Diseases that imitate polymyalgia rheumatica (PMR)

Polymyalgia rheumatica (PMR) has symptoms that are similar to those of rheumatoid arthritis, lupus, and fibromyalgia, among others. As a result, it’s possible for doctors to misdiagnose it.

PMR is characterized by widespread muscle stiffness, soreness, and pain, which is generally worse in the morning or after prolonged periods of inactivity. It is common in people over the age of 50 and affects both sides of the body equally.

Other PMR symptoms include:

This page examines the diseases that resemble PMR, as well as the similarities and distinctions between them. It also discusses how doctors distinguish between various diseases and make a diagnosis.

What is polymyalgia rheumatica?

polymyalgia rheumatica patient

PMR is a disorder that produces widespread aching and stiffness in joints throughout the body, according to the American College of Rheumatology. It frequently has an impact on:

  • upper arms and shoulders
  • neck
  • hips
  • lower back
  • thighs

The average age at which symptoms appear is 70 years old. PMR can affect anyone, however it is more common in white people and occurs significantly more frequently in girls than in males. The causes for this remain a mystery. Doctors aren’t sure what causes PMR, but inflammation appears to be a factor.

PMR usually lasts 1–5 years before it resolves, however this varies. Medications, exercise, and rest can help people manage their symptoms during this time.

Giant cell arteritis, a potentially serious illness that causes narrowing or blockages in big blood arteries around the head, neck, and arms, affects about 15% of people with PMR. The following are some of the signs and symptoms of giant cell arteritis:

  • headaches
  • visual difficulties, such as double vision or vision loss
  • jaw pain while eating
  • scalp tenderness or aching around the temples

What diseases mimic PMR?

Many of the symptoms of polymyalgia rheumatica are similar to those of a variety of other disorders, including:

Rheumatoid arthritis (RA)

Rheumatoid arthritis (RA) is an autoimmune illness in which the immune system attacks the joints. Similar to PMR, it produces joint discomfort and stiffness. Fatigue, a high temperature, a lack of appetite, and weight loss are all people of RA. Because of their similarities, RA and PMR are easily confused.

Furthermore, both RA and PMR affect both sides of the body and are more common in elderly people. Around 30% of people with PMR have edema and degeneration in their joints, which are also RA symptoms.

However, there are some distinctions between PMR and RA symptoms. Joint swelling is not a common symptom of PMR, although it is a common symptom of RA. Furthermore, RA frequently starts in the hands, feet, wrists, and ankles. These joints are normally unaffected by PMR.

Lupus

Another autoimmune disease is lupus. Instead than targeting the joints specifically, the immune system tackles a variety of tissues and organs. Joint and muscular pain, a rash on the nose and cheeks, and intense exhaustion are the prominent symptoms. Apart from the face rash in the shape of a butterfly, lupus can resemble PMR.

Other signs and symptoms of lupus include:

  • mouth sores
  • headaches
  • a high temperature
  • hair loss
  • loss of appetite and weight loss
  • skin that is sensitive to the sun

Fibromyalgia

Fibromyalgia is a persistent pain condition that affects the entire body. It causes muscle stiffness and tension, similar to PMR, especially in the morning. It can also make you feel tired.

Other fibromyalgia symptoms include:

  • increased sensitivity to pain
  • difficulty sleeping
  • difficulty thinking or remembering
  • headaches
  • digestive symptoms similar to irritable bowel syndrome

Because fibromyalgia is not inflammatory, it will not respond to treatments that relieve pain by lowering inflammation.

Lyme disease

Lyme disease is caused by a bacterial infection spread by tick bites. Like PMR, it causes joint pain and stiffness, as well as fever and fatigue. It can also result in:

  • a rash around the bite, which may resemble a bull’s-eye
  • chills
  • swollen lymph nodes

If Lyme disease is not treated, it can progress to more serious symptoms like:

  • severe headaches
  • neck stiffness
  • loss of muscle tone in the face, or facial drooping
  • rashes on other areas of the body
  • severe arthritis, particularly of the knees or larger joints
  • dizziness
  • shortness of breath
  • heart palpitations
  • nerve pain or numbness
  • shooting or tingling sensations in the hands and feet

Tick bites are easy to miss because ticks are so little. Additionally, while there are tests for Lyme disease, they are not always accurate.

If Lyme infection is suspected, antibiotics may be prescribed to treat the infection. If they don’t work, it’s possible that the symptoms aren’t caused by Lyme disease.

Cancer

Fatigue, fever, loss of appetite, and weight loss are some of the symptoms related with PMR in cancer people.

There’s also a link between a PMR diagnosis and an increased cancer risk. During a 40-week follow-up, a 2020 study discovered a greater occurrence of cancer in people with PMR.

What methods do doctors use to make a diagnosis?

Because there is no single test for PMR, it might be difficult to diagnose. Doctors will instead begin by:

  • asking people about their symptoms
  • taking a medical history
  • conducting a physical examination of the affected joints

Blood tests may be used in the following stage of diagnosis to rule out other conditions such lupus and RA. These tests may involve the following:

  • a complete blood count
  • C-reactive protein (CRP)
  • erythrocyte sedimentation rate (ESR)
  • rheumatoid factor (RF)
  • anti-cyclic citrullinated peptide (anti-CCP)
  • antinuclear antibody (ANA)

Inflammation in the body can be a sign of PMR, and CRP and ESR testing can detect it. A doctor is unlikely to diagnose PMR if both the ESR and CRP are normal. Some people with PMR, on the other hand, have normal or slightly elevated levels of both.

Bursitis, or inflammation surrounding the joints, can also be detected using an ultrasound or an MRI scan.

If a patient is suspected of having giant cell arteritis, the doctor will examine the arteries to see if they are inflamed, painful, or have a low pulse. To confirm the diagnosis, they may extract a small tissue sample, but this is not usually necessary.

What are some good questions to ask a doctor?

The following are some questions that people may want to ask a doctor concerning the process of diagnosing PMR:

  • Could these symptoms be due to another condition?
  • What tests will you perform to find out the cause?
  • Do I need to do anything to prepare for the tests?
  • How reliable are the test results?
  • If I have PMR, what are the best treatments?
  • Are there lifestyle changes I need to make to relieve the symptoms?

Conclusion

PMR produces widespread joint discomfort and stiffness, especially in bigger joints like the shoulders. It also causes a fever, exhaustion, loss of appetite, and weight loss. These symptoms are comparable to those of RA, lupus, Lyme disease, and fibromyalgia.

People who have PMR symptoms or conditions that can mimic PMR should see a doctor. This is especially important if they have just been bitten by a tick or have symptoms of giant cell arteritis. PMR, as well as other comparable disorders, can be easier to control if treated early.

Sources

  • https://pubmed.ncbi.nlm.nih.gov/33291857/
  • https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Polymyalgia-Rheumatica
  • https://rarediseases.org/rare-diseases/polymyalgia-rheumatica/
  • https://www.medicalnewstoday.com/articles/diseases-that-mimic-polymyalgia-rheumatica
  • https://www.arthritis.org/diseases/polymyalgia-rheumatica
  • https://www.cdc.gov/arthritis/basics/rheumatoid-arthritis.html