**7.3 Minimise the effects of the toxin already in the body**

Circulating tetanus toxins cause muscle rigidity, spasm and autonomic instability. Treatment of rigidity and spasm is very effective in preventing exhaustion, respiratory failure, aspiration pneumonitis and dysphagia. Spasm and rigidity can be treated effectively with sedation and limiting unnecessary stimulation. Benzodiazepine along or in combination with other drugs such as anticonvulsants have been used with great successes. The first line of treatment is the benzodiazepines.

Diazepam one of the derivative of benzodiazepines and is very effective in tetanus management. It acts by increasing GABA agonism through resistance to endogenous inhibitors of the GABAA receptor. The benefits of diazepam are as anti-convulsant and muscle relaxant that acts to control rigidity and muscle spasms. In addition, diazepam has sedative and anxiolytic effects. Large doses up to 100 mg/h can be administered and may cause mild respiratory depression.

Midazolam, also a benzodiazepine can be used in the absence of Diazepam. It is however relatively short-acting. Morphine can be equally efficacious and is usually used as an adjunct to benzodiazepine sedation.

Propofol has also been used successfully with rapid recovery occurring once the infusion is stopped however, in order to achieve adequate plasma concentrations to relieve muscle rigidity, mechanical ventilation is necessary.

In a patient with tetanus on mechanical ventilation, neuromuscular blocking agents can be used to control the muscle spasm if it continues despite the use of sedatives. Vecuronium is a short-acting neuromuscular blocker. It has minimal cardiovascular effects and does not release histamines. The use of pancuronium and atracurium is not recommended because pancuronium causes tachycardia while atracurium causes bradycardia and hypotension which may trigger mortality in the patient with tetanus. Newer agents such as pipercuronium and rocuronium are long acting and provide good haemodynamic stability they are however expensive compared with older drugs.

Anticonvulsants such as phenobarbitone, (which enhances GABA activity) and phenothiazine such as and chlorpromazine may be used to provide additional sedation. When sedation alone is inadequate, neuromuscular blocking agents and intermittent positive pressure ventilation may be required, usually for a prolonged period.

Baclofen is a structural analogue of GABAB receptor agonist that inhibits presynaptic acetylcholine release and synaptic medullar reflexes. These effects help in an anti-spastic action. They act by lowering calcium permeability in primary afferents. Intrathecal administration of 500-2000μg daily of baclofen had caused decrease muscle spasm in generalised tetanus [7].

## **7.4 Autonomic instability**

Circulatory collapse is a major cause of mortality in tetanus and this is caused by autonomic instability. Sudden cardiac arrest is common and is thought to be precipitated by a combination of high catecholamine levels and the direct action of the tetanus toxin on the myocardium. Prolonged sympathetic activity may end with profound hypotension and bradycardia. Parasympathetic over activity may lead to sinus arrest. Direct damage to the vagal nucleus by the tetanus toxin has been implicated. Sedation with Benzodiazepines, anticonvulsant medication and morphine is the first line maneuver to control autonomic instability and also magnesium sulphate has been used as a preventive measure with success.

## *DOI: http://dx.doi.org/10.5772/intechopen.104876 ICU Management of Tetanus*

Magnesium sulfate is a pre-synaptic neuromuscular blocker. It inhibits catecholamine release from nerves and adrenal medulla and also reduces receptor responsiveness to released catecholamines, anticonvulsants, and vasodilators. Magnesium sulphate is a calcium antagonist in the myocardium and neuromuscular junction and inhibits the release of parathyroid hormone thereby decreasing calcium levels. Doses are initiated with loading dose 75–80 mg/kg in 30 min and followed by 2 g/h in patients under 60 years and 1 g/h for patients over 60 years. Morphine is very useful in maintaining cardiovascular stability. The mechanism of action of morphine includes replacement of endogenous opioids, reduction of sympathetic reflex activity and histamine release [8]. Phenothiazine especially chlorpromazine which acts as anticholinergic and α adrenergic antagonism also play a role in maintaining cardiovascular stability and used as a sedative.

B-blockade, although theoretically useful to control episodes of hypertension and tachycardia, is associated with sudden cardiovascular collapse, pulmonary oedema and death.

## **7.5 Supportive care**

Patients with tetanus suffer weight loss due to several factors. These include inability to swallow, autonomic induced alterations in gastrointestinal function, increased metabolic rate due to pyrexia and muscular activity from convulsion and seizure. Nutrition should therefore be established as early as possible. Due to trismus, oral feeding is not possible. Nasogastric tube should be passed as early as possible to commence feeding. High caloric nutritional supplement is required to meet the high metabolic demand of tetanus. Parenteral nutrition is preferred but it is expensive and majority of tetanus patients are from a poor socio-economic status.

Nosocomial infection such as VAP is common among critically ill patients that are ventilated. The prevalence of VAP is a common indicator for safety and quality of care in critically ill patients admitted to the ICU. This is associated with increased mortality among ventilated patients. Measures taken to prevent VAP include strict hand hygiene with alcohol solutions before airway management, continuous aspiration of subglottic secretions, oral hygiene with chlorhexidine, semi recumbent positioning of patients where possible and selective decontamination of the digestive tract or selective oropharyngeal decontamination.

Venous thromboembolism (VTE) is a common and major complication in the critically ill patients. The use of intermittent pneumatic compression or graduated compression stockings with regular turning of patient help to prevent thromboembolism.

Other supportive measures foot drop splint to prevent ankle contracture, limb and chest physiotherapy, regular turning of patient or use of air/water mattress to prevent decubitus ulcer, care of the patient should be in dark room with minimal stimulus and psychosocial support.
