Difference between revisions of "Myotonia"

From WikiVet English
Jump to navigation Jump to search
m (New page: {{toplink |backcolour = E0EEEE |linkpage = Nervous System - Pathology |linktext =Nervous System |maplink = Nervous System (Content Map) - Pathology |pagetype =Pathology }} <br>)
 
Line 7: Line 7:
 
}}
 
}}
 
<br>
 
<br>
 +
==Myotonia==
 +
 +
* Myotonia is the term given to sustained muscle contraction.
 +
* Myotonia may be congenital or acquired.
 +
 +
===Congenital===
 +
 +
* Myotonia congenita is caused by an ion channel defect.
 +
* Certain breeds of dogs are predisposed to myotonia congenita.
 +
** Chow chow
 +
*** The condition is caused by a defect in the sodium channel.
 +
** Schnauzer
 +
*** The condition is caused by a defect in the chloride channel.
 +
 +
====Clinical Signs====
 +
 +
* Stiffness is present from birth.
 +
** Signs improve with exercise.
 +
* Hypertrophy of the [[Oral Cavity - Tongue - Anatomy & Physiology|tongue]] and appendicular muscles.
 +
* Percussion dimple formation
 +
* Biopsy results may:
 +
** Be normal, or
 +
** Show type 1 fibre predominance or hypertrophy.
 +
 +
====Treatment====
 +
 +
* Exercise avoidance.
 +
* Drugs:
 +
** Metilxantine
 +
** Procainamide
 +
 +
===Acquired===
 +
 +
* Acquired myotonia may be caused by:
 +
** Herbicides
 +
*** For example, (2,4-D) and dicamba.
 +
** Hyperadrenocorticoidism
 +
*** This may be natural (i.e. increased endogenous steroid production), or iatrogenic (i.e. prolonged corticosteroid administration).

Revision as of 10:58, 18 August 2008

WikiPathWikiPath Banner.png
()Map NERVOUS SYSTEM (Map)



Myotonia

  • Myotonia is the term given to sustained muscle contraction.
  • Myotonia may be congenital or acquired.

Congenital

  • Myotonia congenita is caused by an ion channel defect.
  • Certain breeds of dogs are predisposed to myotonia congenita.
    • Chow chow
      • The condition is caused by a defect in the sodium channel.
    • Schnauzer
      • The condition is caused by a defect in the chloride channel.

Clinical Signs

  • Stiffness is present from birth.
    • Signs improve with exercise.
  • Hypertrophy of the tongue and appendicular muscles.
  • Percussion dimple formation
  • Biopsy results may:
    • Be normal, or
    • Show type 1 fibre predominance or hypertrophy.

Treatment

  • Exercise avoidance.
  • Drugs:
    • Metilxantine
    • Procainamide

Acquired

  • Acquired myotonia may be caused by:
    • Herbicides
      • For example, (2,4-D) and dicamba.
    • Hyperadrenocorticoidism
      • This may be natural (i.e. increased endogenous steroid production), or iatrogenic (i.e. prolonged corticosteroid administration).