Tetanus: Physiology, Symptoms, Treatment, and Prevention
Discover the science of Tetanus (Clostridium tetani). Learn about the neurotoxin tetanospasmin, clinical symptoms like lockjaw, and modern treatment protocols.
TETANUS
The Silent Spasm — A Physiological Perspective
MAKENNA KING | BIO340 PRESENTATION
What is Tetanus?
TETANUS
Fatal neurological disease caused by tetanospasmin neurotoxin
C. tetani
Anaerobic • Gram-positive • Spore-forming
Found in: soil, dust, feces
Resistant to heat & antiseptics
CLINICAL DIAGNOSIS
No lab test
Trismus / Risus sardonicus
~30% wound culture +
HOMEOSTASIS DISRUPTION
Balanced nerve signals
Uncontrolled continuous firing
GABA & Glycine BLOCKED
1 in 5
Case fatality rate (untreated)
No reliable lab test — 100% clinical diagnosis
30%
wound cultures confirm C. tetani
CDC Pink Book (2024) | Cook et al., BJA 87(3), 2001 | WHO Fact Sheet (2023)
Systems Affected by Tetanus
PRIMARY SYSTEM
Nervous System
Inhibitory neurons (GABA & glycine) BLOCKED
Tetanospasmin cleaves VAMP/synaptobrevin
→ Continuous muscle contraction
Secondary System
Musculoskeletal
Rigidity & severe spasms
Trismus (jaw lock), opisthotonus, laryngospasm
→ Muscle tears & fractures
Tertiary System
Autonomic Control
Catecholamine (adrenaline) surge unchecked
Tachycardia, hypertension, hyperthermia
→ Autonomic crisis
Toxin Pathway
Cook et al., Br J Anaesthesia 87(3), 2001 | CDC Pink Book (2024) | WHO Fact Sheet (2023)
The Science Behind Tetanus
Tetanospasmin Pathophysiology
Tetanospasmin: The Toxin
2nd most lethal toxin known
Min lethal dose: 2.5 ng/kg
Zinc metalloprotease
cleaves VAMP/synaptobrevin
Produced under anaerobic conditions only
Toxin Structure
How Tetanospasmin Attacks: Step-by-Step
Wound Entry
C. tetani germinates in low-O₂ wound
Toxin Released
Enters bloodstream & lymphatics
NMJ Binding
Binds neuromuscular junctions via heavy chain
Retrograde Transport
Travels UP motor neurons to spinal cord
VAMP Cleavage
GABA & Glycine BLOCKED → continuous spasm
Net Effect on Homeostasis
NORMAL STATE
TETANUS INFECTION
<strong style="color:#00ffff;">Autonomic Note:</strong> Catecholamine surge causes tachycardia, hypertension, hyperthermia.
Cook et al. (2001) BJA; CDC Pink Book (2024); Rhee & Nunley (2024) AJP
CAUSES & HOW INFECTION OCCURS
20% of cases have NO identifiable wound
Spores Enter Wound
Usually via an anaerobic puncture or cut
Germination & Multiplication
C. tetani multiplies rapidly in a low-oxygen environment
Tetanospasmin Released
A potent neurotoxin floods the surrounding tissue
Toxin Reaches CNS
Travels via blood & lymphatic system to the nervous system
Lethal dose = just 2.5 ng/kg — one of the deadliest toxins on Earth
CDC Pink Book (2024) | Cook et al., BJA 87(3), 2001 | Pascual et al., MMWR 52(3), 2003
Signs & Symptoms
Tetanus Clinical Presentation
⚡ VITAL SIGNS
🌡️
Temperature
Fever >38.5°C
❤️
HEART RATE
Tachycardia >120 bpm
🩸
Blood Pressure
Labile Hypertension
💨
Respiratory
Risk of Arrest
🔑 CARDINAL SIGNS
TRISMUS (Lockjaw)
Masseter spasm, jaw won't open.<br/>First sign in 80% of cases.
RISUS SARDONICUS
Fixed sardonic facial grimace from facial spasm.
OPISTHOTONOS
Violent back arching from extensor spasm.
🧠 SYMPTOMS
⚡
Generalized Rigidity
Board-like abdomen, stiff neck
🔊
Stimulus-Triggered Spasms
Sound/light/touch provokes spasm
😮
Dysphagia & Laryngospasm
Throat spasm, choking risk
😵
Autonomic Instability
Arrhythmias, sweating, vasoconstriction
Cook et al., BJA 87(3), 2001 | CDC Pink Book 2024 | Thwaites et al., The Lancet 2006 | WHO Fact Sheet 2023
Who Is Most Affected?
