Tetanus

Organism The bacillus Clostridium tetani, which is a Gram-positive rod with spherical, terminal spores, giving it a characteristic drum-stick appearance.

Clinical features Infection results from the organism entering an abraded surface, such as a cut or scratch. It favours anaerobic conditions, liberating toxin, which produces severe muscle spasms. It is a serious condition in the neonate due to infection of the umbilical cord stump.

The adult presents with muscle spasm and rigidity. There may be trismus, in which the muscles of the jaw and later the back become rigid leading to lock jaw and opisthotonos. Muscle spasms can produce the characteristic half smile, half snarl of 'risus sardonicus' or generalized opisthoto-nos. These spasms are initiated by external stimuli, such as touch or attempts at intubation, and every care must be taken to protect the patient from such stimuli. Neonatal tetanus generally presents as a difficulty in sucking; then the rigidity of muscles and generalized convulsions develop. It usually commences within 5-10 days of birth.

Diagnosis is on the clinical presentation.

Transmission The organism is introduced into a wound from soil, dust or animal faeces. Cutting the umbilical cord with an unsterile instrument, such as a bamboo knife, or traditional practice of treating the umbilical stump are potent methods of causing neonatal tetanus. These can involve covering the stump with an unsterile dressing or customary practice of using a cow dung or earth poultice.

The bacillus is found naturally in the soil where it survives in anaerobic conditions. Many types of soils have been found to harbour C. tetani, but it is more common in cultivated soils, especially those manured with animal faeces. The organism is found in horse and cattle dung and less commonly in pig, sheep and dog faeces. It is occasionally found in human excreta, particularly in people associated with animals.

The vegetative form of the organism is sensitive to antibiotics, disinfectants and heat, but as a spore, it is resistant to all but the super-heated steam of an autoclave. Indeed, the spores of C. tetani are used to test the effectiveness of the sterilizing process because if it cannot survive, then no other organism can (apart from anthrax).

Spores can survive for considerable periods of time, but when they enter a wound or umbilical stump in which there is a low oxygen reduction potential, they release the vegetative form, which grows anaerobically and infection takes place. It is the moist, contaminated umbilical stump or the traumatized wound that provides suitable conditions.

The replication of the organism is not important, but toxin is produced that can have a profound effect out of all proportion to the initial infection. The exotoxin has a high affinity for nervous tissue and as little as 0.1 mg is sufficient to kill a person. Toxin is absorbed along the nerves, reaching the spinal cord where the generalized features of the disease are produced.

Incubation period is from 4-21 days, but most cases occur within 14 days. There is a relationship between incubation period and severity, with an incubation period of less than 9 days having a mortality of 60% and more than 9 days 25% mortality. This is due to the dose of the toxin.

Period of communicability Not transmitted from person-to-person directly or indirectly.

Occurrence and distribution Tetanus occurs worldwide, with higher rates in Africa, Asia (especially Southeast) and the Western Pacific. Neonatal tetanus is a serious problem in Africa, especially where birth practices are rudimentary. There is an association with agricultural areas where animal excreta is commonly used for fertilizing the soil, as a fuel or as a plaster on the walls of houses. Domestic animals either share the same house as their owners or live in such close proximity that their faeces contaminate the surrounding soil.

Control and prevention The aim should always be to prevent tetanus with vaccination and good hygiene practices, especially with the newborn.

The most effective way of preventing neonatal tetanus is the vaccination of all women of childbearing age. The policy is to give all women a lifetime total of five doses of tetanus toxoid. This is preferable to waiting until the woman becomes pregnant because many women do not attend antenatal clinic, especially those who are likely to use traditional applications to the umbilical cord stump. The effectiveness of various strategies is shown in Fig. 10.5. Women should, therefore, be given their first dose of tetanus toxoid at first contact or as early as possible during pregnancy. The second is given 4 weeks later and the third 6-12 months after the previous dose or during the next pregnancy. Doses four and five are given at yearly intervals. Where a woman has a certificate to say that she has received vaccination as a child, then she only needs to have two doses during the first pregnancy and one more before or during the second pregnancy.

