- Large, gram (+), obligate anaerobic, motile bacilli with terminally located spore
- Have peritrichous flagella; maybe in chains or arrange singly
- Grow best in plain liquid or semi-solid media containing thioglycollic acid; also in milk and blood agar media incubated under anaerobic conditions
- Plain agar media at pH 7 to ph 7.5 growth occurs within 48 hours at 37oC with production of carbon dioxide and methylmercaptan
- Produce colonies which are smooth and rough, with compact center surrounded by fine filaments
- Remain alive for several years especially if protected from light
- Toxin produced by the bacilli is destroyed by heat at 650C for 5 minutes, by formalin and by proteolytic enzymes of the digestive tract
- Common inhabitants of the soil, street dust and feces or manure of herbivorous animals
- Producers of toxins and enzymes:
- Tetanolysin/hemolysin: destroys RBC; injures the heart
- Causes tetanus
- An acute disease induced by toxin of the tetanus bacillus growing anaerobically at the site of an injur y.
- Incubation period is variable, ranging from a few days to weeks.
- The length of incubation period is directly related to the distance of the primary wound infection from the central nervous sytem.
A deep punctured wound containing:
- Dead or necrotic tissue
- Calcium salts
- Pyogenic infection from other organisms
- Other objects like pieces of glass, splintered wood, etc.
SIGNS AND SYMPTOMS
- painful muscular contractions, primarily of neck muscles, secondarily of trunk
- rigidity is sometimes confined to the region of injury
TYPES AND CATEGORIES
Three Clinical Forms:
1. Generalized tetanus
- Most common form involving the masseter muscles (trismus, or lockjar is the usual sign in a majority of patients)
- Sardonic smile characteristic of sustained trismus is known as “risus sardonicus”
- Other early signs include drooling, sweating, irritability and persistent back spasms (opistothonus)
- In severe cases, symptoms may involve the autonomic nervous system, with cardiac arrhythmias, fluctutations in blood pressure, profound sweating, and dehydration
2. Localized tetanus
- The disease remains confined to the musculature at the site of primary infection; prognosis is good
3. Cephalic tetanus
- A variant of localized tetanus where the primary site of infection is the head; prognosis is very poor
- Immunization of tetanus toxoid in every child is recommended. It must be followed by booster doses every two to three years.
- Among adults full course of three injections of antitetanus should be given at intervals of six weeks and six months.
- A booster dose of tetanus toxoid is usually given whenever an injury is sustained that might cause tetanus infection to bring the victim’s immunity up to a maximum potential.
- An injection to neutralize tetanus poison may be given after a major injuryActive immunity by administration of tetanus toxoid; passive by tetanus antitoxin. Active immunity wears off in 3 to 4 years; passive immunity in 2 weeks.
- Administration of tetanus antitoxin intravenously in large doses.
- Intramuscular injection of large doses of penicillin or tetracycline or clindamycin as alternative drug.
- Surgical removal of necrotic tissues.
- Administration of muscle relaxants, sedatives and proper ventilation.
- Administration of barbiturates or diazepam for mild tetanospasms.
- Paralyze patient’s muscles by use of curare-like agent so that respiratory function may be maintained by positive-pressure breathing apparatus in case of sever tetanospams.
- Tracheostomy should be performed after onset of the first tetanospasm in order to minimize respiratory complications.
- Good supportive care should include control of the environment to reduce auditory and visual stimuli if tetanospasms are frequent and severe.
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