Topic Editor: Grant E. Fraser, M.D., FRACGP, FACRRM, ASTEM
Review Date: 10/2/2012
Definition
Tetanus is a life-threatening condition caused by a neurotoxin produced by the organism Clostridium tetani. It is characterized by muscular rigidity and intermittent tonic spasms of voluntary muscles, especially in the jaw and neck.
Description
- Tetanus or 'lockjaw' is a potentially life threatening condition due the neurotoxin Tetanospasmin, which is produced by a soil dwelling gram positive spore forming anaerobic bacteria, C. tetani
- Tetanospasmin selectively blocks inhibitory nerve transmission of motor neurons within the central nervous system. The effect is involuntary tonic contractions of skeletal muscles, with the jaw and neck often being most effected
- Four types of tetanus are recognized
- Generalized: This is the most common and severe form of tetanus, characterized by generalized spasms and hypertonicity. Trismus (unable to open mouth normally) is a characteristic symptom of generalized tetanus which is seen in more than half of the patients
- Localized: A mild and persistent form of tetanus with rigidity of the muscles restricted to the area surrounding a wound that contains C. tetani producing neurotoxin. This condition resolves spontaneously in most cases
- Cephalic: Localized tetanus affecting the cranial nerve musculature. It may affect all cranial nerves, especially the 7th (facial nerve). It may progress to become generalized
- Neonatal: Usually occurs in the generalized form. The most common cause is non-sterile treatment of the umbilical cord stump. It has a poor prognosis and extremely high mortality
Epidemiology
Incidence/Prevalence
- Incidence in the U.S. is exceedingly low due to active immunization
- During the period 1998-2000, U.S. annual rates averaged 43 cases. Most cases occurred in non-immunized or partially immunized individuals
- In general, individuals aged 18-65 who were administered a complete childhood/adolescent tetanus immunization series do not get tetanus in first world countries
- Nearly 1 million cases occur each year globally, with the majority occurring in underdeveloped countries.
- Neonatal tetanus is a leading cause of tetanus mortality in developing nations. Nearly 60,000 cases of neonatal tetanus occur each year globally. Cases are extremely rare in the U.S.
- Occurs in all races and genders
- Overall mortality rate in the U.S. is 30%
- Mortality rate increases with advancing age (75% of deaths occur in patients over 60 years)
Risk factors
- Abdominal surgery
- Acupuncture/tattooing/piercing
- Age >60 years
- Burns
- Chronically infected wounds
- Debilitated individuals
- Dental procedures (less likely)
- Diabetic ulcers
- Frostbite
- Incomplete immunization or inadequate boosters
- Infection during the postpartum period
- IV drug abuse
- Middle ear infection (less likely)
- Necrotic tumors
- Neonates
- Wounds (puncture, crush, laceration, surgical) especially when exposed to soil, dirt or fecal matter
Etiology
- The primary causative agent of tetanus is Clostridium tetani , an anaerobic gram positive rod with a drumstick like appearance due to a terminal spore
- These spores are highly resistant to heat and antiseptics and are found in soil contaminated with animal/human feces and to a lesser extent on human skin and contaminated heroin
- C. tetani produces two endotoxins, tetanolysin and tetanospasmin, of which tetanospasmin is responsible for symptoms of tetanus
- Spores gain entry into the body through deep wounds and rapidly germinate under anaerobic conditions
- Toxins produced by C. tetani spread throughout the body via the circulatory and lymphatic systems
- The incubation period is usually 4-14 days post injury
- Tetanospasmin attacks the central and peripheral nervous systems, inhibiting neurotransmitter release (GABA and glycine) and selectively blocking impulse transmission, which produces uncontrolled muscle contraction and spasms
- Tetanospasmin binding to neurons is irreversible with nerve function only returning after growth of new terminals and synapses
- This toxin may also cause seizures and affect the autonomic nervous system
History
- Dysphagia
- Hand or foot spasms (painful)
- History of incomplete vaccination
- Irritability
- Jaw and neck muscle involuntary contraction/spasm
- No fever-potentially fever if complicated by wound infection
- Pain at the wound site
- Sweating
- Urinary or fecal incontinence
Physical findings on examination
- Arched back (opisthotonus)
- Autonomic dysfunction
- Changes in heart rate and BP
- Drooling
- Lockjaw (trismus)
- Muscular rigidity/spasticity
- Painful tonic convulsions
- Respiratory distress
- Risus sardonicus (fixed grin)
- Spatula test: The spatula test is a useful bedside test to evaluate tetanus. The procedure involves touching the oropharynx with a spatula or tongue blade. The test is positive if the patient bites the blade due to masseter reflex spasm and is suggestive of tetanus. A gag reflex resulting in expelling of the spatula indicates negative results. The test has a sensitivity of 94% and specificity of 100%
