Dystonia, or uncontrollable involuntary muscle contraction, is the third most common disorder seen by movement specialists and affects approximately 300,000 people in North America, according to the Dystonia Medical Research Foundation. Dystonia has a wide range of manifestations and can vary considerably in severity. For instance, one individual with dystonia may only have a twitching eyelid, while another may suffer contracture and spasms of multiple limbs. There is no single cause of dystonia -- many times the etiology of the disease is unknown. However, calcium deficiency has been implicated in at least one type of dystonia.
Dystonia
Dystonic spasms are caused by the inability of muscles to relax, activation of opposing muscle groups or activation of muscles not needed for a given movement. Though dystonia has a wide variety of manifestations, affected individuals can be broadly categorized into four groups depending on the disordered part of the body. In individuals with focal dystonia, only one isolated region of the body is involved. For instance, blephorospasm is a type of focal dystonia that causes involuntary contracture of the eyelid. Individuals who have two adjacent disordered regions are said to have segmental dystonia. With multifocal dystonia, multiple non-contiguous regions of the body are affected. Individuals with generalized dystonia have large regions of the body that exhibit involuntary muscle contraction.
Diagnosis
Unfortunately, there is no one test that will confirm a dystonia diagnosis. Correct diagnosis depends on your physician's ability to observe symptoms and put together a complete family and patient history. Your physician may also request blood work, imaging studies, genetic testing and other screening tests.
Cause
Different types of dystonia have different etiologies, and unfortunately, the cause for many types is not well understood. Sometimes dystonia is a symptom of some other disease. For instance, dystonia is frequently a symptom of the degeneration associated with Parkinson's disease. Other types of dystonia appear to be inherited, which makes family history critical for correct diagnosis.
Calcium
Hypocalcemia, a metabolic condition in which there is too little serum calcium, may cause paroxysmal dystonia, according to Medscape. Paroxysmal means that the uncontrolled muscle contractions happen during episodes, between which muscular contraction and movement are normal. The hypocalcemia is itself a symptom of idiopathic hypoparathyroidism, which involves a decrease in the amount of hormones produced by the parathyroid glands in the neck.
References
- John Hopkins Medicine: Dystonia
- Dystonia Medical Research Foundation: Dystonia Defined
- MayoClinic.com; Dystonia; March 2010
- Medscape; Movement Disorders Caused by Medical Disease: Dystonia; Brandon Barton, et. al.; 2009
- Cleveland Clinic; Hypocalcemia; Mario Skugor, M.D.
- Medical Dictionary: Hypoparathyroidism
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