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eMedicine Journal > Emergency Medicine > Infectious Diseases Tetanus

Author Information | Introduction | Clinical | Differentials | Workup | Treatment | Medication | Follow-up | Miscellaneous | Pictures | Bibliography

 

AUTHOR INFORMATION

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Authored by Daniel J Dire, MD, FACEP, COL, MC, USAR, USAWC Senior Service Fellow, Center for Strategic Analysis, University of Texas at Austin

Daniel J Dire, MD, FACEP, COL, MC, USAR, is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, Association of Military Surgeons of the US, and Society for Academic Emergency Medicine

Edited by Theodore Gaeta, Residency Director, Clinical Associate Professor of Emergency Medicine in Medicine, Department of Emergency Medicine, New York Methodist Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Charles V Pollack, Jr, MD, MA, University of Pennsylvania College of Medicine, Associate Professor of Emergency Medicine, Chairman, Department of Emergency Medicine, Pennsylvania Hospital

Author's Email:	Daniel J Dire, MD, FACEP, COL, MC, USAR
Editor's Email:	Theodore Gaeta

eMedicine Journal, May 18 2001, Volume 2, Number 5

INTRODUCTION

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Background: Tetanus is an illness 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 in the US since the 1940s, tetanus still occurs in the US. In the 1990s, tetanus is a severe disease primarily of older adults who are unvaccinated or inadequately vaccinated.

Pathophysiology: Clostridium tetani, an obligate anaerobic, gram-positive bacillus, causes tetanus. This bacterium is nonencapsulated and forms spores, which are resistant to heat, desiccation, and disinfectants. The spores are ubiquitous and are found in soil, house dust, animal intestines, and human feces.

Spores that gain entry can persist in normal tissue for months to years. Under anaerobic conditions, these spores geminate and elaborate tetanospasmin and tetanolysin. Tetanolysin is not felt to be of any significance in the clinical course of tetanus. Tetanospasmin that is released by the maturing bacilli is distributed via the lymphatic and vascular circulations to the end plates of all nerves. Tetanospasmin then enters the nervous system peripherally at the myoneural junction and is transported centripetally into neurons of the central nervous system (CNS).

These neurons become incapable of neurotransmitter release. The neurons, which release gamma-aminobutyric acid (GABA) and glycine, the major inhibitory neurotransmitters, are particularly sensitive to tetanospasmin leading to failure of inhibition of motor reflex responses to sensory stimulation resulting in generalized contractions of the agonist and antagonist musculature characteristic of a tetanic spasm. The shortest peripheral nerves are the first to deliver the toxin to the CNS, which leads to the early symptoms of facial distortion and back and neck stiffness.

Once the toxin becomes fixed to neurons, it cannot be neutralized with antitoxin. Recovery of nerve function from tetanus toxins requires sprouting of new nerve terminals and formation of new synapses.

Frequency:

• In the US: Reported incidence of tetanus has declined substantially since the mid 1940s due to the widespread use of tetanus immunizations. Picture 1 shows the reported number of tetanus cases and average annual incidence rates, by state, in the US from 1995-1997. Picture 2 shows the number of fatal cases of tetanus in the US reported to the CDC from 1982-1991. Picture 3 shows the total number of cases of tetanus reported to the CDC from 1947-1995. Some suggest that only 40% of tetanus cases are reported to the CDC. From 1991-1994, 201 cases were reported in the US. States with highest incidents reported from 1991-1994 were Texas and California. 124 cases were reported to the CDC from 1995-1997. 60% were ages 20-59 and 35% were 60 or older. All 50 states require that children be vaccinated prior to admission to public schools. More than 96% of children have received 3 or more diphtheria and tetanus toxoids plus pertussis (DPT) vaccinations by the time they begin school. Annual incidence has dropped to < 50
  case per year in the US. The incidence in IV drug users increased from 3.6% of all cases from 1991-1994 to 11% of cases 1995-1997.

