Nausea

Overview

Nausea and vomiting have many possible causes, and are not always related to disease of the stomach and digestive system. Sometimes no cause can be found for vomiting. Vomiting is caused by the stimulation of a certain part of the brain, called the vomiting centre. Once the vomiting centre in the brain is stimulated, the natural movement of the intestines goes into reverse. The person first experiences a nauseous feeling in the pit of the stomach and produces large quantities of saliva that contain a lot of mucus. The person may also feel weak and sweaty. The top of the windpipe closes and breathing stops (this prevents the vomit from entering the lungs). An involuntary contraction of the stomach muscles follows, and the content of the stomach is forced out through the mouth.

How we get nausea and vomiting

Nausea and vomiting arise from the stimulation of the vomiting centre in the brain either directly or as a result of its stimulation from another area of the brain (known as the chemo-receptor trigger zone or CTZ). The causes of this stimulation arise from three main areas:-

The stomach and digestive system

Stimulation of the vomiting centre in the brain by the stomach can be caused by drugs (prescribed or abused), toxins (taken accidentally or as an attempt to end life, also high levels or alcohol and nicotine), mechanical stimulation (distension because of the presence of food or growth or blockage) and irritation (of the stomach lining by bacteria, alcohol or ulceration).

The Brain

Behavioural

Sights, smells and emotions can all directly stimulate the vomiting centre in the brain

Toxins and cytotoxic drugs

These stimulate the area of the brain known as the chemoreceptor trigger zone, which in turn stimulates the vomiting centre. The changes in hormones and chemicals produced during pregnancy may stimulate the Chemoreceptor trigger zone which in turn stimulates the vomiting centre and therefore leads to vomiting in the early weeks of the pregnancy.

Migraine or headache

This is thought to change the chemical levels in the brain which stimulates the chemoreceptor trigger zone, which in turn stimulates the vomiting centre.

Middle Ear

Motion sickness, vertigo and other middle ear disorders result in the release of chemicals in the brain which stimulate the Chemoreceptor trigger zone which in turn stimulates the vomiting centre of the brain.

Symptoms

Nausea is often referred to as a “queasy sensation” or a feeling of being “sick to the stomach”. Nausea may occur with or without vomiting, and vomiting can occur without nausea. Other symptoms depend on the factor causing nausea and vomiting and are indicated in the section below discussing Risk Factors.

Risk Factors

Gastroenteritis

This inflammation of the lining of the stomach and intestines is typically caused by a viral infection or bacteria from contaminated food or water. Food usually becomes contaminated from poor sanitation or preparation. Food handlers who do not wash their hands after using the bathroom or have infections themselves often cause contamination. Improperly packaged food stored at the wrong temperature also promotes contamination

The known causes of food poisoning can be divided into two categories. The first is infective agents such as viruses, bacteria and parasites. The second are toxins, such as the pesticides found on fruit and vegetables.

In addition to nausea and vomiting, there is generally watery diarrhoea, abdominal cramps. If it is a viral infection may be associated with other flu-like symptoms, such as high temperature, body aches, runny nose and cough.

Intestinal blockage

Blockage of the intestines may be caused by tumours, hernias, scar tissue, hardened faeces, gallstones, and foreign bodies, twists in the bowel or infection in the bowel. The symptoms of an intestinal blockage may be abdominal swelling, nausea and vomiting (often of faecal matter) and sometimes total constipation for a number of days or even weeks.

Asthma and/ or Cough

It is common for children with asthma (that may be undiagnosed) or a severe cough, to vomit. This is as a result of the lungs attempting to expel mucus from the airways, it is common in asthma for a child to have a dry cough, then to gag and end up vomiting.

Pyloric Stenosis

It is common for babies to regurgitate milk in the first few weeks of life and this is of no concern. There is, however, a condition known as pyloric stenosis in which there is a thickening of the muscular wall around the outlet of the stomach that causes a blockage. It typically occurs in the first few weeks of life in a first-born male. The vomiting is projectile and can be expelled a considerable distance. This condition can be cured by a simple operation.

Middle ear conditions

Conditions that affect the middle ear are generally associated with dizziness, loss of balance sometimes tinnitus (ringing in the ears), nausea and vomiting. The most common conditions to affect the inner ear and cause these symptoms include Meniere’s disease, ‘benign positional vertigo’ and ‘vestibular neuronitis’, which is also known as ‘viral labyrinthitis’ and may result from a viral infection of the middle ear.

