A complete article on Tetanus (Tetanus)

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Product:	Tetanus
Date:	31/03/09 (51 review reads)
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I did a little research about tetanus and wrote an article for a doctor's project. This article has been compiled from various websites around the internet. here it goes....

TETANUS

Tetanus, also called lockjaw, is an illness characterized by an acute onset of hypertonia, painful muscular contractions (usually of the muscles of the jaw and neck), and generalized muscle spasms without other apparent medical causes. Tetanus is acquired when the spores of the bacterium Clostridium Tetani infect a wound or the umbilical stump. Spores are universally present in the soil.

The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, obligate anaerobic bacterium Clostridium tetani. Infection generally occurs through wound contamination, and often involves a cut or deep puncture wound. As the infection progresses, muscle spasms in the jaw develop, hence the name lockjaw. This is followed by difficulty in swallowing and general muscle stiffness and spasms in other parts of the body.


MECHANISM
Clostridium tetani, an obligate anaerobic gram-positive bacillus, causes tetanus. This bacterium is nonencapsulated and forms spores, which are resistant to heat, desiccation, and disinfectants. The spores are ubiquitous and are found in soil, house dust, animal intestines, and human feces.

Spores that gain entry can persist in normal tissue for months to years. Under anaerobic conditions, these spores geminate and elaborate tetanospasmin and tetanolysin. Tetanolysin is not believed to be of any significance in the clinical course of tetanus. Tetanospasmin is a neurotoxin and causes the clinical manifestations of tetanus. Tetanospasmin that is released by the maturing bacilli is distributed via the lymphatic and vascular circulations to the end plates of all nerves. Tetanospasmin then enters the nervous system peripherally at the myoneural junction and is transported centripetally into neurons of the central nervous system (CNS). Per weight, tetanospasmin is one of the most potent toxins known. The estimated minimum lethal dose is 2.5 nanograms per kilogram of body weight (a nanogram is one billionth of a gram), or 175 nanograms for a 70-kg (154-lb) human.

These neurons become incapable of neurotransmitter release. The neurons, which release gamma-aminobutyric acid (GABA) and glycine, the major inhibitory neurotransmitters, are particularly sensitive to tetanospasmin, leading to failure of inhibition of motor reflex responses to sensory stimulation. This results in generalized contractions of the agonist and antagonist musculature characteristic of a tetanic spasm. The shortest peripheral nerves are the first to deliver the toxin to the CNS, which leads to the early symptoms of facial distortion and back and neck stiffness.

Once the toxin becomes fixed to neurons, it cannot be neutralized with antitoxin. Recovery of nerve function from tetanus toxins requires sprouting of new nerve terminals and formation of new synapses.

SIGN AND SYMPTOMS

Tetanus affects skeletal muscle, a type of striated muscle. The other type of striated muscle, cardiac or heart muscle cannot be tetanized, because of its intrinsic electrical properties.

The incubation period of tetanus ranges from 3 to 21 days, with an average onset of clinical presentation of symptoms in 8 days. In general, the further the injury site is from the central nervous system, the longer the incubation period. The shorter the incubation period, the higher the chance of death. In neonatal tetanus, symptoms usually appear from 4 to 14 days after birth, averaging about 7 days. On the basis of clinical findings, four different forms of tetanus have been described.

Local tetanus is an uncommon form of the disease, in which patients have persistent contraction of muscles in the same anatomic area as the injury. The contractions may persist for many weeks before gradually subsiding. Local tetanus is generally milder; only about 1% of cases are fatal, but it may precede the onset of generalized tetanus.

Cephalic tetanus is a rare form of the disease, occasionally occurring with otitis media (ear infections) in which C. tetani is present in the flora of the middle ear, or following injuries to the head. There is involvement of the cranial nerves, especially in the facial area.

Generalized tetanus is the most common type of tetanus, representing about 80% of cases. The generalized form usually presents with a descending pattern. The first sign is trismus, or lockjaw, and the facial spasms called risus sardonicus, followed by stiffness of the neck, difficulty in swallowing, and rigidity of pectoral and calf muscles. Other symptoms include elevated temperature, sweating, elevated blood pressure, and episodic rapid heart rate. Spasms may occur frequently and last for several minutes with the body shaped into a characteristic form called opisthotonos. Spasms continue for 3-4 weeks, and complete recovery may take months.

