Changes

==Tetanus==

==Tetanus==

* In a pathological context, '''"tetanus" is an infectious disease caused by the bacterium [[Clostridium species#Clostridium tetani|''Clostridium tetani'']]'''.

* In a pathological context, '''"tetanus" is an infectious disease caused by the bacterium [[Clostridium tetani|''Clostridium tetani'']]'''.

** Physiologically, the term "tetanus" refers to continuous sustained muscle contraction.

** Physiologically, the term "tetanus" refers to continuous sustained muscle contraction.

*** The disease caused by [[Clostridium species#Clostridium tetani|''Clostridium tetani'']] is characterised by this feature.

*** The disease caused by [[Clostridium tetani|''Clostridium tetani'']] is characterised by this feature.

===Pathogenesis===

===Pathogenesis===

* [[Clostridium species#Clostridium tetani|''Clostridium tetani'']] generally cause infection via wound contamination.

* [[Clostridium tetani|''Clostridium tetani'']] generally cause infection via wound contamination.

** Cuts or deep puncture wounds are most commonly infected.

** Cuts or deep puncture wounds are most commonly infected.

* [[Clostridium species#Clostridium tetani|''Clostridium tetani'']] produces tetanospasmin, a neurotoxin.

* [[Clostridium tetani|''Clostridium tetani'']] produces tetanospasmin, a neurotoxin.

** Tetanospasmin inhibits the release of the neurotransmitters GABA and glycine from interneurons in the spinal cord and brain.

** Tetanospasmin inhibits the release of the neurotransmitters GABA and glycine from interneurons in the spinal cord and brain.

* Without the usual inhibitory influence of glycine and GABA, there is increased excitation of the brainstem and motor neurons.

* Without the usual inhibitory influence of glycine and GABA, there is increased excitation of the brainstem and motor neurons.

** Metronidazole

** Metronidazole

*** Treatment with metronidazole decreases the number of bacteria but has no effect on the bacterial toxin.

*** Treatment with metronidazole decreases the number of bacteria but has no effect on the bacterial toxin.

*** Metronidazole is particularly active against anaerobic bacteria, and so is a good choice for use against [[Clostridium species#Clostridium tetani|''C. tetani'']]

*** Metronidazole is particularly active against anaerobic bacteria, and so is a good choice for use against [[Clostridium tetani|''C. tetani'']]

** Penicillin

** Penicillin

*** Penicillin is becoming a less favoured treatment for tetanus, since there is a theoretical risk of increased spasms.

*** Penicillin is becoming a less favoured treatment for tetanus, since there is a theoretical risk of increased spasms.