Disease

Disease Classification and Terminology

• A disease is an abnormal condition that affects an organism's structure or function.
• Diseases can be physical or psychiatric.
• They can be caused by external factors like pathogens or internal dysfunctions.
• The four main types of diseases are infectious, deficiency, hereditary, and physiological.
• Disease, disorder, morbidity, sickness, and illness are often used interchangeably.
• Disease refers to any condition that impairs normal bodily functioning.
• Infectious diseases result from the presence of pathogenic microbial agents.
• Non-infectious diseases include cancer, heart disease, and genetic disorders.
• Acquired disease occurs after birth, while congenital disease is present at birth.
• Acute diseases are short-term in nature, while chronic diseases persist over time.
• Congenital disorders can be genetic or result from vertically transmitted infections.
• Genetic diseases are caused by genetic mutations, which can be inherited.
• Iatrogenic diseases are caused by medical intervention.
• Idiopathic diseases have unknown causes or sources.
• Incurable diseases cannot be cured but may have manageable symptoms.
• Primary diseases have a root cause, while secondary diseases are complications.
• Terminal diseases are expected to result in death.
• Illness refers to the patient's personal experience of their disease.
• Some diseases have known causes, while others have associations without clear causality.
• The study of diseases is called pathology.
• It includes the study of etiology, or the cause of diseases.
• Pathology helps understand the mechanisms and effects of diseases.
• Medical science continues to uncover causes of previously unknown diseases.
• Some diseases can be managed with medications, even if they are incurable.

Illness, Disorder, and Medical Condition

• Illness can refer to the experience of feeling unwell or distressed without necessarily having a disease.
• Symptoms of illness are often a collection of evolved responses by the body to clear infection and promote recovery.
• A disorder is a functional abnormality or disturbance in the body.
• Medical disorders can be categorized into mental disorders, physical disorders, genetic disorders, emotional and behavioral disorders, and functional disorders.
• The term 'disorder' is often considered more value-neutral and less stigmatizing than 'disease' or 'illness.'
• A medical condition encompasses all diseases, lesions, disorders, or nonpathologic conditions that normally receive medical treatment.
• In some contexts, the term 'medical condition' specifically excludes mental illnesses.
• The Diagnostic and Statistical Manual of Mental Disorders (DSM) uses the term 'general medical condition' to refer to all diseases, illnesses, and injuries except for mental disorders.
• Morbidity refers to a diseased state, disability, or poor health due to any cause.
• It can refer to the existence of any form of disease or the degree to which a health condition affects a patient.
• Morbidity rates are used in actuarial professions to determine insurance premiums and predict the likelihood of developing specific diseases.
• A syndrome is the association of several signs and symptoms that often occur together, regardless of the known cause.
• Some syndromes have a known cause, while others have multiple possible causes.
• Syndromes may retain their name even after an underlying cause is found or when there are multiple possible primary causes.
• Predisease refers to a subclinical or prodromal stage that precedes the development of a disease.
• Identifying legitimate predisease can lead to preventive measures, but labeling a healthy person with an unfounded notion of predisease can result in overtreatment.
• Three criteria for predisease include a high risk for progression to disease, actionability for risk reduction, and a benefit that outweighs the harm of interventions taken.

Stages of Disease

• Incubation period: time between infection and appearance of symptoms
• Latency period: time between infection and ability to spread the disease
• Viral latency: dormant phase of some viruses in the body
• Acute disease: short-lived disease like the common cold
• Chronic disease: long-lasting disease that can be stable or progressive
• Clinical disease: stage that produces characteristic signs and symptoms
• AIDS: clinical disease stage of HIV infection
• Cure: end of a medical condition or treatment
• Remission: disappearance of symptoms, possibly temporarily
• Flare-up: recurrence or onset of more severe symptoms
• Localized disease: affects only one part of the body
• Disseminated disease: spread to other parts of the body
• Systemic disease: affects the entire body
• Metastatic disease: spread of cancer to other parts of the body
• Nosology: classification of diseases by cause, pathogenesis, or symptoms

Causes of Disease

• Pathogens: microorganisms that cause infectious diseases
• Contagious diseases: transmitted from person to person
• Non-infectious diseases: not caused by pathogens, often genetic
• Social determinants of health: social, economic, and environmental factors influencing health
• Misunderstandings of disease cause: cultural beliefs and myths
• Airborne diseases: transmitted through the air
• Foodborne illnesses: caused by contaminated food
• Infectious diseases: resulting from the infection and growth of pathogens
• Lifestyle diseases: influenced by factors like physical activity and nutrition
• Genetic diseases: transmitted from one generation to another

Prevention, Treatments, Epidemiology, and Burdens of Disease

• Prevention: sanitation, proper nutrition, adequate exercise, vaccinations, obligatory face mask mandates
• Treatments: medications, surgery, medical devices, self-care, treatment for medical emergencies
• Epidemiology: study of factors that cause or encourage diseases, identifying risk factors, study design, data collection and analysis, development of statistical models, interaction of diseases in a population
• Burdens of Disease: disease burden measured by financial cost, mortality, morbidity, years of potential life lost (YPLL), quality-adjusted life year (QALY) and disability-adjusted life year (DALY), heart disease and stroke cause the most loss of life

Disease Mentions

Disease Data Sources