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Anorexia is a decreased appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a decreased appetite, some of which may be harmless, while others indicate a serious clinical condition or pose a significant risk.

SpecialtyOncology, Psychiatry

For example, anorexia of infection is part of the acute phase response (APR) to infection. The APR can be triggered by lipopolysaccharides and peptidoglycans from bacterial cell walls, bacterial DNA, and double-stranded viral RNA, and viral glycoproteins, which can trigger production of a variety of proinflammatory cytokines. These can have an indirect effect on appetite by a number of means, including peripheral afferents from their sites of production in the body, by enhancing production of leptin from fat stores. Inflammatory cytokines can also signal to the central nervous system more directly by specialized transport mechanisms through the blood–brain barrier, via circumventricular organs (which are outside the barrier), or by triggering production of eicosanoids in the endothelial cells of the brain vasculature. Ultimately the control of appetite by this mechanism is thought to be mediated by the same factors normally controlling appetite, such as neurotransmitters (serotonin, dopamine, histamine, norepinephrine, corticotropin releasing factor, neuropeptide Y, and α-melanocyte-stimulating hormone).[1] The term is from Ancient Greek ανορεξία: 'ἀν-' "without" + 'όρεξις', spelled 'órexis' meaning "appetite".[2]


An example of severe anorexia (anorexia nervosa)



  • During the post-operative recovery period for a tonsillectomy or adenoidectomy, it is common for adult patients to experience a lack of appetite until their throat significantly heals (usually 10–14 days).[7]
  • Altitude sickness
  • Significant emotional pain caused by an event (rather than a mental disorder) can cause an individual to temporarily lose all interest in food.
  • Psychological Stress
  • Experiencing grotesque or unappealing thoughts or conversations, or viewing similar images
  • Being in the presence of unappealing things such as waste matter, dead organisms, or bad smells


Sudden cardiac deathEdit

Anorexia is a relatively common condition that can lead patients to have dangerous electrolyte imbalances, leading to acquired long QT syndrome which can result in sudden cardiac death. This can develop over a prolonged period of time, and the risk is further heightened when feeding resumes after a period of abstaining from consumption. Care must be taken under such circumstances to avoid potentially fatal complications of refeeding syndrome.[8]


  1. ^ Langhans W (October 2000). "Anorexia of infection: current prospects". Nutrition. 16 (10): 996–1005. doi:10.1016/s0899-9007(00)00421-4. PMID 11054606.
  2. ^ Psyhogeos, Matina (14 April 2016). Page Publishing Inc. (ed.). English Words Deriving from the Greek Language. ISBN 978-1682134283.
  3. ^ Taylor AK, Lebwohl B, Snyder CL, Green PHR (17 September 2015). "Celiac Disease". GeneReviews®. Retrieved 24 September 2017.
  4. ^ "Pinworms in Kids & Adults: Pictures, Symptoms & Treatments Viewer Comments and Reviews: Hypothyroidism - Symptoms - Patients Share Their Knowledge on eMedicineHealth". eMedicineHealth. Retrieved 2017-11-28.
  5. ^ Exton, M. S. (1997). "Infection-Induced Anorexia: Active Host Defence Strategy". Appetite. 29 (3): 369–383. doi:10.1006/appe.1997.0116. PMID 9468766.
  6. ^ Murray, M. J.; Murray, A. B. (1979). "Anorexia of infection as a mechanism of host defense". The American Journal of Clinical Nutrition. 32 (3): 593–596. doi:10.1093/ajcn/32.3.593. PMID 283688.
  7. ^ Home Care After Tonsillectomy and Adenoidectomy
  8. ^ Jáuregui-Garrido, B; Jáuregui-Lobera, I (2012). "Sudden death in eating disorders". Vascular Health and Risk Management. 8: 91–8. doi:10.2147/VHRM.S28652. PMC 3292410. PMID 22393299.

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