She sought out a blood test after experiencing symptoms like nausea and fatigue.

Kim Kardashian is seen in the Lower East Side on June 25, 2019 in New York City.
Credit: Gotham/Getty Images

Last week's Keeping Up with the Kardashians premiere was a stressful watch. Khloé Kardashian struggled with whether to invite Tristan Thompson to their daughter True's birthday party. Kourtney had a crisis at the thought of turning 40. But Kim Kardashian West dealt with the most intense challenge: She found out that her blood tested positive for rheumatoid arthritis and lupus antibodies. (Related: Kim Kardashian and More Celebs Who Are "Obsessed" with CBD Beauty Products)

At the start of the episode, Kardashian West explained that she'd been experiencing a mix of unpleasant symptoms, and her first move was to rule out pregnancy. "I've been feeling so tired, so nauseous, and my hands have been swollen, so I did take a pregnancy test to rule it out," she explained in the episode.

In a later scene, KKW explained that she'd been diagnosed with carpal tunnel a year ago, but that this felt different. "But lately my wrists have started to hurt again, but it's definitely a different feeling from before," she said. "I feel this like in my bones." (Related: Kim Kardashian's Shapewear Collection Has a New Name and People Are Loving It)

After Googling her symptoms, she suspected rheumatoid arthritis, and she went to a doctor for a blood test. She told her doctor that within the past week, her hands had stiffened up and felt swollen and itchy.

When her results were in, Kardashian West got bad news. "As far as your results, your antibodies are positive for lupus and rheumatoid arthritis," her doctor told her over the phone. He went on to inform her on some common rheumatoid arthritis and lupus symptoms. "In addition to swollen joints, you'd have fevers, rash, mouth sores, [and you'd] be really tired."

Both lupus and rheumatoid arthritis are autoimmune disorders, meaning they happen when your body harms its own tissues. Notably, Kardashian West was previously diagnosed with psoriasis, another autoimmune disorder that results in red scaly patches on your skin. That diagnosis might impact her odds of also having lupus or rheumatoid arthritis: In a study published in the Journal of American Dermatology, people with psoriasis were more likely to have an additional autoimmune disease or diseases. (Related: Everything Kim Kardashian Uses for Psoriasis That You Should—and Shouldn't—Try, According to a Dermatologist)

Even though she tested positive for antibodies common in people with lupus or rheumatoid arthritis, Kardashian West doesn't necessarily have either condition. Her doctor assured her that the test can sometimes create a false positive, so KKW booked a follow-up appointment for an ultrasound on her hands—where she's been experiencing the most pain—to get more clarity.

"My blood test results were so scary, but these ultrasounds will really determine what's going on with me," said Kardashian West in last night's KUWTK episode.

Fortunately, KKW received good news: After looking at the ultrasound, Kardashian West's doctor determined that she does not have lupus or rheumatoid arthritis.

"First of all, if you have any evidence for lupus, we would have screened it," he explained in the episode. "You do not have lupus and rheumatoid arthritis. So, you can be reassured."

However, KKW's doctor did note that the SKIMS Solutionwear founder "probably" has psoriatic arthritis, a form of arthritis that sometimes affects people who have psoriasis. Symptoms can include joint pain, stiffness, and swelling on any part of the body (including the hands and fingers, like in KKW's case), according to Mayo Clinic.

Similar to psoriasis, psoriatic arthritis flare-ups often alternate with periods of remission. Since there's no cure for the condition, treatment usually focuses on managing inflammation and preventing pain with various medications, lifestyle changes, and/or surgery.

In KKW's case, she said she's "relieved" to know the cause of her pain.

"The pain is going to come and go sometimes, but I can manage it," she explained in last night's KUWTK episode. "This isn't going to stop me."