TETANUS
Assist Prof Microbiology
College of Medicine, Majmaah
University
LEARNING OBJECTIVES
1. Explain etiology, pathogenesis and
mechanism of transmission
2. Discuss the mechanism of action of tetanus
toxin
3. Discuss the role of immunization in primary
and secondary prevention of tetanus
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
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
VIDEO TETANUS INTRODUCTION
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 tetanuscontaminated equipments to
cut umbilical cord
• African nation-ritual of
putting animal dung on
umbilical stump
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
TETANUS-PATHOGENESIS
• Incubation Period- 3-21
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
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
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
VIDEO NEUROTRANSMISSION
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)
VIDEO NEONATAL TETANUS
TETANUS PREVENTION
PRIMARY PREVENTION
A. PREGNANT LADIES
– Tdap between 27 & 36 weeks
B. NEWBORNS
– DTaP -2,3,4 months
C. PRE-SCHOOL (3-5 years)
– DTaP booster
D. ADULTS(13-18 years)
– Single Td booster
E. ADULTS >19 Years not received
Tdap &
F. PERSON >65 Years-should get
Tdap
TETANUS PREVENTION
SECONDARY PREVENTION
IMMUNIZATION
STATUS
FULLY
IMMUNIZED
NOT IMMUNIZED
OR INCOMPLETE
Minor wound
No immunization
Active immunization
with tetanus toxoid
Tetanus prone wound
Tetanus
Immunoglobulins
(TIG) single dose
Tetanus toxoid & TIG
TETANUS TREATMENT
1. Wound debridement
2. Antimicrobial therapy: Metronidazole preferred over
Penicillin G
3. Penicillin G -structurally similar to GABA and competitively
antagonizes this neurotransmitter
4. Management of clinical tetanus: Human tetanus
immunolobulin (TIG)
5. General supportive management e.g. airway management,
physiotherapy etc.
6. Spasmolytics
MCQ
Tetanus
1.
2.
3.
4.
5.
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
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?
1.
2.
3.
4.
Tetanus toxoid only
Tetanus toxoid and TIG
TIG only
Neither Tetanus toxoid nor TIG
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?
1. Inquire about her immunization status of tetanus
2. Give tetanus toxoid irrespective of her immune
status
3. Give her TIG as a management protocol
4. Reassure the relative as she does not need any
immunization at present
MCQ
What causes the major symptoms of tetanus?
1.
2.
3.
4.
5.
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