Tetany

Tetany ( gr τέτανος tétanos, voltage ') is the motor disorder ( spasmodic ) and sensitivity (tingling ) as a sign of hyperexcitability of the nerves and muscles. In extreme cases, it is a painful muscle spasm.

Cause

The cause is usually a lack of calcium in the blood ( hypocalcemia ).

Calcium ( II) ions have a membrane potential -stabilizing effect, which is mediated by interaction with the voltage regulated sodium channels. This is so stated that the Ca2 ions " clog " the channel commonly. Be correct, but there is a conformational change of the channel, making it less easily activated. The bound on the Na channel Ca2 ions associated with the "free" (ie not bound to plasma proteins ) Ca2 ions in equilibrium.

Symptoms

• In the hypocalcemic tetany occurs tetanic seizures with anxious restlessness, numbness, paresthesia, and muscle spasms, including also blepharospasm.

Clinic

Chvostek and Trousseau signs are positive. The patient has usually a kind of " paws " position one and / or both hands and arms.

Classification

Hypocalcemic tetany

There is a drop of the total calcium in the plasma; the ions diffuse from the Na - channels and an action potential can now be triggered easily. On the muscles which leads to convulsions, even at rest, such as during sleep. The excessive excitability of sensory nerves is perceived as tingling.

Normokalzämische tetany

The total calcium ( free plus bound Ca2 ) in the plasma remains constant; However, there will be a greater Ca2 binding to the plasma proteins. This can be caused alkalosis (for example, hyperventilation, one then also speaks of a Hyperventilationstetanie ).

Psychogenic tetany

In psychiatry, dissociative seizures are also known as psychogenic tetany. This can in extreme cases lead to epilepsy -like manifestations.

Veterinary Medicine

A particular disease in ruminants is the grass tetany.