High Yield Overview

TETANUS PROPHYLAXIS - PREVENTION OF A FATAL DISEASE

Clostridium tetani | Tetanospasmin | Wound Classification | Vaccination + Immunoglobulin

10-70%Case fatality rate untreated

3-21dIncubation period (shorter = worse)

5-10yBooster interval recommended

95%Prevention with full vaccination

WOUND CLASSIFICATION FOR PROPHYLAXIS

Clean Wound

PatternLess than 6 hours old, linear, minimal contamination

TreatmentADT if more than 5 years since booster

Tetanus-Prone

PatternMore than 6 hours, puncture, devitalized tissue, contaminated

TreatmentADT + consider TIG if incomplete vaccination

High-Risk Wound

PatternCompound fracture, burns, septic, necrotic tissue

TreatmentADT + TIG if any doubt about vaccination

Farm/Soil Injury

PatternAgricultural, fecal contamination, deep penetrating

TreatmentADT + TIG unless fully vaccinated

Critical Must-Knows

Tetanus is PREVENTABLE - proper prophylaxis is 95% effective
Check vaccination history - ask about childhood vaccines AND adult boosters
Tetanus-prone wounds: more than 6 hours old, puncture, crush, devitalized, contaminated, burns, frostbite
TIG provides immediate passive immunity (250-500 IU IM) - give at different site from vaccine
Clean wound, fully vaccinated, less than 5 years = no prophylaxis needed

Examiner's Pearls

"
Shorter incubation period = more severe disease (less than 7 days = poor prognosis)
"
TIG does NOT cross blood-brain barrier once toxin is fixed to neurons
"
Vaccination history takes priority over wound type in decision-making
"
Compound fractures and farm injuries are HIGH RISK - give TIG if any doubt

Prophylaxis Products

Available Tetanus Vaccines

Tetanus-Containing Vaccines in Australia

Vaccine	Components	Indication
DTPa	Diphtheria, tetanus, acellular pertussis	Primary course in infants (2, 4, 6 months)
dTpa (Boostrix)	Reduced diphtheria, tetanus, acellular pertussis	Boosters in adolescents and adults
ADT (dT)	Reduced diphtheria + tetanus	Adult booster, wound prophylaxis
TT	Tetanus toxoid only	Rarely used alone - combination preferred

ADT vs dTpa

ADT (dT) is the standard vaccine for wound prophylaxis in adults - it contains tetanus and reduced diphtheria toxoid. dTpa (Boostrix) adds pertussis and is preferred for booster doses where pertussis protection is also needed, but ADT is equally effective for tetanus prophylaxis.

Vaccination Schedule

Primary course: 3 doses at 2, 4, 6 months (gives immunity at 6 months)
Boosters: 18 months, 4 years, 10-15 years (school program)
Adult boosters: Every 10 years recommended, or at 50 years of age
Wound booster: Given if more than 5 years (tetanus-prone) or more than 10 years (clean) since last dose

Management - Prophylaxis Algorithm

Two Questions to Answer

1. What type of wound? Clean vs tetanus-prone 2. What is the vaccination history? Fully vaccinated (3+ doses) vs incomplete/unknown

Clean/Minor Wound Algorithm

Clean Wound Prophylaxis

Vaccination History	ADT Required?	TIG Required?
Fully vaccinated (3+ doses), last dose less than 10 years	NO	NO
Fully vaccinated (3+ doses), last dose more than 10 years	YES	NO
Incomplete (1-2 doses)	YES (complete series)	NO
Unknown or none	YES (start series)	NO

Clean Wound Key Point

TIG is NEVER required for clean wounds regardless of vaccination status. The low bacterial inoculum and non-tetanus-prone environment mean the vaccine alone (starting or completing the series) provides adequate protection.

