Tetanus

 

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