• Internationally: Worldwide, tetanus is predominantly a disease of underdeveloped countries in warm, damp climates and affects all age groups, with special preference for newborns and young persons. In 1992, an estimated 578,000 infant deaths occurred due to neonatal tetanus. In the beginning of the 1990s, an estimated 360,000 cases and 140,000 deaths occurred each year from nonneonatal tetanus. Tetanus is one of the target diseases of the World Health Organization Expanded Program on Immunization. Overall annual incidence is 0.5-1 million cases.

Developed nations have incidences of tetanus similar to that observed in the US. For instance, only 126 cases were reported in England and Wales between 1984 and 1992.

Mortality/Morbidity: Overall, mortality is approximately 45%. The mortality rate in the US is 6% for those who had previous received 1-2 doses of tetanus toxoid to 15% for those unvaccinated.

• From 1995-1997, overall case fatality rate in the US was 11% which is a drop from 25% during the period 1991-1994. All deaths were among those older than 29 years.

• Mortality rate is highest for those older than 60 years (18%).

• Mortality rate is 30% for those who require mechanical ventilation, but only 4% for those who do not.

Race: In the US, African Americans from the rural south have a greater risk of tetanus.

Sex: A difference in the levels of tetanus immunity exists between genders.

• Men are better protected than women, perhaps due to additional vaccinations given during military service or professional activities.

• In the US from 1995-1997, 60% of the cases were in males.

• In developing countries, an increased immunity among women is present where tetanus toxoid is administered to women of childbearing age to prevent neonatal tetanus.

Age: Incidence of tetanus increases with advancing age. Of the patients with tetanus in the US, 54% are older than 59 years and only 5% are younger than 20 years.

CLINICAL

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History:

• In the US from 1995-1997, 81% of cases were generalized tetanus; 13% were localized; 6% were cephalic; and one cases of neonatal tetanus were reported. From 1995-1997, 54% of the reported cases in the US had an unknown tetanus vaccination history, 22% had no known previous tetanus vaccination, 9% had 1 previous dose, 3 % had 2 previous doses, 3% had 3 previous doses, and 9% had 4 or more previous doses.

• The last reported case of neonatal tetanus in the US was in 1998 and this was only the second case since 1989.

• Most reported cases of tetanus worldwide are the neonatal type.

• Median incubation period is 7 days, and for most cases (73%), incubation ranges from 4-14 days.

• This period is shorter than 4 days in 15% of cases and longer than 14 days in 12% of cases.

• Those patients with clinical manifestations occurring within 1 week of an injury have more severe clinical courses.

• Patients with generalized tetanus present with trismus (lockjaw) in 75% of cases.

• Other presenting complaints include stiffness, neck rigidity, dysphagia, restlessness, and reflex spasms.

• Subsequently, muscle rigidity becomes the major manifestation.

• Spread from the jaw and facial muscles occurs over the next 24-48 hours to the extensor muscles of the limbs.

• Dysphagia occurs in moderately severe tetanus, due to pharyngeal muscle spasms, and usually onset is insidious over several days.

• Reflex spasms develop in the majority of patients and can be triggered by minimal external stimuli such at noise, light, or touch.

• The spasms last seconds to minutes, become more intense, increase in frequency with disease progression, and can cause apnea, fractures, dislocations, and rhabdomyolysis.

• Laryngeal spasms can occur at any time and can result in asphyxia.

• Sustained contraction of facial musculature produces a sneering grin expression known as risus sardonicus.

Physical:

• The site of antecedent acute injury is the lower extremity in 52%, upper extremity in 34%, and head or trunk in 5% of patients.

• Autonomic dysfunction in patients with severe tetanus manifests as extremes in blood pressure, dysrhythmias, and cardiac arrest.

• Neonatal tetanus presents with an inability to suck 3-10 days after birth.

