WOUND INFECTION(Tetanus)

TETANUS

This potentially fatal condition also called  LOCK JAW is caused by Clostridium tetani , a gram positive , spore forming bacillus occuring naturally in the intestine of human and animal and in the soil . It enters the body through wound and replicate thriving on the anaerobic conditions present in devitalised tissues . It produce tetanospasmin , a potent exotoxin that binds to the neuromuscular junctions on the central nervous system neurone rendering them incapable of neurotransmeter release . This leads to failure of inhibition of motor reflex responses to sensory stimulation . The result is generalised contractions of agonists and antagonists muscles causing tetanic spasms .The incubation period is 7 days ranging from 4- 14 days .Early symptoms painful spasms of messeter and facial muscles resulting in the classical RISUS SARDONICUS . The spasms spread to involve the muscles of respiration and the laryngeal musculature . Spasms of paravertebral and extensor limb musculature produce OPISTHOTONUS , an arching of the whole body . Laryngeal muscle spasm leads to apnoea and if prolonged to asphyxia and respiratory arrest . The spasms can be brought on by the slightest of sensory stimuli .

The diagnosis is obvious once it is fully menifest . There are three aspects of management ;-

PREVENTION  

wound contaminates with soils are likely to harvour the organisms and  active immunisation is indicated by administering 0.50ml of tetanus toxoid I/M . Patients with gross contamination of deeply cavitating wound should also recieve 250-500 U of human anti tetanus globulin I/M to provide passive immunisation  Wound menipulation should be avoided for 2-3 hours after ATG administration to minimise tetanospasmin release .

LOCAL WOUND CARE

This includes a thorough wound debridement to eliminate the anaerobic condition .I/V administration of  high doses of penicillin G  is effective and should be continued for 10-14days . The wound should be closed using delayed primary or secondary closure technique .

SUPPORTIVE TREATMENT FOR ESTABLISHED DISEASE

            These patients are nursed in ICU envirnment free from sensory stimuli .Unnecessary menipulations are to be avoided . Diazepam is useful in preventing the onset of spasm but if spasms becomes frequent and sustained , the patients should be paralysed , intubated and placed on ventilator .

The overall mortality rate is 45% . prognosis being determined by the incubation period and the time from first symptom to the first tetanic spasm . In general shorter interval indicate poor prognosis . Clinical tetanus does not result in immunity and so survivors should recieve active immunisation to prevent recurrence .