Treatment of Clinical Tetanus

Immediate Management

ICU admission - anticipate respiratory compromise
TIG 3000-6000 IU IM (or 500 IU intrathecally in some protocols)
Wound debridement - remove source of toxin
Metronidazole 500mg IV q8h - kills C. tetani vegetative cells
Benzodiazepines - diazepam for spasm control

Supportive Care

Airway management - early intubation/tracheostomy
Quiet, dark environment - reduces spasm triggers
Nutritional support - NG/PEG feeding
DVT prophylaxis - prolonged immobility
Magnesium sulfate - adjunct for spasm/autonomic control

Why Metronidazole?

Metronidazole is preferred over penicillin for C. tetani because penicillin is a GABA antagonist and may theoretically worsen tetanus symptoms. Metronidazole has no such effect and is effective against anaerobes.

Complications

Complications of Clinical Tetanus

Complication	Mechanism	Prevention/Management
Respiratory failure	Laryngospasm, diaphragm/intercostal spasm	Early intubation, mechanical ventilation
Aspiration pneumonia	Dysphagia, impaired airway protection	Airway protection, NG feeding, antibiotics
Fractures	Violent muscle spasms - especially thoracic vertebrae	Muscle relaxants, sedation, supportive care
Autonomic dysfunction	Sympathetic overactivity - hypertension, tachycardia, arrhythmias	Magnesium, beta-blockers, ICU monitoring
Rhabdomyolysis	Sustained muscle contraction	IV fluids, monitor CK and renal function
Venous thromboembolism	Prolonged immobility, ICU admission	Pharmacological prophylaxis, compression devices
Death	Respiratory failure, cardiac complications	ICU care, early aggressive treatment

Vertebral Fractures in Tetanus

Thoracic vertebral compression fractures can occur from violent opisthotonus spasms. This is a well-documented complication and may be the presentation that brings the orthopaedic surgeon into the case. Always consider tetanus in unexplained vertebral fractures with history of recent wound.

Evidence Base

Effectiveness of Tetanus Toxoid Vaccination

Gergen PJ et al. • N Engl J Med (1995)

Key Findings:

Seroprevalence study of US population (n=10,618)
95.3% protective antibody levels in fully vaccinated
Immunity wanes with age - only 72% protected over 70 years
Three-dose primary series provides long-lasting immunity
Boosters every 10 years maintain protective levels

Clinical Implication: Full vaccination is highly effective. Elderly patients require attention to booster status as immunity wanes with age.

Limitation: Cross-sectional seroprevalence study, not clinical outcomes.

TIG Dosing for Wound Prophylaxis

Blake PA et al. • JAMA (1976)

Key Findings:

Standard dose of 250 IU TIG is adequate for most wounds
Higher doses (500 IU) for heavily contaminated or delayed presentation
TIG provides immediate protection lasting 3-4 weeks
No benefit to doses above 500 IU for prophylaxis
Wound infiltration with TIG may provide additional local benefit

Clinical Implication: 250 IU TIG is the standard prophylactic dose. 500 IU reserved for high-risk situations.

Limitation: Older study, limited sample size for dose comparison.

Metronidazole vs Penicillin in Tetanus Treatment

Ahmadsyah I, Salim A • J Infect Dis (1985)

Key Findings:

RCT comparing metronidazole vs procaine penicillin (n=173)
Mortality 7% metronidazole vs 24% penicillin (pless than 0.05)
Metronidazole group had fewer spasms and shorter ICU stay
Penicillin is a GABA antagonist - may worsen tetanus
Metronidazole now standard of care for C. tetani

Clinical Implication: Metronidazole is the preferred antibiotic for tetanus treatment due to superior outcomes and lack of GABA antagonism.

Limitation: Single-center study, developing country setting.

Wound Age and Tetanus Risk

Brand DA et al. • Ann Emerg Med (1983)

Key Findings:

Review of wound characteristics and tetanus risk
Wounds more than 6 hours old have significantly higher tetanus risk
Puncture, crush, and contaminated wounds are tetanus-prone
Devitalized tissue provides optimal anaerobic environment
Wound classification predicts need for TIG

Clinical Implication: The 6-hour threshold for wound classification is evidence-based. Wound type determines prophylaxis requirements.

