Why is Pearl so afraid to tell her Mother that she is sick?

Within the first two chapters we learn of a horrible tragedy Pearl has been diagnosed with multiple sclerosis a crippling disease that slowly takes away your ability to function. In an normal mother and daughter relationship the mother would of learned of this in a matter of hours of diagnosis but Pearl has kept this from her for quite some time now. Its not like Pearl has not tried to tell her mother of her disease but each time she has the courage to tell her mother her mother goes off on some tangent. I think Pearl does not  persistently pursue to tell her mother because she thinks her mother will see this as some form of bad luck caused by herself. We already know that Pearl openly does not believe in all the good luck and bad luck stuff, so I don't think Pearl will want her mother to blame herself for the disease. So actually I think Pearl is keeping this away from her mother not because she does not trust her but because she does not want her mother to blame her self for the crippling disease that Pearl is afflicted with. Another reason that she could be hiding this sickness from her mother is that she does not want her mother hovering over her head more than she already does. When Pearl stays at her mothers house she is under constant surveillance. This would be greatly intensified after Winnie learns of Pearls sickness every move she made would be questioned. Her mother may even try her herbal cures or some ritual from the form of religion she believes in.