I'm not a health care specialist, just someone that has had chiari malformation surgery and has done research, so don't take my word as gospel, but basically "yes" to both questions.
All types of Chiari are congenital - that means you are born with it. And you can pass it along. That's not to say you will for sure, I've heard the statistics are around 14% chance - not a huge number, but a number to pay attention to.
I believe there are 5 types of Chiari. The scale of severity is rated 1 - 4, with 4 being the most severe. Types 3 and 4 are very rare. You don't go from one type to another, but they can get progressively worse in each catagory. For instance if you have Chiari 1, you won't ever have Chiari 2, but what you have can get worse. If you've been diagnosed with Chiari 1 and they haven't mentioned surgery, you'll just need to keep track of any symptoms and get regular MRI's.
The most common form of Chiari Malformation is Type 1, it often manifests later in life (not at birth, but sometimes in children) with headaches and cerebellar symptoms like dizziness and memory/concentration problems. The cerebellum in the lower back of the brain starts extending down past the skull into the spine. This herniation can, and often does, get worse. If you are diagnosed with Chiari 1, you generally will be told how far the herniation extends in millimeters. At around 8 mm, doctors start considering surgery. This isn't a set number and can be more or less, often the decision is made because of possibe damage to the spine - syringomyelia ( a blockage of spinal fluid that can lead to paralysis) is often (almost always) eventually assoiciated with Chiari. Mine was at 20mm and I was starting to show signs of paralysis when mine was discovered, so I was rushed to surgery. I only knew of the existance of Chiari for 3 weeks before my surgery, some people may be diagnosed and watched for years, even decades, before they need surgery.
Type 2 and beyond are often noticable at birth. They often causes partial or complete paralysis below the spinal defect and generally have noticable malformed brains at least on an MRI.
Type 3 causes severe neurological defects.
Type 4 involves a failure of brain development
I've also heard of Chiari "0", which is a form that doesn't have a tonsillar herniation, but can still cause symptoms.
There, that may be a lot more info than you were asking for or need, but...I sorta got on a roll :).
Can Chiari get worse?
Yes it can, but it doesn't always. It will not progress to from Chiari I to Chiari II, though. You either are born with type I or type II (or 3, 4, etc.). There are people that live there entire life never knowing that they have Chiari I.
Is Chiari hereditary?
Yes it is congenital.
chiari can get worse depending on size and etc . you may need surgery .
you can get Chiari from auto accidents etc and yes you can be born with it .
It is not a life sentence . Go to a NS not a NL . see what they say .
I have alot of the symptoms of Chiari ! and finally was diagnosed. I have less than 3mm herniation which my neurosurgeon says is still in the normal range. So I was sent to a headache clinic for treatment to rule out migraines. Went to the DR again yesterday for the headaches and she said I should go back to the neurosurgeon to discuss what to do next. She said if the neurological symptoms I was having were due to migraines they would have improved along with the pain. From what I have read Chiari is rare but for it to be so rare there sure are many of us out there suffering needlessly because our doctors don't have the proper education to at least know what it is and where to send us for help. I also have suffered since I was a child and have recently become very symptomatic. While talking to my siblings there are 4 of us that are having similar symptoms one has been confirmed and the others may or may not go to find out due to money issues and insurance. My biggest problem is the headaches and the constant tingling and pain. Sleeping is the worst. The headaches come in the middle of the night and they hurt so bad. Laughing is a real issue the pain is so intense it travels to my face, jaw and numbs my tongue. I feel like I'm paralyized. I can't speak or do anything but just sit there and hope it will pass quiclky. It's so scary!! I'm glad there are people like you we can talk to. Thanks for being there for us
You are welcome. I'll try to answer any questions that I can.
Have your bother talk to his Primary Care Physicain and explain to them about Chiari and point out that 2 siblings have it and he needs to get checked. This way, the PCP can order it, thus insurance should cover it. Have him print of a basic fact sheet about Chiari for his PCP to read and even place in your brothers charts. A lot of PCP's know very little if anything about it.
If this bothers or insults his PCP or he refuses to schedule an MRI . . . change doctors!
The quicker this is diagnosed, the quicker it can be dealt with. Time is a MAJOR factor in Chiari.
Thanks for the info I'll pass it on!! Maybe you could answer a ? for me. If there is little or no herniation and the MRI hasn't changed much in 10 years how is it the symptoms keep getting worse. I woke up a couple of weeks ago and my left side of my tongue was completely numb. It felt like somebody was trying to pull it out with a pliers.. the pain was unbelievable. Did you have problems when you laughed?