Nausea and vomiting are symptoms of an underlying disease and not a specific illness. Nausea is the sensation that the stomach wants to empty itself, while vomiting (emesis) or throwing up, is the act of forcible emptying of the stomach.
Vomiting is a violent act in which the stomach has to overcome the pressures that are normally in place to keep food and secretions within the stomach. The stomach almost turns itself inside out – forcing itself into the lower portion of the esophagus (the tube that connects the mouth to the stomach) during a vomiting episode.
What causes nausea or vomiting?
There are numerous causes of nausea and vomiting. These symptoms may be due to the following:
association with other illnesses remote from the stomach
medications and medical treatments
mechanical obstruction of the bowel
Acute gastritis (gastro=stomach + it is= inflammation) is often caused by an offending agent which irritates the lining of the stomach. Examples of these include:
Infections: Infections are often the cause, whether it is a common virus or an infection that is contracted from travel. There may be associated crampy upper abdominal pain, fever ,and chills may be present. Common viral infections include noroviruses and rotavirus. Parasitic infections often are associated with diarrhea but may also have a component of nausea and vomiting. Infection by bacteria in the Helicobacter family (like H. Pylori) can also be the infectious agent.
Stomach flu:Stomach flu is a non-specific term used to describe vomiting and diarrhea associated with a viral infection. It should not be confused with influenza, whose symptoms include fever, chills, cough, and myalgias (muscle pain).
Food poisoning:Food poisoning may cause significant vomiting and usually is caused by a bacterial toxin. Symptoms begin within a couple hours of eating contaminated or poorly prepared food and may last for 1-2 days. Sources of food poisoning include Salmonella, Campylobacter, Shigella, E. coli, Listeria, or Clostridium botulinum (botulism).