Makindo Medical Notes

Related Subjects: |Relapsing Polychondritis |Reactive Arthritis |Raynaud's Phenomenon |Polymyositis |Osteoporosis |Osteogenesis Imperfecta |Osteopetrosis

If there is an associated headache or visual changes, consider temporal arteritis (giant cell arteritis) due to its risk of causing blindness.

About

• PMR is a vasculitis primarily affecting extracranial arteries and causes systemic non-specific symptoms.
• Closely related to temporal arteritis, which can lead to severe complications such as blindness.

Aetiology

• Exact cause unknown, but likely involves an immune response.
• Characterized by a Th1 cell-mediated immune response with elevated IL-6.
• Association with HLA DR4 gene.

Clinical Features Suggestive of PMR

• Age over 50 years and symptom duration greater than 2 weeks.
• Bilateral aching of the shoulder or pelvic girdle (or both).
• Morning stiffness lasting more than 45 minutes.
• Presence of an acute-phase response, indicated by elevated ESR or CRP levels.

Clinical Presentation

• Typically affects patients over the age of 50, with symptoms worse in the morning.
• Sudden onset of generalized aches, headaches, and pain, often accompanied by depression.
• Severe, symmetrical shoulder stiffness, along with weight loss and fever.
• Proximal muscle weakness and nocturnal sweats.
• Symptoms often show a rapid response to corticosteroids.

Conditions to Exclude

• Active infection or malignancy.
• Rheumatic diseases: rheumatoid arthritis, inflammatory arthropathies, SLE, other connective tissue diseases, and inflammatory myopathies.
• Drug-induced myalgia, e.g., due to statins.
• Pain syndromes, such as fibromyalgia.
• Endocrine disorders, such as thyroid disease.
• Neurological conditions, such as Parkinson’s disease.

Investigations

• FBC: may reveal normocytic, normochromic anaemia.
• U&E, LFT, CK, and TFT for general health status and to rule out other causes.
• ESR (often elevated, typically over 50-120) and CRP (elevated in most cases).
• ALP may be elevated in 30% of cases.
• Rheumatoid factor for differential diagnosis.
• CXR if systemic features or respiratory symptoms are present.
• Dipstick urinalysis to assess kidney function and rule out infections.

Management

• Initial dose of prednisolone 15 mg daily for 3 weeks, followed by a gradual taper:
  • 12.5 mg daily for 3 weeks.
  • 10 mg daily for 4-6 weeks, then reduce by 1 mg every 4-8 weeks.
• If response is inadequate, consider increasing the dose to 20 mg daily. Treatment duration is typically 1-2 years.
• Consider bone protection therapy with calcium and vitamin D supplements.
• Monitor for corticosteroid-related adverse effects: weight gain, diabetes, osteoporosis, hypertension, and dyslipidemia.

References

• Guidelines for the Management of Polymyalgia Rheumatica (PMR)