Lawyer Olga Michailova told the independent television channel Dožd on Wednesday that A. Navalnas is also starting to feel out of hand.
Last week, Navaln went on hunger strike, complaining that he was suffering from severe back pain and numb legs, but the prison doctor only prescribed him painkillers.
On Tuesday, the head of the Navalnas-backed union “Doctors’ Alliance” was arrested after trying to go to prison and talk to the doctors working there.
Russia’s state prison service assures that the Kremlin critic is receiving all the necessary medical care.
Ms Michailova said one of her client’s hernias was difficult to treat and that one neurologist consulted by Ms Navaln’s organization said the treatment prescribed to her in prison was ineffective.
Navalnas reported on Monday that he was suffering from a severe cough and high fever, and that three people from his prison were hospitalized for tuberculosis.
The pro-Kremlin newspaper Izvestia later reported, based on a local branch of the Federal Penitentiary Service (FSIN), that the opposition was being transferred to the colony’s medical department for monitoring due to breathing problems and fever.
Ms Mikhailova said on Wednesday that Ms Navaln’s temperature had already dropped, but he was still coughing and tired of weakness due to a hunger strike.
Mr Navaln has not yet fully recovered from an attempt to poison him last August, when he felt unwell and unconscious on a plane flying from Siberia to Moscow. The plane was forced to land in Omsk.
He was treated by local doctors for a few days and was later flown to Berlin for treatment.
Western experts have found that Navaln was poisoned with the Novičiok, a nerve-paralyzing substance created in the Soviet Union, although Russian officials have repeatedly denied any involvement in the poisoning.
For many months, A. Navaln was treated in Germany, underwent physiotherapy procedures, and again had to learn to walk or lift a glass of water.
The opposition is serving a two-and-a-half-year prison sentence in the infamous Pokrov colony. As soon as he returned to Russia from Germany, where he was receiving treatment after an attempt to poison him, he was arrested and soon convicted of violating the terms of his probation in a 2014 case of fraud and embezzlement while receiving treatment abroad.