Nausea and Vomiting

• Nausea and vomiting are symptoms of a disease or condition. The underlying cause of the illness causing nausea and vomiting should be identified and treated.
• Nausea and vomiting symptom control is important both for comfort's sake and to prevent dehydration.
• Dehydration can worsen nausea and vomiting.
• Medication may be available to control symptoms of nausea and vomiting.

Nausea and vomiting are symptoms of an underlying illness and not a specific disease. 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. The term "dry heaves" refers to an episode of vomiting where there is no food in the stomach to vomit, and only clear secretions are vomited.

Vomiting is a violent act in which 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, expelling food and secretions.

There are numerous causes of nausea and vomiting. These symptoms may be due to the following:

• Acute gastritis (direct irritation of the stomach lining)
• Central causes in which signals from the brain cause nausea and vomiting
• Other illnesses not due to stomach problems
• Medications and medical treatments
• Mechanical obstruction of the bowel

Acute gastritis is often caused by an something that irritates the lining of the stomach. Examples of these circumstances include:

• Infections: Infections are often the cause of stomach irritation, whether it is a common virus or another type of infection. There may be associated crampy upper abdominal pain that is associated with the nausea and vomiting. Fever ,and chills may be present. Common viral infections include noroviruses and rotavirus. Infection by bacteria in the Helicobacter family (such as H. Pylori) can also be the infectious agent.
• Stomach flu: Stomach flu (gastroenteritis) is when vomiting and diarrhea occur together that is associated with a viral infection. It should not be confused with influenza (symptoms include fever, chills, cough, and muscle pain.
• Food poisoning: Food poisoning may cause significant vomiting, and the most common cause is a toxin released by the bacteria Staphylococcus aureus.  Symptoms of food poisoning begin within a couple hours of eating contaminated or poorly prepared food. Other bacterial causes of food poisoning include Salmonella, Campylobacter, Shigella, E. coli, Listeria, or Clostridium botulinum (botulism).
• Other stomach irritants: alcohol, smoking, and nonsteroidal anti-inflammatory medications (NSAIDs) such as aspirin and ibuprofen may irritate the stomach lining and cause nausea and vomiting.
• Peptic ulcer disease: Peptic ulcer disease can range from mild irritation of the stomach lining to the formation of a defect in the protective lining of the stomach called an ulcer.

• Gastroesophageal reflux disease (GERD, reflux esophagitis): Nausea or vomiting is also associated with GERD (acid from the stomach is refluxed into the esophagus).

Source: MedicineNet.com
http://www.medicinenet.com/nausea_and_vomiting/article.htm