Nausea and vomiting
Nausea
and vomiting have many possible causes, and are not always related to disease of
the gastro-intestinal tract
Vomiting starts in the brain in a
specific location in the hypothalamus, called the vomiting centre
Vomiting is a reflex where the
vomiting centre tells the intestines to reverse their peristaltic movements in
order to force the contents of the stomach out through the mouth
Most of the time nausea and
vomiting are mild and self-limiting
In
cases where a person cannot keep anything down, oral dehydration and treatment
is not practical and hospitalisation is required
When
treating vomiting, the first important thing is to prevent dehydration or to
treat it if it has already developed, and then to investigate and treat the
cause
Small
children can dehydrate very fast, and should be treated if they are ill for
longer than half a day, or as soon as they start showing signs of dehydration
Description
Nausea is an unpleasant feeling in the pit of the stomach that one is
about to vomit. Vomiting is a reflex where the vomiting centre in the brain
tells the intestines to reverse their peristaltic movements in order to force
the contents of the stomach out through the mouth.
Cause
Nausea
and vomiting have many possible causes, and are not always related to disease of
the gastro-intestinal tract. Sometimes no cause can be found for vomiting.
Vomiting is induced in the brain in a specific location in the hypothalamus,
called the vomiting centre.
The
vomiting centre can be stimulated by:
Psychological problems, when it is
referred to as psychogenic or functional nausea and vomiting
Severe pain or shock
Unpleasant
smells or pictures
Disturbances
in the inner ear in conditions such as altitude sickness, Meniere’s disease,
motion sickness and labyrinthitis. Sometimes middle-ear infection in children
can cause vomiting, but then it is caused by an irritated nerve that runs
through the middle ear
Diseases of the internal organs
(viscera):
Gastro-intestinal disease such as
gastritis, peptic ulcer, stomach cancer, gut obstruction, appendicitis and
mesenteric adenitis
Disease
of the liver or gallbladder such as cholecystitis, hepatitis and cirrhosis
Pancreatitis
Disease of the heart such as
myocarditis, severe hypertension, heart attack (myocardial infarction) and
congestive heart failure
Disease of the brain such as migraine,
stroke (cerebrovascular accident), brain tumors, cerebral hypoxia and epilepsy
Disease of the urinary tract such as
urinary tract infections and renal colic
Chemicals
and toxins
Infections
lead to the production of certain chemicals that can cause fever (pyrogens) and
also stimulate the vomiting centre, for example:
Bacterial
and viral infections, such as cholera and salmonella, that can cause either
gastro-intestinal or systemic infections
Parasitic infections, such as malaria
Meningitis
Sinusitis
Certain
endocrine problems, such as hyperparathyroidism, hyperthyroidism and diabetes
mellitus, produce chemical imbalances that stimulate the vomiting centre
The waste products that accumulate in
the body with renal failure and other electrolyte disturbances can stimulate the
vomiting centre in the brain
Certain drugs and hormones can
stimulate the vomiting centre, causing nausea and vomiting: digoxin, morphine,
estrogens, iron preparation and aminophylline
Other conditions, such as morning
sickness, haemolytic anaemia, porphyria, alcoholism and radiotherapy
Self-induced
vomiting in psychiatric conditions such as bulimia nervosa
Congenital malformations of the
gastro-intestinal tract such as pyloric stenosis and gastro-oesophageal reflux
Course
Once the
vomiting centre in the brain is stimulated, the peristaltic 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 glottis 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.
Most of
the time nausea and vomiting are mild and self-limiting.
More
severe cases of vomiting may cause fluid and electrolyte loss. In such cases
oral rehydration and treatment is not practical and hospitalisation is required
for intravenous therapy.