Limitation: Retrospective analysis, variable wound assessment methods.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

Scenario 1: Compound Fracture in Farmer

EXAMINER

"A 55-year-old farmer presents with an open tibial fracture (Gustilo IIIA) after being kicked by a cow. The wound is heavily contaminated with soil and manure. He thinks he had 'some injections as a child' but has not had any boosters. How would you manage tetanus prophylaxis?"

EXCEPTIONAL ANSWER

This is a **high-risk tetanus-prone wound** (compound fracture, farm injury, soil/fecal contamination) in a patient with uncertain/incomplete vaccination history. My management would be: **1) TIG 500 IU IM** given the heavy contamination - I would give this immediately at a different anatomical site from the vaccine. **2) ADT vaccine** in the opposite deltoid to begin the primary vaccination series. **3) Document** that prophylaxis was given in the operation note. **4) Arrange follow-up** for second (4-8 weeks) and third (6-12 months) vaccine doses through GP. **5) Thorough surgical debridement** is essential to remove contaminated/devitalized tissue, reducing the anaerobic environment for C. tetani. I would use the higher TIG dose (500 IU rather than 250 IU) due to the heavy contamination and delayed presentation typical of farm injuries.

KEY POINTS TO SCORE

High-risk tetanus-prone wound - compound fracture + farm injury + heavy contamination

Uncertain vaccination history treated as incomplete - needs ADT + TIG

Higher TIG dose (500 IU) for heavily contaminated wounds

TIG and vaccine given at DIFFERENT anatomical sites

Thorough debridement is essential adjunct to prophylaxis

COMMON TRAPS

✗Forgetting TIG because patient 'had some injections as a child'

✗Giving TIG and vaccine at the same site - reduces vaccine efficacy

✗Using standard 250 IU TIG dose for heavily contaminated wound

✗Not documenting prophylaxis in operation note

✗Omitting plan for completing vaccination series

LIKELY FOLLOW-UPS

"What if he was fully vaccinated with booster 3 years ago?"

"Why is thorough debridement important for tetanus prevention?"

"What are the clinical features of tetanus?"

VIVA SCENARIOStandard

Scenario 2: Clean Surgical Wound

EXAMINER

"A 45-year-old woman is having an elective total hip replacement. During pre-assessment, she mentions she received her last tetanus booster 12 years ago after cutting her hand. Should she receive tetanus prophylaxis?"

EXCEPTIONAL ANSWER

This is an **elective clean surgical wound** in a patient who appears to be fully vaccinated (assuming standard childhood course plus adult booster). For a clean wound, the booster threshold is **10 years**. Since her last booster was 12 years ago, I would recommend **ADT vaccine** given pre-operatively or in the post-operative period. **TIG is NOT required** for clean wounds regardless of vaccination status. I would confirm her vaccination history if possible through her GP records. The key point is that elective surgery in a clean field is low-risk for tetanus, but updating her tetanus immunity is good preventive medicine. I would document this in her notes and ensure she receives a booster before or during her admission.

KEY POINTS TO SCORE

Elective surgery = clean wound - low tetanus risk

Clean wound threshold for booster is 10 years (vs 5 years for tetanus-prone)

TIG is NEVER required for clean wounds

12 years since booster = ADT indicated

Good opportunity to update routine immunizations

COMMON TRAPS

✗Giving TIG for a clean surgical wound

✗Using 5-year threshold (that's for tetanus-prone wounds)

✗Ignoring the opportunity to update vaccination

✗Not documenting vaccination status and prophylaxis decision

LIKELY FOLLOW-UPS

"What if she had a compound fracture instead?"

"What defines a tetanus-prone wound?"

"How long does immunity from a tetanus vaccine last?"

