Giant Cell Arteritis and PMR:
Key Differences and Overlaps

Giant Cell Arteritis and PMR: Key Differences and Overlaps

Giant Cell Arteritis (GCA) and Polymyalgia Rheumatica (PMR) are two closely related inflammatory conditions that often confuse patients and even clinicians due to their overlapping symptoms. Both conditions involve immune system activity targeting tissues, but they differ significantly in affected areas, severity, and treatment approaches. At IRIS Clinics, our rheumatology team frequently evaluates patients with symptoms suggestive of these conditions, making accurate differentiation essential to prevent complications, especially in GCA where vision loss can occur if untreated.

GCA is a form of vasculitis, meaning it causes inflammation of blood vessels, particularly medium and large arteries in the head, neck, and sometimes the aorta and its branches. PMR, on the other hand, primarily affects the muscles and soft tissues around the shoulders, hips, and neck, causing stiffness and pain but without damaging blood vessels. Despite these differences, many patients with GCA also have PMR symptoms, and about 10-20% of those with PMR eventually develop GCA. Understanding their relationship is crucial for early diagnosis and prevention of long-term complications.

Early detection of GCA and PMR is critical. At IRIS Clinics, our multidisciplinary team uses advanced imaging, blood tests, and clinical expertise to identify subtle signs and tailor treatments for each patient, reducing the risk of disability and improving quality of life.

Typical symptoms of PMR include aching pain and significant morning stiffness lasting more than 30 minutes, mainly affecting the shoulders, upper arms, neck, and hips. GCA symptoms can be more severe and alarming, often including new or unusual headaches, scalp tenderness, jaw claudication (pain when chewing), visual disturbances, and systemic symptoms like fever and fatigue. Both conditions are inflammatory in nature, often showing elevated ESR and CRP levels in blood tests, but GCA requires more urgent attention due to the risk of vision loss and other vascular complications.

Diagnosis at IRIS Clinics involves a combination of detailed medical history, physical examination, and cutting-edge tools. Ultrasound of temporal arteries, MRI, and sometimes PET scans are employed for GCA detection. Temporal artery biopsy remains the gold standard to confirm GCA. For PMR, diagnosis is often clinical but supported by blood markers and the dramatic response to low-dose corticosteroids. Our rheumatologists work closely with radiologists to ensure accuracy and avoid misdiagnosis.

GCA and PMR: Key Clinical Features

Here’s how these two conditions typically present and differ:

1. Giant Cell Arteritis (GCA)
- Severe or new-onset headaches, often localized to the temples.
- Tenderness over scalp or temples, making it uncomfortable to comb hair or wear hats.
- Jaw claudication (pain while chewing) and visual changes like blurred or double vision.
- Risk of serious complications including permanent vision loss or stroke if untreated.
- Requires high-dose corticosteroids and close monitoring, sometimes with immunosuppressants.

2. Polymyalgia Rheumatica (PMR)
- Aching pain and stiffness around shoulders, hips, and neck.
- Stiffness is most pronounced in the morning or after periods of rest.
- Rarely causes joint swelling, but significant impact on mobility and daily activities.
- Typically responds well to low to moderate doses of corticosteroids, with gradual tapering.

3. Overlap and Association
- Approximately 15-20% of PMR patients develop GCA symptoms.
- Both conditions share elevated inflammatory markers (ESR, CRP).
- Some patients may initially present with PMR-like symptoms but later show signs of vascular involvement.
- Continuous follow-up is critical to detect early transition to GCA.

At IRIS Clinics, treatment is patient-centered, combining prompt medical therapy with long-term monitoring. Corticosteroids remain the mainstay of treatment, but new biologic therapies and steroid-sparing agents are increasingly used to minimize side effects. Regular eye checks, vascular imaging, and functional assessments are part of our care protocol. Patient education is equally important; we counsel individuals to recognize red flag symptoms like sudden vision changes or severe headaches and seek immediate care.