Prevalence
Psychogenic or functional nausea and vomiting have many causes and can occur in
different ways. This kind of vomiting happens either voluntarily or
involuntarily. For instance a person can start vomiting involuntarily in a very
stressful situation; or if somebody had been brought up with the perception that
a certain kind of food is repulsive, then eating that food may cause involuntary
vomiting. On the other hand, some people deliberately induce vomiting to gain
something like sympathy, or to get out of a difficult situation.
People
who receive cancer treatment often feel nauseous afterwards. Radiation therapy
causes certain by-products that stimulate the vomiting centre in the brain,
while the drugs used for chemotherapy directly stimulate the vomiting centre.
Children
are more prone to vomiting for trivial reasons such as a mild fever.
Most infants tend to bring up small amounts of milk when winded, and
this should not cause any worry. Changing the feeding conditions often helps,
for example reducing the feed, or changing the nipple size.
Some
women experience nausea and vomiting during the first trimester of pregnancy,
while others have no problems at all. The hormones produced by the placenta
cause this nausea. It usually occurs early in the morning, but may occur at any
time of the day. The nausea and vomiting of first trimester of pregnancy is
usually mild and medication should be avoided.
‘Morning
sickness’, as it is called, mostly occurs during the first six to eleven weeks
of pregnancy. Only a few women are nauseous after twelve weeks into the
pregnancy.
Hyperemesis gravidarum is more rare and occurs in about five of every 1 000
pregnancies. It is persistent vomiting in pregnant women to the extent that they
become starved (do not gain weight) and dehydrated. This may even cause severe
liver damage. Although many pregnant women feel as if they are vomiting all
their food, this condition exists only if they fail to gain weight or if they
have become dehydrated. Initially Hyperemesis gravidarum is treated with
intravenous water, glucose and electrolytes, and later with bland oral feedings
in small quantities. Psychological factors and personality traits play an
important role in this condition. High levels of human chorionogonadotropin (a
hormone) also cause this condition, as well as multiple pregnancies.
Many
people experience nausea and/or vomiting when travelling by road, train, sea or
air. This is called motion or travel sickness. Children in particular are prone
to travel sickness.
Bulimia
nervosa affects primarily females of the upper and middle class.
When to
see a Doctor
If
vomiting persists for longer than 24 hours
If
a child under the age of 9 months stays ill for longer than half a day. A child
at this age may lose a dangerous amount of body fluid in such a short time
If signs of dehydration
develop, such as a dry tongue, severe thirst, fast breathing, sunken eyes, dry
skin or if less urine than normal is passed
If the person has had
diarrhoea or vomiting very recently and he/she becomes confused
If vomiting and/or nausea
accompanies any of these symptoms:
Fever, temporary hearing loss,
vomiting and pulling of the ear in young children, especially after a cold –
there may be a middle-ear infection
Neurological
signs such as numbness, loss of speech, which may indicate a stroke (cerebrovascular
accident)
Blood or a coffee ground-like
substance in the vomit, which may indicate a bleeding peptic ulcer
Jaundice (eyes and skin turn yellow,
and may be accompanied by dark urine, light-coloured stools and general
itching), which may indicate hepatitis
Mild
fever, headache, vomiting and muscular pain, and sudden chills and intense
shivering some time after visiting a malaria area
Disturbed
vision, feeling of numbness, pins and needles and headache, which may indicate
migraine
Cramping
pain, distention of the abdomen and constipation, which may indicate bowel
obstruction
Generalised abdominal pain that later
shifts to lower right side, and loss of appetite, which may indicate
appendicitis
Pain
in the right upper side of the abdomen that radiates to between the shoulder
blades or the right shoulder, a possible indication of cholecystitis
Sudden onset of severe abdominal pain
after a big meal, especially if the person has gallbladder disease or drinks
heavily, which may indicate pancreatitis
Repeated projectile vomiting in an
infant, or increasing amounts of vomit, which may indicate pyloric stenosis or
gastro-oesophageal reflux.