VIVA SCENARIOChallenging

Scenario 3: Unknown Vaccination in Elderly Patient

EXAMINER

"An 82-year-old man presents with a closed distal radius fracture after a fall at home. The fracture requires manipulation and K-wire fixation. He has no idea about his vaccination history and has no GP records available. How would you approach tetanus prophylaxis?"

EXCEPTIONAL ANSWER

This requires careful consideration. The procedure (K-wire fixation of closed fracture) creates a **clean surgical wound** in terms of tetanus risk - there is no pre-existing contaminated wound. For elderly patients with unknown vaccination history, I would treat him as having **incomplete vaccination**. For a clean wound with incomplete/unknown vaccination, the algorithm recommends **ADT vaccine** to begin the primary series - **TIG is NOT required** for clean wounds. However, I would have a low threshold to classify this as tetanus-prone if there were any concerns about the procedure or wound. The elderly are at higher risk for severe tetanus due to waning immunity, so I would definitely give ADT. I would arrange for him to complete the vaccination series with second and third doses through his GP. I would also take this opportunity to discuss other age-appropriate vaccinations (influenza, pneumococcal, shingles).

KEY POINTS TO SCORE

Closed fracture with K-wire fixation = clean surgical wound

Unknown vaccination in elderly - treat as incomplete

Clean wound + incomplete vaccination = ADT only (no TIG)

Elderly have waning immunity - vaccination especially important

Arrange completion of vaccine series through GP

COMMON TRAPS

✗Giving TIG for a clean wound (TIG never needed for clean wounds)

✗Assuming elderly patient doesn't need vaccination

✗Not considering that elderly may have never had modern vaccination schedule

✗Forgetting to arrange completion of primary series

LIKELY FOLLOW-UPS

"If this was an open fracture, how would your approach change?"

"Why is tetanus more severe in elderly patients?"

"What is the mechanism of tetanospasmin?"

Australian Context

Australian Immunisation Handbook Guidelines

The Australian Immunisation Handbook (published by the Australian Government Department of Health) provides the definitive guidelines for tetanus prophylaxis in Australia. The current recommendations align with those outlined in this topic, with specific attention to the National Immunisation Program (NIP) schedule.

Australian Vaccination Schedule

The NIP provides funded tetanus-containing vaccines at 2, 4, 6, and 18 months, 4 years (DTPa), and 10-15 years (dTpa through school programs). Adult boosters are recommended at age 50 if more than 10 years since last dose. Many Australians born before 1966 may not have received childhood tetanus vaccination and should be considered for catch-up vaccination.

Clinical Practice in Australia

Australian emergency departments and trauma units routinely assess tetanus prophylaxis for all wounds. ADT vaccine is readily available in all hospitals and general practices. TIG (CSL Behring, human-derived) is stocked in hospital pharmacies and emergency departments. The Australian Red Cross Blood Service also supplies TIG. Remote and rural Australia may have delays in accessing TIG, so consideration should be given to giving ADT and arranging TIG administration or transfer if indicated. Telehealth consultation with infectious diseases or toxicology is available for complex cases. Documentation of tetanus prophylaxis is a standard component of trauma and emergency documentation.

Tetanus Prophylaxis - Exam Day Quick Reference

High-Yield Exam Summary

Key Definitions

•Tetanus = disease from tetanospasmin toxin produced by C. tetani
•Clean wound = less than 6 hours, linear, superficial, minimal contamination
•Tetanus-prone = more than 6 hours, puncture, crush, devitalized, contaminated, burns
•Fully vaccinated = 3 or more doses of tetanus toxoid

Wound Assessment (6 DIRTY Ps)

•More than 6 hours old
•Devitalized tissue
•Infected/contaminated (soil, feces, saliva)
•Ragged/stellate configuration
•Tissue loss (burns, frostbite)
•Yielding to depth (puncture), Penetrating foreign body

Clean Wound Prophylaxis

•Fully vaccinated + less than 10 years = NO prophylaxis
•Fully vaccinated + more than 10 years = ADT only
•Incomplete/unknown = ADT (start/complete series)
•TIG is NEVER required for clean wounds

