisoning'''
| |
| |bgcolor="Beige"|
| |
| [[Cadmium poisoning]], | |
| [[Dicamba]],
| |
| [[Fluoride poisoning]],
| |
| [[Hexane-2,5-dione]],
| |
| [[Temik]],
| |
|
| |
|
| |-
| | ==[[Muscle weakness risk factors|Risk Factors]]== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Dermatologic'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Drug Side Effect'''
| |
| |bgcolor="Beige"|
| |
| [[3-Quinuclidinyl benzilate]], | |
| [[Acamprosate (patient information)]],
| |
| [[Acitretin (patient information)]],
| |
| [[Aluminum Hydroxide (patient information)]],
| |
| [[Amiloride and Hydrochlorothiazide (patient information)]],
| |
| [[Amiodarone Oral (patient information)]],
| |
| [[Beclomethasone Oral Inhalation (patient information)]],
| |
| [[Benztropine Mesylate Oral (patient information)]],
| |
| [[Bezafibrate (patient information)]],
| |
| [[Brompheniramine (patient information)]],
| |
| [[Budesonide Inhalation Powder (patient information)]],
| |
| [[Chloroquine Phosphate Oral (patient information)]],
| |
| [[Chlorothiazide (patient information)]],
| |
| [[Chlorpheniramine (patient information)]],
| |
| [[Chlorthalidone (patient information)]],
| |
| [[Ciclesonide Nasal Spray (patient information)]],
| |
| [[Clofibrate (patient information)]],
| |
| [[Colistimethate Injection (patient information)]],
| |
| [[Cyanocobalamin Injection (patient information)]],
| |
| [[Cyproheptadine (patient information)]],
| |
| [[Cytarabine (patient information)]],
| |
| [[Daptomycin]],
| |
| [[Desipramine (patient information)]],
| |
| [[Dexamethasone Oral (patient information)]],
| |
| [[Dextroamphetamine and Amphetamine (patient information)]],
| |
| [[Dicyclomine (patient information)]],
| |
| [[Diphenhydramine Oral (patient information)]],
| |
| [[Donepezil (patient information)]],
| |
| [[Dorzolamide and Timolol Ophthalmic (patient information)]],
| |
| [[Doxazosin (patient information)]],
| |
| [[Doxylamine (patient information)]],
| |
| [[Ezetimibe (patient information)]],
| |
| [[Fexofenadine and Pseudoephedrine (patient information)]],
| |
| [[Fludrocortisone Acetate (patient information)]],
| |
| [[Flunisolide Nasal Inhalation (patient information)]],
| |
| [[Fluticasone and Salmeterol Oral Inhalation (patient information)]],
| |
| [[Fluvastatin (patient information)]],
| |
| [[Galantamine (patient information)]],
| |
| [[Gemeprost]],
| |
| [[Glucocorticoids]],
| |
| [[Hydrochlorothiazide (patient information)]],
| |
| [[Hydrocortisone Injection (patient information)]],
| |
| [[Hydrocortisone Oral (patient information)]],
| |
| [[Hydroxychloroquine (patient information)]],
| |
| [[Hydroxyzine (patient information)]],
| |
| [[Imiquimod (patient information)]],
| |
| [[Insulin lispro injection (patient information)]],
| |
| [[Interferon Beta-1b Injection (patient information)]],
| |
| [[Leflunomide (patient information)]],
| |
| [[Letrozole (patient information)]],
| |
| [[Levalbuterol Oral Inhalation (patient information)]],
| |
| [[Lisinopril and Hydrochlorothiazide (patient information)]],
| |
| [[Lithium (patient information)]],
| |
| [[Loprazolam]],
| |
| [[Lormetazepam]],
| |
| [[Lovastatin (patient information)]],
| |
| [[Mepyramine]],
| |
| [[Methyclothiazide (patient information)]],
| |
| [[Methyldopa and Hydrochlorothiazide (patient information)]],
| |
| [[Methylprednisolone Oral (patient information)]],
| |
| [[Metolazone (patient information)]],
| |
| [[Nitrazepam]],
| |
| [[Nitrofurantoin (patient information)]],
| |
| [[Oxcarbazepine (patient information)]],
| |
| [[Pramipexole (patient information)]],
| |
| [[Pravastatin (patient information)]],
| |
| [[Prazosin and polythiazide (patient information)]],
| |
| [[Prednisone]],
| |
| [[Procyclidine (patient information)]],
| |
| [[Pseudoephedrine and triprolidine (patient information)]],
| |
| [[Pyridostigmine (patient information)]],
| |
| [[Reserpine, hydralazine, and hydrochlorothiazide (patient information)]],
| |
| [[Riluzole (patient information)]],
| |