Fever
in an infant, which may indicate an infection
Black,
tarry stools (also called melena), which is blood that has been altered in the
digestive tract. It may indicate an ulcer or cancer of the gastro-intestinal
tract
Severe
headaches, sleepiness, lethargy or stiff neck. It may indicate bleeding in the
meningis or, if fever is also present, it may indicate meningitis
Recent
bump on the head and vomiting afterwards
Pregnancy
and an inability to keep food down
Chest pain that radiates into the jaw
or left arm, sweating, shortness of breath, which may indicate angina or a heart
attack (myocardial infarct)
Chest
pain, fever, shortness of breath and palpitations, which may indicate
myocarditis or pericarditis
A
headache that is worse after lying down, when coughing and sneezing, and
vomiting that occurs early in the morning. It may indicate raised intracranial
pressure associated, for instance, with brain cancer
If
you think the medication you are taking is making you ill
Visit
preparation
When you decide to consult a health professional about nausea and/or
vomiting, make sure you take note of the following:
The amount vomited – vomiting large
quantities of food and other gastric secretions later in the day may indicate
gastric outlet obstruction
The color of the vomit:
bright
red blood suggests bleeding from the oesophagus
dark red vomit with liver-like clots
suggests profuse bleeding in the stomach, such as of a peptic ulcer
coffee
ground-like vomit suggests less acute bleeding in the stomach, because the
gastric acid has had time to change the composition of the blood
yellow
vomit suggests bile and is an indication that the pyloric valve is open en bile
is flowing into the stomach (this is more common in older people)
If the vomit is sour and
contains recent food
The relationship to eating
The time of day that it occurs –
vomiting in the morning may indicate pregnancy, alcoholism or anxiety
If
vomiting is preceded by nausea or if it occurs suddenly – the absence of nausea
may indicate raised pressure in the brain
If vomiting relieves abdominal pain
(it may be due to a peptic ulcer)
If there is persistent vomiting
without weight loss, which may indicate of a psychological problem
Complications
The problem with vomiting alone is
that body water is lost, as well as electrolytes such as sodium and chloride. If
untreated, this may lead to dehydration. Dehydration is marked by thirst, dry
mouth, fast breathing, sunken eyes and a reduction in the amount of urine
passed.
If
a person vomits for a long time, the oesophagus may tear and this may lead to
massive bleeding and the vomiting of big amounts of bright red blood, a
condition which is called Mallory Weiss syndrome.
In
prolonged or repeated vomiting, they hydrochloric acid in the gastric juices may
damage the enamel of the teeth.
Treatment
It is most important to try and keep up the body’s supply of water by
taking in as much clear fluid as possible. Rehydration liquids are an excellent
choice, as they also contain electrolytes, but remember to take a small quantity
at a time.
If
dehydration does occur, or if the person is not able to keep any fluids down,
he/she will have to be hospitalised and treated with intravenous water,
electrolytes and glucose.
If an
unconscious person vomits, he or she can inhale the vomit, which can lead to
aspiration pneumonitis, or even worse choke to death on that vomit. For that
reason you should always turn an unconscious on his or her side and make sure
that the airway remains open.
The next
stage is to try and treat or eliminate the cause of the vomiting. It will be
necessary to consult a health professional. For example, if it is caused by non-cytotoxic
drugs, the health professional may reduce the dose, change the route via which
the drug is taken, or change the kind of medication.
If the
health professional suspects a peptic ulcer, the person will be referred for a
gastroscopy to confirm the diagnosis.
Medication
There are numerous preparations available over the counter for the
treatment of nausea and vomiting.
For the treatment or prevention of travel or motion sickness, try the
following:
Promethazine: Brunazine, Daralix
A mixture of sugar and phosphoric
acid: Emetrol, Emex
Cyclizine: Ryccard, Valoid
Cinnarizine: Stugeron
For
rehydration, try one of these solutions:
Darrowped
Electrona
Electropak
Hydrol
powder
Rehidrat
Scripto-lyte
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