Epidemiology & Demographics
~1 MILLION
cases/year globally
213K–293K deaths/year
~30 cases/yr
37 in 2025 (10-yr high)
Neonates
~27K deaths/yr globally
Drug Users
Contaminated needles
Males
More commonly affected
Diabetics
Slower wound healing
84% DTP3 global infant coverage
92.1% US DTaP kindergarten coverage (2025)
WHO Fact Sheet (2023) | Pascual et al., MMWR 52(3), 2003 | Roper et al., The Lancet 370, 2007
TREATMENT APPROACHES
WOUND CARE
Debridement
NEUTRALIZE TOXIN
TIG 500 IU
ANTIBIOTICS
Metronidazole 7–10 days
SPASM CONTROL
Benzodiazepines + Mg²⁺
AUTONOMIC MGMT
Beta-blockers + Morphine
ICU CARE
Tracheostomy + Sedation
⚠️ Antibiotics do NOT reverse spasms — toxin damage is irreversible once bound
🔑 KEY: Treat the toxin first, then the symptoms
CDC Pink Book (2024) | Cook et al., BJA 87(3), 2001 | Saltoglu et al., J Infection 48(1), 2004
PROGNOSIS — With & Without Treatment
WITH TREATMENT
10–20%
Case Fatality Rate
Week 1–2: Spasms peak
Week 3–4: Spasms subside
Month 2–6: Full recovery
Full recovery possible
No natural immunity gained
Early treatment = best outcome
WITHOUT TREATMENT
70–90%
Mortality Rate
85–100% pre-vaccine era
NEONATAL: 90–95% fatal
Respiratory failure
Cardiac arrhythmia
Autonomic crisis
MODIFIED ABLETT SEVERITY SCALE
Grade I
No spasms, mild trismus
Grade II
Moderate spasms, mild autonomic dysfunction
Grade III
Severe spasms, tachycardia, hyperthermia
Grade IV
Violent spasms, severe autonomic instability
Saltoglu et al., J Infection 48(1), 2004 | Thwaites et al., The Lancet 385, 2015 | CDC MMWR (2003)
Prevention — Vaccines & Public Health
Nearly 100% with full series + boosters
DTaP
Diphtheria, Tetanus, Pertussis
For children under 7. 5 doses at 2, 4, 6, 15–18 months, and 4–6 years.
Td
Tetanus & Diphtheria booster
Required every 10 years for adults to maintain immunity.
Tdap
Includes pertussis
Once for adults + every pregnancy at 27–36 weeks.
POST-EXPOSURE PROPHYLAXIS
Clean wound + vaccinated
Td only if >10 years since last dose
Dirty wound + vaccinated
Td if >5 years since last dose
Unvaccinated / unknown
BOTH TIG (passive immunity) + full Td vaccine series
GLOBAL PROGRESS
787,000
97% REDUCTION
~25,000
11 countries still lack elimination status. Vaccine access gaps and hesitancy remain the primary barriers.
Tetanus is
100% PREVENTABLE
through vaccination. It exists today only because of vaccine hesitancy, access gaps, and waning immunity.
CDC Pink Book (2024) | WHO Fact Sheet (2023) | Thwaites et al., The Lancet 385(9965), 2015
WHO Fact Sheet (2023) | CDC Pink Book (2024) | Roper et al., The Lancet 370(9603), 2007
References / Sources Cited
All sources accessed March 2026.
Centers for Disease Control and Prevention. (2024). Tetanus: Epidemiology and prevention of vaccine-preventable diseases (The Pink Book). CDC. https://www.cdc.gov/tetanus
World Health Organization. (2023). Tetanus. WHO Fact Sheet. https://www.who.int/news-room/fact-sheets/detail/tetanus
Cook, T. M., Protheroe, R. T., & Handel, J. M. (2001). Tetanus: A review of the literature. British Journal of Anaesthesia, 87(3), 477–487. https://doi.org/10.1093/bja/87.3.477
Rhee, P., & Nunley, M. (2024). Peripheral flaccid paralysis precedes central spastic paralysis in local tetanus. American Journal of Pathology. https://doi.org/10.1016/j.ajpath.2024
Saltoglu, N., Tasova, Y., Midikli, D., & Aksu, H. S. (2004). Tetanus: Clinical features, intensive care management, complications, and outcomes in 68 patients. Journal of Infection, 48(1), 44–47.
Roper, M. H., Vandelaer, J. H., & Gasse, F. L. (2007). Maternal and neonatal tetanus. <i>The Lancet</i>, 370(9603), 1947–1959.
Thwaites, C. L., Beeching, N. J., & Newton, C. R. (2015). Maternal and neonatal tetanus. <i>The Lancet</i>, 385(9965), 362–370.
Pascual, F. B., McGinley, E. L., Zanardi, L. R., Cortese, M. M., & Murphy, T. V. (2003). Tetanus surveillance — United States, 1998–2000. MMWR Surveillance Summaries, 52(3), 1–8.
- tetanus
- clostridium-tetani
- physiology
- medical-education
- vaccination
- immunology
- lockjaw
- neurology