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Treatment is summarized in Table 156–2. Admit patients with tetanus to the intensive care unit. Respiratory compromise requires immediate neuromuscular blockade and intubation. Minimize environmental stimuli to prevent the precipitation of reflex convulsive spasms.
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TETANUS IMMUNOGLOBULIN
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Human tetanus immunoglobulin neutralizes circulating tetanospasmin and toxin in the wound but not toxin that is already fixed in the nervous system. Even though tetanus immunoglobulin does not ameliorate the clinical symptoms of tetanus, early reports suggest it reduces mortality.14 The dose varies depending on the purpose. For postexposure prophylaxis, a single dose of 250 units (4 units/kg in children) IM given in the anterolateral thigh or deltoid is recommended. For the treatment of actual tetanus, the optimal dose of tetanus immunoglobulin is unknown, but 3000 to 6000 units IM is the usual recommended dose, administered in a separate syringe and opposite the site of tetanus toxoid administration. At least a portion of the dose should be administered around the wound itself.5 Tetanus immunoglobulin should be given before wound debridement, because exotoxin may be released during wound manipulation. Repeated doses of tetanus immunoglobulin are unnecessary because of its long half-life of 28 days.
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Identify and debride the wound to improve the oxidation-reduction potential of infected tissue and to prevent further toxin production.
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Antibiotics are of limited value but are traditionally administered, and parenteral metronidazole is the antibiotic of choice.15,16 Do not give penicillin because it may potentiate the effects of tetanospasmin.6
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Tetanospasmin prevents neurotransmitter release at inhibitory interneurons, and therapy of tetanus is aimed at restoring normal inhibition. The benzodiazepines are centrally acting inhibitory agents that have been used extensively for this purpose. However, the large IV doses of benzodiazepines required in tetanus may result in metabolic acidosis secondary to the propylene glycol vehicle in IV lorazepam or diazepam. Thus, many prefer midazolam, a water-soluble agent, for muscle relaxation.6 The effects of baclofen, a specific γ-aminobutyric acid agonist, vary.6
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NEUROMUSCULAR BLOCKADE
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Prolonged neuromuscular blockade aids in control of ventilation, muscular spasms, secondary fractures, and rhabdomyolysis. Succinylcholine can be given early for emergency airway control, whereas vecuronium is a good option for prolonged blockade because of minimal cardiovascular side effects.15
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TREATMENT OF AUTONOMIC DYSFUNCTION
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One randomized controlled trial in 256 patients with severe tetanus demonstrated that magnesium sulfate reduced autonomic instability and muscle spasm in the disease.7 Furthermore, magnesium sulfate has been shown to reduce urinary catecholamine excretion in patients with severe tetanus.8 However, a meta-analysis failed to show a benefit of magnesium sulfate on tetanus mortality, and the effect of the drug on duration of intensive care unit and hospital stay and need for ventilatory support was unclear.17
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Adrenergic blocking agents may treat the autonomic dysfunction of severe tetanus. Choose either a short-acting β-blocker, such as esmolol, or labetalol, a combined α- and β-adrenergic blocking agent, if treating this manifestation of tetanus.
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Morphine sulfate reduces sympathetic α-adrenergic tone and central sympathetic efferent discharge and produces peripheral arteriolar and venous dilatation.6 Clonidine, a central α2-receptor agonist, may act to reduce the sympathetic hyperactivity that causes autonomic dysfunction and thereby provide better control of crises.18