P.S I've just found this which may help regarding Charlotte's death...no certainty but a name is put to the illness.

"Her death is now believed to have been caused by a condition known as 'Hyperemesis Gravidarun', which basically, is severe, persistent vomiting, typically occurring during pregnancy, and leading to dehydration and emaciation [hence, the original 'Phthisis' diagnosis] - easily treated today by attaching the patient to a drip"