WASHINGTON — Sen. Dianne Feinstein, D-Calif., experienced more complications than were publicly disclosed from a recent case of shingles that left her absent from Washington for nearly three months.

Feinstein, 89, had also suffered from Ramsay Hunt syndromewhich occurred when the shingles spread to his head and neck, and a case of encephalitisthat it’s inflammation of the brain, a person familiar with her situation confirmed to NBC News on Thursday.

His previously unrevealed complications were first reported by The New York Times.

Feinstein, when he made brief appearances on Capitol Hill this week, appeared to have facial paralysis on the left side of his face, a side effect of Ramsay Hunt syndrome.

Sen. Dianne Feinstein, D-Calif., during a Senate meeting on Thursday.Kent Nishimura/Los Angeles Times via Getty Images

One of former House Speaker Nancy Pelosi’s daughters, Nancy Corrine Prowda, has been helping Feinstein navigate the halls of Congress as she recovers from shingles, fueling speculation among Washington experts that the political motives to prevent Feinstein from withdrawing from the Senate.

«Nancy Corrine has been a dear friend of Senator Feinstein for more than 40 years,» a Feinstein spokesperson told NBC News. «She has been spending time with the senator as he continues to recover from shingles.»

Feinstein has already announced that she will not seek another Senate term, setting up a competitive Democratic primary to replace her. If Feinstein retires before her term is up, California Gov. Gavin Newsom would name a temporary replacement, which some say could benefit one of the candidates in the primary race.

Feinstein has been using a wheelchair. Prowda’s attendance was first reported by Politico.

Feinstein returned to Capitol Hill last week after being diagnosed as single in February and hospitalized in San Francisco. He attended a Senate Judiciary Committee meeting where he helped Democrats advance three judicial nominees to the floor on party-line votes.

Some Democrats have called for Feinstein to resign from Congress because of her health, but she has been adamant about staying.

The veteran Democratic senator said earlier this year that she plans to retire from Congress at the end of 2024 after serving three decades in the Senate and more than 50 years in public office. She is currently the oldest sitting senator and the longest-serving senator from California after being elected to the upper house in 1992.