Indications of a specific illness, including psychiatric
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition.
Signs are objective and externally observable; symptoms are a person's reported subjective experiences.[1] A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showing on a medical scan. A symptom is something out of the ordinary that is experienced by an individual such as feeling feverish, a headache or other pains in the body.[2][3]
Asign is different from an "indication" – the activity of a condition 'pointing to' (thus "indicating") a remedy, not the reverse (viz., it is not a remedy 'pointing to' a condition)[5] – which is a specific reason for using a particular treatment.[clarification needed]
A symptom is something felt or experienced, such as pain or dizziness. Signs and symptoms are not mutually exclusive, for example a subjective feeling of fever can be noted as sign by using a thermometer that registers a high reading.[6] The CDC lists various diseases by their signs and symptoms such as for measles which includes a high fever, conjunctivitis, and cough, followed a few days later by the measles rash.[7]
Cardinal signs and symptoms are specific even to the point of being pathognomonic. A cardinal sign or cardinal symptom can also refer to the major sign or symptom of a disease.[8] Abnormal reflexes can indicate problems with the nervous system. Signs and symptoms are also applied to physiological states outside the context of disease, as for example when referring to the signs and symptoms of pregnancy, or the symptoms of dehydration. Sometimes a disease may be present without showing any signs or symptoms when it is known as being asymptomatic.[9] The disorder may be discovered through tests including scans. An infection may be asymptomatic which may still be transmissible.[9]
Signs and symptoms are often non-specific, but some combinations can be suggestive of certain diagnoses, helping to narrow down what may be wrong. A particular set of characteristic signs and symptoms that may be associated with a disorder is known as a syndrome. In cases where the underlying cause is known the syndrome is named as for example Down syndrome and Noonan syndrome. Other syndromes such as acute coronary syndrome may have a number of possible causes.[citation needed]
When a disease is evidenced by symptoms it is known as symptomatic. There are many conditions including subclinical infections that display no symptoms, and these are termed asymptomatic. Signs and symptoms may be mild or severe, brief or longer-lasting when they may become reduced (remission), or then recur (relapseorrecrudescence) known as a flare-up. A flare-up may show more severe symptoms.[10]
The term chief complaint, also "presenting problem", is used to describe the initial concern of an individual when seeking medical help, and once this is clearly noted a history of the present illness may be taken. The symptom that ultimately leads to a diagnosis is called a cardinal symptom.[citation needed] Some symptoms can be misleading as a result of referred pain, where for example a pain in the right shoulder may be due to an inflamed gallbladder and not to presumed muscle strain.[11]
Many diseases have an early prodromal stage where a few signs and symptoms may suggest the presence of a disorder before further specific symptoms may emerge. Measles for example has a prodromal presentation that includes a hacking cough, fever, and Koplik's spots in the mouth.[12] Over half of migraine episodes have a prodromal phase.[13]Schizophrenia has a notable prodromal stage,[14] as has dementia.[15]
Some symptoms are specific, that is, they are associated with a single, specific medical condition.[citation needed]
Nonspecific symptoms, sometimes also called equivocal symptoms,[16] are not specific to a particular condition. They include unexplained weight loss, headache, pain, fatigue, loss of appetite, night sweats, and malaise.[17] A group of three particular nonspecific symptoms – fever, night sweats, and weight loss – over a period of six months are termed B symptoms associated with lymphoma and indicate a poor prognosis.[18]
Other sub-types of symptoms include:
constitutionalorgeneral symptoms, which affect general well-being or the whole body, such as a fever;[19][20]
concomitant symptoms, which are symptoms that occur at the same time as the primary symptom;[21]
prodromal symptoms, which are the first symptoms of an bigger set of problems;[22]
delayed symptoms, which happen some time after the trigger;[23] and
objective symptoms, which are symptoms whose existence can be observed and confirmed by a healthcare provider.[24]
Vital signs are the four signs that can give an immediate measurement of the body's overall functioning and health status. They are temperature, heart rate, breathing rate, and blood pressure. The ranges of these measurements vary with age, weight, gender and with general health.[25]
A digital application has been developed for use in clinical settings that measures three of the vital signs (not temperature) using just a smartphone, and has been approved by NHS England. The application is registered as Lifelight First, and Lifelight Home is under development (2020) for monitoring-use by people at home using just the camera on their smartphone or tablet. This will additionally measure oxygen saturation and atrial fibrillation. Other devices are then not needed.[26]
Many conditions are indicated by a group of known signs, or signs and symptoms. These can be a group of three known as a triad; a group of four ("tetrad"); or a group of five ("pentad").[citation needed]