Migraine or headache

An intense headache, such as a migraine can cause nausea and vomiting. It may also cause other gastrointestinal symptoms such as abdominal cramps and diarrhoea. (link Headache)

Anxiety and eating disorders

Nausea and vomiting are common in those with anxiety disorders; it may be associated with abdominal pain, difficulty in swallowing, dizziness and many other symptoms.

Bulimia nervosa is a condition where binge-eating is generally followed by vomiting or other measures to control weight gain.

Alcohol, nicotine and other toxins

High levels of toxins in the blood – including alcohol, nicotine and drugs such as antibiotics can cause nausea and vomiting, this is due to your body trying to protect itself from these toxins. If swallowed, a toxic substance may irritate the stomach or intestine which directly stimulates the vomiting centre and leads to vomiting, thus limiting absorption of the poison. . Some toxins may get through these safeguards and therefore such toxins stimulate the chemoreceptor trigger zone in the brain which as discussed earlier leads to vomiting and therefore limits further ingestion of toxins.

Head Injury

It is common for a person who has had a head injury to experience nausea and vomiting, along with other symptoms directly after the injury occurs. If the nausea or vomiting worsen, however, or fail to subside it may be a cause of concern and medical advice should be sought.

Brain tumour

A brain tumour can obstruct the flow of fluid to and from the brain to the spinal cord, which results in a build up of fluid in the brain and that increases the pressure in the brain. Nausea, vomiting, and headaches are common symptoms.

Infection of the brain

Infections affecting the brain, such as meningitis and encephalitis may cause vomiting along with other symptoms.

Medical treatment

Vomiting is often associated with anti-cancer drugs and radiation therapy. It may also be associated with other medication, such as antibiotics, non-steroidal anti-inflammatories, steroids and hormones. Nausea and vomiting occur due to direct irritation of the stomach and stimulation of certain areas of the brain (as in alcohol, nicotine and other toxins).

Hormones

The hormonal changes of early pregnancy (and some of the chemicals produced) can cause nausea and lead to vomiting. This occurs most commonly during the first three months (first trimester) of pregnancy. These symptoms are usually gone by the fourth month. Although this condition is often called morning sickness, most women usually have symptoms throughout the day. Very rarely, a pregnant woman may experience a more serious condition involving severe vomiting, dehydration, and weight loss.

Surges in hormones that often occur in periods of intense stress can also lead to nausea and vomiting

Problems with the thyroid gland, where it is producing either too much thyroid hormone or not enough, can also result in nausea.

Peptic ulcers

Peptic ulcers are open sores that develop on the lining of the stomach, upper small intestine or oesophagus. The classic symptom is burning pain anywhere from your navel to your breastbone, but peptic ulcers may cause nausea and vomiting as well

Gallstones

Gallstones are solid deposits of cholesterol or calcium salts that form in the gallbladder or nearby bile ducts. Sometimes gallstones cause nausea, vomiting, indigestion and abdominal pain.

Pancreatitis

Pancreatitis is a condition in which digestive enzymes attack the pancreas rather than break down food in the small intestine. The condition causes mild to severe abdominal pain often accompanied by nausea, vomiting and high temperature.

Complications

Dehydration

Dehydration is the real threat with most vomiting. The speed with which dehydration develops depends on the size of the individual, the frequency of the vomiting, and the presence of diarrhoea. Therefore, infants with frequent vomiting and diarrhoea are at risk, as are the elderly who are often dehydrated at the outset of the attack.

Signs of dehydration are:

  • In children, sleepiness, drowsiness, irritability and unresponsiveness.
  • Marked thirst.
  • Infrequent urination or dark yellow urine.
  • Dry mouth or eyes that appear sunken.
  • Skin that has lost its normal elasticity.

(To determine this, gently pinch the skin on the stomach using all five fingers. When you release it, it should spring back immediately; compare with another person’s skin if necessary. When the skin remains tented up and doesn’t spring back normally, the person may be dehydrated.)

Lack of absorption of medication

In cases where causes of vomiting are not serious the lack of absorption of medication may only occur for as long as the vomiting occurs (possibly two to three days). This can still cause serious problems for those on the oral contraceptive pill (who may become pregnant as a result of the failure of even one pill to be absorbed into the bloodstream) and for those on medication to control epileptic seizures (where the lack or absorption of one to two days medication may result in a seizure). In vomiting lasting for some time, that is caused by more serious diseases, lack of absorption of most medication and nutrients will cause serious problems.