| [[Rosuvastatin (patient information)]],
| |
| [[Salmeterol oral inhalation (patient information)]],
| |
| [[Selegiline (patient information)]],
| |
| [[Spironolactone (patient information)]],
| |
| [[Tamoxifen (patient information)]],
| |
| [[Telbivudine (patient information)]],
| |
| [[Teriparatide (rDNA origin) Injection (patient information)]],
| |
| [[Tocopherol]],
| |
| [[Topiramate]],
| |
| [[Trastuzumab (patient information)]],
| |
| [[Triamcinolone Nasal Inhalation (patient information)]],
| |
| [[Triamterene (patient information)]],
| |
| [[Trimeprazine (patient information)]],
| |
| [[Zoledronic Acid Injection (patient information)]],
| |
|
| |
|
| |-
| | ==[[Muscle weakness screening|Screening]]== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Ear Nose Throat'''
| |
| |bgcolor="Beige"|
| |
| [[Acute viral nasopharyngitis (common cold)]], | |
|
| |
|
| |-
| | ==[[Muscle weakness natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Endocrine'''
| |
| |bgcolor="Beige"|
| |
| [[Addison's disease]], | |
| [[Cushing's syndrome]],
| |
| [[Graves' Disease]],
| |
| [[Hyperaldosteronism]],
| |
| [[Hyperpituitarism]],
| |
| [[Hyperthyroidism]],
| |
| [[Hypothyroidism]],
| |
| [[Kennedy disease]],
| |
| [[Thyrotoxicosis]],
| |
|
| |
|
| |- | | ==Diagnosis== |
| |-bgcolor="LightSteelBlue" | | [[Muscle weakness history and symptoms|History and Symptoms]] | [[Muscle weakness physical examination|Physical Examination]] | [[Muscle weakness laboratory findings|Laboratory Findings]] | [[Muscle weakness electrocardiogram|Electrocardiogram]] | [[Muscle weakness chest x ray|Chest X Ray]] | [[Muscle weakness CT|CT]] | [[Muscle weakness MRI|MRI]] | [[Muscle weakness other imaging findings|Other Imaging Findings]] | [[Muscle weakness other diagnostic studies|Other Diagnostic Studies]] |
| | '''Environmental''' | |
| |bgcolor="Beige"| No underlying causes | |
| |- | |
| |-bgcolor="LightSteelBlue" | |
| | '''Gastroenterologic''' | |
| |bgcolor="Beige"| [[Cirrhosis]], | |
|
| |
|
| |-
| | ==Treatment== |
| |-bgcolor="LightSteelBlue"
| | [[Muscle weakness medical therapy|Medical Therapy]] | [[Muscle weakness primary prevention|Primary Prevention]] | [[Muscle weakness secondary prevention|Secondary Prevention]] | [[Muscle weakness cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Muscle weakness future or investigational therapies|Future or Investigational Therapies]] |
| | '''Genetic'''
| |
| |bgcolor="Beige"|
| |
| [[Bassen-Kornzweig syndrome]], | |
| [[Becker's muscular dystrophy]],
| |
| [[Carnitine palmitoyltransferase I deficiency]],
| |
| [[Dejerine Sottas syndrome]],
| |
| [[Devic's disease]],
| |
| [[Engelmann syndrome]],
| |
| [[Glutaric aciduria type 1]],
| |
| [[Glycogen storage disease type II]],
| |
| [[GM1 gangliosidoses]],
| |
| [[Hereditary inclusion body myopathy]],
| |
| [[Hereditary spastic paraplegia]],
| |
| [[Metachromatic leukodystrophy]],
| |
| [[Nemaline myopathy]],
| |
| [[Phosphofructokinase deficiency]],
| |
| [[Primary carnitine deficiency]], | |
| [[Pyruvate carboxylase deficiency]], | |
| [[Sandhoff disease]], | |
| [[Walker-Warburg syndrome]], | |
|
| |
|
| |-
| | ==Case Studies== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Hematologic'''
| |
| |bgcolor="Beige"|
| |
| [[Acute intermittent porphyria]],
| |
| [[Variegate porphyria]],
| |
|
| |
|
| |-
| | [[Muscle weakness case study one|Case #1]] |
| |-bgcolor="LightSteelBlue"
| |
| | '''Iatrogenic'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Infectious Disease'''
| |
| |bgcolor="Beige"|
| |
| [[Botulism]], | |
| [[Group A streptococcal infection]],
| |
| [[HIV]],
| |
| [[Influenza]],
| |
| [[Polymyositis]],
| |
| [[Pott's disease]],
| |
| [[Rhinovirus]],
| |
|
| |
|
| |-
| | ==Related Chapters== |
| |-bgcolor="LightSteelBlue"
| |
| | '''Musculoskeletal / Ortho'''
| |
| |bgcolor="Beige"|
| |
| [[Arthrogryposis]],
| |
| [[Congenital muscular dystrophy]],
| |
| [[Congenital myasthenic syndrome]],
| |
| [[Congenital myopathy]],
| |
