Is It Polymyalgia Rheumatica or Something Else?

The journey to a polymyalgia rheumatica (PMR) diagnosis can be long, but it’s an important one to take. Because this condition has symptoms that overlap with several other diseases, doctors must often use a process of elimination to rule out other causes until a diagnosis is reached.

Receiving the correct diagnosis is crucial for easing your symptoms with the right treatment and care as quickly as possible. Here’s what to know about PMR and the conditions that share similar symptoms.

Understanding Polymyalgia Rheumatica (PMR)

 PMR symptoms typically begin quickly and are more pronounced in the morning, per the Mayo Clinic.

“This is an inflammatory rheumatic condition that’s really characterized by symptoms of aching and morning stiffness, predominantly in the shoulder and hip girdle,” says rheumatologist Carol Langford, MD, Director of the Center for Vasculitis Care and Research at Cleveland Clinic. “It can be associated with some symptoms in the peripheral joints [located in the limbs], which is where differential diagnosis comes into play.”

In other words, because PMR can affect several different joints, it’s important to consider other conditions that may cause similar symptoms when you and your doctor are working toward a diagnosis.

PMR symptoms can also include the following:

• Appetite loss
• Depression
• Fatigue
• Limited range of motion
• Malaise (generally not feeling well)
• Mild fever
• Unintended weight loss

Certain people are at higher risk for PMR: It usually impacts those who are older than 65 — and is most common between ages 70 and 80. Women are about two to three times more likely than men to develop PMR. It’s most common in people with ancestry tracing back to Scandinavia or northern Europe.

“There is no absolute diagnostic criteria or diagnostic test for PMR, which is one of the things that can make it challenging,” says Dr. Langford. “There are classification criteria that were published in 2012 by the American College of Rheumatology, jointly with the European Alliance of Associations for Rheumatology, but these were not intended for diagnosis of the individual patient.”

Instead, the classification criteria were created to classify people in a standardized manner for enrollment into clinical trials or other research studies. Because of that, your doctor will consider a number of factors when arriving at a PMR diagnosis.

“Luckily, we do have different clues within our physical exam, the patient’s story, and bloodwork and imaging that can help us get to the right diagnosis,” says rheumatologist Anisha Dua, MD, MPH, Associate Professor of Rheumatology at Northwestern University.

For instance, X-rays can help your doctor rule out osteoarthritis — and bloodwork that checks your rheumatoid factor can rule out rheumatoid arthritis (RA), since these conditions may cause similar symptoms.

PMR is typically treated with medications like corticosteroids (such as prednisone), sometimes along with methotrexate. Physical therapy is also sometimes helpful for those who have had long stretches of inactivity due to PMR.

Conditions with Similar Symptoms

There are a variety of conditions that share symptoms with PMR, ranging from RA to Lyme disease to cancer. Here we take a closer look at several of the more common conditions that may feel or look like PMR but require their own diagnosis and treatment plan.

Fibromyalgia

Similar to PMR, there are no specific lab or imaging tests for fibromyalgia, per the National Institute of Arthritis and Musculoskeletal and Skin Diseases. However, based on your medical history and physical exam, your doctor will work on ruling out other conditions.

“Fibromyalgia is a widespread syndrome that tends to be associated with pain, not only in the joints, but also in the soft tissues and muscles,” says Dr. Langford. “It’s more widespread than PMR, which tends to be more focused on the shoulder and hip girdle.”

PMR has a more acute onset than fibromyalgia. Plus, fibromyalgia is associated with normal sedimentation rate and C-reactive protein, markers of inflammation that are typically elevated with PMR.

Fibromyalgia is treated with medications like pain relievers, anti-seizure medicines (which can lessen pain and improve sleep), and antidepressants (even if you’re not depressed, these may help with fibromyalgia).

“We would not expect fibromyalgia to usually respond dramatically to low-dose prednisone in the manner that we see with PMR,” says Dr. Langford.