Neonatal tetanus is a form of generalized tetanus that occurs in newborn infants. It occurs in infants who have not acquired passive immunity because the mother has never been immunized. It usually occurs through infection of the unhealed umbilical stump, particularly when the stump is cut with a non-sterile instrument.

Spatula test

The "spatula test" for tetanus involves touching the posterior pharyngeal wall with a sterile, soft-tipped instrument, and observing the effect. A positive test result is the involuntary contraction of the jaw (biting down on the "spatula"), and a negative test result would normally be a gag reflex attempting to expel the foreign object.

A short report in The American Journal of Tropical Medicine and Hygiene states that in a patient research study, the spatula test had a high specificity (zero false-positive test results) and a high sensitivity (94% of infected patients produced a positive test result).


HISTORY
Although records from antiquity (5th century BC) contain descriptions of tetanus, it was Carle and Rattone in 1884 who first produced tetanus in animals. This was accomplished by injecting them with pus from a fatal human tetanus case. During that same year, Nicolaier produced tetanus in animals by injecting them with soil. In 1889, Kitasato isolated the organism from an infected human, showed that it produced disease when injected into animals, and reported that the toxin could be neutralized by specific antibodies. In 1897, Nocard demonstrated the protective effect of passively transferred antitoxin. Passive immunization in humans was used for treatment and prophylaxis during World War I. Tetanus toxoid was developed by Descombey in 1924. It was first widely used during World War II.



EPIDEMIOLOGY

Time distribution:
Tetanus can occur at any time of the year but the risk is high during rainy seasons and during summer, when the hot and humid environment promotes the growth of bacteria in the soil or other degerating organic matter.

Place distribution:
Tetanus is a global health problem, as C. tetani spores are ubiquitous. Tetanus occurs worldwide but is more common in hot, damp climates with soil rich in organic matter. This is particularly true with manure-treated soils, as the spores are widely distributed in the intestines and faeces of many non-human animals such as horses, sheep, cattle, dogs, cats, rats, guinea pigs, and chickens. In agricultural areas, a significant number of human adults may harbour the organism. The spores can also be found on skin surfaces and in contaminated heroin.

Risk group:
People of all ages can get tetanus but the disease is particularly common and serious in newborn babies ("neonatal tetanus").
Apart from the risk for a variety of infections for mother and child, there is a serious risk for the mother and child to get infected by tetanus if the delivery is not carried out on a clean surface or with clean hands, or if the umbilical cord is not cut with a clean razor/pair of scissors, and if the mother is not immunized.
Most tetanus cases occur among people who are inadequately vaccinated and who sustain an acute injury.
Heroin users, particularly persons who inject themselves subcutaneously, appear to be at high risk for tetanus. Quinine is used to dilute heroin and may support the growth of C tetani.
Similarly people who are in constant contact with the soil like gardeners and farmers are at high risk as the bacteria may be introduced in their bodies through injusries.
Risk factors for Tetanus can be summarized as follow:
* Soil
* Manure
* Wound
* Farming
* Gardening
* Forestry
* Outdoor sports
* Outdoor occupations
* Animal feces
* Puncture wounds
* Burns
* Ulcers
* Bites
* Surgery sites
* Injection sites
* Umbilical cord stump
* Childbirth - can cause a uterine infection.


Association with rust

Tetanus is often associated with rust, especially rusty nails, but this concept is somewhat misleading. Objects that accumulate rust are often found outdoors, or in places that harbour anaerobic bacteria, but the rust itself does not cause tetanus nor does it contain more C. tetani bacteria. The rough surface of rusty metal merely provides a prime habitat for a C. tetani endospore to reside, and the nail affords a means to puncture skin and deliver endospore into the wound. An endospore is a non-metabolising survival structure that begins to metabolise and cause infection once in an adequate environment. Because C. tetani is an anaerobic bacterium, it and its endospores will thrive in an environment that lacks oxygen. Hence, stepping on a nail (rusty or not) may result in a tetanus infection, as the low-oxygen (anaerobic) environment of a puncture wound provides the bacteria with an ideal breeding ground.