| [[Dermatomyositis]],
| |
| [[Diabetic amyotrophy]],
| |
| [[Duchenne muscular dystrophy]],
| |
| [[Emery-Dreifuss Muscular Dystrophy]],
| |
| [[Facioscapulohumeral muscular dystrophy]],
| |
| [[Inclusion body myositis]],
| |
| [[Rhabdomyolysis]],
| |
| [[Spondylosis]],
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Neurologic'''
| |
| |bgcolor="Beige"|
| |
| [[Accessory nerve disorder]],
| |
| Acute peripheral neuropathy,
| |
| [[Amyotrophic lateral sclerosis]],
| |
| [[Arnold-Chiari malformation]],
| |
| [[Chronic inflammatory demyelinating polyneuropathy]],
| |
| [[Diabetic neuropathy]],
| |
| [[Epidural hematoma]],
| |
| [[Friedreich's ataxia]],
| |
| [[Guillain-Barre syndrome]],
| |
| [[Juvenile primary lateral sclerosis]],
| |
| [[Machado-Joseph disease]],
| |
| [[Marinesco-Sjogren syndrome]],
| |
| [[Motor neurone disease]],
| |
| [[Multiple sclerosis]],
| |
| [[Myasthenia gravis]],
| |
| [[Peripheral neuropathy]],
| |
| [[Sturge-Weber syndrome]],
| |
| [[Tabes dorsalis]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Nutritional / Metabolic'''
| |
| |bgcolor="Beige"|
| |
| [[3-Methylglutaconic aciduria]],
| |
| [[Guanidinoacetate methyltransferase deficiency]],
| |
| [[Metabolic acidosis]],
| |
| [[Vitamin D deficiency]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Obstetric/Gynecologic'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Oncologic'''
| |
| |bgcolor="Beige"|
| |
| [[Adrenal carcinoma]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Opthalmologic'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
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| | '''Overdose / Toxicity'''
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| |bgcolor="Beige"|
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| [[Benztropine Mesylate Oral (patient information)]],
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| [[Fexofenadine and Pseudoephedrine (patient information)]],
| |
| [[Galantamine (patient information)]],
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| [[Salmeterol oral inhalation (patient information)]],
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| [[Topiramate]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Psychiatric'''
| |
| |bgcolor="Beige"|
| |
| [[Anorexia nervosa]],
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| [[Bulimia nervosa]],
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| [[Tension myositis syndrome]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Pulmonary'''
| |
| |bgcolor="Beige"|
| |
| [[Hopkins syndrome]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Renal / Electrolyte'''
| |
| |bgcolor="Beige"|
| |
| [[Hypercalcemia]],
| |
| [[Hyperkalaemic periodic paralysis]],
| |
| [[Hypermagnesemia]],
| |
| [[Hypermethioninemia]],
| |
| [[Hypokalemic periodic paralysis]],
| |
| [[Hypomagnesemia]],
| |
| [[Hypophosphatemia]],
| |
| [[Uremia]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Rheum / Immune / Allergy'''
| |
| |bgcolor="Beige"|
| |
| [[Congenital myasthenic syndrome]],
| |
| [[Graves' Disease]],
| |
| [[Krabbe disease]],
| |
| [[Lambert-Eaton myasthenic syndrome]],
| |
| [[Rheumatoid Arthritis]],
| |
| [[Scleroderma]],
| |
| [[Sjogren's Syndrome]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Sexual'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Trauma'''
| |
| |bgcolor="Beige"|
| |
| [[Brachial plexus injury]],
| |
| | |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Urologic'''
| |
| |bgcolor="Beige"| No underlying causes
| |
| |-
| |
| |-bgcolor="LightSteelBlue"
| |
| | '''Miscellaneous'''
| |
| |bgcolor="Beige"|
| |
| [[Alcoholic polyneuropathy]],
| |
| [[Chronic fatigue syndrome]],
| |
| [[Mitochondrial trifunctional protein deficiency]],
| |
| [[Spinal cord injury]],
| |
| [[Spinal disc herniation]],
| |
| [[Spinal stenosis]],
| |
| |-
| |
| |}
| |
| | |
| ==True vs. perceived==
| |
| The term subsumes two other more specific terms, ''true weakness'' and ''perceived weakness''.
