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, 09:52, 30 June 2010
* 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.
*** The disease caused by [[Clostridium tetani|''Clostridium tetani'']] is characterised by this feature.
===Pathogenesis===
* [[Clostridium tetani|''Clostridium tetani'']] generally cause infection via wound contamination.
** Cuts or deep puncture wounds are most commonly infected.
* [[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.
* Without the usual inhibitory influence of glycine and GABA, there is increased excitation of the brainstem and motor neurons.
** This leads to unopposed muscle contraction.
*** The frequency of action potentials at the neuromuscular junctions increases above a threshold.
*** Above this threshold, muscle fibres enter a state of tetanus.
**** Muscle spasm is initially present in the muscles of the jaw.
**** This is followed by a difficulty in [[Deglutition|swallowing]].
**** General muscle stiffness and spasms then develop in other parts of the body.
** Other effects may include:
*** Seizures
*** Effects on the autonomic nervous system
===Diagnosis===
* Diagnosis is made by taking into account the animal's:
** History
** Clinical signs
* Very rarely a wound where the bacteria may have entered may be seen.
===Treatment===
* Wound debridement
** Surgical removal of dead and infected tissue from the wound.
* Antibiotic treatment.
** Metronidazole
*** 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 tetani|''C. tetani'']]
** Penicillin
*** Penicillin is becoming a less favoured treatment for tetanus, since there is a theoretical risk of increased spasms.
* Muscle relaxants
** Diazepam
** Midazolam
* Supportive therapy, for example:
** Administering fluids
** Providing appropriate nutrition
** Maintaining a quiet environment with dimmed light.
* Remission take several weeks to months
[[Category:To_Do_-_Clinical]]