2 Tetanus Flashcards
how does tetanospasmin work
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
incubation period of tetanus
ranges from <24 hours to >1 month
characteristic facial expression in tetanus
risus sardonicus (sardonic smile)
remarks on tetanus
mental status is normal, an important consideration in differentiating tetanus from other disorders
remarks on autonomic dysfunction and hypersympathetic state in tetanus
occur during the second week of clinical generalized tetanus
include tachycardia, labile hypertension, profuse sweating, hyperpyrexia
most closely mimics the clinical picture of generalized tetanus
Strychnine poisoning
remarks regarding immunity from tetanus
The disease does not result in immunity
remarks on respiratory compromise in tetanus
Respiratory compromise requires immediate neuromuscular blockade and intubation
remarks on tetanus immunoglobulin
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
antibiotic therapy in tetanus
metronidazole 500mg IV every 6 hours
Penicillin can theoretically potentiate the effects of tetanospasm
summary of treatment of tetanus
- Respiratory management
- Immunotherapy
- Wound care
- Antibiotic therapy
- Muscle relaxation
- Management of autonomic dysfunction
possible management options for autonomic dysfunction
Magnesium sulfate
Labetalol
Morphine sulfate
Clonidine
dosing of magnesium sulfate
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
remarks on morphine
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
tetanus vaccine of choice based on age
<7 y/o: DTaP (diphtheria and tetanus toxoids and acellular pertussis vaccines
≥7 y/o: Td (tetanus diphteria)
Because of recent increase in the incidence of pertussis, adults should receive a single lifetime dose of
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
tetanus immunization in pregnancy
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
tetanus immunization in the immunocompromised
Patients with HIV infection or severe immunodeficiency who have contaminated wounds should also receive tetanus immunoglobulin, regardless of their tetanus immunization history
Examples of dirty wounds
wounds >6 hours old
contaminated with soil, saliva, feces, or dirt
puncture or crush wounds
avulsions
wounds from missiles, burns, or frostbite
primary immunization of tetanus
3 doses total
day 0, 4 weeks, 6 months
what to give in:
clean wounds
with unknown or in incomplete tetanus vaccination
Td or Tdap only
what to give in:
clean wounds
with complete tetanus vaccination
None
BUT, if last dose was >10 years, give Tdap/Td
what to give in:
dirty wounds
with unknown or incomplete tetanus vaccination
Td or Tdap
AND TIG
what to give in:
diry wounds
with complete tetanus vaccination
None
BUT, if last dose was >5 years, give Tdap/Td
exaggerated local reactions in tetanus immunization
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
when to give tetanus immunoglobulin?
in dirty wounds AND with unknown or incomplete tetanus vaccination
Remarks on serum antitoxin titers
Serum antitoxin titers >0.01 IU/mL are usually protective
