Pathogenesis
Clostridium tetani (C. tetani) spores usually enter the body through a wound or breach in the skin. Neonatal tetanus usually occurs because of umbilical stump infections. In the presence of anaerobic conditions, the spores germinate. The bacteria produce very potent toxins, most of which the blood stream and lymphatic system disseminate through the body. Toxins act at several sites within the central nervous system, including peripheral motor end plates, spinal cord, and brain, as well as in the sympathetic nervous system. Tetanus toxin causes the typical clinical manifestations of tetanus by interfering with the release of neurotransmitters and blocking inhibitor impulses. This leads to unopposed muscle contraction and spasm. Seizures may occur, and the autonomic nervous system may also be affected.
Risk Groups
Nearly all cases of tetanus in the United States today are among people who
- Have never received a tetanus vaccine
- Didn’t stay up to date on their 10-year booster shots
Most reported cases occur in adults. From 2009–2017, more than 60% of the 264 reported cases were among people 20 through 64 years of age. In addition, a quarter of those reported cases were among people 65 years old or older. The risk of death from tetanus is highest among people 65 years old or older.
Diabetes, a history of immunosuppression, and intravenous drug use may be risk factors for tetanus. From 2009 through 2017, persons with diabetes was associated with 13% of all reported tetanus cases, and a quarter of all tetanus deaths. Intravenous drug users accounted for 7% of cases from 2009 through 2017.
Risk during Natural Disasters
In most settings, a disaster (e.g., earthquake, hurricane, flood, tsunami) does not increase the risk for tetanus. Minimize the risk of tetanus among your patients who are disaster survivors and emergency responders by following routine vaccination recommendations and providing proper wound care.
Symptoms and Diagnosis
Tetanus is a clinical syndrome without confirmatory laboratory tests. Characteristic symptoms of tetanus are painful muscular contractions, primarily of the masseter and neck muscles and secondarily of trunk muscles. Trismus, or lockjaw, is a common sign of tetanus (see generalized tetanus under Clinical Features). A common first sign suggestive of tetanus in older children and adults is abdominal rigidity, although rigidity is sometimes confined to the region of injury. Generalized spasms occur, frequently induced by sensory stimuli. History of an injury or apparent portal of entry may be lacking. Clinicians rarely recover the organism from the site of infection.
Clinical Features
The incubation period ranges from 3 to 21 days, averaging about 10 days. In general, the further the injury site is from the central nervous system, the longer the incubation period. A shorter incubation period is associated with more severe disease, complications, and a higher chance of death. In neonatal tetanus, symptoms usually appear from 4 to 14 days after birth, averaging about 7 days.
There are three clinical forms of tetanus:
- Generalized
- Localized
- Cephalic
Generalized Tetanus
Generalized tetanus is the most common form, accounting for more than 80% of cases. The most common initial sign is spasm of the muscles of the jaw or “lockjaw”. Other signs may follow “lockjaw.” These can include painful spasms in other muscle groups in the neck, trunk, and extremities and generalized, seizure-like activity or convulsions in severe cases. Nervous system abnormalities, as well as a variety of complications related to severe spasm and prolonged hospitalization, can accompany generalized tetanus. The clinical course of generalized tetanus is variable and depends on the
- Degree of prior immunity
- Amount of toxin present
- Age and general health of the patient
Even with modern intensive care, generalized tetanus is associated with death rates of 10% to 20%.
Localized Tetanus
Localized tetanus is an unusual form of the disease consisting of muscle spasms in a confined area close to the site of the injury. Although localized tetanus often occurs in people with partial immunity and is usually mild, progression to generalized tetanus can occur.
Cephalic Tetanus
The rarest form, cephalic tetanus, is associated with lesions of the head or face and may also be associated with otitis media. The incubation period is short, usually 1 to 2 days. Unlike generalized and localized tetanus, cephalic tetanus results in flaccid cranial nerve palsies rather than spasm. Spasm of the jaw muscles may also be present. Like localized tetanus, cephalic tetanus can progress to the generalized form.
Complications of Tetanus
- Laryngospasms
- Fractures
- Hypertension
- Nosocomial infections
- Pulmonary embolism
- Aspiration pneumonia
- Death
Treatment
Tetanus is a medical emergency requiring
- Hospitalization
- Immediate treatment with human tetanus immune globulin (TIG)
- Agents to control muscle spasm
- Aggressive wound care
- Antibiotics
- A tetanus toxoid booster
If TIG is unavailable, clinicians can use Immune Globulin Intravenous (IGIV).
Clinicians should maintain a patent airway. Depending on the severity of disease, endotracheal intubation or tracheostomy and mechanically assisted respiration may be lifesaving. Clinicians should use sedation and muscle relaxant drugs as indicated to control muscle spasms. Agents to control autonomic nervous system instability may be required. Initiate active immunization concurrently with treatment.
Treatment of tetanus cases with TIG
Medical experts recommend a single dose of human TIG for treatment of persons with tetanus. Researchers have not established the optimal therapeutic dose. However, experts recommend 500 international units (IU), which appears to be as effective as higher doses ranging from 3,000 to 6,000 IU and causes less discomfort.
