TETANUS By Dr Kuma Gbanan
Tetanus is a devastating disease of muscle spasm(tightening) and autonomic instability with a high mortality. Despite being easily preventable by a highly effective vaccine, it remains a significant source of morbidity and mortality worldwide. It is a medical emergency. Tetanus is caused by Clostridium tetani(an anaerobic, gram positive rod/baccillus).
The focus of infection include contaminated wounds especially deep wounds which may be visible or not, the wounds may be trivial and even forgotten, contaminated umbilical cord. The most common are puncture wounds and lacerations.
The toxin is tetanospasmin. The toxin exert its inhibitory effect on the synapses in the motor area of the spinal cord leading to uninhibited motor action(spasms in this case) and excess sympathetic action.
The incubation period(time between infection and first syptom) is few days to few weeks.
The types include generalized(commonest), localized, cephalic and then neonatal tetanus.
Clinical features include generalized malaise, fever, headache, trismus(painful contraction of the masseter muscle), risus sardonicus(spasm of facial muscles giving a grinning/smiling appearance).
Spasms could be spontaneous or provoked. Backward arching of the trunk(opisthotonus) is also a clinical feature. Spasms involving the oesophagus and urethral could lead to difficulty in swallowing(dysphagia) and acute urinary retention. Laryngeal spasms could lead to respiratory difficulties.
Spasms could be provoked by noise, bright light, needle pricks, sneezing.
The treatment for tetanus include the following:
•Control of spasms/sedation.
The above could be achieved with intramuscular paraldehyde or intravenous diazepam. Dosage is titrated until control is achieved. Chlorpromazine can be used for sedation. Magnesium sulphate could be used also. With magnesium sulphate, the need for sedation and mechanical ventilation is greatly reduced.
•Neutralization of the absorbed toxin with human tetanus immunoglobulin.
•Prevention of further toxin production.
This could be achieved with debridement, cleaning and open dressing of wound site if present. Penicillin could be used, and then metronidazole. Metronidazole is the preferred antibiotic because it is effective against anaerobes and again the problem of allergy is not there.
•Cardiovascular instability in severe tetanus is notoriously difficult to treat; increased sedation (e.g with magnesium sulphate or morphine or administration of short-acting agents that work specifically on the cardiovascular system (e.g esmolol, calcium antagonists, inotropes) may be required.
•Nurse in a quiet room and then factors that could precipitate spasms should be eliminated.
The following factors are associated with poor outcome: cephalic type, extremes of age, short incubation period, late presentation, delayed commencement of treatment.
Tetanus is associated with huge morbidity and mortality. Early diagnosis and appropriate treatment is vital.
Vaccination effectively prevents disease.
References: Harrison’s Manual of Medicine (International Edition), Protocol for Management of Medical Emergencies of the Department of Medicine Aminu Kano Teaching Hospital, All Round Ward Round- Christian Medical and Dental Students Association of the Ahmadu Bello University Teaching Hospital Zaria.