Chiari Malformations (kee-AH-ree) is a congenital disorder and symptoms can occur at any age. 
Treating Chiari in Paediatrics has some considerations:
 - Cerebellar tonsils can sit lower in kids and with age, some cases of cerebellar herniation can resolve. 
 - Children tend to present differently to adults. 
 - Kids with asymptomatic chiari that is incidentally found won't always develop symptoms later in life. 

Symptoms:
While children can suffer all the same symptoms as adults they may not have the ability to verbalise this. They may also believe that the symptoms are "normal" so don't report them. Some suggestions for identifying Chiari issues in kids include:
 - Holding back of the head and crying/upset
 - Favouring one side
 - Sleep Issues (especially central sleep apnoea)
 - Avoiding exercise of things like laughing can cause headaches. 

Surgery:
Surgery remains the same for Children and is done for the same reasons seen in adults (improving headache, large syrinx etc). Surgical outcomes are considered quite good among the paediatric population with many only requiring that one surgery. 

Outcomes:
Many kids go on to live lives with minimal to no restrictions or symptoms. Most restrictions if needed revolved around contact sports. However, this is often a case by case basis needing to be discussed with your doctor. While it is scary to have a child diagnosed with this there is hope that the treatment will be highly effective. 

Genetics of Chiari.
Current genetic research from Duke University feels around 10-13% of Chiari cases are familial. There are definite cases where multiple generations have Chiari to suggest at least in some cases there is a genetic link. This is still ongoing research.

Should I get my Kids checked if I have Chiari?
This is a decision that has to be reached with your doctor. The general consensus is if there are no symptoms then it's not worth screening children. However, most doctors agreed that if children start displaying Chiari-like symptoms with a parent who has Chiari it is worth screening them. 

The 2021 Chiari and Syringomyelia Consensus Statement for Kids is free to read here.