• Irritability

• Excessive crying

• Grimaces

• Intense rigidity

• Opisthotonus

• Tetanic seizures may occur and portend a poor prognosis.

• Frequency and severity of seizures are related to severity of the disease.

• They resemble epileptic seizures with the presence of a sudden burst of tonic contractions

• However, the patient does not lose consciousness and usually experiences severe pain.

• They frequently occur in the muscle groups causing opisthotonos, flexion and abduction of the arms, clenching of the fists on the thorax, and extension of the lower extremities.

• Localized tetanus is characterized by painful spasms of the group of muscles in close proximity to the site of injury. This disorder may persist for several weeks, but usually is self-limiting.

• Cephalic tetanus usually is secondary to chronic otitis media or head trauma.

• It is characterized by variable cranial nerve (CN) palsies; CN VII most frequently is involved.

• Ophthalmoplegic tetanus is a variant that develops after penetrating eye injuries and results in CN III palsies and ptosis.

• Untreated cases of cephalic tetanus progress to generalized tetanus.

• Patients with tetanus may present with abdominal tenderness and guarding, mimicking an acute abdomen.

• Patients have been taken to the operating room for exploratory laparotomies before the correct diagnosis was apparent.

Causes:

• Tetanospasmin has a disinhibitory effect on the autonomic nervous system (ANS).

• ANS dysfunction becomes progressively evident as the level of toxin in the CNS increases.

• ANS disturbances, such as sweating, fluctuating blood pressure, episodic tachydysrhythmia, and increased release of catecholamines are observed.

• Drugs with beta-blocker effects have been used to control the cardiovascular manifestations of ANS instability, but they also have been associated with increased risk of sudden death.

• Only 12% of patients with tetanus in the US have received a primary series of tetanus toxoid.

• In 77% of the cases in the US, tetanus occurred after an acute injury, including 49% of puncture wounds, 22% of lacerations, 12% of abrasions, and 2.6% of animal bites.

• Of those who obtained medical treatment for their injury in the US from 1995-1997, 88% were administered Tetanus Immune Globulin as a part of their treatment. 48% required the uses of assisted ventilation and 18% of these died.

• Stepping on a nail accounted for 39% of the puncture wounds.

• Tetanus can occur in burn victims, patients receiving intramuscular injections, and with frostbite, dental infections (eg, periodontal abscesses), penetrating eye injuries, and umbilical stump infections.

• Other reported risk factors include diabetes, chronic wounds (eg, skin ulcers, abscesses, gangrene), parenteral drug abuse, and recent surgery (4% of cases in US).

• Median time interval between surgery and onset of tetanus is 7 days.

• Tetanus has been reported after tooth extractions, root canal therapy, and intraoral soft tissue trauma.

• Worldwide risk factors for neonatal tetanus

• Unvaccinated mothers, home delivery, and unhygienic cutting of the umbilical cord

• History of neonatal tetanus in a previous child

• Potentially infectious substances applied to the umbilical stump (eg, animal dung, clarified butter)

• Immunity from tetanus decreases with advancing age.

• Serological testing for immunity has revealed a low level among the elderly in the US.

• Approximately 50% of adults older than 50 years are nonimmune from having never been vaccinated or not receiving appropriate booster doses.

• Prevalence of immunity to tetanus in the US is greater than 80% for those aged 6-39 years, but only 28% for persons older than 70 years.

DIFFERENTIALS

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Conversion Disorder
Dislocations, Mandible
Encephalitis
Hypocalcemia
Meningitis
Peritonsillar Abscess
Rabies
Spider Envenomations, Widow
Stroke, Hemorrhagic
Subarachnoid Hemorrhage
Toxicity, Medication-Induced Dystonic Reactions

Other Problems to be Considered:

Intraoral disease
Odontogenic infections
Globus hystericus
Hepatic encephalopathy
Hysteria
Strychnine poisoning
Acute abdomen
Intracranial hemorrhage

WORKUP

Section 5 of 11