Problem statement:
Tetanus is a global health problem, as C. tetani spores are ubiquitous.
Reported incidence of tetanus has declined substantially since the mid 1940s because of the widespread use of tetanus immunizations
Worldwide, tetanus is predominantly a disease of underdeveloped countries located in warm, damp climates. Tetanus affects all age groups, with the highest prevalence found in newborns and young people. In 1992, an estimated 578,000 infant deaths occurred due to neonatal tetanus. In 1998, 215,000 deaths occurred with more than 50% of these on the Africa continent. Tetanus is one of the target diseases of the World Health Organization Expanded Program on Immunization. Overall, the annual incidence of tetanus is 0.5-1 million cases.
Overall, the mortality rate is approximately 45%. Clinical tetanus is less severe among patients who have a history of receiving a primary series of tetanus toxoid sometime during their life as compared with patients who are inadequately vaccinated or unvaccinated.
Tetanus - particularly the neonatal form - remains a significant public health problem in non-industrialized countries. There are about one million cases of tetanus reported worldwide annually, causing an estimated 300,000 to 500,000 deaths each year.
Nearly all of the cases in the developed countries occur in unimmunized individuals or individuals who have allowed their inoculations to lapse, whereas most cases in developing countries are due to the neonatal form of tetanus.

Prevention:
Tetanus is the only vaccine-preventable disease that is infectious but is not contagious.
Tetanus can be prevented by vaccination. The CDC recommends that adults receive a booster vaccine every ten years, and standard care practice in many places is to give the booster to any patient with a puncture wound who is uncertain of when he or she was last vaccinated, or if he or she has had fewer than 3 lifetime doses of the vaccine. The booster cannot prevent a potentially fatal case of tetanus from the current wound, however, as it can take up to two weeks for tetanus antibodies to form.
In children under the age of seven, the tetanus vaccine is often administered as a combined vaccine, DPT/DTaP vaccine, which also includes vaccines against diphtheria and pertussis.
For adults and children over seven, the Td vaccine (tetanus and diphtheria) or Tdap (tetanus, diphtheria, and acellular pertussis) is commonly used.
For pregnant ladies, the first dose is given in the 7th month of pregancy which is followed by another dose in the 8th month.

WHO strategy for Nenatal Tetanus:
Worldwide, all countries are committed to "elimination" of maternal and neonatal tetanus (MNT), i.e. a reduction of neonatal tetanus incidence to below one case per 1000 live births per year in every district. As of December 2007, 47 countries remain that have not eliminated MNT.
The initiative's aim is to reduce the number of cases to such low levels that it is no longer a major problem. Unlike polio and smallpox, the disease cannot be eradicated (the tetanus spores are present in the environment), but through immunization of child bearing age women (CBAW) and of pregnant women, and through the promotion of more hygienic deliveries, the disease can be eliminated (which is defined as less than one case of Neonatal Tetanus per 1000 live births in every district)

At the end of the 1980s, neonatal tetanus was considered a major public health problem. WHO estimated that in 1988, 787,000 newborn children died of neonatal tetanus, hence a rate of 6.5 cases per 1000 live births

In 1989, the 42nd World Health Assembly called for elimination of neonatal tetanus by 1995

In 1990, the World Summit for Children listed neonatal tetanus elimination as one of its goals, which were endorsed by the 44th World Health Assembly in 1991

Due to slow implementation of the recommended strategies, the target date for elimination was postponed to 2000 and later, while adding maternal tetanus elimination as a goal, to 2005.

While progress has been made, by the end of 2008, there still remains 46 countries to eliminate MNT. Activities continue in these countries, to achieve the goal in the near future.

WHO estimates that in 2004 the latest year for which estimates are available, 128,000 newborns died of Neonatal Tetanus.

Summary: A deadly disease.