Dr-wijdan
TETANUSEpidemiology
Tetanus is an acute,often fatal,disease caused by an exotoxin produced by the
bacterium Clostridiumtetani. But prevented by immunization with tetanus toxoid.
It is characterized by generalized rigidity and convulsive spasms of skeletal
muscles.The muscle stiffness usually involves the jaw (lockjaw)and neck and then
becomes generalized.
Tetanus was first described in Egypt over 3000 years ago(Edwin smith papyrus).
It was again described by Hippocrates
Carle and Rattone in 1884 who first noticed tetanus in animals by injecting them
with pus from a fatal human tetanus case.
During the same year,Nicolaier produced tetanus in animals by injecting them
with samples of soil.
In 1889,Kitasato isolated the organism from a human victim,showed that it
produced disease when injected into animals,and reported that the toxin could be
neutralized by specific antibodies.
Nocard demonstrated the protective effect of passively transferred antitoxin,and
passive immunization in humans
Passive immunization and prophylaxis for tetanus during World War I
Tetanus Toxoid was first widely used during world war II
Tetanus - Greek Word -- Tetanos-to Contract
Tetanus Remains a Major Public Health Problem in the Developing World and Is
Still Encountered in the Developed World.
There Are Between 800 000 and 1 Million Deaths Due to Tetanus Each Year. Eighty
Per Cent of These Deaths Occur in Africa and South East Asia and It Remains
Endemic in 90 Countries World Wide.
1998 - U.K,USA 7 Cases, 41 Cases Including One Neonate
C.tetani is a slender,gram-positive,anaerobic rod that may develop a terminal
spore,giving it a drumstick appearance.
The organism is sensitive to heat and cannot survive in the presence of
oxygen.The spores,in contrast,are very resistant to heat and the usual
antiseptics.
They can not survive autoclaving at 249.8 °F (121 °C)for 20 minutes.
The spores are also relatively resistant to phenol and other chemical agents.
The spores are widely distributed in soil and in the intestines and faeces of
horses,sheep,cattle,dogs,cats,rats, guinea pigs,and chickens.Manure-treated soil
may contain large numbers of spores.Spores may persist for months to years.
C. tetani produces two exotoxins, tetanolysin and tetanospasmin. The function of
tetanolysin is not known with certainty. Tetanospasmin is a neurotoxin and
causes the clinical manifestations of tetanus.
Tetanospasmin estimated Human lethal dose 2.5 ng/kg
Age : I t is the disease of active age (5-40 years), New born baby, female
during delivery or abortion
Sex : Higher incidence in males than females
Occupation : Agricultural workers are at higher risk
Rural –Urban difference:Incidence of tetanus is much lower than in rural areas
Immunity : Herd immunity does not protect the individual
Environmental and social factors: Unhygienic custom habits,Unhygienic delivery
practices
Tetanus Toxins
• Germination of spores and production of toxins under anaerobic
conditions:
1.Tetanolysin:
• Potentiates infection but not involved in
pathogenesis
• Its role not known w/certainty
2.Tetanospasmin: (tetanustoxin)
• Potent neurotoxin released with growth of C. tetani at site of infection
• One of the most potent toxins known on a weight basis
• Estimated minimum human lethal dose is 2.5 ng/kg Causes clinical tetanus
Tetanus Pathogenesis
C. tetani enters body through a wound in anaerobic
Conditions---- spores germinate -----toxins produced ---- disseminated via blood
and lymphatics acts at several sites:
• Central nervous system
• Spinal cord
• Brain
• Sympathetic nervous system
Tetanus Clinical Features
• Incubation period 8 days (range= 3-21 days)
• The further the injury site from the CNS, the longer the
incubation period
• The shorter the incubation period, the higher the chance of death
Four clinical forms:
– Localized (uncommon)
– Cephalic (rare)
– Generalized (most common)
- Neonatal
Diagnosis Of Tetanus
Clinically it is confirmed by noticing the following features:
Risus sardonicus or fixed sneer.
Lock jaw.
Opisthotonos (extension of lower extremities, flexion of upper extremities and
arching of the back. The examiners hand can be passed under the back of the
patient when he lies on the bed in supine position.)
Neck rigidity
Three Objectives of Management of Tetanus
(1)To provide supportive care until the tetanospasmin that is fixed in tissue
has been metabolized
(2)To neutralize circulating toxin
(3)To remove the source of tetanospasmin.
Methods of ControlA- Preventive Measures
· Active Immunization
· Passive Immunization
· Active and passive Immunization
· Antibiotics
1) Educate the public on necessity for complete immunization with tetanus
toxoid.
2) universal active immunization with adsorbed tetanus toxoid which gives
durable protection for at least 10 years.
3) Prophylaxes in wound management: careful assessment of wether the wound is
clean or contaminated , the immunization status of the patient, proper use of
tetanus toxoid, and or TIG, wound cleaning and when required- surgical
debridement and the proper use of antibiotic.
TETANUS TOXOID
• •Tetanus toxoid was developed in 1924,• •Tetanus toxoid immunizations were used extensively in the armed
services during World War II.
• •Tetanus toxoid consists of a formaldehyde-treated toxin.
• •There are two types of toxoid available —adsorbed (aluminum salt
precipitated)toxoid and fluid toxoid.
• •Although the rates of seroconversion are about equal,the adsorbed
toxoid is preferred because the antitoxin response reaches higher titers and is
longer lasting than that following the fluid toxoid
Active Immunization
• •1st dose - 6th week
• •2nd dose - 10th week
• •3rd dose - 14th week
• •1st booster - 18th month
• •2nd booster - 6th year
• •3rd booster - 10th year
Passive Immunization
. Passive Immunization: with at least 250 IU of human –derived TIG IM ( or
1500 to 5000 IU of antitoxin of animal origin if globulin is not available),
regardless of the patients age , is indicated for patients with other than
clean, minor wounds and a history of no, unknown or fewer than 3 previous
tetanus toxoid doses.
Elimination of Neo natal tetanus
1- High risk district:a) Neo natal death rate > 1/1000 live births
b) 2 doses of tetanus toxoid coverage < 70%
c) Deliveries attended by trained dais < 50%
2- Medium risk district:
a) Neo natal death rate < 1 / 1000 live births
b) 2 doses of tetanus toxoid coverage> 70%
c) Deliveries attended by dais > 50%
3- Low risk district:
a) NNT <0.1/1000 Live Birth
b) 2 Doses of T.T Coverage >90%
c) Delivery attended by Trained Dais >75%
PREVENTION OF NEONATAL TETANUS
2 doses of T.T to all pregnant women between 16 to 36 weeks of pregnancy with an
interval of 1 to 2 months between the two doses.
The first dose as early as possible & the second dose a month later preferably 3
weeks before delivery.
If the pregnant woman is previously immunized, a booster dose is sufficient.
If the pregnant woman is not immunized, then the new born should be protected
against tetanus by giving tetanus human immunoglobulin 750 IU with in 6 hours of
birth.