Tetanus-Prone Wound Prophylaxis

•Fully vaccinated + less than 5 years = NO prophylaxis
•Fully vaccinated + more than 5 years = ADT only
•Incomplete (1-2 doses) = ADT + TIG (250-500 IU)
•Unknown vaccination = ADT + TIG (250-500 IU)

TIG Administration

•Dose: 250 IU IM (500 IU for heavy contamination)
•Give at DIFFERENT site from vaccine
•Provides immediate passive immunity
•Cannot neutralize toxin already fixed to neurons

High-Risk Wounds (Always Tetanus-Prone)

•Compound fractures - all Gustilo grades
•Farm/agricultural injuries - soil contamination
•Burns and frostbite - devitalized tissue
•Bite wounds - human, dog, cat
•Gunshot wounds - deep contaminated tracts

Clinical Tetanus Features

•Incubation 3-21 days (shorter = more severe)
•Trismus (lockjaw) - earliest sign
•Risus sardonicus - sardonic smile
•Opisthotonus - arched back
•Spasms triggered by noise, touch, light

Tetanus Treatment

•ICU admission - anticipate respiratory failure
•TIG 3000-6000 IU IM (treatment dose, not prophylaxis)
•Metronidazole 500mg IV q8h (NOT penicillin)
•Wound debridement
•Benzodiazepines for spasms
•Early intubation/tracheostomy

References

Australian Technical Advisory Group on Immunisation (ATAGI). Australian Immunisation Handbook. Australian Government Department of Health. 2024. Available at: immunisationhandbook.health.gov.au
Gergen PJ, McQuillan GM, Kiely M, et al. A population-based serologic survey of immunity to tetanus in the United States. N Engl J Med. 1995;332(12):761-766. doi:10.1056/NEJM199503233321201
Ahmadsyah I, Salim A. Treatment of tetanus: an open study to compare the efficacy of procaine penicillin and metronidazole. BMJ. 1985;291(6496):648-650. doi:10.1136/bmj.291.6496.648
Blake PA, Feldman RA, Buchanan TM, et al. Serologic therapy of tetanus in the United States, 1965-1971. JAMA. 1976;235(1):42-44. doi:10.1001/jama.1976.03260270024017
Brand DA, Acampora D, Gottlieb LD, et al. Adequacy of antitetanus prophylaxis in six hospital emergency rooms. N Engl J Med. 1983;309(11):636-639. doi:10.1056/NEJM198309153091104
Cook TM, Protheroe RT, Handel JM. Tetanus: a review of the literature. Br J Anaesth. 2001;87(3):477-487. doi:10.1093/bja/87.3.477
Thwaites CL, Beeching NJ, Newton CR. Maternal and neonatal tetanus. Lancet. 2015;385(9965):362-370. doi:10.1016/S0140-6736(14)60236-1
Rodrigo C, Fernando D, Rajapakse S. Pharmacological management of tetanus: an evidence-based review. Crit Care. 2014;18(2):217. doi:10.1186/cc13797
Centers for Disease Control and Prevention. Tetanus: For Clinicians. CDC. 2024. Available at: cdc.gov/tetanus/clinicians.html
Public Health England. Tetanus: The Green Book, Chapter 30. 2020. Available at: gov.uk/government/publications/tetanus-the-green-book-chapter-30

Vaccine

Components

Indication

DTPa

Diphtheria, tetanus, acellular pertussis

Primary course in infants (2, 4, 6 months)

dTpa (Boostrix)

Reduced diphtheria, tetanus, acellular pertussis

Boosters in adolescents and adults

ADT (dT)

Reduced diphtheria + tetanus

Adult booster, wound prophylaxis

Tetanus toxoid only

Rarely used alone - combination preferred

Vaccination History

ADT Required?

TIG Required?

