Tetanus (Clostridium tetani)
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Tetanus is caused by the tetanospasmin exotoxin released from Clostridium tetani. Tetanus spores are present in soil and may be introduced into the body from a wound, which is often unnoticed. Tetanospasmin prevents release of the inhibitory neurotransmitter GABA.
C. tetani release a second, less significant, exotoxin called tetanolysin. Tetanolysin causes local tissue damage and may help to optimise conditions for the organism but has no known role in the pathogenesis of the clinical tetanus.
Epidemiology
Tetanus incidence has significantly decreased in countries with comprehensive immunization programs. However, it remains a concern in areas with low vaccination coverage. Neonatal tetanus, resulting from umbilical stump infections, is a notable cause of infant mortality in some regions.
Management of suspected cases of clinical tetanus
Management involves the following steps:
Early recognition and treatment are vital due to the high mortality rate associated with tetanus. Healthcare professionals should be vigilant for symptoms, particularly in unvaccinated individuals or those with uncertain immunization status.
Note 1: Clean wound is defined as wounds less than 6 hours old, non penetrating with negligible tissue damage.
Note 2: At least 3 doses of tetanus vaccine at appropriate intervals. This definition of ‘adequate course’ is for the risk assessment of tetanus-prone wounds only. The full UK schedule is 5 doses of tetanus containing vaccine at appropriate intervals.
Note 3: If TIG is not available, HNIG may be used as an alternative.
High-risk tetanus-prone wounds include: Any of the above with either:
Clinical features
- prodrome fever, lethargy, headache
- trismus (lockjaw)
- risus sardonicus (abnormal, sustained spasm of the facial muscles that appears to produce grinning)
- opisthotonus (arched back, hyperextended neck)
- spasms (e.g. dysphagia)
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Opisthotonus or opisthotonos is a state of severe hyperextension and spasticity in which an individual's head, neck and spinal column enter into a complete bridging or arching position. Click on image to enlarge
Pathophysiology
C. tetani spores germinate in anaerobic conditions, releasing tetanospasmin. This toxin enters nerve endings at the neuromuscular junction and interferes with the release of the inhibitory neurotransmitter GABA. This leads to muscle rigidity and spasms. Initial symptoms often include stiffness in the jaw (lockjaw) and neck, progressing to generalised muscle stiffness.C. tetani release a second, less significant, exotoxin called tetanolysin. Tetanolysin causes local tissue damage and may help to optimise conditions for the organism but has no known role in the pathogenesis of the clinical tetanus.
Tetanus Key Points
- Tetanus is the disease caused by Clostridium tetani.
- Clostridium tetani is a gram positive rod shaped obligate anaerobe.
- Clostridium tetani has an incubation period of 3-21 days (average 10 days)
- Immunisation is with an inactivated vaccine that do not contain live bacteria.
- Tetanus disrupts neurological signalling by inhibiting GABA.
Epidemiology
Tetanus incidence has significantly decreased in countries with comprehensive immunization programs. However, it remains a concern in areas with low vaccination coverage. Neonatal tetanus, resulting from umbilical stump infections, is a notable cause of infant mortality in some regions.
Prevention
Immunization is the most effective preventive measure. In the UK, the routine vaccination schedule includes five doses of tetanus-containing vaccine, starting in infancy.| Dose | Vaccine | Age | Additional Information |
|---|---|---|---|
| 1 | DTaP/IPV/Hib (6-in-1) | 8 weeks | Part of the routine childhood immunization program. Protects against diphtheria, tetanus, pertussis, polio, and Haemophilus influenzae type b. |
| 2 | DTaP/IPV/Hib (6-in-1) | 12 weeks | Second dose of the 6-in-1 vaccine. |
| 3 | DTaP/IPV/Hib (6-in-1) | 16 weeks | Third dose of the 6-in-1 vaccine. |
| 4 | DTaP/IPV (4-in-1 preschool booster) | 3 years 4 months to 5 years | Booster dose to provide continued protection against diphtheria, tetanus, pertussis, and polio. |
| 5 | Td/IPV (3-in-1 teenage booster) | 14 years (Year 9 in school) | Booster to provide long-term protection against tetanus, diphtheria, and polio. |
| Booster (if needed) | Tetanus-containing vaccine (e.g., Td/IPV) | Post-injury or travel-related as needed | For individuals at risk of exposure to tetanus or those traveling to regions where tetanus protection is required. |
Tetanus vaccine
In the UK tetanus vaccine is made from a cell-free purified toxin extracted from a strain of C. tetani. This is treated with formaldehyde that converts it into tetanus toxoid. This is adsorbed onto an adjuvant, either aluminium phosphate or aluminium hydroxide, to improve its immunogenicity.
Tetanus vaccines used for primary immunisation contain not less than 40IU of tetanus toxoid; vaccines used for boosters contain not less than 20IU.
The tetanus vaccine is only given as part of combined products for the UK national vaccination programme:
Tetanus toxoid vaccines work by producing antibodies which bind to tetanospasmin toxin and neutralise it.
In the UK tetanus vaccine is made from a cell-free purified toxin extracted from a strain of C. tetani. This is treated with formaldehyde that converts it into tetanus toxoid. This is adsorbed onto an adjuvant, either aluminium phosphate or aluminium hydroxide, to improve its immunogenicity.