An example of a triad is Meltzer's triad presenting purpura a rash, arthralgia painful joints, and myalgia painful and weak muscles. Meltzer's triad indicates the condition cryoglobulinemia. Huntington's disease is a neurodegenerative disease that is characterized by a triad of motor, cognitive, and psychiatric signs and symptoms.[27] A large number of these groups that can be characteristic of a particular disease are known as a syndrome. Noonan syndrome for example, has a diagnostic set of unique facial and musculoskeletal features.[28] Some syndromes such as nephrotic syndrome may have a number of underlying causes that are all related to diseases that affect the kidneys.[29]
Sometimes a child or young adult may have symptoms suggestive of a genetic disorder that cannot be identified even after genetic testing. In such cases the term SWAN (syndrome without a name) may be used. Often a diagnosis may be made at some future point when other more specific symptoms emerge but many cases may remain undiagnosed. The inability to diagnose may be due to a unique combination of symptoms or an overlap of conditions, or to the symptoms being atypical of a known disorder, or to the disorder being extremely rare.[30]
It is possible that a person with a particular syndrome might not display every single one of the signs and/or symptoms that compose/define a syndrome.[citation needed]
Sensory symptoms can also be described as positive symptoms, or as negative symptoms depending on whether the symptom is abnormally present such as tingling or itchiness, or abnormally absent such as loss of smell. The following terms are used for negative symptoms – hypoesthesia is a partial loss of sensitivity to moderate stimuli, such as pressure, touch, warmth, cold. Anesthesia is the complete loss of sensitivity to stronger stimuli, such as pinprick. Hypoalgesia (analgesia) is loss of sensation to painful stimuli.[31]
Positive symptoms are those that are present in the disorder and are not normally experienced by most individuals and reflects an excess or distortion of normal functions.[33] Examples are hallucinations, delusions, and bizarre behavior.[citation needed]
Dynamic symptoms are capable of change depending on circumstance, whereas static symptoms are fixed or unchanging regardless of circumstance. For example, the symptoms of exercise intolerance are dynamic as they are brought on by exercise, but alleviate during rest. Fixed muscle weakness is a static symptom as the muscle will be weak regardless of exercise or rest.[citation needed]
A majority of patients with metabolic myopathies have dynamic rather than static findings, typically experiencing exercise intolerance, muscle pain, and cramps with exercise rather than fixed weakness.[34] Those with the metabolic myopathy of McArdle's disease (GSD-V) and some individuals with phosphoglucomutase deficiency (CDG1T/GSD-XIV), initially experience exercise intolerance during mild-moderate aerobic exercise, but the symptoms alleviate after 6–10 minutes in what is known as "second wind".
In contrast to a pathognomonic cardinal sign, the absence of a sign or symptom can often rule out a condition. This is known by the Latin term sine qua non. For example, the absence of known genetic mutations specific for a hereditary disease would rule out that disease.[42] Another example is where the vaginal pH is less than 4.5, a diagnosis of bacterial vaginosis would be excluded.[43]
Anamnestic signs (from anamnēstikós, ἀναμνηστικός, "able to recall to mind") are signs that indicate a past condition, for example paralysis in an arm may indicate a past stroke.[47]: 81
Some diseases including cancers, and infections may be present but show no signs or symptoms
and these are known as asymptomatic.[9] A gallstone may be asymptomatic and only discovered as an incidental finding.[9] Easily spreadable viral infections such as COVID-19 may be asymptomatic but may still be transmissible.[48]
A symptom (from Greek σύμπτωμα, "accident, misfortune, that which befalls",[49] from συμπίπτω, "I befall", from συν- "together, with" and πίπτω, "I fall") is a departure from normal function or feeling. Symptomatology (also called semiology) is a branch of medicine dealing with the signs and symptoms of a disease.[50][51][52] This study also includes the indications of a disease.[53] It was first described as semioticsbyHenry Stubbe in 1670 a term now used for the study of sign communication.[citation needed]
Prior to the nineteenth century there was little difference in the powers of observation between physician and patient. Most medical practice was conducted as a co-operative interaction between the physician and patient; this was gradually replaced by a "monolithic consensus of opinion imposed from within the community of medical investigators".[54][55] Whilst each noticed much the same things, the physician had a more informed interpretation of those things: "the physicians knew what the findings meant and the layman did not".[47]: 82
A number of advances introduced mostly in the 19th century, allowed for more objective assessment by the physician in search of a diagnosis, and less need of input from the patient.[54][55][56] During the 20th century the introduction of a wide range of imaging techniques and other testing methods such as genetic testing, clinical chemistry tests, molecular diagnostics and pathogenomics have made a huge impact on diagnostic capability.[57]
In 1761 the percussion technique for diagnosing respiratory conditions was discovered by Leopold Auenbrugger.[58] This method of tapping body cavities to note any abnormal sounds had already been in practice for a long time in cardiology.[58] Percussion of the thorax became more widely known after 1808 with the translation of Auenbrugger's work from Latin into French by Jean-Nicolas Corvisart.[59]
In 1819 the introduction of the stethoscopebyRené Laennec began to replace the centuries-old technique of immediate auscultation – listening to the heart by placing the ear directly on the chest, with mediate auscultation using the stethoscope to listen to the sounds of the heart and respiratory tract. Laennec's publication was translated into English, 1824, by John Forbes.
