Tetanus

Question 1

Tetanus - cause

Answer 1

Clostridium tetani
Anaerobic gram positive
‘Drumstick’ appearance

Question 2

Tetanus - toxin

Answer 2

Only toxigenic C tetani causes tetanus. Tetanus toxin - similar structure to botulinum A
Toxin taken up through motor nerves, undergoes conformational changes to allow it to be retrogradely taken up into CNS - across synapse to GABAergic neurons - inhibiting leading to uncontrolled motor neuron discharge

Question 3

Tetanus - scoring score

Answer 3

Modified Ablett score
Grade 1-4
1 = no spasm
2 = mild short lived spasms - not interfering with respiration
3 = prolonged spams interfering with respiration
4 = grade 3 but autonomic dysfunction

Question 4

Tetanus - signs

Answer 4

Trismus = unable to open mouth
Risus sardonicus = sustained spasm of facial muscles
Opisthotonus = violent arching of back [ddx cerebral malaria in children]

Autonomic dysfunction - loss of preganglionic sympathetic neurons

Question 5

Tetanus - diagnosis

Answer 5

Clinical diagnosis - WHO definition
At least one of the following:
-Trismus
-Risus sardonicus
-Painful muscle contractions

NOT a microbiological diagnosis

Question 6

Tetanus - clinical forms

Answer 6

Generalised tetanus [80%]
Localised tetanus
Cephalic tetanus [IP = days] = lower cranial nerve muscles, facial palsy, pharyngeal/laryngeal spasms
Neonatal tetanus

Question 7

Tetanus - management

Answer 7

Support:
-Airway = tracheostomy
-Muscle spasm control = BZD, chlorpromazine, mg sulphate
-Environment control = minimise light, sounds, stimulus

Turn off toxin:
-Neutralise toxin = human hyperimmune globulin or anti-tetanus globulin [equine]
-Source control =debridement
-Antibiotic = metronidazole

Complications:
-Autonomic dysfunction = labetalol, mg sulphate

Question 8

Tetanus - prevention

Answer 8

Vaccinate:
-Patient will not have natural immunity following infection
-[WHO] - primary course - 3 doses TTCV [Tetanus toxoid containing vaccine] plus 3 boosters

If complete vaccination - no additional booster or passive immunisation

If incomplete vaccination - booster, and passive immunisation [if v high risk]

If incomplete primary course - booster and passive immunisation [if wound not clean]

Question 9

Tetanus - elimination

Answer 9

Elimination defined as <1 NNT case per 1,000 live births in every district per year

Question 10

Tetanus - disease complications

Answer 10

Bone fractures
Rhabdomyolysis [renal failure]
Persistent rigidity
Nosocomial infection
Pulmonary embolisms
Pressure sores
Memory loss