Senator Dianne Feinstein suffered brain inflammation

The oldest member of the US Senate contracted encephalitis, a brain inflammation, her office has said, after a bout of shingles that left her unable to sit on key committee.

Dianne Feinstein, 89, also developed Ramsay Hunt syndrome, which can cause facial paralysis, her office said.

The encephalitis resolved itself, but she continues to deal with Ramsay Hunt syndrome, the statement said.

She returned to Washington on 10 May after nearly three months of absence.

The California Democrat was admitted to hospital after being diagnosed with shingles in late February and recovered at home in San Francisco.

A spokesperson for the senator told the BBC on Thursday: "The senator previously disclosed that she had several complications related to her shingles diagnosis."

The statement added "those complications included Ramsay Hunt syndrome and encephalitis".

It continued: "While the encephalitis resolved itself shortly after she was released from the hospital in March, she continues to have complications from Ramsay Hunt syndrome."

Other high-profile figures to be diagnosed with Ramsay Hunt syndrome include Canadian pop star Justin Bieber.

Encephalitis, meanwhile, can result in symptoms including personality changes, seizures, confusion and problems with sight or hearing, according to the Mayo Clinic.

The specifics of Ms Feinstein's shingles complications had not been previously disclosed.

When she arrived at the Capitol last week, she was using a wheelchair - which her office said may be required at times now due to her impaired vision and balance since her illness.

In a statement, she said her doctors had advised her to work "a lighter schedule".

Upon her return, the Senate Judiciary Committee gave her a standing ovation, and confirmed three of President Joe Biden's judicial nominees.

Her absence had delayed the committee's efforts to confirm federal judges as it has only a slim one-seat Democratic majority.

Members of her own party have led calls for her to resign, saying she is no longer fit to serve constituents.

She is not seeking re-election in 2024 and several Democratic members of Congress - Barbara Lee, Katie Porter and Adam Schiff - have already jumped into the race to succeed her.