Infants are given tetanus toxoid as part of their childhood vaccination programme as DTP at 6, 10 and 14 weeks of age. An additional booster dose of DTP can be given at 18 months to 4 years of age. School children or adults who have not been vaccinated before should be given two doses of adsorbed tetanus toxoid (0.5 ml), separated by 4 weeks and a third dose of 1 ml 6 months later. Booster doses every 10 years will maintain a high level of immunity.

In the event of a person being injured and presenting with a contaminated wound that could produce tetanus, the following action should be taken - clean out the wound, give penicillin, then the following:

• If the person has been fully vaccinated in the past, a booster dose of toxoid is required only if this is more than 10 years ago.

• If there is no record of tetanus vaccination or protection is in doubt, then give the first dose of tetanus toxoid plus 250 units of human tetanus immune globulin or 1500 units of equine tetanus antitoxin, following a test dose. Instruct the person to return at 4 weeks and then 6 months to complete the course of vaccination.

Good birth practices are important in preventing neonatal tetanus and several countries have developed systems for contacting traditional birth attendants (TBAs) and giving them courses of instruction. Prepacked sterilized blades for cutting the cord can be given and iodine, spirit or similar antiseptic provided to apply to the cord stump. Where there is no system of TBAs but delivery takes place at home with the assistance of mother or other female relative, then an instruction sheet in the local language can be given to the pregnant woman when she attends the antenatal clinic or at any other contact with the health services. Figure 10.6 illustrates several strategies for reducing neonatal tetanus as tried out in rural Haiti.

Treatment Tetanus is a self-limiting disease and if the patient can be kept alive for 3 weeks, then complete recovery should take place, but keeping the patient alive for this period of time is the problem. It is the toxin that is causing the symptoms and once this is fixed in the nerves, only support can be given to the patient to

Schedule

A

3 DPT in infancy

B

3 DPT in infancy and 1 DPT in 2nd year

Wl

C

As in B plus 1 DT at school entry

III

III

D

As in C plus 1 DT at school leaving

III

11

E

2 DT at school

F

3 DT at school

ill_

1

G

5 TT as recommended by EPI

rnl— 1

Fig. 10.5. Expected duration of tetanus immunity after different vaccination schedules. DPT, diphtheria, pertussis and tetanus; DT, diphtheria and tetanus; TT, tetanus toxoid; EPI, Expanded Programme of Immunization. (Reproduced by permission of the World Health Organization, Geneva.)

1940 - 1948

1949 - 1955

1956 - 1962

1963 - 1966

1967 - 1968

1969 - 1970

1971 - 1972

262.2

136.63

78.54

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

0 50 100 150 200 250 300

Mortality rates per 1000 live births

Fig. 10.6. Neonatal mortality per 1000 live births in rural Haiti, 1940-1972, from a retrospective study of 2574 mothers. 1, before national programme for training TBAs; 2, national programme for training TBAs; 3, hospital treatment for tetanus, training of TBAs by hospital nurse; 4, immunization of pregnant women in hospital clinics; 5, immunization of women in market places by hospital team; 6, immunization after door-to-door invitation by community workers. (Reproduced by permission of the World Health Organization, Geneva.)

maintain respiration, urinary output and nutrient intake. The patient is sedated to reduce spasms and in all ways, expertly nursed. The contaminated wound must be cleaned and excised, antitoxin or immuno-globulin administered and penicillin given to kill any remaining organisms. Sadly, the mortality from tetanus is high - 40% in adults and 90% in neonates, so the objective should always be to try and prevent it.

Surveillance WHO has set out to eliminate maternal and neonatal tetanus (it can never be eradicated because C. tetani will always remain in the environment) as a health problem by 2005, by intensified vaccination, the promotion of clean delivery practices and a programme of school vaccination. High-risk areas need to be identified from a knowledge of the birth practices, lack of health facilities or preponderance of cases. All children at school entry should be required to bring their vaccination certificates with them and if these are not adequate, receive a course of tetanus toxoid.

Allergy Relief

Allergy Relief

Have you ever wondered how to fight allergies? Here are some useful information on allergies and how to relief its effects. This is the most comprehensive report on allergy relief you will ever read.

Get My Free Ebook


Post a comment