Tetanus vaccines used for primary immunisation contain not less than 40IU of tetanus toxoid; vaccines used for boosters contain not less than 20IU.
The tetanus vaccine is only given as part of combined products for the UK national vaccination programme:
- diphtheria/tetanus/acellular pertussis/inactivated polio vaccine/Haemophilus influenzae type b/Hepatitis B (DTaP/IPV/Hib/HepB)
- diphtheria/tetanus/acellular pertussis/inactivated polio vaccine (DTaP/IPV or dTaP/IPV)
- tetanus/diphtheria/inactivated polio vaccine (Td/IPV)
Tetanus toxoid vaccines work by producing antibodies which bind to tetanospasmin toxin and neutralise it.
Management of suspected cases of clinical tetanus
Management involves the following steps:
- ABCDE approach to ensure airway is secure and circulatory system supported as needed
- IV access and send blood for CK, tetanus toxin and serology
- Immediate thorough cleaning of contaminated wounds (tetanus-prone injuries) with early wound debridement
- Administration of human IV tetanus immunoglobulin (TIG) is recommended to provide passive immunity OR intravenous immunoglobulin (IVIG - see box below)
- Antibiotics using agents reliably active against anaerobes e.g. intravenous benzylpenicillin or metronidazole
- Vaccination with tetanus toxoid following recovery
- Supportive measures including benzodiazepines for muscle spasms, treatment of autonomic dysfunction, maintenance of ventilation, nursing in a quiet room.
Tetanus immunoglobulin (TIG) and intravenous immunoglobulin (IVIG)
IV tetanus immunoglobulin (IV-TIG) had been a mainstay of treatment for clinical tetanus in the UK for many years however long term supply shortages mean TIG is frequently not available for use. Intravenous immunoglobulin (IVIG) may be used as an alternative, at a dose of 5,000 units in patients under 50kg, and 10,000 units in those over.
IV tetanus immunoglobulin (IV-TIG) had been a mainstay of treatment for clinical tetanus in the UK for many years however long term supply shortages mean TIG is frequently not available for use. Intravenous immunoglobulin (IVIG) may be used as an alternative, at a dose of 5,000 units in patients under 50kg, and 10,000 units in those over.
Early recognition and treatment are vital due to the high mortality rate associated with tetanus. Healthcare professionals should be vigilant for symptoms, particularly in unvaccinated individuals or those with uncertain immunization status.
Tetanus (local and generalised) is a notifiable disease
Tetanus prone wounds
Tetanus prone wounds will typically require:- Thorough cleaning of wounds
- Surgical debridement of devitalised tissue in high risk tetanus–prone wounds
- If the wound, burn or injury fulfils the high risk criteria (see info box below), IM-TIG or human normal immunoglobulin (HNIG) should be given to neutralise toxin.
- A reinforcing dose of tetanus-containing vaccine depending on vaccination status and wound type (see table below)
- Treat tetanus prone-wounds with antibiotics (metronidazole, benzylpeniciilin or coamoxiclav) depending on clinical severity
| Immunisation status | Immediate treatment: clean wound | Immediate treatment: tetanus prone | Immediate treatment: high risk tetanus prone | Later treatment |
|---|---|---|---|---|
| Those aged 11 years and over, who have received an adequate priming course of tetanus vaccine [note 2] with the last dose within 10 years Children aged 5 to 10 years who have received priming course and pre-school booster Children under 5 years who have received an adequate priming course | None required | None required | None required | Further doses as required to complete the recommended schedule (to ensure future immunity) |
| Received adequate priming course of tetanus vaccine [note 2] but last dose more than 10 years ago Children aged 5 to 10 years who have received an adequate priming course but no preschool booster Includes UK born after 1961 with history of accepting vaccinations | None required | Immediate reinforcing dose of vaccine | Immediate reinforcing dose of vaccine One dose of human tetanus immunoglobulin [note 3] in a different site | Further doses as required to complete the recommended schedule (to ensure future immunity) |
| Not received adequate priming course of tetanus vaccine [note 2] Includes uncertain immunisation status and/or born before 1961 | Immediate reinforcing dose of vaccine | Immediate reinforcing dose of vaccine One dose of human tetanus immunoglobulin [note 3] in a different site | Immediate reinforcing dose of vaccine One dose of human tetanus immunoglobulin [note 3] in a different site |
Note 2: At least 3 doses of tetanus vaccine at appropriate intervals. This definition of ‘adequate course’ is for the risk assessment of tetanus-prone wounds only. The full UK schedule is 5 doses of tetanus containing vaccine at appropriate intervals.
Note 3: If TIG is not available, HNIG may be used as an alternative.
Tetanus-prone wounds
Tetanus-prone wounds include:- puncture-type injuries acquired in a contaminated environment and likely therefore to contain tetanus spores e.g. gardening injuries
- wounds containing foreign bodies
- compound fractures
- wounds or burns with systemic sepsis
- certain animal bites and scratches - although smaller bites from domestic pets are generally puncture injuries animal saliva should not contain tetanus spores unless the animal has been routing in soil or lives in an agricultural setting
High-risk tetanus-prone wounds include: Any of the above with either:
- heavy contamination with material likely to contain tetanus spores e.g. soil, manure
- wounds or burns that show extensive devitalised tissue
- wounds or burns that require surgical intervention that is delayed for more than six hours are high risk even if the contamination was not initially heavy