| |
| | |
| * '''True weakness''' (or "objective weakness") describes a condition where the instantaneous force exerted by the muscles is less than would be expected. For instance, if a patient suffers from [[amyotrophic lateral sclerosis]] (ALS), [[motor neuron]]s are damaged and can no longer stimulate the muscles to exert normal force.
| |
| | |
| * '''Perceived weakness''' (or "subjective weakness") describes a condition where it seems to the patient that more effort than normal is required to exert a given amount of force.<ref>{{cite journal |author=Enoka RM, Stuart DG |title=Neurobiology of muscle fatigue |journal=J. Appl. Physiol. |volume=72 |issue=5 |pages=1631-48 |year=1992 |pmid=1601767 |doi=}}</ref> For instance, in some people with [[chronic fatigue syndrome]] (CFS) who may struggle to climb a set of stairs when feeling especially fatigued, their muscle strength when objectively measured (eg, the maximum weight they can press with their legs) is essentially normal, though this is not true for CFS patients who may be disabled through post-exertional weakness/malaise etc. and in severe cases may not be able to climb a flight of stairs.
| |
| | |
| In some conditions, such as [[myasthenia gravis]] muscle strength is normal when resting, but ''true weakness'' occurs after the muscle has been subjected to exercise. This is also true for some cases of CFS, where objective post-exertion muscle weakness with delayed recovery time has been measured and is a feature of some of the published definitions. <ref>Paul L, Wood L, Behan WM, Maclaren WM; Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome. European Journal of Neurology 1999 Jan;6(1):63-69 PMID: 10209352</ref><ref>McCully K K, Natelson B H; Impaired oxygen delivery to muscle in chronic fatigue syndrome. Clinical Science 1999:97:603-608</ref><ref>Pascale De Becker, PhD; Johan Roeykens, PT; Masha Reynders, PT; Neil McGregor, MD, PhD; Exercise Capacity in Chronic Fatigue Syndrome. Archives of Internal Medicine Vol. 160 No. 21, November 27, 2000 </ref><ref>De Becker P, McGregor N, De Meirleir K. A definition-based analysis of symptoms in a large cohort of patients with chronic fatigue syndrome. J Intern Med 2001;250:234-240.</ref><ref>Bruce M Carruthers, Anil Kumar Jain, Kenny L De Meirleir, Daniel L Peterson, Nancy G Klimas et al, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical Working Case Definition, Diagnostic and Treatment Guidelines, A Consensus Document Journal of Chronic Fatigue Syndrome 11(1):7-115, 2003. ISBN 0-7890-227-9</ref><ref>Jammes Y, Steinberg JG, Mambrini O, Bregeon F, Delliaux S; Chronic fatigue syndrome: assessment of increased oxidative stress and altered muscle excitability in response to incremental exercise. J Intern Med., 2005 Mar;257(3):299-310.</ref>.
| |
| | |
| ==Topically==
| |
| In addition to true/perceived, muscle weaknes can also be central, neural and peripheral. Central muscle weakness manifests as an overall, bodily or systemic, sense of energy deprivation, and peripheral weakness manifests as a local, muscle-specific incapacity to do work. <ref>{{cite journal |author=Gandevia SC, Enoka RM, McComas AJ, Stuart DG, Thomas CK |title=Neurobiology of muscle fatigue. Advances and issues |journal=Adv. Exp. Med. Biol. |volume=384 |issue= |pages=515-25 |year=1995 |pmid=8585476 |doi=}}</ref><ref>{{cite journal |author=Kent-Braun JA |title=Central and peripheral contributions to muscle fatigue in humans during sustained maximal effort |journal=European journal of applied physiology and occupational physiology |volume=80 |issue=1 |pages=57-63 |year=1999 |pmid=10367724 |doi=}}</ref>. Neural weakness can be both central and peripheral.
