Definition
Acute disease
- characterised by generalized rigidity & convulsions
- caused by exotoxins/neurotoxins produced in Clostridia Tetani infections
Epidemiology
Annual world mortality is 1 million
West 15-100/year
Aetiology / Pathology
Clostridium Tetani
- anaerobic
- spore-bearing Gram positive Bacillus
Spores
- drumstick appearance
- in faeces, dust & soil, manure
- especially hot damp climates
- resistant to antiseptics & heat
Infection
- occurs when spores enter tissues & produce vegetative forms
- entry through puncture / laceration
Tetanospasmin
- exotoxin released when vegetative bacteria lysed in wound
- potent neurotoxin
- spreads to CNS via PNS / BV / lymphatics
- blocks inhibitory pathways to cord
- muscle rigidity with paroxysmal spasms or convulsions result
Tetanolysin / haemolysin
Tetanus-Prone Wound
Open fractures
Puncture >1cm
Foreign Body
Contamination / Tissue damage
Bite
Ischaemic / denervated tissue
Crush / burn / frostbite
Prophylaxis
Active Primary Immunization
- Tetanus Toxoid
- Triple antigen / Diphtheria-Tetanus-Pertussis / ADT
Children
- Triple Antigen at 2, 4 & 6 /12
- ADT at 18 /12 & 5 years
Adult
- for those never immunised
- 3 courses of TT
- 6-12 /7 between 1st & 2nd
- 6-12/12 between 2nd & 3rd
Booster
- ADT booster every 10 years
- if more than 20 years since booster, 2 boosters with 4-6/52 interval
After Injury 2° Prophylaxis
- if immunised, ADT will produce protective AB in 1/7
- if patient not immune full TT course
Passive Immunisation
- TIG / Tetanus Immuglobulin
- solution of Gamma-Globulin fraction of donated plasma
- give in tetanus-prone wounds in non immune patient
Clinical
Mean incubation 1 / 52
- can be up to 2 months
- rapid onset = severe
Pain & stiffness
- Jaw / Abdo / Back
Difficulty swallowing
Generalised rigidity
- spinal extension & neck retraction
- upper limb flexion / lower limb extension
Clenched teeth expression / Trismus or lockjaw
Reflex spasms
- 2° external stimuli (eg. Noise)
Glottic spasms = Arrest
Sympathetic dysfunction
- HT, tachycardia, sweating
- arrhythmias, Ileus
Prognosis
60 % die in 2/52
- spasms disappear by 1-3 /52
- if survive, recover by 6 /52
- respiratory compromise is major cause of death
Investigations
No specific tests
C. Tetani cultured in one third of wounds
Management Tetanus
1. Wound care
- debride necrotic & contaminated tissue
2. Penicillin G
- tetanus spores destroyed by AB
- vegetative form sensitive to AB
- 2 Million units q6h for 10/7
3. Antitoxin
- a more concentrated TIG for treating clinical tetanus
- neutralises circulating toxin
- doesn't affect toxins already fixed in CNS
4. Other
Spasms control
Quiet dark room
Diazepam
Consider thiopental infusion
Care of airway (may need ventolation)
Hydration & nutrition