A syndrome is a set of medical
signs and symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
which are correlated with each other and often associated with a particular
disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
or disorder. The word derives from the
Greek σύνδρομον, meaning "concurrence".
When a syndrome is paired with a definite cause this becomes a disease.
In some instances, a syndrome is so closely linked with a
pathogenesis or cause that
the words ''syndrome'', ''disease'', and ''disorder'' end up being used interchangeably for them. This substitution of terminology often confuses the reality and meaning of medical diagnoses.
[ This is especially true of inherited syndromes. About one third of all ]phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
s that are listed in OMIM are described as dysmorphic, which usually refers to the facial gestalt. For example, Down syndrome
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...
, Wolf–Hirschhorn syndrome, and Andersen–Tawil syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the ''syndrome'' nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; premotor syndrome can be caused by various brain lesions; and premenstrual syndrome
Premenstrual syndrome (PMS) refers to emotional and physical symptoms that regularly occur in the one to two weeks before the start of each menstrual period. Symptoms resolve around the time menstrual bleeding begins. Different women experienc ...
is not a disease but simply a set of symptoms.
If an underlying genetic cause is suspected but not known, a condition may be referred to as a genetic association
Genetic association is when one or more genotypes within a population co-occur with a phenotypic trait more often than would be expected by chance occurrence.
Studies of genetic association aim to test whether single-locus alleles or genotype fre ...
(often just "association" in context). By definition, an association indicates that the collection of signs and symptoms occurs in combination more frequently than would be likely by chance alone.[
Syndromes are often named after the physician or group of physicians that discovered them or initially described the full clinical picture. Such ]eponym
An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''.
Usage of the word
The term ''epon ...
ous syndrome names are examples of medical 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 from nosology
Nosology () is the branch of medical science that deals with the classification of diseases. Fully classifying a medical condition requires knowing its cause (and that there is only one cause), the effects it has on the body, the symptoms that ...
and differential diagnosis
In healthcare, a differential diagnosis (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that p ...
generally, which inherently involve pattern recognition (both sentient
Sentience is the capacity to experience feelings and sensations. The word was first coined by philosophers in the 1630s for the concept of an ability to feel, derived from Latin '' sentientem'' (a feeling), to distinguish it from the ability to ...
and automated) and differentiation among overlapping sets of signs and symptoms. Teratology (dysmorphology) by its nature involves the defining of congenital syndromes that may include birth defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
s (pathoanatomy), dysmetabolism (pathophysiology), and neurodevelopmental disorder
Neurodevelopmental disorders are a group of disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. The effects of neurodevelopmental ...
s.
Subsyndromal
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"; but subclinical
In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asym ...
is not always interchangeable since it can also mean "not detectable or producing effects that are not detectable by the usual clinical tests"; i.e., asymptomatic.
Usage
General medicine
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 include encephalitis
Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...
and hepatitis
Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pa ...
, which can both have several different infectious causes. The more specific definition employed in medical genetics
Medical genetics is the branch
tics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the caus ...
describes a subset of all medical syndromes.
Psychiatry and psychopathology
Psychiatric syndromes often called ''psychopathological syndromes'' (psychopathology
Psychopathology is the study of abnormal cognition, behaviour, and experiences which differs according to social norms and rests upon a number of constructs that are deemed to be the social norm at any particular era.
Biological psychopatholo ...
refers both to psychic dysfunctions occurring in mental disorders
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
, and the study of the origin, diagnosis, development, and treatment of mental disorders).
In Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
those psychopathological syndromes are used in modern clinical practice and described in psychiatric literature in the details: asthenic syndrome, obsessive syndrome, emotional syndromes (for example, manic syndrome, depressive syndrome), Cotard's syndrome
Cotard's syndrome, also known as Cotard's delusion or walking corpse syndrome, is a rare mental disorder in which the affected person holds the delusional belief that they are dead, do not exist, are putrefying, or have lost their blood or intern ...
, catatonic syndrome, hebephrenic syndrome, delusion
A delusion is a false fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some o ...
al and hallucinatory
A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...
syndromes (for example, paranoid syndrome, paranoid-hallucinatory syndrome, Kandinsky- Clérambault's syndrome also known as syndrome of psychic automatism, hallucinosis), paraphrenic syndrome, psychopathic syndromes (includes all personality disorders), clouding of consciousness syndromes (for example, twilight clouding of consciousness, amential syndrome also known as amentia, delirious syndrome, stunned consciousness syndrome, oneiroid syndrome
Oneiroid syndrome (OS) is a condition involving dream-like disturbances of one's consciousness by vivid scenic hallucinations, accompanied by catatonic symptoms (either catatonic stupor or excitement), delusions, or psychopathological experience ...
), hysteric syndrome, neurotic syndrome, Korsakoff's syndrome
Korsakoff syndrome (KS) is a disorder of the central nervous system characterized by amnesia, deficits in explicit memory, and confabulation. This neurological disorder is caused by a deficiency of thiamine (vitamin B1) in the brain, and it is ...
, hypochondriacal syndrome, paranoiac syndrome, senestopathic syndrome, encephalopathic syndrome.
Some examples of psychopathological syndromes used in modern Germany are psychoorganic syndrome Psychoorganic syndrome (POS), also known as organic psychosyndrome, is a progressive disease comparable to presenile dementia. It consists of psychopathological complex of symptoms that are caused by organic brain disorders that involve a reductio ...
, depressive syndrome, paranoid-hallucinatory syndrome, obsessive-compulsive syndrome, autonomic syndrome, hostility syndrome, manic syndrome, apathy syndrome.
Münchausen syndrome
Factitious disorder imposed on self, also known as Munchausen syndrome, is a factitious disorder in which those affected feign or induce disease, illness, injury, abuse, or psychological trauma to draw attention, sympathy, or reassurance to th ...
