Chiari 1 Malformation: description, symptoms and treatment

Chiari 1 Malformation is one type of Chiari Malformation, a condition in which brain tissue from the back of the brain protrudes into the spinal canal.

This condition appears most often in adults.  The skull is abnormally small and misshapen, so the problem develops as you are growing and often shows up in late childhood or adulthood.  (Chiari Malformation type 2 is present at birth)

These types of abnormalities were first discovered in 1891 by doctor and researcher Hans von Chiari.  Since then, researchers have tried to understand exactly what the cause is, and how it can best be treated.

When the lower part of the cerebellum is pushed into the upper spinal canal, there can be an obstruction of the normal flow of cerebrospinal fluid (CSF).  This fluid is very important for protecting your brain, and is also key in getting signals to the rest of your body.  Also, the fact that the lower part of your brain may become stretched or compressed further interferes with normal function.

See an excellent diagram of a Chiari 1 Malformation here.

Chiari 1 Malformation symptoms

Chiari 1 Malformation can cause some strange symptoms (though in a few patients there are no visible symptoms at all).  The most classic symptom is headache - often like a migraine attack and severe.  The pain can be in the back of the head, and even in the neck and shoulders.

There are also commonly problems with coordination - difficulty walking steadily, or a lack of fine motor skills, and muscle weakness.  Numbness in the extremities, dizziness, even slurred speech and blurred or double vision.  Sleep apnea may be a symptom.  Many are misdiagnosed as having a mental or emotional problem.

The pain from Chiari 1 Malformation often starts with exertion, such as coughing, sneezing or straining.

Rarely do patients have just one symptom - most often they're dealing with several.

How is it diagnosed?

Your doctor will want to give you an examination, and check your medical history.  If headache is your major symptom, she will want to rule out other causes.  She will want to check your fine motor skills, and your ability to swallow.

The major test, however, is an MRI (magnetic resonance imaging) scan.  It will show your doctor a 3D image of your head's structure, and show up abnormalities.  Your doctor may also want a CT scan.

Chiari 1 Malformation treatment

Treatment is very much dependent on how severe your symptoms are.  Many people go through life never knowing there's a problem.  In others, the symptoms are quite severe.

Sometimes a doctor will recommend pain medication, for occasional symptoms, or while you wait for further treatment.

Most doctors will recommend surgery when you're dealing with symptoms from Chiari 1 Malformation.  There's more than one kind of surgery, but basically the goal is to keep the abnormality from getting worse, reduce the pressure on the cerebellum and the spinal cord, get the CSF flowing properly, and ultimately cut down your symptoms.

In summary

If your symptoms are tipping you off that you may have Chiari 1 Malformation, talk to your doctor.  If you can, it's best to see a doctor who has experience diagnosing Chiari Malformation.  This may be a neurologist or neurosugeon.  The World Arnold Chiari Malformation Association has a list of doctors here.

Be sure you're ready to share your medical history, and a description of your symptoms, with your doctor.  Remember, these are not just headache symptoms.  Your doctor may ask you about some of the issues above, as well as urination and bowel movements, chest pain, and trouble breathing.

The good news is that, unlike many other forms of headache, the abnormality can usually be spotted in an MRI.  Most people are helped with surgery, though you may not become completely symptom-free.

See the Mayo Clinic website for a good summary of Chiari 1 Malformation information.  More technical information about Chiari I Malformation can be found here.


References:  Chiari I Malformation by Dr Nasir H Siddiqi and Dr Lakshmana Das Narla (2005); Chiari malformation info at the Mayo Clinic (2008); NINDS Chiari Malformation Information Page prepared by the Office of Communications and Public LiaisonNational Institute of Neurological Disorders and Stroke (2007); the Conquer Chiari website; the World Arnold Chiari Malformation Association website; Hans Chiari at Who Named It?