| |
| | |
| ===Central===
| |
| The central component to muscle fatigue is generally described in terms of a reduction in the [[nervous system|neural]] drive or nerve-based motor command to working muscles that results in a decline in the force output.<ref>{{cite journal |author=Gandevia SC |title=Spinal and supraspinal factors in human muscle fatigue |journal=Physiol. Rev. |volume=81 |issue=4 |pages=1725-89 |year=2001 |pmid=11581501 |doi=}}</ref><ref>{{cite journal |author=Kay D, Marino FE, Cannon J, St Clair Gibson A, Lambert MI, Noakes TD |title=Evidence for neuromuscular fatigue during high-intensity cycling in warm, humid conditions |journal=Eur. J. Appl. Physiol. |volume=84 |issue=1-2 |pages=115-21 |year=2001 |pmid=11394239 |doi=}}</ref><ref>{{cite journal |author=Vandewalle H, Maton B, Le Bozec S, Guerenbourg G |title=An electromyographic study of an all-out exercise on a cycle ergometer |journal=Archives internationales de physiologie, de biochimie et de biophysique |volume=99 |issue=1 |pages=89-93 |year=1991 |pmid=1713492 |doi=}}</ref> It has been suggested that the reduced neural drive during exercise may be a protective mechanism to prevent organ failure if the work was continued at the same intensity.<ref>{{cite journal |author=Bigland-Ritchie B, Woods JJ |title=Changes in muscle contractile properties and neural control during human muscular fatigue |journal=Muscle Nerve |volume=7 |issue=9 |pages=691-9 |year=1984 |pmid=6100456 |doi=10.1002/mus.880070902}}</ref><ref>{{cite journal |author=Noakes TD |title=Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance |journal=Scandinavian journal of medicine & science in sports |volume=10 |issue=3 |pages=123-45 |year=2000 |pmid=10843507 |doi=}}</ref> The exact mechanisms of central fatigue are unknown although there has been a great deal of interest in the role of serotonergic pathways.<ref>{{cite journal |author=Davis JM |title=Carbohydrates, branched-chain amino acids, and endurance: the central fatigue hypothesis |journal=International journal of sport nutrition |volume=5 Suppl |issue= |pages=S29-38 |year=1995 |pmid=7550256 |doi=}}</ref><ref>Newsholme, E. A., Acworth, I. N., & Blomstrand, E. 1987, 'Amino acids, brain neurotransmitters and a functional link between muscle and brain that is important in sustained exercise', in G Benzi (ed.), Advances in Myochemistry, Libbey Eurotext, London, pp. 127-133.</ref><ref>{{cite journal |author=Newsholme EA, Blomstrand E |title=Tryptophan, 5-hydroxytryptamine and a possible explanation for central fatigue |journal=Adv. Exp. Med. Biol. |volume=384 |issue= |pages=315-20 |year=1995 |pmid=8585461 |doi=}}</ref>
| |
| | |
| ===Neural===
| |
| [[Nerve]]s are responsible for controlling the contraction of muscles, determining the number, sequence and force of muscular contraction. Most movements require a force far below what a muscle could in potential generate, and barring [[pathology]] nervous fatigue is seldom an issue. For extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, nervous fatigue can be a limiting factor in untrained individuals. In novice [[strength training|strength trainers]], the muscle's ability to generate force is most strongly limited by nerve’s ability to sustain a high-frequency signal. After a period of maximum contraction, the nerve’s signal reduces in frequency and the force generated by the contraction diminishes. There is no sensation of pain or discomfort, the muscle appears to simply ‘stop listening’ and gradually cease to move, often [[Muscle contraction#Eccentric contraction|going backwards]]. As there is insufficient stress on the muscles and tendons, there will often be no [[delayed onset muscle soreness]] following the workout. Part of the process of strength training is increasing the nerve's ability to generate sustained, high frequency signals which allow a muscle to contract with their greatest force. It is this neural training that causes several weeks worth of rapid gains in strength, which level off once the nerve is generating maximum contractions and the muscle reaches its physiological limit. Past this point, training effects increase muscular strength through myofibrilar or sarcoplasmic [[Muscle_hypertrophy#Strength_training|hypertrophy]] and metabolic fatigue becomes the factor limiting contractile force.
