Tetanus

Facial muscle spasm produces a characteristic expression with a fixed smile and elevated eyebrows (risus sardonicus). Rigidity or spasm of abdominal, neck, and back muscles and sometimes opisthotonos (generalized rigidity of the body with arching of the back and neck) may occur. Sphincter spasm causes urinary retention or constipation. Dysphagia may interfere with nutrition.

Characteristic painful, generalized tonic spasms with profuse sweating are precipitated by minor disturbances such as a draft, noise, or movement. Mental status is usually clear, but coma may follow repeated spasms. During generalized spasms, patients are unable to speak or cry out because of chest wall rigidity or glottal spasm. Rarely, fractures result from sustained spasms.

Spasms also interfere with respiration, causing cyanosis or fatal asphyxia.

Temperature is only moderately elevated unless a complicating infection, such as pneumonia, is present. Respiratory and pulse rates are increased. Reflexes are often exaggerated. Protracted tetanus may manifest as a very labile and overactive sympathetic nervous system, including periods of hypertension, tachycardia, and myocardial irritability.

Respiratory failure Overview of Respiratory Failure Acute respiratory failure is a life-threatening impairment of oxygenation, carbon dioxide elimination, or both. Respiratory failure may occur because of impaired gas exchange, decreased ventilation... read more is the most common cause of death. Laryngeal spasm and rigidity and spasms of the abdominal wall, diaphragm, and chest wall muscles cause asphyxiation. Hypoxemia can also induce cardiac arrest, and pharyngeal spasm leads to aspiration of oral secretions with subsequent pneumonia, contributing to a hypoxemic death. Pulmonary embolism is also possible. However, the immediate cause of death may not be apparent.

In localized tetanus, there is spasticity of muscles near the entry wound but no trismus; spasticity may persist for weeks.

Cephalic tetanus is a form of localized tetanus that affects the cranial nerves. It is more common among children; in them, it may occur with chronic otitis media or may follow a head wound. Incidence is highest in Africa and India. All cranial nerves can be involved, especially the 7th. Cephalic tetanus may become generalized.

Tetanus in neonates is usually generalized and frequently fatal. It often begins in an inadequately cleansed umbilical stump in children born of inadequately immunized mothers.

Onset during the first 2 weeks of life is characterized by rigidity, spasms, and poor feeding. Bilateral deafness may occur in surviving children.

The patient should be kept in a quiet room. Several principles should guide all therapeutic interventions:

Because dirt and dead tissue promote C. tetani growth, prompt, thorough debridement, especially of deep puncture wounds, is essential. Antibiotics are not substitutes for adequate debridement and immunization but typically are given.

The benefit of human-derived antitoxin depends on how much tetanospasmin is already bound to the synaptic membranes—only free toxin is neutralized. For adults, TIG 500 units IM once appears as effective as higher doses ranging from 3000 to 6000 units and causes less discomfort. Some medical experts recommend infiltration of part of the dose locally around the wound, but its efficacy has not been proved.

Antitoxin of animal origin is far less preferable because it does not maintain the patient’s serum antitoxin level well and risk of serum sickness is considerable. If horse serum must be used, the usual dose is 50,000 units IM or IV. (CAUTION: See Skin testing Skin testing .)

If necessary, IVIG or antitoxin can be injected directly into the wound, but this injection is not as important as good wound care.

Tetanus infection does not confer immunity, so unless their vaccination history indicates completion of a full primary series, patients should receive a full primary tetanus vaccination series using an age-appropriate preparation (see Prevention Prevention Tetanus is acute poisoning resulting from a neurotoxin produced by Clostridium tetani. Symptoms are intermittent tonic spasms of voluntary muscles. Spasm of the masseters accounts for... read more below). Antitoxin and vaccine should be injected into different body sites to avoid neutralizing the vaccine.

Medications are used to manage spasms.

Benzodiazepines are the standard of care to control rigidity and spasms. They block reuptake of an endogenous inhibiting neurotransmitter, gamma-aminobutyric acid (GABA), at the GABA_A receptor.

Diazepam can help control seizures, counter muscle rigidity, and induce sedation. Dosage varies and requires meticulous titration and close observation.

Diazepam has been used most extensively, but midazolam is water soluble and preferred for prolonged therapy. Midazolam reduces risk of lactic acidosis due to propylene glycol solvent, which is required for diazepam and lorazepam, and reduces risk of long-acting metabolites accumulating and causing coma.

Benzodiazepines may not prevent reflex spasms, and effective respiration may require neuromuscular blockade with vecuronium or other paralytic medications and mechanical ventilation. Pancuronium has been used but may worsen autonomic instability. Vecuronium is free of adverse cardiovascular effects but is short-acting. Longer-acting medications (eg, pipecuronium, rocuronium) also work, but no randomized clinical comparative trials have been done.

Intrathecal baclofen (a GABA_A agonist) is effective in treating reflex spasms but has no clear advantage over benzodiazepines. Coma and respiratory depression requiring ventilatory support are potential adverse effects.

Dantrolene can be given initially by infusion and thereafter for up to 60 days. Hepatotoxicity and expense limit its use.

Morphine may be given every 4 to 6 hours to control autonomic dysfunction, especially cardiovascular; total daily dose is 20 to 180 mg.

Beta-blockade is used to control episodes of hypertension and tachycardia, but use of long-acting medications such as propranolol is not recommended. Sudden cardiac death is a feature of tetanus, and beta-blockade can increase risk; however, esmolol, a short-acting beta-blocker, has been used successfully. IV atropine has been used at high doses; blockade of the parasympathetic nervous system markedly reduces excessive sweating and secretions. Lower mortality has been reported in clonidine-treated patients than in those treated with conventional therapy.

Magnesium sulfate given by IV continuous infusion at doses that maintain serum levels between 4 to 8 mEq/L has a stabilizing effect, eliminating catecholamine stimulation (1 Treatment references Toxins produced by Clostridioides difficile strains in the gastrointestinal tract cause pseudomembranous colitis, typically after antibiotic use. Symptoms are diarrhea, sometimes bloody... read more ). Patellar tendon reflex is used to assess overdosage. Tidal volume may be impaired, so ventilatory support must be available. Serum magnesium levels and electrical cardiac activity need to be closely monitored throughout the infusion period.

Other medications that may prove useful include

Corticosteroids are of unproven benefit; their use is not recommended.

The role of antibiotic therapy is minor compared with wound debridement and general support.

Metronidazole is the recommended antibiotic.

In moderate or severe cases, patients should be intubated. Mechanical ventilation is essential when neuromuscular blockade is required to control muscle spasms that impair respirations.

IV hyperalimentation avoids the hazard of aspiration secondary to gastric tube feeding. Because constipation is usual, stools should be kept soft. A rectal tube may control distention. Bladder catheterization is required if urinary retention occurs.

Chest physiotherapy, frequent turning, and forced coughing are essential to prevent pneumonia. Analgesia with opioids is often needed.