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| Credit: Wikipedia |
Botulism (Latin, botulus, a sausage) is a rare and potentially fatal illness caused by a toxin produced by the bacterium Clostridium
botulinum. The
disease begins with weakness, trouble seeing, feeling tired, and trouble
speaking. This may then be followed by weakness of the arms, chest muscles, and
legs. The disease does not usually affect consciousness or cause a fever.
Botulism can
occur in a few different ways. The bacterial spores that cause it are common in
both soil and water. They produce the botulinum
toxin when exposed to low oxygen levels and certain temperatures.
Foodborne botulism happens when food containing the toxin is eaten. Infant
botulism happens when the bacteria develops in the intestines and releases the toxin. This
typically only occurs in children less than six months old, as protective
mechanisms develop after that time. Wound botulism is found most often among
those who inject
street drugs. In
this situation spores enter a wound and, in the absence of oxygen, release the
toxin. It is not passed directly between people. The diagnosis is confirmed by
finding the toxin or bacteria in the person in question.
Prevention
is primarily by proper food preparation. The toxin, though not the organism, is
destroyed by heating it to more than 85 °C (185 °F) for longer than
5 minutes. Honey can contain the organism, and
for this reason honey should not be fed to children under 12 months. Treatment
is with an antitoxin. In those who lose their ability to breathe on their
own, mechanical
ventilation,
potentially for months, may be required. Antibiotics may be used for wound botulism.
Death occurs in 5 to 10% of people. Botulism can affect many other animals.
Signs and symptoms
The muscle
weakness of botulism characteristically starts in the muscles supplied by
the cranial
nerves. A group of
twelve nerves controls eye
movements, the facial muscles and the muscles
controlling chewing and swallowing. Double vision, drooping of both eyelids, loss of facial expression and
swallowing problems may therefore occur. In addition to affecting the voluntary
muscles, it can also
cause disruptions
in the autonomic nervous system. This is experienced as a dry mouth and throat(due to decreased production of
saliva), postural
hypotension (decreased
blood pressure on standing, with resultant lightheadedness and risk of
blackouts), and eventually constipation (due to decreased peristalsis). Some of the toxins (B and E) also
precipitate nausea and vomiting. difficulty with talking. The weakness then spreads to the
arms (starting in the shoulders and proceeding to the forearms) and legs (again
from the thighs down to the feet).
Severe
botulism leads to reduced movement of the muscles
of respiration, and
hence problems with gas
exchange. This may
be experienced as dyspnea (difficulty breathing), but
when severe can lead to respiratory
failure, due to the
buildup of unexhaled carbon dioxide and its resultant depressant
effect on the brain. This may lead to coma and eventually death if untreated.
Clinicians
frequently think of the symptoms of botulism in terms of a classic triad: bulbar palsy and descending paralysis, lack
of fever, and clear senses and mental status ("clear sensorium").
Infant botulism
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| Credit: Wikipedia (Infant with
botulism. He is unable to move or open his eyes. His cry was weak. He is not
asleep or sedated.) |
Infant
botulism (also referred to as floppy
baby syndrome) was
first recognized in 1976, and is the most common form of botulism in the United
States. There were 17 diagnosed cases of infant botulism in the United States
in 2013. Infants are susceptible to infant botulism in the first year of life,
with more than 90% of cases occurring in infants younger than six months. Infant botulism results from the ingestion of
the C.
botulinum spores,
and subsequent colonization of the small intestine. The infant gut may be
colonized when the composition of the intestinal microflora (normal flora) is insufficient
to competitively inhibit the growth of C.
botulinum and
levels of bile acids (which normally inhibit clostridial growth) are lower than
later in life.
The growth
of the spores releases botulinum
toxin, which is then absorbed into the bloodstream and taken throughout the
body, causing paralysis by blocking the release of acetylcholine at the neuromuscular
junction. Typical
symptoms of infant botulism include constipation, lethargy, weakness,
difficulty feeding and an altered cry, often progressing to a complete
descending flaccid
paralysis. Although
constipation is usually the first symptom of infant botulism, it is commonly
overlooked.
Honey is a known dietary reservoir
of C.
botulinum spores
and has been linked to infant botulism. For this reason honey is not
recommended for infants less than one year of age. Most cases of infant botulism, however, are
thought to be caused by acquiring the spores from the natural environment. Clostridium
botulinum is a
ubiquitous soil-dwelling bacterium. Many infant botulism patients have been
demonstrated to live near a construction site or an area of soil disturbance.
Infant
botulism has been reported in 49 of 50 US states, and
cases have been recognized in 26 countries on five continents.
Complications
Infant
botulism has no long-term side effects, but can be complicated by hospital-acquired infections. The case
fatality rate is
less than 1% for hospitalized infants with botulism.
Botulism can
result in death due to respiratory failure.
However, in the past 50 years, the proportion of patients with botulism who die
has fallen from about 50% to 7% due to improved supportive care. A patient with
severe botulism may require mechanical
ventilation (breathing
support through a ventilator) as well as intensive medical and nursing care,
sometimes for several months. The respiratory failure and paralysis that occur
with severe botulism may require a person to be on a breathing machine
(ventilator) for weeks or months. The person may require rehabilitation therapy
after leaving the hospital. Read more >>
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