Disorder - Myotonia

Organ Systems Involved
Musculoskeletal

Alternative Names
Myotonic Myopathy

Brief Description

Congenital myotonia is a muscle disorder in which overexcitable muscle cell membranes cause sustained contraction and delayed relaxation of muscle, which results in lack of muscular control.

Presenting Signs

The clinical signs of myotonia first become evident when the puppy begins to walk. Myotonia is characterised by general muscle stiffness and muscular spasms, and delayed relaxation of muscle. Affected dogs will have stiff limbs and will experience difficulty in rising and walking, and may waddle, 'bunny-hop' (run moving both hind legs forward together) or fall over. Muscle stiffness may decrease with exercise. A localised contraction of muscle will appear as a dimple when the muscle is tapped. are made worse by cold weather and excitement. The skeletal muscles are often greatly enlarged. Other signs include tongue protrusion, an arched back, extended hips, extended stifles and hocks, excessive panting, vomiting, coughing and gagging, difficulty in opening the jaw, episodes of breathlessness lasting for several minutes, and diarrhoea. Myotonia may also cause the third eyelids to cover the eyes for prolonged periods. Affected dogs have normally functioning mental activity and normal perception of body movement and position."

Treatment

Medical

Related Disorders

Hyperadrenocorticism
Hypothyroidism

PubMed References
Myotonia

Further Reference Material [OMIA Number]
698


Contributor
Elisabeth Range