Kulsoom, who is in her mid-sixties, recently won Lahore's NA-120 seat which was seen as referendum on the disqualification of Sharif by the Supreme Court in the Panama Papers case.
The seat fell vacant after Supreme Court disqualified 67- year-old Sharif on July 28 in the case.
Her daughter, who is in London to be with her ailing mother, tweeted, "Ami (mom) was taken & admitted to the hospital again late last night".
On September 21, Kulsoom underwent a third operation for lymphoma (Throat cancer), for which she was diagnosed last month.
Quoting doctors, the Sharif family had said that Kulsoom's cancer was curable.