Fully vaccinated (3+ doses), last dose less than 10 years

Fully vaccinated (3+ doses), last dose more than 10 years

YES

Incomplete (1-2 doses)

YES (complete series)

Unknown or none

YES (start series)

Complication

Mechanism

Prevention/Management

Respiratory failure

Laryngospasm, diaphragm/intercostal spasm

Early intubation, mechanical ventilation

Aspiration pneumonia

Dysphagia, impaired airway protection

Airway protection, NG feeding, antibiotics

Fractures

Violent muscle spasms - especially thoracic vertebrae

Muscle relaxants, sedation, supportive care

Autonomic dysfunction

Sympathetic overactivity - hypertension, tachycardia, arrhythmias

Magnesium, beta-blockers, ICU monitoring

Rhabdomyolysis

Sustained muscle contraction

IV fluids, monitor CK and renal function

Venous thromboembolism

Prolonged immobility, ICU admission

Pharmacological prophylaxis, compression devices

Death

Respiratory failure, cardiac complications

ICU care, early aggressive treatment

Effectiveness of Tetanus Toxoid Vaccination

Gergen PJ et al. • N Engl J Med (1995)

Key Findings:

Seroprevalence study of US population (n=10,618)
95.3% protective antibody levels in fully vaccinated
Immunity wanes with age - only 72% protected over 70 years
Three-dose primary series provides long-lasting immunity
Boosters every 10 years maintain protective levels

Clinical Implication: Full vaccination is highly effective. Elderly patients require attention to booster status as immunity wanes with age.

Limitation: Cross-sectional seroprevalence study, not clinical outcomes.

TIG Dosing for Wound Prophylaxis

Blake PA et al. • JAMA (1976)

Key Findings:

Standard dose of 250 IU TIG is adequate for most wounds
Higher doses (500 IU) for heavily contaminated or delayed presentation
TIG provides immediate protection lasting 3-4 weeks
No benefit to doses above 500 IU for prophylaxis
Wound infiltration with TIG may provide additional local benefit

Clinical Implication: 250 IU TIG is the standard prophylactic dose. 500 IU reserved for high-risk situations.

Limitation: Older study, limited sample size for dose comparison.

Metronidazole vs Penicillin in Tetanus Treatment

Ahmadsyah I, Salim A • J Infect Dis (1985)

Key Findings:

RCT comparing metronidazole vs procaine penicillin (n=173)
Mortality 7% metronidazole vs 24% penicillin (pless than 0.05)
Metronidazole group had fewer spasms and shorter ICU stay
Penicillin is a GABA antagonist - may worsen tetanus
Metronidazole now standard of care for C. tetani

Clinical Implication: Metronidazole is the preferred antibiotic for tetanus treatment due to superior outcomes and lack of GABA antagonism.

Limitation: Single-center study, developing country setting.

Wound Age and Tetanus Risk

Brand DA et al. • Ann Emerg Med (1983)

Key Findings:

Review of wound characteristics and tetanus risk
Wounds more than 6 hours old have significantly higher tetanus risk
Puncture, crush, and contaminated wounds are tetanus-prone
Devitalized tissue provides optimal anaerobic environment
Wound classification predicts need for TIG

Clinical Implication: The 6-hour threshold for wound classification is evidence-based. Wound type determines prophylaxis requirements.

Limitation: Retrospective analysis, variable wound assessment methods.

Element	Details to Record
Vaccination history	Number of prior doses, date of last dose, source (patient/records)
Wound assessment	Type, time since injury, contamination, tissue viability
Prophylaxis given	ADT (brand, batch, site), TIG (dose, site), date/time
Follow-up plan	Completing vaccine series if needed, GP notification
Patient education	Warning signs, importance of booster doses, injury prevention

Element	Details to Record
Vaccination history	Number of prior doses, date of last dose, source (patient/records)
Wound assessment	Type, time since injury, contamination, tissue viability
Prophylaxis given	ADT (brand, batch, site), TIG (dose, site), date/time
Follow-up plan	Completing vaccine series if needed, GP notification
Patient education	Warning signs, importance of booster doses, injury prevention