When PMR Isn’t Quite PMR: How Rheumatic Diseases Can Evolve Over Time
One of the more interesting aspects of rheumatology is that diseases do not always read the textbook before showing up in clinic.
I am currently caring for an 80-year-old gentleman who presented with relatively rapid onset pain and stiffness involving the hips and lower flank region, along with elevated inflammatory markers (sedimentation rate and C-reactive protein). His primary care physician appropriately started prednisone 15 mg daily, and he had a brisk response within about 24 hours.
At first glance, this looked very much like polymyalgia rheumatica (PMR).
What is polymyalgia rheumatica (PMR)?
PMR is an inflammatory condition that typically affects adults over age 50, most commonly in their 70s and 80s.
Patients often develop:
Aching and stiffness in the shoulders and hips
Difficulty getting out of bed or rising from a chair
Pain in the neck, thighs, or upper arms
Significant morning stiffness
Elevated inflammatory markers such as ESR and CRP
One of the hallmark features of PMR is a dramatic response to prednisone. Many patients feel substantially better within 24-72 hours after starting treatment.
How is PMR diagnosed?
PMR is largely a clinical diagnosis. There is no single blood test that definitively confirms it.
Rheumatologists put together the overall story and look for pattern recognition:
Age of the patient
Pattern of symptoms
Laboratory inflammation markers
Physical examination findings
Imaging when appropriate
Response to steroids
Exclusion of diseases that can mimic PMR
What disease is PMR associated with?
PMR is closely associated with giant cell arteritis (GCA), another inflammatory condition involving medium and large blood vessels.
GCA most commonly affects arteries around the temples and scalp.
Symptoms may include:
New headaches
Scalp tenderness
Jaw pain with chewing
Vision changes
Sudden vision loss
This association is important because untreated GCA can become a medical emergency and threaten vision. Patients with PMR should always be monitored for symptoms concerning for GCA.
What does MGUS mean?
This particular patient also has a history of MGUS, which stands for monoclonal gammopathy of undetermined significance.
In simple terms, MGUS means there is a small abnormal protein in the blood produced by plasma cells.
Many individuals with MGUS never develop serious disease, but it does require periodic monitoring because in some cases it can evolve over time into more significant blood disorders.
MGUS is also sometimes seen alongside inflammatory and autoimmune conditions, including PMR.
So why didn’t this case fit perfectly?
As we looked more closely, the story became more nuanced.
He mentioned chronic right wrist pain that he had largely ignored for years. His wrist X-ray showed significant narrowing of the radiocarpal joint, one of the major wrist joints, with changes more suggestive of rheumatoid arthritis (RA).
Interestingly, his rheumatoid factor and anti-CCP antibodies were negative.
This is an important teaching point in rheumatology:
Not all rheumatoid arthritis patients have positive antibodies.
This is called seronegative rheumatoid arthritis.
Can rheumatoid arthritis be mistaken for PMR?
Absolutely — especially in older adults.
Sometimes patients who initially appear to have PMR actually turn out to have rheumatoid arthritis. The two conditions can overlap significantly early on.
Both can cause:
Elevated inflammatory markers
Morning stiffness
Fatigue
Shoulder and hip pain
Dramatic steroid responsiveness
Additionally, rheumatoid arthritis in older adults does not always present like the “classic textbook” version involving swollen knuckles and obvious hand arthritis.
Some patients initially present with shoulder and hip girdle symptoms that strongly mimic PMR before the arthritis declares itself more clearly over time.
This is one reason why longitudinal follow-up matters so much in rheumatology. Diagnoses sometimes evolve over months rather than revealing themselves on day one.
What are the treatments for PMR?
Prednisone remains the traditional first-line treatment for PMR and is often very effective.
The challenge is that long-term steroid exposure can carry significant risks including:
Osteoporosis
Diabetes
Weight gain
Muscle loss
Cataracts
Infection risk
Elevated blood pressure
Because of this, rheumatologists increasingly look for steroid-sparing therapies in appropriate patients.
Why did I choose Kevzara (sarilumab)?
This patient was started on sarilumab (Kevzara), an IL-6 inhibitor.
IL-6 is one of the major inflammatory signaling proteins involved in PMR.
In 2023, Kevzara became the first FDA-approved biologic medication for PMR following the phase 3 SAPHYR trial, which demonstrated improved sustained remission rates and reduced steroid exposure in patients who struggled during prednisone tapering.
I also selected this medication strategically because if his disease eventually evolves into a clearer rheumatoid arthritis phenotype, IL-6 blockade is also an established and effective treatment pathway for RA.
Important Takeaways
Know your body and continue to be a good reporter of your symptoms.
Rheumatic diseases can evolve over time, and patterns sometimes only become clear through careful observation and follow-up.
Rheumatic diseases can be complex. It is important to have a trusted rheumatologist in your corner—someone who can help evaluate your symptoms, answer your questions, and provide the guidance you need to make informed, proactive decisions about your health.