Nausea and Vomiting

The body responds in a number of ways to protect itself from a wide variety of invaders and irritants. Sneezing ejects intruders from the nose, coughing from the throat and lungs, diarrhoea from the intestines and vomiting from the stomach. Nausea is the uneasiness of the stomach of having an urge to vomit. Vomiting is the forceful emptying /’throwing up’ of the stomach contents out of the mouth.

During vomiting the diaphragm contracts downwards. At the same time the abdominal muscles tighten against the relaxed stomach with an open gastro-oesophageal sphincter. The content of the stomach is then propelled up and out. The body produces more saliva just before vomiting as part of the vomiting reflex.  Vomiting is a complex reflex coordinated by the vomiting centre of the brain. There is a wide range of stimuli that trigger vomiting from food poisoning to migraines to kidney stones. Sometimes just seeing someone else vomit will start a vomiting reflex.  It responds to various stimuli including:

• from the mouth, stomach and intestines,
• the bloodstream which may contain medicine of infections.
• balancing systems in the ear as in motion sickness
• the brain itself including unnerving sights, smells or thoughts.

Causes of nausea and vomiting

Nausea and vomiting is a symptom of many conditions. Causes of vomiting are summarised in table 1.

Table 1 the possible causes of vomiting

The causes of vomiting differ according to age. For children, it is common to vomit from viral infections, food poisoning, milk allergy, motion sickness, over eating or feeding, coughing or blocked intestines and illness in which the child has a high fever.

The timing of the nausea and vomiting can indicate the cause. When it starts shortly after a meal in may be as a result of food poisoning, gastritis, an ulcer or bulimia. Nausea or vomiting one to eight hours after a meal may also be as a result of food poisoning. Certain food borne bacteria, such as salmonella can take longer to produce symptoms.

Treatment of nausea and vomiting

Most of the time nausea and vomiting are harmless and do not require urgent medical attention. However it can be a sign of more serious illness such as concussions, intestinal blockages, appendicitis and meningitis or brain tumour. If the symptoms continue for more than one day, are severe and  food and fluids cannot be kept down for any length of time, there is blood in the vomit, severe abdominal pain, a fever over 38°C or diarrhoea, rapid breathing and pulse,  immediate treatment needs to be initiated.

Dehydration is the main concern with most vomiting. Adults have a lower risk of becoming dehydrated because they can usually detect the symptoms of dehydration (such as increased thirst and dry lips or mouth). But, children have a greater risk of becoming dehydrated, especially if they also have diarrhoea, because young children are often unable to communicate symptoms of dehydration. Adults caring for sick children need to be aware of these visible signs of dehydration: dry lips and mouth, sunken eyes, and rapid breathing or pulse. In infants, also watch for decreased urination and a sunken fontanelle (soft spot on top of the baby’s head).

Recurrent vomiting in pregnancy can lead to a serious condition called hyperemesis gravidarum where the mother may develop fluid and mineral imbalances that can endanger her life or that of her unborn

Treatment for vomiting (regardless of age or cause) includes:

1. Recognise and correct the dehydration and electrolyte imbalance.

• Drinking gradually larger amounts of clear liquids.
• Avoiding solid food until the vomiting episode has passed.
• On advice of the healthcare provider temporarily discontinue all oral medications (which can irritate the stomach and make vomiting worse).
• If vomiting and diarrhoea last more than 24 hours, an oral rehydrating solution such as Rehydrate® should be used to prevent and treat dehydration.
• Those with significant dehydration or electrolyte abnormalities and those who cannot tolerate liquids by mouth usually require intravenous fluids.

1. Try to identify the underlying cause of the nausea and vomiting and that should be treated.
   1. If no specific cause can be identified OTC medications for nausea and vomiting include cyclizine (Valoid® or Adco-Cyclizine®) or buclizine (Vomifene®). These are antihistamines which block the messages going to the vomiting centre in the brain. These work well if they are taken before the symptoms appear e.g. as a prevention of motion sickness.  Ensure that patients are not taking any other antihistamines in cold and flu medication or pain killers and anti-allergy medication to avoid overdosing. There is various prescription anti-emetics that are indicated for post-operative nausea and vomiting and that associated with cancer treatments. Emetrol ®or Emex® which are sucrose and phosphoric acid combinations can also be administered for nausea in motion sickness and early pregnancy.

Prevention of nausea

There are several ways to try and prevent nausea from developing. Nausea and vomiting as a result of motion sickness can be avoided by the patient sitting so that they look out of the front windshield. Watching fast movement out of the side windows can make the nausea worse.  Advise that the patients do not eat and work/play at the same time. The food should settle in the stomach before activity is started. Patients should drink small amounts of clear liquids frequently. Eat small meals throughout the day instead of three large meals. Eat slowly. Avoid ‘hard to digest’ foods. Consume foods that are cold or room temperature to avoid the nausea from the smell of hot or warm foods. Eat when they are feeling less nauseated.

Conclusion

Nausea and vomiting are common symptoms of an underlying disorder. The dehydration as a result of vomiting is the concern that should be addressed first in the treatment. A doctor should be consulted if the vomiting is severe and the cause cannot easily be identified.