Editing Weakness (section)

==={{anchor|Asthenia}}Asthenia vs. myasthenia===
'''Asthenia''' or '''asthaenia''' ({{langx|el|ἀσθένεια}}, literally ''lack of strength'' but also ''disease'') is a medical term referring to a condition in which the body lacks or has lost strength either as a whole or in any of its parts. It is a poorly defined condition that can include true or primary [[muscle weakness]] or perceived muscle weakness.<ref>{{Citation |last1=Kauffman |first1=Timothy L. |title=Chapter 16 - Muscle weakness and therapeutic exercise |date=2014-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780702045882000164 |work=A Comprehensive Guide to Geriatric Rehabilitation (Third Edition) |pages=112–119 |editor-last=Kauffman |editor-first=Timothy L. |access-date=2023-11-19 |place=Oxford |publisher=Churchill Livingstone |isbn=978-0-7020-4588-2 |last2=Kemmis |first2=Karen |editor2-last=Scott |editor2-first=Ron |editor3-last=Barr |editor3-first=John O. |editor4-last=Moran |editor4-first=Michael L.}}</ref> For perceived muscle weakness, asthenia has been described as the feeling of weak or tired muscles in the absence of muscle weakness, that is the muscle can generate a normal amount of force but it is perceived as requiring more effort.<ref name=":0">{{Cite journal |last=Saguil |first=Aaron |date=2005-04-01 |title=Evaluation of the Patient with Muscle Weakness |url=https://www.aafp.org/pubs/afp/issues/2005/0401/p1327.html |journal=American Family Physician |language=en-US |volume=71 |issue=7 |pages=1327–1336 |pmid=15832536 |quote=Asthenia is a sense of weariness or exhaustion in the absence of muscle weakness.}}</ref><ref>{{Cite web |date=2021-06-28 |title=Muscle Weakness and Fatigue {{!}} Causes and Treatment |url=https://patient.info/signs-symptoms/tiredness-fatigue/muscle-weakness |access-date=2023-11-19 |website=patient.info |language=en |quote=Muscle tiredness: This is sometimes called asthenia. It is a sense of weariness or exhaustion that you feel when using the muscle. The muscle isn't genuinely weaker, it can still do its job but it takes you more effort to manage it.}}</ref>

General asthenia occurs in many chronic wasting diseases (such as tuberculosis and cancer), sleep disorders or chronic disorders of the heart, lungs or kidneys, and is probably most marked in diseases of the adrenal gland. Moreover, asthenia can be a symptom of [[mast cell activation syndrome|mast cell activation syndrome (MCAS)]].<ref name="PMID27012973">{{cite journal |vauthors=Afrin LB, Butterfield JH, Raithel M, Molderings GJ |title=Often seen, rarely recognized: mast cell activation disease--a guide to diagnosis and therapeutic options |journal=The American Journal of the Medical Science |volume=48 |issue=3 |date=2016 |pages=190-201 |DOI=10.3109/07853890.2016.1161231 |PMID=27012973 |url=|doi-access=free}}</ref> Asthenia may be limited to certain [[organ (anatomy)|organs]] or systems of organs, as in [[asthenopia]], characterized by ready fatiguability. Asthenia is also a side effect of some medications and treatments, such as [[Ritonavir]] (a [[Protease inhibitor (pharmacology)|protease inhibitor]] used in [[HIV]] treatment). <ref>{{Cite web |date=28 November 2022 |title=PubChem Compound Summary for CID 392622, Ritonavir |url=https://pubchem.ncbi.nlm.nih.gov/compound/ritonavir |access-date=28 November 2022 |website=NCBI}}</ref> 

Differentiating psychogenic (perceived) asthenia and true asthenia from myasthenia is often difficult, and in time apparent psychogenic asthenia accompanying many chronic disorders is seen to progress into a primary weakness.{{citation needed|date=August 2021}}

Myasthenia or myasthaenia (my- from {{langx|el|μυο}} meaning "muscle" + -asthenia [''{{lang|el|ἀσθένεια}}''] meaning "weakness"), or simply muscle weakness, is a lack of muscle strength. The causes are many and can be divided into conditions that have either true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in [[neuromuscular disease]]s, such as myasthenia gravis. Perceived muscle weakness occurs in diseases such as sleep disorders, and depression.<ref name=":0" />