Asyndrome is a set of medicalsigns and symptoms which are correlated with each other and often associated with a particulardisease or disorder.[1] The word derives from theGreek σύνδρομον, meaning "concurrence".[2]: 1818 When a syndrome is paired with a definite cause this becomes a disease.[3] In some instances, a syndrome is so closely linked with apathogenesis or cause thatthe wordssyndrome,disease, anddisorder end up being used interchangeably for them. This substitution of terminology often confuses the reality and meaning of medical diagnoses.[3] This is especially true ofinherited syndromes. About one third of allphenotypes that are listed inOMIM are described as dysmorphic, which usually refers to the facial gestalt. For example,Down syndrome,Wolf–Hirschhorn syndrome, andAndersen–Tawil syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite thesyndrome nomenclature. In other instances, a syndrome is not specific to only one disease. For example,toxic shock syndrome can be caused by various toxins; another medical syndrome named as premotor syndrome can be caused by various brain lesions; andpremenstrual syndrome is not a disease but simply a set of symptoms.
Syndromes are often named after the physician or group of physicians that discovered them or initially described the full clinical picture. Sucheponymous syndrome names are examples ofmedical eponyms. Recently, there has been a shift towards naming conditions descriptively (by symptoms or underlying cause) rather than eponymously, but the eponymous syndrome names often persist in common usage.
The defining of syndromes has sometimes been termed syndromology, but it is usually not a separate discipline fromnosology anddifferential diagnosis generally, which inherently involve pattern recognition (bothsentient andautomated) and differentiation among overlapping sets of signs and symptoms.Teratology (dysmorphology) by its nature involves the defining of congenital syndromes that may includebirth defects (pathoanatomy), dysmetabolism (pathophysiology), andneurodevelopmental disorders.
When there are a number of symptoms suggesting a particular disease or condition but does not meet the defined criteria used to make a diagnosis of that disease or condition. This can be a bit subjective because it is ultimately up to the clinician to make the diagnosis. This could be because it has not advanced to the level or passed a threshold or just similar symptoms cause by other issues. Subclinical is synonymous since one of its definitions is "where some criteria are met but not enough to achieve clinical status";[4] butsubclinical is not always interchangeable since it can also mean "not detectable or producing effects that are not detectable by the usual clinical tests";[5] i.e., asymptomatic.
In medicine, a broad definition of syndrome is used, which describes a collection of symptoms and findings without necessarily tying them to a single identifiable pathogenesis. Examples of infectious syndromes includeencephalitis andhepatitis, which can both have several different infectious causes.[6] The more specific definition employed inmedical genetics describes a subset of all medical syndromes.[citation needed]
Early texts by physicians noted the symptoms of various maladies and introduced diagnoses based upon those symptoms. For example,Avicenna'sThe Canon of Medicine (1025) describes diagnosingpleurisy by its symptoms, including chronic fever, cough, shooting pains, and labored breathing.[7] The 17th century doctorThomas Sydenham likewise approached diagnoses based upon collections of symptoms.[8]
Psychiatric syndromes often calledpsychopathological syndromes (psychopathology refers both to psychic dysfunctions occurring inmental disorders, and the study of the origin, diagnosis, development, and treatment of mental disorders).[citation needed]
The most important psychopathological syndromes were classified into three groups ranked in order of severity by German psychiatristEmil Kraepelin (1856—1926). The first group, which includes the mild disorders, consists of five syndromes: emotional, paranoid,hysterical,delirious, and impulsive.[12] The second, intermediate, group includes two syndromes:schizophrenic syndrome andspeech-hallucinatory syndrome.[12] The third includes the most severe disorders, and consists of three syndromes:epileptic,oligophrenic anddementia.[12] In Kraepelin's era, epilepsy was viewed as a mental illness;Karl Jaspers also considered "genuine epilepsy" a "psychosis", and described "the three major psychoses" as schizophrenia, epilepsy, andmanic-depressive illness.[13]
In the field of medical genetics, the term "syndrome" is traditionally only used when the underlying genetic cause is known. Thus,trisomy 21 is commonly known as Down syndrome.[citation needed]
Until 2005,CHARGE syndrome was most frequently referred to as "CHARGE association". When the major causative gene (CHD7) for the condition was discovered, the name was changed.[14] The consensus underlying cause ofVACTERL association has not been determined, and thus it is not commonly referred to as a "syndrome".[15]
In orbital mechanics and astronomy,Kessler syndrome refers to the effect where the density of objects inlow Earth orbit (LEO) is high enough that collisions between objects could cause a cascade in which each collision generatesspace debris that increases the likelihood of further collisions.[16]
Inquantum error correction theory syndromes correspond to errors in code words which are determined with syndrome measurements, which only collapse the state on an error state, so that the error can be corrected without affecting the quantum information stored in the code words.
There is no set common convention for the naming of newly identified syndromes. In the past, syndromes were often named after the physician or scientist who identified and described the condition in an initial publication. These are referred to as "eponymous syndromes". In some cases, diseases are named after the patient who initially presents with symptoms,[17] or their home town (Stockholm syndrome). There have been isolated cases of patients being eager to have their syndromes named after them, while their physicians are hesitant.[18] When a syndrome is named after a person, there is some difference of opinion as to whether it should take thepossessive form or not (e.g.Down syndrome vs. Down's syndrome). North American usage has tended to favor the non-possessive form, while European references often use the possessive.[19] A 2009 study demonstrated a trend away from the possessive form in Europe in medical literature from 1970 through 2008.[19]
Even in syndromes with no knownetiology, the presence of the associated symptoms with a statistically improbable correlation normally leads the researchers to hypothesize that there exists an unknown underlying cause for all the described symptoms.[citation needed]
^Slack, R. C. B. (2012)."Infective syndromes". In Greenwood, D.; Barer, M.; Slack, R.; Irving, W. (eds.).Medical Microbiology (18th ed.). Churchill Livingstone. pp. 678–688.ISBN978-0-7020-4089-4.
^Сметанников, П. Г. (1995).Психиатрия: Краткое руководство для врачей [Psychiatry: A Brief Guide for Physicians] (in Russian).Saint Petersburg: СПбМАПО. pp. 86–119.ISBN5-85077-025-9.