The 1846 introduction by surgeon John Hutchinson (1811–1861) of the spirometer, an apparatus for assessing the mechanical properties of the lungs via measurements of forced exhalation and forced inhalation. (The recorded lung volumes and air flow rates are used to distinguish between restrictive disease (in which the lung volumes are decreased: e.g., cystic fibrosis) and obstructive diseases (in which the lung volume is normal but the air flow rate is impeded; e.g., emphysema).)[citation needed]
The 1851 invention by Hermann von Helmholtz (1821–1894) of the ophthalmoscope, which allowed physicians to examine the inside of the human eye.
The 1882 introduction of bacterial cultures by Robert Koch, initially for tuberculosis, being the first laboratory test to confirm bacterial infections.
The 1895 clinical use of X-rays which began almost immediately after they had been discovered that year by Wilhelm Conrad Röntgen (1845–1923).
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^And, from this, a "contraindication" is an additional factor that is 'pointing away from' a remedy that was (otherwise) "indicated" by a particular condition, and not the reverse.
^Marie T. O'Toole, ed., Mosby's Medical Dictionary, 9th ed. (St. Louis, MO: Elsevier/Mosby, 2013), Kindle loc. 154641. ISBN978-0323085410
^"Measles Signs and Symptoms". Centers for Disease Control and Prevention. 5 November 2020. Archived from the original on 11 November 2020. Retrieved 31 December 2020.
^Shiel WC Jr (20 June 2019). "Definition of Flare". MedicineNet. Archived from the original on 23 January 2020. Retrieved 21 December 2019.
^Greenberger N.J., Paumgartner G (2012). Chapter 311. Diseases of the Gallbladder and Bile Ducts. In Longo D.L., Fauci A.S., Kasper D.L., Hauser S.L., Jameson J, Loscalzo J (Eds), Harrison's Principles of Internal Medicine, 18e
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^Diagnostic and statistical manual of mental disorders : DSM-5 (5th ed.). Arlington, VA: American Psychiatric Association. 2013. pp. 99–105. ISBN978-0-89042-555-8.
^Sherman C, Liu CS, Herrmann N, Lanctôt KL (February 2018). "Prevalence, neurobiology, and treatments for apathy in prodromal dementia". Int Psychogeriatr. 30 (2): 177–184. doi:10.1017/S1041610217000527. PMID28416030. S2CID46788701.
^"Symptoms & Causes | NIDDK". National Institute of Diabetes and Digestive and Kidney Diseases. Archived from the original on 9 October 2019. Retrieved 10 March 2021.
^Lynch HT, Lynch JF, Lynch PM, Attard T (2008). "Hereditary colorectal cancer syndromes: molecular genetics, genetic counseling, diagnosis and management". Fam Cancer. 7 (1): 27–39. doi:10.1007/s10689-007-9165-5. PMID17999161. S2CID20103607.
^Mańka W, Adrianowicz L, Wesołek Z, Adrianowicz K (2002). "[The value of determining vaginal secretion reaction (pH) as a screening test of bacterial vaginosis]". Wiad Lek (in Polish). 55 (1–2): 51–5. PMID12043316.
^"Definition of REFLEX". Merriam-Webster. 30 June 2023. Archived from the original on 8 February 2021. Retrieved 4 February 2021.
^Tsouyopoulos N (1988). "The mind-body problem in medicine (the crisis of medical anthropology and its historical preconditions)". Hist Philos Life Sci. 10 Suppl: 55–74. PMID3413276.
^Demuth A, Aharonowitz Y, Bachmann TT, Blum-Oehler G, Buchrieser C, Covacci A, et al. (May 2008). "Pathogenomics: an updated European Research Agenda". Infection, Genetics and Evolution. 8 (3): 386–93. doi:10.1016/j.meegid.2008.01.005. hdl:10033/30395. PMID18321793.
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