Clinicians must administer available preparations intramuscularly; TIG preparations available in the United States are not licensed or formulated for intrathecal or intravenous use.
Some medical experts recommend infiltration of part of the dose locally around the wound (see Red Book), although its efficacy has not been proven.
If TIG is not available, clinicians can use IGIV at a dose of 200 to 400 milligrams per kilogram (mg/kg). However, the Food and Drug Administration has not approved IGIV for this use. In addition, anti-tetanus antibody content varies from lot to lot.
Vaccination during Recovery
Tetanus disease does not result in tetanus immunity. Clinicians should begin or continue active immunization with a tetanus toxoid-containing vaccine as soon as the person’s condition has stabilized.
Wound Management for Tetanus Prevention
Risk of tetanus disease depends on the type and condition of the wound and immune status of the patient. Clinicians should take the following steps to prevent tetanus:
- Assess the type of wound and provide appropriate wound care.
Wounds may be clean or contaminated and dirty, superficial or deep and penetrating. Dirty wounds pose an increased risk for tetanus. Clinicians should consider wounds dirty if contaminated with dirt, soil, feces, or saliva (e.g., animal or human bites). Consider penetrating or puncture wounds contaminated, possibly posing a higher risk for tetanus. Wounds containing devitalized tissue (e.g., necrotic or gangrenous wounds), frostbite, crush injuries, avulsion fractures, and burns are particularly conducive for proliferation of C. tetani. Clinicians should clean all wounds, remove dirt or foreign material, and remove or debride necrotic material. - Evaluate the immunization status of the patient. Unvaccinated persons should start and complete a primary series with an age-appropriate tetanus toxoid-containing vaccine (i.e., DTaP, TdaP, Td) as currently recommended by CDC. Consider persons with unknown or uncertain history of receiving previous prior doses tetanus toxoid-containing vaccines to have had no previous tetanus toxoid-containing vaccine. They should complete a primary series. This is because early doses of toxoid may not induce adequate immunity, but only prime the immune system. Persons who have completed a 3-dose primary tetanus vaccination series:
- If the last dose of a tetanus toxoid-containing vaccine was received less than 5 years earlier, consider them protected against tetanus. They do not require another dose of tetanus toxoid-containing vaccine as part of the current wound management.
- If the last dose of a tetanus toxoid-containing vaccine was received 5 or more years earlier, then administer a booster dose of an age-appropriate tetanus toxoid-containing vaccine.
- Rarely have cases of tetanus occurred in persons with a documented primary series of tetanus toxoid.
- Assess need for administering TIG for prophylaxis.
TIG provides temporary immunity by directly providing antitoxin. TIG can help remove unbound tetanus toxin but cannot neutralize toxin that is already bound to nerve endings. Persons who have contaminated and dirty wounds and are either unvaccinated or have not received a primary series of tetanus toxoid-containing vaccines should receive TIG for prophylaxis. The dose of TIG for prophylaxis is 250 IU administered intramuscularly. Persons with HIV infection or severe immunodeficiency who have contaminated wounds (including minor wounds) should also receive TIG, regardless of their history of tetanus immunizations. - Do not use antibiotics for prophylaxis against tetanus.
Medical experts do not recommend antibiotic prophylaxis against tetanus. However, clinicians should observe wounds for signs of infection and promptly treated if they detect signs of infection.
Guide to Tetanus Prophylaxis with TIG in Routine Wound Management
| History of adsorbed tetanus toxoid-containing vaccines (doses) | Clean, minor wound | All other wounds |
|---|
| DTaP, Tdap or Td | TIG | DTaP, Tdap or Td | TIG |
|---|
| Unknown or <3 | Yes | No | Yes | Yes |
|---|
| ≥3 | No | No | No | No |
|---|
Footnotes
Abbreviations: DTaP = Diphtheria and Tetanus toxoids and acellular pertussis vaccine; Tdap = tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; Td = tetanus and diphtheria toxoids; TIG = Tetanus immune globulin
*Such as, but not limited to, wounds contaminated with dirt, feces, soil, and saliva; puncture wounds; avulsions; and wounds resulting from missiles, crushing, burns, and frostbite.
† DTaP is recommended for children <7 years of age. Tdap is preferred to Td for persons aged 11 years or older who have not previously received Tdap. Persons aged 7 years or older who are not fully immunized against pertussis, tetanus, or diphtheria should receive one dose of Tdap (preferably the first) for wound management and as part of the catch-up series; if additional tetanus toxoid-containing doses are required, either Td or Tdap vaccine can be used.
‡ People with HIV infection or severe immunodeficiency who have contaminated wounds (including minor wounds) should also receive TIG, regardless of their history of tetanus immunizations.
§ Yes, if ≥10 years since the last tetanus toxoid-containing vaccine dose.
¶ Yes, if ≥5 years since the last tetanus toxoid-containing vaccine dose.
Prevention through Routine Vaccination
Since people cannot naturally acquire immunity to tetanus, the best way to prevent tetanus is to vaccinate your patients. CDC recommends tetanus vaccines for all infants and children, preteens and adolescents, and adults. See Diphtheria, Tetanus, and Pertussis Vaccination: Information for Healthcare Professionals for information on all tetanus vaccine recommendations by vaccine and age.