What are the symptoms?

Because Chiari involves the nervous system, symptoms can be numerous and varied.  In fact, one large study showed that the vast majority of Chiari patients reported 5 or more symptoms, and 49 distinct symptoms were reported by 2 or more patients.  Despite this variety, the most common Chiari symptom, and the hallmark of the disease, is a headache.  Usually, the Chiari headache is described as an intense pressure in the back of the head and is brought on, or aggravated, by exercise, straining, coughing, sneezing, laughing, bending over, or similar activities. 

Other common symptoms include balance problems and fullness in the ears.  In very young children, trouble swallowing is one of the most frequent symptoms.  When thinking about symptoms, it is also important to keep in mind that once a person's health is compromised in one way (with Chiari for example), secondary problems are more likely to develop, especially if a person is in chronic pain.  Research has shown that people with chronic pain are much more likely to develop other chronic conditions, so not every symptom may be a direct result of a Chiari Malformation. 

Does the size of the malformation matter ?

Traditionally, Chiari Malformation has been defined as the cerebellar tonsils descending more than 3-5mm out of the skull.  However, research has shown there is no real correlation between the amount of descent (or herniation) and clinical symptoms.  Some people with herniations of less than 3mm are extremely symptomatic and some people with quite large herniations are symptom free.  Because of this, doctors are now focusing on whether the cerebellar tonsils block the normal flow of cerebrospinal fluid (CSF).  The current theory is that disruption of CSF flow is a more important measure than the size of the herniation.  Size doesn't matter.