| |
| | |
| ===Peripheral===
| |
| Peripheral muscle fatigue during physical work is considered an inability for the body to supply sufficient energy or other metabolites to the contracting muscles to meet the increased energy demand. This is the most common case of physical fatigue--affecting a national average of 72% of adults in the work force in 2002. This causes contractile dysfunction that is manifested in the eventual reduction or lack of ability of a single muscle or local group of muscles to do work. The insufficiency of energy, i.e. sub-optimal [[cellular respiration|aerobic metabolism]], generally results in the accumulation of [[lactic acid]] and other [[acid|acidic]] anaerobic metabolic by-products in the muscle, causing the stereotypical burning sensation of local muscle fatigue.
| |
| | |
| The fundamental difference between the peripheral and central theories of muscle fatigue is that the peripheral model of muscle fatigue assumes failure at one or more sites in the chain that initiates muscle contraction. Peripheral regulation is therefore dependent on the localised metabolic chemical conditions of the local muscle affected, whereas the central model of muscle fatigue is an integrated mechanism that works to preserve the integrity of the system by initiating muscle fatigue through muscle derecruitment, based on collective feedback from the periphery, before cellular or organ failure occurs. Therefore the feedback that is read by this central regulator could include chemical and mechanical as well as cognitive cues. The significance of each of these factors will depend on the nature of the fatigue-inducing work that is being performed.
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| | |
| Though not universally used, ‘metabolic fatigue’ is a common alternative term for peripheral muscle weakness, because of the reduction in contractile force due to the direct or indirect effects of the reduction of substrates or accumulation of metabolites within the [[muscle fiber]]. This can occur through a simple lack of energy to fuel contraction, or interference with the ability of Ca<sup>2+</sup> to stimulate [[actin]] and [[myosin]] to contract.
| |
| | |
| ====Substrates====
| |
| [[Substrate (biochemistry)|Substrates]] within the muscle generally serve to power muscular contractions. They include molecules such as [[adenosine triphosphate]] (ATP), [[glycogen]] and [[Phosphocreatine|creatine phosphate]]. ATP binds to the [[myosin]] head and causes the ‘ratchetting’ that results in contraction according to the [[Sliding filament mechanism|sliding filament model]]. Creatine phosphate stores energy so ATP can be rapidly regenerated within the muscle cells from [[adenosine diphosphate]] (ADP) and inorganic phosphate ions, allowing for sustained powerful contractions that last between 5-7 seconds. Glycogen is the intramuscular storage form of [[glucose]], used to generate energy quickly once intramuscular creatine stores are exhausted, producing [[lactic acid]] as a metabolic byproduct.
| |
| | |
| Substrates produce metabolic fatigue by being depleted during exercise, resulting in a lack of intracellular energy sources to fuel contractions. In essence, the muscle stops contracting because it lacks the energy to do so.
| |
| | |
| ====Metabolites====
| |
| Metabolites are the substances (generally waste products) produced as a result of muscular contraction. They include ADP, [[Magnesium|Mg<sup>2+</sup>]], [[reactive oxygen species]] and inorganic phosphate. Accumulation of metabolites can directly or indirectly produce metabolic fatigue within muscle fibers through interference with the release of calcium from the sarcoplasmic reticulum or reduction of the sensitivity of contractile molecules [[actin]] and [[myosin]] to calcium.
| |
| | |
| =====Chloride=====
| |
| Intracellular [[chloride]] inhibits the contraction of muscles, preventing them from contracting due to "false alarms", small stimuli which may cause them to contract (akin to [[myoclonus]]). This natural brake helps muscles respond solely to the conscious control or [[Tendon reflex|spinal reflexes]] but also has the effect of reducing the force of conscious contractions.
| |
| | |
| =====Potassium=====
| |
| High concentrations of [[potassium]] also causes the muscle cells to decrease in efficiency, causing cramping and fatigue. Potassium builds up in the [[t-tubule]] system and around the muscle fiber in general. This has the effect of depolarizing the muscle fiber, preventing the [[Na+/K+-ATPase|sodium-potassium pump]] from moving [[Sodium|Na<sup>+</sup>]] out of the cell. This reduces the amplitude of [[action potential]]s, or stops them entirely, resulting in [[#nervous fatigue|neurological fatigue]].
