1. Assist Prof Microbiology College of Medicine, Majmaah University
TETANUS
Assist Prof Microbiology
College of Medicine, Majmaah University

2. LEARNING OBJECTIVES
Explain etiology, pathogenesis and mechanism of transmission
Discuss the mechanism of action of tetanus toxin
Discuss the role of immunization in primary and secondary prevention of tetanus

3. TETANUS-ETIOLOGY Tetanus is caused by Clostridium tetani
Gram positive anaerobic bacillus
One of two genera that form spores
Two forms: vegetative form and spore form
Vegetative form: actively secretes toxin and cause disease
Spore form: Dormant and metabolically inert, important in disease transmission

4. TETANUS-ETIOLOGY
Spores present in soil, dust, manure, dirty metallic objects e.g. nails, sharp rusted metallic objects, wood pieces, etc.
Spores excreted in feces of horse, sheep, chicken and other animals
Soil mixed with feces-spores remain in soil for long time
Non communicable disease

5. VIDEO TETANUS INTRODUCTION

6. TETANUS-TRANSMISSION
Non invasive disease
C. tetani remains localized to devitalized tissue
Spores (& not Vegetative form) are important in disease transmission
Spores enter body through cuts, lacerations, deep wounds, puncture wound etc.
Neonatal tetanus-contaminated equipments to cut umbilical cord
African nation-ritual of putting animal dung on umbilical stump

7. TETANUS-TRANSMISSION
The spore can get into the body through broken skin -injuries from contaminated objects.
Breaks in skin more likely to get infected
Wounds contaminated with dirt, feces, spit (saliva)
Puncture wounds- nail, needle, thorn
Burns
Crush injuries
Injuries with dead tissue
Rare ways of transmission
Clean superficial wounds, surgical procedures, insect/ animal bites, compound fractures, I/V drug users

8. TETANUS-PATHOGENESIS
Incubation Period days(1day-several months)
Average IP 10 days
Spores carried deep inside wound
Anaerobic atmosphere: dead tissue, deep in tissue, foreign body, co-infection with aerobic organisms
Spores germinate into vegetative form

9. TETANUS-PATHOGENESIS
Vegetative form remain localized to wound
Secrete toxin Tetanospasmin
Active fragment binds to pre-synaptic motor neurons
Retrograde axonal transport- to spinal cord and brain stem
Toxin diffuses to inhibitory cells-Glycinergic and GABAergic neurons
Toxin degrades Synaptobrevin-docking protein of pre-synaptic vesicles

10. TETANUS-PATHOGENESIS
Release of inhibitory neurotransmitters Glycine & GABA is blocked
Uninhibited spastic contraction of muscles
Hyper-reflexia, spastic paralysis of muscles
Lock jaw, trismus, neck stiffness, difficulty swallowing
Opisthotonus

11. NEUROTRANSMISSION VIDEO

12. TETANUS-PATHOGENESIS
COMPLICATIONS
Laryngospasm
Fractures
Hospital-acquired infections
Pulmonary embolism
Aspiration pneumonia
Breathing difficulty, possibly leading to death (10-20% of cases are fatal especially very young and old)

13. VIDEO NEONATAL TETANUS

14. TETANUS PREVENTION PRIMARY PREVENTION PREGNANT LADIES NEWBORNS
Tdap between 27 & 36 weeks
NEWBORNS
DTaP -2,3,4 months
PRE-SCHOOL (3-5 years)
DTaP booster
ADULTS(13-18 years)
Single Td booster
ADULTS >19 Years not received Tdap &
PERSON >65 Years-should get Tdap

15. TETANUS PREVENTION SECONDARY PREVENTION NOT IMMUNIZED OR INCOMPLETE
FULLY IMMUNIZED
IMMUNIZATION STATUS
Active immunization with tetanus toxoid
No immunization
Minor wound
Tetanus toxoid & TIG
Tetanus Immunoglobulins (TIG) single dose
Tetanus prone wound

16. TETANUS TREATMENT Wound debridement
Antimicrobial therapy: Metronidazole preferred over Penicillin G
Penicillin G -structurally similar to GABA and competitively antagonizes this neurotransmitter
Management of clinical tetanus: Human tetanus immunolobulin (TIG)
General supportive management e.g. airway management, physiotherapy etc.
Spasmolytics

17. MCQ Tetanus Is caused by Clostridium botulinum
Causative organism secretes toxin tetanolysin
Has an average incubation period of 3 days
Is not a contagious disease
Vegetative form is important in disease transmission

18. MCQ
A 21-years-young boy met RTA and sustained multiple deep penetrating wounds on body. He has never been vaccinated for any disease in his life. Regarding secondary prevention of tetanus for this man, which of the following vaccination protocol should be followed?
Tetanus toxoid only
Tetanus toxoid and TIG
TIG only
Neither Tetanus toxoid nor TIG

19. MCQ
A 39-years-old lady is brought to ER with clinical diagnosis of tetanus after a penetrating wound sole 15 days back. Regarding management of tetanus, what should be line of action?
Inquire about her immunization status of tetanus
Give tetanus toxoid irrespective of her immune status
Give her TIG as a management protocol
Reassure the relative as she does not need any immunization at present

20. MCQ What causes the major symptoms of tetanus?
Multiplication of the organisms at the site of infection
Production of botulin toxin
Super-infection due to antibiotic therapy
Bacteria multiplying in the bloodstream
Production of tetanospasmin