12/19/2013 11:59 am ET Updated Jan 25, 2014

Lupus Myelitis: Actress Kristen Johnston's Diagnosis, Explained

Chris Pizzello/Invision/AP

After months of experiencing a mysterious sickness, actress Kristen Johnston announced that doctors have finally diagnosed her with a rare complication of lupus, called lupus myelitis.

The 3rd Rock From The Sun star wrote on her Facebook page:

I just was diagnosed 2 days ago with a rare form of Lupus called "Lupus Myelitis"--google it.
I'm not on my death bead...far from it. I'm gonna be fine.

Johnston, who is currently starring in "The Exes" on TV Land, said that she had been experiencing muscle weakness since September, making it hard for her to climb stairs or even hold her head up without a neck brace.

Lupus myelitis is a rare complication of lupus that causes paralysis -- whether it just be one limb, or all the lower extremities of the body. According to Lupus International, it occurs when the the sac around the spinal cord becomes inflamed, a condition called lupus vasculitis. It can also be caused when blood clots occur in the arteries connected to the spinal cord, which is caused by antiphospholipid antibodies. The Lupus Book points out that about half of lupus myelitis cases are from lupus vasculitis, while the other half come from antiphospholipid antibodies.

Treatment for lupus myelitis usually first involves steroid administration to combat inflammation, according to The Lupus Book. From there, anticoagulant drugs may be prescribed to the patient.

Lupus itself is a mysterious disease, with no known cure. It's an inflammatory disease, meaning the immune system attacks the healthy tissue in the body, but inflammation from lupus can occur in different parts of the body (such as the joints, brain, heart and lungs), according to the Mayo Clinic. Symptoms of lupus differ from person to person, but most often involve fatigue, a butterfly-shaped face rash, chest pain, joint pain and stiffness and shortness of breath.



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