Haitian Child

Haitian Child

Sunday, December 13, 2015

Tetanus in Haiti

Haiti is the only country in the Western Hemisphere where neonatal tetanus has not been eliminated. 

Clostridium tetani is a bacteria that forms spores that are resistant to heat, desiccation, and disinfectants. The bacteria is found in soil, house dust, animal intestines, and human feces.

To germinate, the spores require specific anaerobic conditions such as wounds with dead or devitalized tissue or a foreign body. The source of infection is often a minor wound such as a wood or metal splinter, or a thorn. Stepping on a nail is a common antecedent injury. Once the spores germinate, the typical symptoms are caused by a toxin that is released from the spores.

Tetanospasmin is the toxin responsible for the symptoms. By weight this toxin is one of the most potent known. The estimated lethal dose is only 2.5 nanograms per kg body weight!

Tetanus usually presents with the acute onset of hypertonia, painful muscular contractions of the muscles of the jaw and neck, and generalized muscle spasms without any other apparent medical cause.

Generalized tetanus usually presents with trismus (lockjaw), which is the inability to open the mouth secondary to masseter muscle spasm. Risus sardonicus, the scornful smile of tetanus, results from facial muscle involvement. Localized tetanus presents with persistent rigidity in a muscle group close to the injury site. 

The "spatula test" is a simple diagnostic bedside test that involves touching the back of the throat with a tongue depressor. In a normal individual this should elicit a gag reflex and the patient should try to expel the tongue depressor. In a person with tetanus, the patient develops reflex spasm of the jaw muscles and bites the tongue depressor.

In countries without a comprehensive immunization program, tetanus mostly develops in neonates and young children. 

Neonatal tetanus results from umbilical cord contamination during delivery. The risk factors for neonatal tetanus include an unvaccinated mother, home delivery, unhygienic cutting of the umbilical cord, a history of neonatal tetanus in a previous child, and application of a potentially infected substance to the umbilical stump (mud, clarified butter).

At the end of the first week of life, infected infants become irritable, suck and feed poorly, and develop facial grimacing and severe spasms and rigidity precipitated by touch. Mortality with neonatal tetanus exceeds 70%.

Antimicrobials are used to reduce the number of bacteria and production of the toxin. Metronidazole has superseded penicillin as the drug of choice. 

Passive immunization with human tetanus immune globulin (3,000-6,000 units as 1 dose) shortens the course of tetanus and might lessen its severity.

Once the tetanospasmin becomes fixed to nerve cells, the toxin cannot be neutralized by tetanus immune globulin. Recovery of nerve function requires the formation of new nerve terminals and the formation of new synapses. Recovery is slow and usually occurs over 2 to 4 months. 


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