| |
| | |
| =====Lactic acid=====
| |
| It was once believed that [[lactic acid]] build-up was the cause of muscle fatigue.<ref>Muscle fatigue and lactic acid accumulation. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3471061&dopt=Citation abstract]</ref> The assumption was lactic acid had a "pickling" effect on muscles, inhibiting their ability to contract. The impact of lactic acid on performance is now uncertain, it may assist or hinder muscle fatigue.
| |
| | |
| Produced as a by-product of [[lactic acid fermentation|fermentation]], lactic acid can increase intracellular acidity of muscles. This can lower the sensitivity of contractile apparatus to Ca<sup>2+</sup> but also has the effect of increasing [[cytoplasm|cytoplasmic]] Ca<sup>2+</sup> concentration through an inhibition of the [[sodium-calcium exchanger|chemical pump]] that [[Active transport|actively transports]] calcium out of the cell. This counters inhibiting effects of [[#Potassium|K<sup>+</sup>]] on muscular action potentials. Lactic acid also has a negating effect on the chloride ions in the muscles, reducing their inhibition of contraction and leaving potassium ions as the only restricting influence on muscle contractions, though the effects of potassium are much less than if there were no lactic acid to remove the chloride ions. Ultimately, it is uncertain if lactic acid reduces fatigue through increased intracellular calcium or increases fatigue through reduced sensitivity of contractile proteins to Ca<sup>2+</sup>.
| |
| | |
| ==Associated conditions==
| |
| Muscle weakness may be due to problems with the [[neuropathy|nerve supply]], [[neuromuscular disease]] such as [[myasthenia gravis]]) or problems with muscle itself. The latter category includes [[polymyositis]] and other [[myopathy|muscle disorders]]
| |
| | |
| * [[Amyotrophic lateral sclerosis]]
| |
| * [[Botulism]]
| |
| * [[Centronuclear myopathy (including myotubular myopathy)|Centronuclear myopathy]]
| |
| * Myotubular [[myopathy]]
| |
| * [[Dysautonomia]]
| |
| * [[Charcot-Marie-Tooth disease]]
| |
| * [[Hypokalemia]]
| |
| * [[Motor neurone disease]]
| |
| * [[Muscular dystrophy]]
| |
| * [[Myasthenia Gravis]]
| |
| * [[Progressive muscular atrophy]]
| |
| * [[Spinal muscular atrophy]]
| |
| * [[Cerebral palsy]]
| |
| * [[Infectious mononucleosis]]
| |
| * [[Herpes Zoster]]
| |
| * [[Vitamin D deficiency]]
| |
| * [[Fibromyalgia]]
| |
| * [[Celiac Disease]]
| |
| * [[Hypercortisolism]] ([[Cushing's syndrome]])
| |
| * [[Hypocortisolism]] ([[Addison's disease]])
| |
| * [[Primary hyperaldosteronism]] ([[Conn's syndrome]])
| |
| * [[Ehlers-Danlos syndrome]]
| |
| | |
| ==See also==
| |
| * [[Asthenia]] | | * [[Asthenia]] |
| * [[Paresis]] | | * [[Paresis]] |
| Line 641: |
Line 50: |
| * [[Dystrophy]] | | * [[Dystrophy]] |
|
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|
| ==Diagnostic Findings==
| | {{Symptoms and signs}} |
| | | {{WikiDoc Help Menu}} |
| [http://www.peir.net Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology]
| | {{WikiDoc Sources}} |
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Spinal cord ependymoma.jpg|Spinal cord ependymoma
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| </gallery>
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| </div>
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| | |
| ==References==
| |
| | |
| {{reflist|2}} | |
| | |
| {{Symptoms and signs}} | |
|
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|
| | [[Category:Disease]] |
| | [[Category:Emergency medicine]] |
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| | [[Category:Immunology]] |
| | [[Category:Metabolic disorders]] |
| | [[Category:Neurology]] |
| | [[Category:Orthopedics]] |
| | [[Category:Rheumatology]] |
| [[Category:Symptoms]] | | [[Category:Symptoms]] |
| [[Category:Neurology]] | | [[Category:Signs and symptoms]] |
| | [[Category:Medical signs]] |
| [[Category:Muscular system]] | | [[Category:Muscular system]] |
| [[Category:Overview complete]]
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| [[Category:Signs and symptoms]]
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| [[Category:primary care]]
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