'Christina Applegate is spiraling. She isn't doing well at all': With star almost 'unable to move', friends say she is stuck in 'horrific' new health crisis after multiple sclerosis misdiagnosis

Christina Applegate was 'basically immobile' and desperately seeking treatment when she was told she had been misdiagnosed for years with multiple sclerosis, the Daily Mail has learned.

The 54-year-old star, who became one of Hollywood's most recognizable advocates for MS after revealing her diagnosis in 2021, announced this week that she learned she does not have the debilitating neurological condition after all.

The actress was rushed to a Los Angeles-area hospital at the end of March, for what she believed was an excruciating MS flare-up, according to a source who has known the 'Anchorman' actress for nearly two decades.

'She was exhausted, almost unable to move, basically immobile. And that's when she found out that it wasn't MS, as I understand it,' the source told the Daily Mail.

Applegate spent four agonizing months in the hospital, and was visited by friends and family 'every day' until her discharge on August 3. 

'She went into the hospital to manage the flare up. Corticosteroids, plasma, physical therapy. She went in with a game plan that they were going to manage this, and she came out with less answers, totally unsure.'

The misdiagnosis has left Applegate emotionally shattered, the close source said, as she continues to experience worsening symptoms.

'She's living with this 24/7, she's getting worse, and now she doesn't even have a name for it. It's horrific,' the close source said. 

'She is spiraling. She isn't doing well at all.'

Applegate initially kept the medical revelation a secret before telling the people closest to her, the source said, adding that Applegate is now grappling with her health as well as her identity as a prolific advocate for MS.

'There was fear there, because MS has become a big part of her persona. And now MS is not what she's got,' the close source said.

For years, Applegate and fellow actress Jamie-Lynn Sigler, who also has MS, have used their podcast MeSsy to speak candidly about living with the disease, becoming prominent voices for others facing similar struggles.

Applegate announced her misdiagnosis on the podcast on Tuesday.

'It's weird because I feel like I let everybody down,' Applegate admitted during the emotional episode. 'I'm back at square one.'

After years of receiving treatment for what she thought was MS, doctors now must determine what has actually been causing her symptoms, and whether an unidentified illness may have gone untreated during that time.

The source said Applegate is now facing another grueling round of medical investigations, including blood tests, MRIs and consultations with additional specialists.

'What she said on the podcast is the tip of the iceberg about how she is managing things. She's so upset; it's so awful,' the close source said.

Another insider close to Applegate told the Daily Mail that the misdiagnosis has left her scared and confused.

'The last few years of her life now feel like a nightmare. She doesn't know how to deal with it all and it's exhausting having to explain to friends what she is going through,' the insider told the Daily Mail.

'It is going to be a long time for her to get over it. How can she trust any doctors anymore?'

The actress has considered whether to pursue legal action against the doctors responsible for her original diagnosis, although it is not high on her priority list.

'She has thought about suing the doctors who misdiagnosed her, but really what's the point?' the first source said.

'It would be just to keep it from happening to someone else, and that's a lot for her to take on right now. So I don't think that's on the front burner.'

The Daily Mail has reached out to representatives for Applegate for comment.  

Meanwhile, the source claimed Applegate is deliberately avoiding online commentary about her mystery condition, particularly unsolicited medical advice and speculation about what might be wrong.

'She said she wasn't going to go online to see what people are saying,' the source explained.

'I think people mean well but they're going to blame it on the Covid vaccine, or tell her she needs to eat healthy, or recommend some sort of homeopathic remedy.'

Indeed, online rumors have started to flood social media, with medical skeptics quickly and baselessly blaming vaccines, veganism and even breast implants for Applegate's grueling condition. 

 'Whatever people come up with, don't you think she has already thought about this? She's been living this 24/7/365. She's been over it all.'

Outside of the online commentary, Applegate is receiving emotional support from friends and is speaking with a therapist as she tries to process the upheaval.

'She says everyone has been great, everyone has loved her and cared for her,' the source said.

'She's being supported by friends now, and trying to process the shock, even after a few weeks,' the source said.

Applegate first became a household name as Kelly Bundy on 'Married... with Children,' before building a successful film and television career that included Anchorman and the acclaimed Netflix series Dead to Me.

She won an Emmy award in 2003 for her portrayal of Rachel Green's spoiled sister, Amy, on the critically acclaimed sitcom 'Friends.'

Following her initial diagnosis, the actress has struggled with debilitating fatigue, pain and mobility problems, sometimes requiring a cane or wheelchair simply to attend medical appointments.

'I lost everything. I lost my job,' she said through tears on her podcast.

'I still have to use wheelchairs when I go to the doctor's office. I can't walk from the car to the room.'

Applegate has faced serious health challenges before.

In 2008, she was diagnosed with breast cancer and underwent a double mastectomy after discovering she carried a BRCA1 genetic mutation. She subsequently became an outspoken advocate for breast cancer awareness and early detection.

Doctors are now trying to establish what is causing Applegate's symptoms, which she said have continued to worsen despite the revised diagnosis.

Speaking to Applegate and Sigler on their podcast on Tuesday, Dr Marwa Kaisey, an associate professor in Cedars-Sinai's neurology department, explained that MS misdiagnoses are 'fairly common' because there is no single test for the disease.

'It's not like we have something like a pregnancy test that says, 'Yes. You have it.' 'No. You don't.' It's a list of criteria,' she said, describing a group of patients in which nearly one in five had been incorrectly diagnosed.

For Applegate, learning that she does not have MS did not bring the kind of relief one might expect. 

'If anything, I've gotten worse in some ways, and so I'm back at square one,' Applegate told her podcast listeners on Tuesday.

'I don't know what's going on with me.'