Giant Cell Arteritis Flashcards
What is giant cell arteritis (GCA)?
Giant cell arteritis (GCA) is a granulomatous vasculitis of large and medium-sized arteries. It primarily affects branches of the external carotid artery, and it is the most common form of systemic vasculitis in adults.
Who does GCA commonly affect?
GCA typically occurs in people aged 50 years or older and is more common in women.
What is the most serious consequence of GCA?
The most common serious consequence of GCA is irreversible loss of vision due to optic nerve ischaemia.
Which artery is commonly affected in GCA?
It typically presents with symptoms affecting the temporal arteries and is also known as temporal arteritis.
Which condition is GCA commonly linked to?
There is a strong link with polymyalgia rheumatica.
Briefly describe the pathophysiology of GCA
GCA is an immune-mediated vasculitis characterised by granulomatous inflammation in the wall of medium-sized and large arteries. The extracranial branches of the carotid artery are preferentially involved, although the aorta and its major branches are often targeted as well. Affected arteries contain inflammatory lesions arranged in granulomas composed of T cells and macrophages. Multinucleated giant cells are present in about 50% of cases, but they are not required to make the diagnosis of GCA.
What causes GCA?
The exact cause remains unknown; however, genetic and environmental factors are thought to contribute to the development of GCA. The condition is probably triggered by an environmental cause in a genetically predisposed person.
What are the risk factors of GCA?
- >50 years
- Female sex
- Norther European ancestry
What are the clinical features of GCA?
- Headache
- Scalp pain or tenderness
- Aching and stiffness
- Extremity (limb) claudication
- Loss of vision
- Jaw and tongue claudication
- Arterial tenderness, thickening or nodularity
- Fever
- Muscle aches
- Fatigue
- Weight loss
- Loss of appetite
- Peripheral oedema
What investigations should be ordered for GCA?
- CRP
- ESR
- FBC
- Vascular ultrasonography
- Temporal artery biopsy
- LFTs
- U&Es
What investigation are required for the definitive diagnosis of GCA?
- Clinical presentation
- Raised ESR: usually 50 mm/hour or more
- Temporal artery biopsy findings
What cells are found on the temporal artery biopsy for GCA?
Multinucleated giant cells are found on the temporal artery biopsy.
What level of ESR indicates GCA?
Raised ESR: usually 50 mm/hour or more.
What does FBC show on GCA?
Normocytic anaemia and thrombocytosis (raised platelets)
What do LFTs show for GCA?
Raised alkaline phosphatase.
What does a duplex ultrasound show on GCA?
The temporal artery shows the hypoechoic halo sign.
Briefly describe the initial management of GCA
Steroids:
- Start steroids immediately before confirming the diagnosis to reduce the risk of permanent sight loss
- Start 40-60mg prednisolone per day
- 60mg is given depending where there are jaw claudication or visual symptoms
- Review the response to steroids within 48 hours
- There is usually a rapid and significant response to treatment
Other medications:
- Aspirin 75mg daily decreases visual loss and strokes
- Proton pump inhibitor (e.g. omeprazole) for gastric prevention while on steroids
Referrals:
- Vascular surgeons for a temporal artery biopsy in all patients with suspected GCA
- Rheumatology for specialist diagnosis and management
- Ophthalmology review as an emergency same day appointment if they develop visual symptoms
Briefly describe the ongoing management of GCA
Once the diagnosis is confirmed they will need to continue high dose steroids (40-60mg) until the symptoms have resolved. They then need to slowly wean off the steroids. This can take several years. This is a similar process to managing polymyalgia rheumatica.
There are additional measures for patients on steroids that can be remembered by the mnemonic “Don’t STOP”:
- DON’T – Don’t stop taking steroids abruptly
- There is a risk of adrenal crisis
- S – Sick Day Rules
- T – Treatment Card
- O – Osteoporosis prevention with bisphosphonates and supplemental calcium and vitamin D
- P – Proton pump inhibitor for gastric protection
Briefly describe the “Don’t STOP” rules for those taking steroids
- DON’T – Don’t stop taking steroids abruptly
- There is a risk of adrenal crisis
- S – Sick Day Rules
- T – Treatment Card
- O – Osteoporosis prevention with bisphosphonates and supplemental calcium and vitamin D
- P – Proton pump inhibitor for gastric protection
There are additional measures for patients on steroids that can be remembered by the mnemonic “Don’t STOP”:
DON’T – Don’t stop taking steroids abruptly
There is a risk of adrenal crisis
S – Sick Day Rules
T – Treatment Card
O – Osteoporosis prevention with bisphosphonates and supplemental calcium and vitamin D
P – Proton pump inhibitor for gastric protection
What are the complications fo GCA?
- Vision loss
- Cerebrovascular accident (stroke)
- Glucocorticoid-related adverse effects
- Aortitis leading to aortic aneurysm and aortic dissection
What differentials should be considered for GCA?
- Polymyalgia rheumatica
- Solid organ cancers and haematological malignancies
- Takayasu’s arteries
- Chronic infection
- Rheumatoid arthritis
- Amyloidosis
