Nausea

Nausea

A 1681 painting depicting a person vomiting
ICD-10	R11
ICD-9	787.0

Nausea (Latin nausea, from Greek ναυσίη, nausiē, "motion sickness", feeling sick," queasy or "wamble"^[1]), is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit.^[2] It often, but not always, precedes vomiting. A person can suffer nausea without vomiting. Some common causes of nausea are motion sickness, gastroenteritis (stomach infection) or food poisoning, side effects of many medications including cancer chemotherapy, nauseants or morning sickness in early pregnancy. Medications taken to prevent nausea are called antiemetics and include diphenhydramine, metoclopramide and ondansetron. Nausea may also be caused by stress and depression.^[3][4][5]

Differential diagnosis

The causes of nausea are many. One organization listed 700 in 2009.^[6] Gastrointestinal infections (37%) and food poisoning are the two most common causes.^[2][7] While side effects from medications (3%) and pregnancy are also relatively frequent.^[2][7] In 10% of people the cause remains unknown.^[7]

Food poisoning

Food poisoning usually causes an abrupt onset of nausea and vomiting one to six hours after ingestion of contaminated food and lasts for one to two days.^[8] It is due to toxins produced by bacteria in food.^[8]

Medications

Many medications can potentially cause nausea.^[8] Some of the most frequently associated include cancer chemotherapy regimens and general anaesthetic agents.

Pregnancy

Nausea or "morning sickness" is common during early pregnancy but may occasionally continue into the second and third trimesters. In the first trimester nearly 80% of women have some degree of nausea.^[9] Pregnancy should therefore be considered as a possible cause of nausea in any women of child bearing age.^[8] While usually it is mild and self limiting severe cases known as hyperemesis gravidarum may require treatment.^[10]

Disequilibrium

A number of conditions involving balance such as motion sickness and vertigo can lead to nausea and vomiting.

Stress and depression

Nausea may be caused by stress and depression.^[3][4][5]

Potentially serious

While most causes of nausea are not serious, some serious causes do occur. These include: diabetic ketoacidosis, brain tumor, surgical problems, pancreatitis, small bowel obstruction, meningitis, appendicitis, cholecystitis, Addisonian crisis, Choledocholithiasis (from gallstones) and hepatitis, as a sign of carbon monoxide poison and many others.^[2]

Diagnostic approach

Often no investigations are needed, however basic lab tests may be appropriate.^[2] If a bowel obstruction is possible, abdominal x-rays may be useful.^[2]

Treatment

If dehydration is present due to loss of fluids from severe vomiting and/or accompanying diarrhea, rehydration with oral electrolyte solutions is preferred.^[2] If this is not effective or possible, intravenous rehydration may be required.^[2]

Medications

Dimenhydrinate (Gravol) is an inexpensive and effective medication for preventing postoperative nausea and vomiting.^[11] Meclozine is another antihistamine antiemetic. In certain people, cannabinoids may be effective in reducing chemotherapy associated nausea and vomiting.^[12][13] Ondansetron (Zofran) is effective for nausea and vomiting but is expensive.^[8] Pyridoxine or metoclopramide are the first line treatments for pregnancy related nausea and vomiting.^[10] Medical marijuana may be prescribed where allowed for certain indications.

Prognosis

While short-term nausea and vomiting are generally harmless, they may sometimes indicate a more serious condition. When associated with prolonged vomiting, it may lead to dehydration and/or dangerous electrolyte imbalances.

Epidemiology

Nausea and or vomiting is the main complaint in 1.6% of visits to family physicians in Australia.^[7] However only 25% of people with nausea visit their family physician.^[2] It is most common in those 15–24 years old and less common in other ages.^[7]

References