Ehlers-Danlos Syndrome and Chiari Malformation: What’s the Connection?

The most common form of Ehlers-Danlos syndrome (EDS type 3) occurs in an estimated 1 in 5,000 people, according to Medline Plus. It is a genetic disorder that affects connective tissues throughout the body. The pain of EDS varies from mild to extreme, but can become chronic over time and require lifelong physical therapy as well as surgical and pharmacological treatment. There are many types of EDS, which may have multiple comorbid conditions. For instance, some individuals with EDS type 3 also have a hindbrain herniation called Chiari malformation (CM). Some research suggests that having EDS may dispose people to developing an acquired form of Type I CM that can be difficult to manage appropriately even with advanced surgical intervention.

Genetics and Birth Defects
While EDS develops before birth, CM in EDS patients can be acquired later in life as a result of the unstable connective tissues throughout the neck and spine pulling the brain downward. Cranio-cervical Instability (CCI) and Tethered Cord Syndrome (TCS) are features found regularly in EDS patients that may contribute to the occurrence or severity of the CM. EDS is considered an inherited disorder because it is caused by genetic mutations that affect collagen. Collagen is a building block of proteins that gives connective tissues their strength. According to the Lister Hill National Center for Biomedical Communication, the following gene mutations may lead to EDS:

· COL1A1 and COL1A2
· COL3A1
· COL5A1 and COL5A2
· ADAMTS2
· TNXB
· PLOD1

Although CM may indeed have a genetic component in the congenital form, the only genetic link in the acquired form is the presence of connective tissue disorders like EDS. While considered an uncommon disorder, CM typically appears during childhood or early adulthood, although symptoms can surface at anytime and may be triggered or exacerbated by accidents, falls or blows to the head. During this stage of development, CM can become apparent because the skull cannot adequately contain the cerebellum and this crowding at the base of the skull can disrupt the essential flow of cerebral spinal fluid (CSF), as well as impinge important nerves and even disrupt blood flow. While CM is largely considered a congenital condition by most neurosurgeons, there is a growing body of evidence that it runs in families, just like EDS, and furthermore, that people with EDS may be predisposed to developing CM, although they were not necessarily born with the CM as a congenital abnormality.

Similarities and Differences in Pain
Perhaps the biggest similarity between EDS and CM is chronic pain. People with EDS are often misconceived as being clumsy or as having imaginary pain because of the fact that they may look completely healthy on the outside. The reality is that the range of pain spans from mild to severe, but can occur anywhere along the body where connective tissues are present. If you suffer from EDS, you may bruise easily and have unusual scars after a wound heals. Your skin may be unusually stretchy, and you might have prominent, visible blood vessels. EDS is also known for causing joint pain and frequent joint dislocations and subluxations throughout the body, which can necessitate the need for joint bracing and careful physical therapy to retain independence and mobility.

CM causes several different types of chronic pain, including a severe characteristic headache at the base of the skull, as well as pain throughout the neck, spine, and throat. It can also trigger severe nerve pain throughout the body. Individuals afflicted with CM may experience serious neurological deficits, trouble swallowing, tinnitus, vision disturbances and balance disruption that can lead to trouble walking and/or clumsiness.

Does EDS Cause CM?
Several studies suggest there is a complex connection between the two disorders that goes beyond the typical “cause and effect” association. According to the Hypermobility Syndromes Association, the causes of CM in a patient with EDS may be different than those in a patient without EDS. Furthermore, EDS patients seem to be more prone to Type 1 CM, which is the most common form of the disorder. The Association reports that a study of 2,813 Type 1 CM patients found that about 357 of them also had EDS symptoms.

More studies are needed to determine precisely how EDS causes CM. The only way to accurately determine the severity and cause of your condition/s is to seek appropriate testing and evaluation from a team of specialized medical professionals including neurologists, neurosurgeons and geneticists. EDS Type 3 can be diagnosed by a geneticist who administers a Beighton Scale Test while CM can be diagnosed by a neurologist or neurosurgeon through an MRI of the brain and cervical spine, preferably an upright MRI in those with suspected connective tissue disorders. Ideally, you should also seek out a doctor that specializes in chronic pain disorders to help manage the daily pain since medical testing isn’t the only assessment of pain disorders.

Kristeen Cherney is a freelance health and lifestyle writer who focuses on preventive measures for a better quality of life. Cherney holds a BA in Communication, and is currently finishing her MA in English.

Resources
· Chiari Malformation (2013, August 21). Retrieved from http://www.mayoclinic.org/diseases-conditions/chiari-malformation/basics/definition/con-20031115
· Chiari Malformation and EDS (2014, April 15). Retrieved from http://hypermobility.org/help-advice/chiari-malformation-eds/
· Ehlers-Danlos Syndrome (n.d.). Retrieved from http://www.nlm.nih.gov/medlineplus/ehlersdanlossyndrome.html
· Ehlers-Danlos Syndrome Myths and Facts (2009). Retrieved from http://www.ehlersdanlosnetwork.org/myths-facts.html
· What is Ehlers-Danlos Syndrome? (2006, May). Retrieved from http://ghr.nlm.nih.gov/condition/ehlers-danlos-syndrome
· Underlying Causes of Dysautonomia
http://www.dysautonomiainternational.org/page.php?ID=150