Tetanus is characterized by an acute onset of hypertonia, painful muscular contractions (usually of the muscles of the jaw and neck), and generalized muscle spasms without other apparent medical causes. Despite widespread immunization of infants and children since the 1940s, tetanus still occurs in the United States. Currently, tetanus primarily affects older adults because of their higher rate of being unvaccinated or of being inadequately vaccinated. The image below illustrates tetanus cases in the United States from 1947-2012.
Reported number of tetanus cases in the United States from 1947-2012. Image from National Notifiable Disease Surveillance System (NNDSS), Centers for Disease Control and Prevention (CDC).
See Pediatric Vaccinations: Do You Know the Recommended Schedules?, a Critical Images slideshow, to help stay current with the latest routine and catch-up immunization schedules for 16 vaccine-preventable diseases.
Tetanus may be categorized into the following 4 clinical types:
Approximately 50-75% of patients with generalized tetanus present with trismus (“lockjaw”), which is the inability to open the mouth secondary to masseter muscle spasm. Nuchal rigidity and dysphagia are also early complaints that cause risus sardonicus, the scornful smile of tetanus, resulting from facial muscle involvement.
As the disease progresses, patients have generalized muscle rigidity with intermittent reflex spasms in response to stimuli (eg, noise, touch). Tonic contractions cause opisthotonos (ie, flexion and adduction of the arms, clenching of the fists, and extension of the lower extremities). During these episodes, patients have an intact sensorium and feel severe pain. The spasms can cause fractures, tendon ruptures, and acute respiratory failure.
Patients with localized tetanus present with persistent rigidity in the muscle group close to the injury site. The muscular rigidity is caused by a dysfunction in the interneurons that inhibit the alpha motor neurons of the affected muscles. No further central nervous system (CNS) involvement occurs in this form, and mortality is very low.
Cephalic tetanus is uncommon and usually occurs after head trauma or otitis media. Patients with this form present with cranial nerve (CN) palsies. The infection may be localized or may become generalized.
Neonatal tetanus (tetanus neonatorum) is a major cause of infant mortality in underdeveloped countries but is rare in the United States. Infection results from umbilical cord contamination during unsanitary delivery, coupled with a lack of maternal immunization. At the end of the first week of life, infected infants become irritable, feed poorly, and develop rigidity with spasms. Neonatal tetanus has a very poor prognosis.
Although at present, tetanus is rare, it has not been eradicated, and early diagnosis and intervention are lifesaving. Prevention is the ultimate management strategy for tetanus.