General treatment items
Non-Pharmacological treatment
- Airway support may be needed, including mechanical ventilation after placement of endotracheal tube or tracheostomy
- Quiet and dark surroundings can be helpful
- Wound debridement removes spores, necrotic tissue and eliminates the anerobic conditions required for growth of clostridium
Pharmacological treatment- Human tetanus immunoglobulin (HTIg) should be given immediately. If HTIg is unavailable, normal human immunoglobulin (IV) may be administered
- Antibiotic therapy is indicated to eradicate vegetative cells which are the source of the toxin. Metronidazole is the primary choice due to its high efficacy. Penicillin G is the secondary choice
- Doxycycline, erythromycin, or clindamycin are all tertiary antibiotic options and can be used in patients allergic to other preferred options
- IV diazepam should be given to control muscle spasm, and provide anxiolysis and sedation
- Other agents used for spasm control include muscle relaxants such as baclofen and dantrolene. Intrathecal administration of baclofen requires specialist guidance
- A randomized controlled trial has demonstrated that magnesium sulfate by IV infusion can be useful in controlling muscle spasms and autonomic dysfunction
- ß-blockers such as labetalol may be used to control sympathetic hyperactivity
Medications indicated with specific doses
Immunoglobulins
- Tetanus immune globulin [IM]
- Immune globulin human [IV]
Antibiotics- Clindamycin [IM/IV]
- Doxycycline [IV]
- Erythromycin [IV]
- Metronidazole [IV]
- Penicillin G sodium [IM/IV]
Muscle relaxants- Baclofen [Intrathecal]
- Dantrolene [Oral]
- Diazepam [Oral]
- Diazepam [IM/IV]
- Magnesium sulfate [IM/IV]
AntihypertensivesDietary or Activity restrictions
- Patients must be fed through nasogastric (NG)/PEG tube until recovery
Disposition
Admission Criteria
- Almost all cases of tetanus require admission to an ICU
Discharge Criteria
- Tetanus resolved, able to mobilize, swallow normally and all complications of tetanus treated
Prevention
- Immunization with a full series, along with keeping up to date with 10 yearly boosters prevents almost all cases of tetanus
- Patients with contaminated burns or wounds (contaminated with soil or other material which could contain spores) should be given human tetanus immunoglobulin if they have not had a full tetanus immunization series or are not up to date with boosters
- Wounds should be cleaned and debrided to prevent growth of spores
Vaccination- Tetanus can be prevented with active immunization
- The tetanus vaccine is a purified Clostridium tetani toxin inactivated with formaldehyde to produce tetanus toxoid
- Tetanus toxoid is available in the following forms:
- Single-antigen preparation
- Combined with diphtheria toxoid as pediatric diphtheria-tetanus toxoid (DT) or adult tetanus-diphtheria (Td)
- Combined with diphtheria toxoid and acellular pertussis vaccine (DTaP or Tdap)
- Combined with diphtheria toxoid, acellular pertussis vaccine, hepatitis B vaccine and poliomyelitis vaccine (DTaP-HepB-IPV)
- Combined with diphtheria toxoid, acellular pertussis vaccine, poliomyelitis vaccine and Hemophilus influenzae type b (DTaP-IPV/Hib)
- Current recommendations for infants and children are for DTaP vaccine 0.5 mL IM at ages 2 months, 4 months, 6 months, 12-15 months, and between 4-6 years
- Unimmunized children aged >7 years and unimmunized adults should receive tetanus toxoid (Td) 0.5 mL IM as first two doses 4-8 weeks apart, third dose 6-12 months after the second dose and a booster dose every 10 years. The first dose should be a Tdap vaccine to provide protection against pertussis
- Fully immunized adolescents and adults should receive a tetanus booster dose every 10 years, and if receive a high risk wound, as soon as 5 years after prior immunization
Prognosis
- Patients who survive typically make a full recovery
- Mortality rate is around 60% for severe cases and 6% for mild cases
- Neonatal tetanus has the worst prognosis, followed by generalized, cephalic and localized tetanus
- Prognostic factors include:
- Co-morbid conditions
- Extremes of age
- Incubation period (time from injury to first symptom)
- Immunity status of individual
- Infection site
- Onset period (time from first symptom to first spasm)
- Severity of symptoms
Pregnancy/Pediatric effects on condition
- Maternal and neonatal tetanus are a significant cause of mortality in developing countries
- Maternal immunization along with aseptic obstetric and post-natal care practices can prevent maternal and neonatal tetanus
- Treatment of tetanus occurring in pregnancy is identical to treating a non-pregnant individual. Tetanus or human immunoglobulin can be administered during pregnancy
- Certain antibiotics such as doxycycline should not be administered during pregnancy
Synonyms/Abbreviations
Synonyms
ICD-9-CM
- 037 Tetanus
- 771.3 Tetanus neonatorum
ICD-10-CM
- A33 Tetanus neonatorum
- A34 Obstetrical tetanus
- A35 Other tetanus