, Ganser syndrome
Ganser syndrome is a rare dissociative disorder characterized by nonsensical or wrong answers to questions and other dissociative symptoms such as fugue, amnesia or conversion disorder, often with visual pseudohallucinations and a decreased state ...
, neuroleptic-induced deficit syndrome
Neuroleptic-induced deficit syndrome (NIDS) is a psychopathological syndrome that develops in some patients who take high doses of an antipsychotic for an extended time. It is most often caused by high-potency typical antipsychotics, but can also b ...
, olfactory reference syndrome are also well-known.
History
The most important psychopathological syndromes were classified into three groups ranked in order of severity by German psychiatrist Emil Kraepelin (1856—1926). The first group, which includes the mild disorders, consists of five syndromes: emotional, paranoid, hysterical, delirious
Delirious may refer to:
* A state of delirium
Film and television
* Delirious (1991 film), ''Delirious'' (1991 film), an American comedy directed by Tom Mankiewicz, starring John Candy
* Delirious (2006 film), ''Delirious'' (2006 film), an Americ ...
, and impulsive. The second, intermediate, group includes two syndromes: schizophrenic
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
syndrome and speech-hallucinatory syndrome. The third includes the most severe disorders, and consists of three syndromes: epileptic, oligophrenic and dementia
Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...
. In Kraepelin's era, epilepsy was viewed as a mental illness; Karl Jaspers
Karl Theodor Jaspers (, ; 23 February 1883 – 26 February 1969) was a German-Swiss psychiatrist and philosopher who had a strong influence on modern theology, psychiatry, and philosophy. After being trained in and practicing psychiatry, Jasper ...
also considered "genuine epilepsy" a "psychosis
Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior ...
", and described "the three major psychoses" as schizophrenia, epilepsy, and manic-depressive illness
Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
.
Medical genetics
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.
Until 2005, CHARGE syndrome
CHARGE syndrome (formerly known as CHARGE association) is a rare syndrome caused by a genetic disorder. First described in 1979, the acronym "CHARGE" came into use for newborn children with the congenital features of coloboma of the eye, heart ...
was most frequently referred to as "CHARGE association". When the major causative gene (''CHD7
Chromodomain-helicase-DNA-binding protein 7 also known as ATP-dependent helicase CHD7 is an enzyme that in humans is encoded by the ''CHD7'' gene.
CHD7 is an ATP-dependent chromatin remodeler homologous to the Drosophila trithorax-group protei ...
'') for the condition was discovered, the name was changed. The consensus underlying cause of VACTERL association has not been determined, and thus it is not commonly referred to as a "syndrome".
Other fields
In biology, "syndrome" is used in a more general sense to describe characteristic sets of features in various contexts. Examples include behavioral syndrome
In behavioral ecology, a behavioral syndrome is a correlated suite of behavioral traits, often (but not always) measured across multiple contexts. The suite of traits that are correlated at the population or species level is considered the behavi ...
s, as well as pollination syndromes and seed dispersal syndromes.
In orbital mechanics and astronomy, Kessler syndrome refers to the effect where the density of objects in low Earth orbit
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...
(LEO) is high enough that collisions between objects could cause a cascade in which each collision generates space debris
Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) are defunct human-made objects in space—principally in Earth orbit—which no longer serve a useful function. These include derelict spacecr ...
that increases the likelihood of further collisions.
In quantum error correction
Quantum error correction (QEC) is used in quantum computing to protect quantum information from errors due to decoherence and other quantum noise. Quantum error correction is theorised as essential to achieve fault tolerant quantum computing that ...
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.
Naming
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, or their home town (Stockholm syndrome
Stockholm syndrome is a condition in which hostages develop a psychological bond with their captors. It is supposed to result from a rather specific set of circumstances, namely the power imbalances contained in hostage-taking, kidnapping, an ...
). There have been isolated cases of patients being eager to have their syndromes named after them, while their physicians are hesitant. When a syndrome is named after a person, there is some difference of opinion as to whether it should take the possessive
A possessive or ktetic form (abbreviated or ; from la, possessivus; grc, κτητικός, translit=ktētikós) is a word or grammatical construction used to indicate a relationship of possession in a broad sense. This can include strict owne ...
form or not (e.g. Down syndrome
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...
vs. Down's syndrome). North American usage has tended to favor the non-possessive form, while European references often use the possessive. Even in Europe, there has been a trend away from the possessive form, over the period between 1970 and 2008.
History
Avicenna
Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic G ...
, in '' The Canon of Medicine'' (published 1025), pioneered the idea of a syndrome in the diagnosis of specific diseases.[Lenn Evan Goodman (2003), ''Islamic Humanism'', p. 155, ]Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books ...
, . The concept of a medical syndrome was further developed in the 17th century by Thomas Sydenham.
Underlying cause
Even in syndromes with no known etiology
Etiology (pronounced ; alternatively: aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek (''aitiología'') "giving a reason for" (, ''aitía'', "cause"); and ('' -logía''). More completely, e ...
, 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.
See also
* List of syndromes
* Toxidrome
A toxidrome (a portmanteau of ''toxic'' and ''syndrome'') is a syndrome caused by a dangerous level of toxins in the body. The term was coined in 1970 by Mofenson and Greensher. It is often the consequence of a drug overdose. Common symptoms incl ...
* Symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
* Sequence (medicine) In medicine, a sequence is a series of ordered consequences due to a single cause.
It differs from a syndrome in that seriality is more predictable: if A causes B, and B causes C, and C causes D, then D would not be seen if C is not seen. However, ...
References
External links
Whonamedit.com
- a repository of medical eponyms
{{Authority control
Medical terminology