EM Infectious 4 - Tetanus

Question 1

how does tetanospasmin work

Answer 1

it prevents the release of the inhibitory neurotransmitters glycine and GABA from presynaptic nerve terminals, releasing the nervous system from its normal inhibitory control

Loss of inhibition may also affect the preganglionic sympathetic neurons, resulting in sympathetic overactivity and high circulating catecholamine levels

Question 2

incubation period of tetanus

Answer 2

ranges from <24 hours to >1 month

Question 3

characteristic facial expression in tetanus

Answer 3

risus sardonicus (sardonic smile)

Question 4

remarks on tetanus

Answer 4

mental status is normal, an important consideration in differentiating tetanus from other disorders

Question 5

remarks on autonomic dysfunction and hypersympathetic state in tetanus

Answer 5

occur during the second week of clinical generalized tetanus

include tachycardia, labile hypertension, profuse sweating, hyperpyrexia

Question 6

most closely mimics the clinical picture of generalized tetanus

Answer 6

Strychnine poisoning

Question 7

remarks regarding immunity from tetanus

Answer 7

The disease does not result in immunity

Question 8

remarks on respiratory compromise in tetanus

Answer 8

Respiratory compromise requires immediate neuromuscular blockade and intubation

Question 9

remarks on tetanus immunoglobulin

Answer 9

as postexposure prophylaxis
single dose of 250 units (4 units/kg in children) IM given in aterolateral thigh or deltoid

as treatment of clinical tetanus:
3000-6000 units iM

Give tetanus immunoglobulin before wound debridement because exotoxin may be released during wound manipulation

Question 10

antibiotic therapy in tetanus

Answer 10

metronidazole 500mg IV every 6 hours

Penicillin can theoretically potentiate the effects of tetanospasm

Question 11

summary of treatment of tetanus

Answer 11

1. Respiratory management
2. Immunotherapy
3. Wound care
4. Antibiotic therapy
5. Muscle relaxation
6. Management of autonomic dysfunction

Question 12

possible management options for autonomic dysfunction

Answer 12

Magnesium sulfate
Labetalol
Morphine sulfate
Clonidine

Question 13

dosing of magnesium sulfate

Answer 13

40 mg/kg IV loading dose, then 2 g/hour (1.5 g/h if ≤45 kg) continuous infusion to maintain blood level of 2.0 to 4.0 mmol/L

Question 14

remarks on morphine

Answer 14

Morphine sulfate reduces sympathetic a-adrenergic tone and central sympathetic efferent discharge and produces peripheral arteriolar and venous dilatation

dose: 0.5-1 mg/kg/h

Question 15

tetanus vaccine of choice based on age

Answer 15

<7 y/o: DTaP (diphtheria and tetanus toxoids and acellular pertussis vaccines

≥7 y/o: Td (tetanus diphteria)

Question 16

Because of recent increase in the incidence of pertussis, adults should receive a single lifetime dose of

Answer 16

Tdap (tetanus toxoid with lower doses of diphtheria and acellular pertussis thant DTaP) to replace one Td booster

An inadvertent dose of DTaP in an adult would count as the single lifetime dose of Tdap

Question 17

tetanus immunization in pregnancy

Answer 17

administer a dose of Tdap during each pregnancy, irrespective of the patient’s prior history of receiving Tdap or interval since last injection, to maximize the maternal antibody response and passive antibody levels in the newborn.

Tdap may be given at any point during pregnancy, with optimal timing between 27 and 36 weeks of gestation unless treating a specific wound

For women who have never received Tdap, it should be given to the mother immediately postpartum

Question 18

tetanus immunization in the immunocompromised

Answer 18

Patients with HIV infection or severe immunodeficiency who have contaminated wounds should also receive tetanus immunoglobulin, regardless of their tetanus immunization history

Question 19

Examples of dirty wounds

Answer 19

wounds >6 hours old
contaminated with soil, saliva, feces, or dirt
puncture or crush wounds

avulsions
wounds from missiles, burns, or frostbite

Question 20

primary immunization of tetanus

Answer 20

3 doses total
day 0, 4 weeks, 6 months

Question 21

what to give in:
clean wounds
with unknown or in incomplete tetanus vaccination

Answer 21

Td or Tdap only

Question 22

what to give in:
clean wounds
with complete tetanus vaccination

Answer 22

None
BUT, if last dose was >10 years, give Tdap/Td

Question 23

what to give in:
dirty wounds
with unknown or incomplete tetanus vaccination

Answer 23

Td or Tdap
AND TIG

Question 24

what to give in:
diry wounds
with complete tetanus vaccination

Answer 24

None
BUT, if last dose was >5 years, give Tdap/Td

Question 25

exaggerated local reactions in tetanus immunization

Answer 25

Arthus reactions
- occur occasionally and involve extensive pain and swelling of the entire extremity
- occur most often in adults with high serum tetanus antitoxin levels who have received frequent doses of tetanus toxoid, whic is the reason thies therapy is limited to 10-year intervals

Question 26

when to give tetanus immunoglobulin?

Answer 26

in dirty wounds AND with unknown or incomplete tetanus vaccination