# Disease
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A **disease** is a specific sickness that is caused by a [[pathogen]] or [[toxin]] that is not caused by injury. The study of disease and how it spreads through a population is [[epidemiology]].
- A **disease** is a pathophysiological response to internal or external factors.
- A **disorder** is a disruption to regular bodily structure and function.
- A **syndrome** is a collection of signs and symptoms associated with a specific health-related cause.
- A **condition** is an abnormal state of health that interferes with normal or regular feelings of wellbeing. this term is sort of a catch-all and used more as a neutral term is desired.
## Types of Disease
An incomplete list:
- **Nosocomial infections** (from the Greek: *nosokomeion* meaning "infirmary" or "hospital"), also called [[healthcare associated infection|health-care associated infections (HAIs)]] are infections that are contracted due to the particular location, such as a hospital.
- [[neurocognitive disorders|Neurocognitive disorders]] are disease that affect the mind.
### Acute & Chronic Disease
- Acute illness is short, with an abrupt onset and short span
- May or may not be life-limiting
- May or may not require medical or lifestyle change
- Can be an exacerbation of a chronic illness
- Chronic illness is prolonged, lasting for months or years
- Have irreversible changes or permanent impairment or disability
- May present with remissions/exacerbations
- Often no cure
- goals involve preventing flair ups, managing symptoms, improving/maintaining quality of life
- Requires medical management/lifestyle changes
## Terminology
***Signs* of disease:** Objective evidence of a disease, that can be observed and measured by someone other than the patient. For examples: [[fever]] , [[inflammation]]
***Symptoms* of disease:** Subjective evidence of a disease, that only the person who is sick can detect. For examples: fatigue, anxiety
**Primary infection:** The root cause of a person's current health problem.
**Secondary infection:** An infection that only occurs after a primary infection has taken place. These are usually done by [[pathogen|opportunistic pathogens]], who only set in after the immune system has been weakened by another infection. For example: The primary infections of [[AIDS]] can lead to secondary infections, like Kaposi's Sarcoma.
### Course of Disease
**Incubation period:** After infection but before disease
**Prodromal period:** First signs of disease...kind of sick but not really.
**Illness period:** Really sick. Different diseases produce different illnesses.
**Convalescent period:** felling better
**Latent:** The person is harboring the pathogen but doesn't have any signs/symptoms of disease.
**Carrier:** a person with a latent disease, who doesn't show signs/symptoms, but can still transmit the disease
**Bacteremia:** presence of bacteria in the blood
**Toxemia:** presence of toxins in the blood
**Viremia:** presence of viruses in the blood
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