Thursday, November 20, 2014



Facial spasm and risus sardonicus 

Tetanus is a life-threatening illness manifested by muscle rigidity and spasms; it is caused by a neurotoxin (tetanospasmin) produced by Clostridium tetani.

● Trismus (“lockjaw”)
● Risus sardonicus (“peculiar grin”), characteristic grimace that results from contraction of the facial muscles (Fig.)
● Generalized muscle spasms causing severe pain and, at times, respiratory compromise and death
● Rigid abdominal muscles, fl exed arms, and extended legs
● Autonomic dysfunction several days after onset of illness
● Leading cause of death: fl uctuations in heart rate and blood pressure
● Usually, absence of fever
● Localized tetanus

1. Rigidity of muscles near the injury
2. Weakness as a result of lower motor neuron injury
3. May be self-limited and resolve spontaneously
4. More often progresses to generalized tetanus
5. Cephalic tetanus:
a. May occur with head injuries or chronic otitis with localized ear or mastoid infection with C. tetani
b. Can manifest as cranial nerve dysfunction

● C. tetani is a gram-positive, spore-forming bacillus that resides primarily in the soil.
● Majority of cases are caused by punctures and lacerations.
● Toxin is elaborated from organisms in a contaminated wound.
● Local symptoms are caused by inhibition of neurotransmitter at presynaptic sites.

1. Over the next 2 to 14 days, the toxin travels up the neurons to the CNS, where it acts on inhibitory neurons to prevent neurotransmitter release.
2. Unopposed motor activity results in tonic contractions of muscles.

● Strychnine poisoning
● Dystonic reaction caused by neuroleptic agents
● Local infection (dental or masseter muscle) causing trismus
● Severe hypocalcemia
● Hysteria

● Positive wound culture is not helpful in diagnosis.
● Isolation of organism is possible in patients without the illness.

● Usually, normal blood counts and chemistries
● Toxicology of serum and urine to rule out strychnine poisoning

● Monitoring in a hospital ICU: keep surroundings dark and quiet
● Intubation or tracheostomy for severe laryngospasm
● Débridement of wound
● Human tetanus immunoglobulin (HTIg) via IM injection
● Tetanus toxoid (Td) by IM injection at a different site
● Metronidazole or penicillin G IV
● IV diazepam to control muscle spasms
● Neuromuscular blockade if necessary


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