A possibly YA thriller book where a US couple adopts an Eastern European orphan who may not be who she says she is

From what I recall, the mother starts to suspect her daughter may not be who she says she is, but they end up snowed in in a cabin. I vaguely recall spooky things happening in the present, but vividly recall the horror of the orphanage in flashbacks. I believe the book is from the perspective of the mother. The daughter may have had some significant medical problems that the orphanage hid, and may result in her death (but I can’t fully recall).

I believe I read it between 2006 and 2012, which would be end of high school/college age for me. I checked it out from the public library. I unfortunately cannot remember anything from the cover but the book is outside my typical genre so it’s probably pretty cool.