Nausea

Nausea is the sensation of having an urge to vomit. Vomiting is forcing the contents of the stomach up through the esophagus and out of the mouth.

Causes
The body has a few ways to respond to an ever-changing, wide variety of bacteria and irritants:
 * Sneezing ejects the intruders from the nose
 * Coughing ejects the intruders from the lungs and throat
 * Diarrhea ejects the intruders from the intestines
 * Vomiting ejects the intruders from the stomach

Vomiting is a forceful action accomplished by a fierce, downward contraction of the diaphragm. At the same time, the abdominal muscles tighten against a relaxed stomach with an open sphincter (the muscle between the esophagus and the stomach, which usually closes and keeps food in the stomach). The contents of the stomach are propelled up and out of the mouth and nose.

Vomiting is a complex, coordinated reflex orchestrated by the vomiting center of the brain. It responds to signals coming from:


 * The mouth, stomach, and intestines
 * The bloodstream, which may contain medicines or infections
 * The balancing systems in the ear (in the case of motion sickness)
 * The brain itself, including unsettling sights, smells, or thoughts

An amazing variety of stimuli can trigger vomiting, from migraines to kidney stones and urinary tract infections.

Vomiting is common. Almost all children will vomit several times during their childhood. In most cases, it is due to a viral gastrointestinal infection.

“Spitting up,” the gentle sloshing of stomach contents up and out of the mouth, sometimes with a burp, is an entirely different process. Some spitting up is normal for babies, and usually gets gradually better over time. If spitting up worsens or is more frequent, it might be reflux disease.

Most of the time, nausea and vomiting do not require urgent medical attention. However, if the symptoms continue for days, if they are severe, or if the child cannot keep down any food or fluids, this may indicate a more serious condition.

Dehydration is the main concern with most vomiting. The onset of dehydration depends on many factors including body size, frequency of vomiting, and the presence or absence of diarrhea.

The following are also possible causes of vomiting:


 * Viral infections
 * Medications
 * Seasickness or motion sickness
 * Migraine headaches
 * Morning sickness during pregnancy
 * Food poisoning
 * Food allergies
 * Brain tumors
 * Chemotherapy in cancer patients
 * Bulimia
 * Alcoholism

These are possible causes of vomiting in infants (0 - 6 months):


 * Congenital pyloric stenosis, a constriction in the outlet from the stomach (the infant vomits forcefully after each feeding but otherwise appears to be healthy)
 * Food allergies or lactose intolerance
 * Gastroenteritis (infection of the digestive tract that usually causes vomiting with diarrhea)
 * Gastroesophageal reflux
 * An inborn error of metabolism
 * Wrong sized bottle nipple, leading to overfeeding
 * Infection, often accompanied by fever or runny nose
 * Intestinal obstruction, evidenced by recurring attacks of vomiting and crying or screaming as if in great pain
 * Accidentally ingesting a drug or poison

Self-care

 * It is important to stay hydrated. Small amounts of clear liquids, such as electrolyte solutions help prevent dehydration. Other clear liquids (such as water, ginger ale, or fruit juices) also work unless the vomiting is severe or it is a baby who is vomiting.


 * For breastfed babies, breastmilk is usually best. Formula-fed babies usually need clear liquids.


 * It is important not to drink too much at one time. Stretching the stomach can make nausea and vomiting worse.


 * Avoid solid foods until there has been no vomiting for six hours, and then work slowly back to a normal diet.


 * An over-the-counter bismuth stomach remedy (like Pepto-Bismol) is effective for upset stomach, nausea, indigestion, and diarrhea. Because it contains aspirin-like salicylates, it should not be used in children or teenagers who might have (or recently had) chickenpox or the flu.


 * Most vomiting comes from mild bacterial or viral illnesses.

The following may help treat vomiting due to motion sickness:


 * Lying down
 * Over-the-counter antihistamines (such as Dramamine)
 * Scopolamine prescription skin patches (such as Transderm Scop) are useful for extended trips, such as an ocean voyage. The patch needs to be placed 4 - 12 hours before setting sail.
 * Scopolamine is effective but may produce dry mouth, blurred vision, and some drowsiness. Therefore, Scopolamine is for adults only and should not be given to children.

Medical Assistance may be required if:


 * Vomiting lasts longer than 24 hours
 * Blood or bile is in the vomit
 * Severe abdominal pain is experienced
 * Headache and stiff neck is experienced
 * Signs of dehydration are present

Signs of dehydration include:


 * Increased thirst
 * Infrequent urination or dark yellow urine
 * Dry mouth
 * Eyes that appear sunken
 * Crying without tears
 * Loss of normal skin elasticity (if you touch or squeeze the skin, it doesn't bounce back the way it usually does)

For children, medical attention should be considered if:


 * A child displays lethargy or has marked irritability
 * An infant vomits repeatedly
 * A child is unable to retain any fluids for 8 hours or more
 * Vomiting is recurrent
 * An adult is unable to retain any fluids for 12 hours or more.
 * There is a decrease in urination (including a baby who is not wetting the normal amount of diapers).
 * Nausea persists for a prolonged period of time (in a person who is not pregnant).

Treatment
The following diagnostic tests may be performed:


 * Blood tests (such as CBC with differential and basic electrolytes)
 * Urinalysis
 * X-rays of the abdomen

If dehydration is severe, intravenous fluids may be administered. This may require hospitalization, although it can often be done in the doctor's office. The use of antivomiting drugs (anti-emetics) is controversial, and they should be used only in severe cases.

Prevention
A number of medicines are effective at preventing vomiting. These include Ondansetron, Promethazine, and Cyclazine.