When to seek medical advice

  • When you are taking care of a child or elderly person if they have not urinated in six to eight hours (or has dry nappies for that period of time).
  • When you are taking care of a baby if they have sunken fontanels (the soft spot on top of the baby’s head).
  • If you are vomiting blood. It may be bright red or dark brown (like coffee grounds).
  • If you are experiencing nausea or vomiting and severe stomach pain.
  • Vomiting with high temperature, especially in a child.
  • If vomiting won’t stop and you have been unable to keep down any fluids for the last twenty four hours.
  • The Vomiting continues for more than two to three days.
  • If you have a known head injury.
  • If there are other medical conditions present such as heart disease or diabetes.
  • If you observe any signs of confusion or extreme weakness.
  • If a new or severe headache is also present.

Treatment

As well as addressing the feelings of nausea and trying to control vomiting it is also very important to replace fluids and salts that have been lost through vomiting. Many over-the-counter preparations are not suitable for those who are pregnant or for children under two years of age and may not be suitable for other individuals, so it is always important to talk to your pharmacist when buying preparations for nausea and vomiting over-the-counter.

Prokinetic agents (e.g. domperidone)

Domperidone helps the stomach to empty more quickly and therefore reduces the feeling of nausea. It also helps to reduce reflux (stomach acid coming back up) and the sensation of fullness.

Rehydration salts

Oral rehydration salts contain a variety of salts (electrolytes) and sugar. The combination of electrolytes and sugar stimulates water and electrolyte absorption from the gut. It therefore prevents or reverses dehydration and replaces lost salts in vomiting. Its should be made up with exactly the quantity of water (not fruit juices) that is stated on the packaging and for babies and infants under one year boiled and cooled water should be used. If vomiting is occurring frequently in infants, children or the elderly, or has persisted for more than twenty four hours in an adult, it would be wise to encourage an infant or child to drink two to three litres and an adult or elderly person to drink three to four litres of such a rehydration replacement, a day.

Brand name of preparations available and their ingredients

To relieve nausea

Motilium tablets contain the prokinetic domperidone, this helps the stomach to empty more quickly and reduces the feeling of nausea. The tablets should be taken three times a day half to one hour before meals. It does not cause drowsiness.

To replace lose fluids in dehydration or to prevent dehydration

Dioralyte sachets contain sodium chloride 0.47g, Potassium chloride 0.3g, disodium hydrogen citrate 0.53g and glucose 3.56g.

Rehidrat sachets contain sodium chloride 0.44g, potassium chloride 0.38g, sodium bicarbonate 0.42g, glucose 4.12g and sucrose 8.1g.

The combination of electrolytes and sugar stimulates water and electrolyte absorption from the gut. It therefore prevents or reverses dehydration and replaces lost salts in vomiting. Each sachet should be dissolved in exactly 200ml water to obtain the concentration that suits the body best. They do not cause drowsiness.

Prevention

Change your eating habits

Nausea can be prevented by: eating small meals throughout the day instead of three large meals; eating slowly; avoiding hard-to-digest foods; and consuming foods that are cold or at room temperature to avoid becoming nauseated from the smell of hot or warm foods. Resting after eating and keeping your head elevated about twelve inches above your feet helps reduce nausea.

If you feel nauseated when you wake up in the morning, eat some crackers before getting out of bed or eat a high protein snack (lean meat or cheese) before going to bed. Drink liquids between (instead of during) meals, and drink at least six to eight glasses of water a day to prevent dehydration. Try to eat when you feel less nauseated.

Follow safe food-handling procedures.

To avoid vomiting caused by food poisoning, keep hot foods hot and cold foods cold. Wash your hands often while cooking. Don’t place any other food on a surface where raw meat has been. Cook all meats thoroughly, until the juices run clear.

Once you feel nauseated, how do you prevent vomiting?

Vomiting can be prevented by consuming small amounts of clear, sweetened liquids such as lemonade and fruit juices (except orange and grapefruit because these are too acidic). Drinks containing sugar calm the stomach better than other liquids. Rest either in a sitting position or in a propped lying position. Activity may worsen nausea and may lead to vomiting.

For children, control persistent coughs and temperature with over-the-counter medicines. To treat motion sickness in a car, seat your child so that he or she faces the front windscreen (watching fast movement out the side windows can make the nausea worse). Limit snacks, and do not serve sweet snacks with fizzy drinks. Do not let children eat and play at the same time. Encourage them to take a break during their snack time.

Self-Care

For nausea

Food and drink

Drink clear or ice-cold drinks slowly. Eat light bland foods (bread or crackers) in small amounts, more frequently and more slowly. Avoid mixing hot and cold foods and fried, greasy or sweet foods. Rest after eating or drinking.

For vomiting
Drink larger amounts of clear liquids, particularly those made up of rehydration salts. Avoiding solid food until the vomiting episode has passed or starve of food for twenty-four hours.