Author Topic: TETANUS!!  (Read 8438 times)

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Offline IsseGole

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TETANUS!!
« on: February 21, 2007, 02:59:05 PM »
CLOSTRIDIUM TETANI
 
Tetanus is a disease affecting the nervous system 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, and it is caused by infection by clostridium tetani. 
The 8th day disease ( in India), the non-exceeding 7 days disease (in Somalia), the lockjaw (in America), and other various names known to be the tetanus are scattered worldwide pointing at the medical importance, famousness, and the need for prevention of the disease.
The word tetanus comes from the Greek tetanos, which is derived from the term teinein, meaning to stretch.

Morphology:

1- Clostridium tetani is a Gram-positive spore bearing anaerobic bacilli.
2- tetanus bacillus is an obligate anaerobe, non-capsulated, motile, and has numerous peritrichous flagella.
3- it grows on Blood agar, producing a thin spreading film.
4- it appears on MI as a straight, slender rod with rounded nuclei; as drumstick with large rounded nuclei in fully developed strains.
5- The spore are found in soil, dust, intestines and feces of animals and humans which may persist for months to years.  Manure treated soil may contain large number of spores.
6- Resistance: 120oC for 20 minutes kills the spores, iodine and H2O2 kills them in few minutes.

Cultural characters:

The spores grow in the wound only in absence of oxygen, optimum temperature 37oC, pH 7.4, grows in ordinary media,

The toxin:

1- C. tetani produces an oxygen labile hemolysin (tetanolysin).
2- It also produces at the site of injury its neurotoxin (tetanospasmin); the essential pathogenic product.
3- Tetanospasmin is heat labile, oxygen stable. .
4- It –tetanospasmin- binds  to the peripheral motor neuron terminals, enter the axon and is transported to the nerve cell body in the brain stem and spinal cord by retrograde intraneuronal transport. The tetanus toxin interferes with neurotransmitter release blocking inhibitor impulses which leads to unopposed muscle contraction and spasm.
5- Third toxin: Non-spasmodic peripherally active neurotoxin.

Modes of transmission:

The spores  are found in soil, dust, intestines and feces of animals and humans
Through contamination of wounds with tetanus spores: pin pricks, skin abrasions, puncture wounds, burns, human bites, animal bites and stings, un-sterile surgery, intrauterine death, bowel surgery, dental extractions, injections, un-sterile division of umbilical cord, compound fracture, otitis media, chronic skin ulcers, eye infections and gangrenous limbs.

Pathogenesis:

the steps of disease respectively:
Trauma or any other route of transmission
Tissue damage and contamination with C. tetani spores
Incubation period 8 days (3—12 days )
Germination and outgrowth of C. spores
Multiplication of obligate anaerobes with production of toxins
Toxins bind to peripheral motor neuron terminals and so on
It affects the spinal cord, brain, motor end plates, and sympathetic nerve fibers causing spasms and convulsions
Death from respiratory and renal failure in 70%.

Clinical features:
 
trismus (Lockjaw)  risus sardonicus  Opisthotonus  neck stiffness
Type of tetanus clinically:
1. Traumatic tetanus.
2. Tetanus neonatorum.
3. Post-abortal, puerperal tetanus.
4. Splanchnic tetanus.
5. Cephalic tetanus.
6. Otogenic tetanus.
7. Idiopathic (cryptogenic) tetanus.

Laboratory diagnosis:

It is always diagnosed clinically, but confirmed by bacteriology.
1. Microscopic examination: smear from the wound, on gram stain, gram +ve anaerobic bacilli with drumstick appearance.
2. Culture: this is more dependable, discussed earlier, if we are suspicious of another bacteria contamination we heat it.
3. Animal inoculation: on mouse with another control one.

Prophylaxis and prevention:

Tetanus – fortunately – is a preventable disease.
1. Active immunization: 2 injections of tetanus toxoid, IM, of 1 ml each, at interval of 6 weeks. Third injection is 6 to 12 months later, this makes full immunization for 10 years.
2. Passive immunization: an emergency procedure used only once, ATS: 1800 IU SCorIM, as early as possible after wounding, half life for 2 days. It carries risk with hypersensitivity.
Without risk: ATG: smaller dose (250IU), longer hl (3-5 wks)
3. Combined immunization: both, preferred directly after wounding.





Towards a better healthy Somalia!!
Unless all parts of the society participate equally in the health process, nothing could be expected.