CE/CME

Tetanus: Debilitating Infection

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COMPLICATIONS AND MORTALITY

Tetanus can lead to many complications, including long bone and spine fractures from severe muscle spasms, as well as renal failure and aspiration. Most spinal fractures involve the thoracic spine, but lumbar spine fractures have been reported.22 Burst-type fractures of the vertebrae may cause cauda equina syndrome or directly injure the spinal cord if fragments are retropulsed.22 Persistent muscle spasm can also cause rhabdomyolysis and renal failure. Lab test results, including elevated levels of creatine phosphokinase and myoglobin (rhabdomyolysis) as well as blood urea nitrogen and creatinine (renal failure), can indicate presence of complications. Muscle relaxation and hydration are key to prevention.

Patients with trismus are often unable to swallow and maintain oral hygiene, leading to caries and dental abscess. The trismus itself can also cause dental or jaw fractures.2,13 Aspiration can occur when laryngeal muscles are affected, resulting in pneumonia in 50% to 70% of autopsied cases of tetanus.10 Additionally, the paralyzed patient receiving ventilatory support can develop pneumonia, deep vein thrombosis, and pulmonary embolism.5,13 Neonatal tetanus often results in complications such as cerebral palsy or cognitive delay.1

A number of factors influence the severity and outcome of tetanus. Untreated tetanus is typically fatal, with respiratory failure the most common cause of death in settings where mechanical ventilation is unavailable.1 Where mechanical ventilation is accessible, autonomic dysfunction accounts for most deaths.20 Ventilation aside, the case-fatality rate varies according to the medical system. The rate is often less than 20% where modern ICUs are available but can exceed 50% in undeveloped countries with limited facilities.1,5 A review of outcomes data for 197 of the 233 tetanus cases reported in the US during 2001-2008 (modern medical care was provided in all) showed an overall case-fatality rate of 13.2%.7

Age and vaccination status also affect outcomes, with higher case-fatality rates seen in older (18% in those ≥ 60, 31% in those ≥ 65) and unvaccinated (22%) patients. 7,10 In the study of tetanus cases from 2001-2008, the fatality rate was five times higher in patients ages 65 or older compared with patients younger than 65.7 This study also showed that severity of tetanus may be inversely related to the number of vaccine doses the individual has received, and that having previous vaccination was associated with improved survival, as only four of the 26 deaths occurred in patients with prior vaccination.7

Patients who survive the first two weeks of tetanus have a better chance of recovery. Those with multiple chronic comorbidities, such as chronic obstructive pulmonary disease (COPD), diabetes, or cardiovascular disease, are more likely to die because of the physiologic stress of the illness and its treatment.1,7,12 The provision of ventilator support is more complicated in those with COPD; similarly, the autonomic effects of tetanus can be more problematic for patients with chronic cardiac disease or neurologic complications of chronic diabetes.13

PATIENT EDUCATION

Widespread vaccination against tetanus, which began in the US in the mid-20th century, has greatly reduced disease incidence.7 However, vaccination coverage rates remain below target.

In 2012, only 82.5% of children ages 19 to 35 months received the recommended four doses of diphtheria-tetanus-pertussis (DTaP) vaccine, and 94.3% received at least three doses.23 Only 84.6% of teens ages 13 to 17 years received the primary four doses as well as the recommended booster dose.24 The same year, only 55% of patients ages 65 and older and 64% of adults ages 19 to 64 had received a tetanus booster within the previous 10 years.25

Vaccination rates are lower for black, Hispanic, and Asian adults in the US.25 Clinicians should proactively recommend tetanus booster immunization to all adults.

CONCLUSION

Although few clinicians in developed countries will see a case of tetanus, all should be alert for it. Elderly patients and those not fully vaccinated are at risk. Routine immunization decreases but does not eliminate the risk. Tetanus differs from other illnesses controlled by national immunization efforts in that unvaccinated persons do not benefit from herd immunity, because the disease is not contagious. The diagnosis is clinical and should always be considered in patients with trismus, dysphagia, and/or adrenergic excess. Wounds that place a patient at risk for tetanus involve devitalized tissues and anaerobic conditions. Prompt diagnosis is essential, because it allows for early neutralization of unbound tetanospasmin. Wound care including debridement, antibiotic therapy, control of muscle spasms and the effects of autonomic instability, and airway care are fundamental to the treatment of tetanus.

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