What is nausea and vomiting?
Nausea is the unpleasant urge to vomit. Vomiting is the forceful ejection of stomach contents through the mouth. This is generally a protective mechanism to remove harmful ingested substances, but can occur from many unrelated infectious and inflammatory conditions in the body. Muscles in the abdominal wall contract vigorously to create the pressure necessary for vomiting (retching). Retching, also called ‘dry heaving’ can also occur without vomiting, or can precede or follow vomiting. Similarly, nausea can occur without vomiting or may precede vomiting.

Vomiting must be differentiated from regurgitation, which is the effortless movement of swallowed food contents or stomach acid from the stomach back into the mouth. Regurgitation is not associated with nausea or retching. When regurgitated material tastes sour and bitter, it may be a manifestation of reflux disease, but when it tastes the same as ingested food, it indicates a problem with food movement from the swallowing tube into the stomach. Rumination is another symptom that may resemble vomiting. Rumination consists of regurgitation of ingested food followed by rechewing and reswallowing, and is a learned behavior that may be considered pleasurable by the patient.

Treatment for nausea and vomiting

The treatment of nausea and vomiting may depend on the cause. However, the following general measures are appropriate for any patient with significant nausea and vomiting.

1. Correction of Fluid and Electrolyte Imbalance: Loss of body fluids results in dehydration and alteration in levels of minerals in the blood. Fluid replacement is usually performed with intravenous saline solution containing potassium. Potassium and sometimes magnesium levels may be low in the blood and may need to be added to the intravenous fluid.

2. Nutritional Support. Initially, patients should not eat solid food or may need to stop consuming food and drink. When feeding resumes, clear liquids are given first and diet advances as tolerated. When obstruction or chronic symptoms makes feeding by mouth impossible, alternate access for nutrition and fluid support are used. A nasoenteric tube can be placed through the nose into the small intestine and feeding solutions may be administered directly into the intestines (enteral feeding or tube feeding). Alternatively, a feeding tube can be directly placed through the abdominal wall into the stomach (percutaneous endoscopic gastrostomy or PEG tube) or intestines (percutaneous endoscopic jejunostomy or PEJ tube). Another option is to place a venous catheter into an arm vein or other vein and infuse a prepared solution containing essential nutrients and vitamins directly into the blood stream, total parenteral nutrition or hyperalimentation.

3. Therapy for Symptom Relief. Patients with upper abdominal discomfort resulting from fluid in the stomach or intestines (usually in the presence of a blockage) improve if a tube is placed through the nose into the stomach to suction out stomach contents. Medications for nausea and vomiting may be given to prevent symptoms (e.g., before chemotherapy or immediately after surgery) or to suppress symptoms after they have begun. Several types of medications are available and include phenothiazines (such as Compazine and Phenergan), 5-HT3 antagonists (such as Zofran), dopamine receptor antagonists (such as Reglan), antihistamines (Antivert, Dramamine, Benadryl) and anticholinergics (Scopolamine). Other agents that may be used for chronic nausea and vomiting, especially when a cause is not evident in the stomach or intestines, include benzodiazepines (Ativan) and tricyclic antidepressants (Elavil, Pamelor). Medicine to reduce acid production may also be necessary in patients with prolonged vomiting. These agents are administered to protect the esophagus from acidic content of the vomitus.

4. Other agents: Several alternative approaches are available for nausea and vomiting. The best-studied alternative therapy is perhaps the use of acupressure for pregnancy related nausea and vomiting. Wristbands with acupressure buttons are commercially available, inexpensive, safe and have been shown to provide relief of mild nausea and vomiting. Ginger and vitamin B6 supplements have also been used successfully as symptom suppressants in pregnancy. Electrical stimulation, usually at the wrist, has also been used to prevent postoperative nausea and vomiting with some success. Hypnosis has been used with some success to address the fear of vomiting in patients with psychogenic nausea and vomiting, chemotherapy and pregnancy-related nausea and vomiting. Therapy focuses on hypnotic suggestions for relaxation and symptom reduction as well as distraction through guided imagery.

5. Gastric stimulation: An implanted device with attached electrodes into the gastric wall can be an option for patients with refractory nausea and vomiting. This is utilized in patients with prolonged and persistent nausea and vomiting, usually in the setting of decreased ability of the stomach muscles to push food into the intestines, especially when medical treatment with multiple different medication regimens has failed in controlling symptoms. Gastric stimulation involves a surgical procedure to implant an electronic device into the abdomen, with wires (electrodes) that are attached to the stomach wall. While stomach emptying is typically not improved with this device, nausea and vomiting may improve in about half the patients where this device is implanted.

Can nausea and vomiting be prevented or successfully cured?

Episodic nausea and vomiting with a known cause such as motion sickness, chemotherapy, or surgical anesthesia can be prevented with medicines taken just before the causative event or medication. Symptoms due to medications and toxins improve when the drug or toxin is stopped. Morning sickness of pregnancy will usually resolve as the pregnancy progresses or with delivery. Nausea and vomiting due to chronic disorders such as functional problems, psychiatric disorders, endocrine disorders or cancer may be difficult to treat and may need chronic medications to control the symptoms. If nausea and vomiting are related to an infectious or inflammatory condition, symptoms will generally resolve completely with treatment of the primary condition.