Rheumatoid Arthritis

RA and PMR can look very similar to one another. RA typically presents as swelling and stiffness in the small joints of the hands and wrists — but PMR can also cause some symptoms in these peripheral joints. There are a few things that can differentiate the two.

“Rheumatoid arthritis tends to be more symmetric, meaning it involves both sides of the body,” says Dr. Langford. “Patients with rheumatoid arthritis will frequently have abnormalities and blood tests with rheumatoid factor and anti-CCP.”

However, what makes diagnosis even more difficult is that not all types of RA show the presence of autoantibodies, also known as seropositive rheumatoid arthritis.

“A lot of PMR patients can have peripheral inflammatory arthritis, which can look a lot like late-onset rheumatoid arthritis, which can be seronegative or seropositive,” says Dr. Dua. “Some patients don’t have those markers for rheumatoid arthritis and have debilitating symptoms, which can be part of PMR — but also part of seronegative rheumatoid arthritis.”

About 20 percent of patients with PMR are eventually diagnosed with RA, since the two conditions have so many similarities early on in the disease course, per the Johns Hopkins Arthritis Center.

Giant Cell Arteritis (GCA)

PMR is related to giant cell arteritis (GCA), another inflammatory condition, per the Mayo Clinic. It’s possible to have PMR and GCA at the same time.

“About 40 to 60 percent of people who have giant cell arteritis will have features of polymyalgia rheumatica,” says Dr. Langford. “There are also people who appear to present with isolated polymyalgia rheumatica, but anywhere from 10 to 20 percent of them may develop features of giant cell arteritis either very shortly or many years later.”

GCA impacts the same demographics as PMR, per the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Although both can involve pain and flu-like feelings, symptoms unique to giant cell arteritis include headaches and scalp tenderness, jaw pain, vision issues, and large artery involvement (like inflammation of the aorta, the body’s main blood vessel).

Other Potential Conditions

Lupus and chronic fatigue syndrome can resemble PMR, but also have distinct characteristics.

An autoimmune disease that can cause damage in any part of the body, lupus is more common among women ages 15 to 44, per the U.S. Centers for Disease Control and Prevention (CDC). Lupus symptoms can include muscle and joint pain or fatigue like PMR — but also the following:

• Anemia
• Blood clotting
• Chest pain
• Eye disease
• Fever
• Hair loss
• Kidney problems
• Light sensitivity
• Memory problems
• Rashes

Meanwhile, chronic fatigue syndrome can impact those of all ages, but is most common in those ages 40 to 60. It can involve symptoms like fatigue that’s not improved by rest, but also sleep problems, trouble thinking and concentrating, pain, and dizziness, per the CDC.

About 90 percent of people with chronic fatigue syndrome have not been diagnosed. This may be partly due to limited access to health care or lack of education around chronic fatigue syndrome among health care providers. Most medical schools in the United States don’t include chronic fatigue syndrome as part of their training for physicians.

Differential Diagnosis and Evaluation

Since many of these conditions cause similar symptoms, your provider may use differential diagnosis — a step-by-step process of ruling conditions until they arrive at the condition that is most likely to be causing your symptoms, per the National Library of Medicine.

Although this process can take time, it’s important to make sure no leaf is unturned when determining the cause of your condition. Correct diagnosis is crucial for getting the right treatment.

To conduct differential diagnosis, your doctor will ask questions about your:

• Symptoms
• Medical history
• Medicines and supplements
• Family health history
• Life and habits

After that, they’ll conduct a physical exam, create a list of suspected conditions, then order the following tests to rule out certain conditions:

• Biopsies
• Imaging tests
• Lab tests
• Mental health screenings

“If you have symptoms, it’s important to seek care so your doctor can start getting the right lab testing and do an examination to make a diagnosis — especially because we know that PMR symptoms are really responsive to somewhat low doses of prednisone,” says Dr. Dua. “You don’t want patients suffering when we know something can make them feel better.”

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This article was made possible with support from Sanofi.