Tetanus (quick review)

14 Feb

 -Caused from Clostridium tetani, a nonencapsulated anaerobic gram positive rod 

-Exist in either spore forming or vegetative state

 

-Once converted into vegetative form, it produces two exotoxins

1.  tetanolysin,  which helps spread the bacteria

2.  Tetanospasmin, responsible for clinical manifestations of tetanus

 

Effects of tetanospasmin:  

Acts on the motor end plates of skeletal muscle,

preventing the release of the inhibitory neurotransmitters glycine and GABA from presynaptic nerve terminals,

preventing normal inhibitory control of nervous system

 

-Overall features:  muscular rigidity, muscle contractions, autonomic nervous system instability

Incubation period is <24 hours to more than 1 month

 

-Types of Tetanus:

                1.  Generalized Tetanus

-Most common form (80% of cases)

Masseter muscle stiffness/pain (Lockjaw) most common complaint

-Shorter axon nerves affected first (facial muscles), with descending progression of the neck, trunk, extremities

-Transition of stiffness to rigidity leads to trismus and characteristic facial expression (risus sardonicus).

-Generally get dysphagia, arm flexing, wrist clenching, and lower extremity extension. 

-Autonomic disturbances include labile hypertension, hyperpyrexia, tachycardia, increased catecholamine release

                2.  Neonatal tetanus

-Frequently occur after unsterile treatment of umbilical cord stump with inadequately immunized mothers

-Generally present as weak, unable to suck, and irritable during 2nd week of life

                3.  Cephalic tetanus

                                -Generally occurs after head wounds

                                -Present with cranial nerve dysfunctions, traditionally cranial nerve 7

                4.  Local tetanus

                                -Rigidity of muscles near site of injury

                                -Resolves after weeks to months

-Diagnosed clinically

 

Treatment:

1.  Tetanus immunoglobulin– neutralizes circulating tetanospasmin.  Unknown dose needed but 3000 to 6000 units IM is recommended.  GIVE BEFORE WOUND DEBRIDEMENT .  Lasts in your system for 28 days so no need to repeat dosing

2.  Wound debridement- prevent further toxin production

3.  Metronidazole traditionally administered. 

4.  Muscle relaxants

5.  Autonomic dysfunction- Magnesium sulfate has been shown to decrease catecholamine release.  Labetalol can also be used.

6.   Active immunization- give them a TDAP

 

Submitted by Joey Grover.

 

Sources: Tintinalli’s Emergency Medicine:  7th Edition; Rosen’s Emergency Medicine:  7th Edition; picture

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