Introduction
Temporal arteritis (also known as giant cell arteritis: GCA) is a vasculitis of unknown cause that affects medium and large-sized vessels arteries. It occurs in those over 50 years old, with a peak incidence in patients who are in their 70s.
It requires early recognition and treatment to minimize the risk of complications such as permanent loss of vision. Hence, when temporal arteritis is suspected, treatment must be started promptly with high-dose prednisolone as well as urgent referral for assessment by a specialist.
There is an overlap between temporal arteritis and polymyalgia rheumatica (PMR) - around 50% of patients will have features of PMR.
It requires early recognition and treatment to minimize the risk of complications such as permanent loss of vision. Hence, when temporal arteritis is suspected, treatment must be started promptly with high-dose prednisolone as well as urgent referral for assessment by a specialist.
There is an overlap between temporal arteritis and polymyalgia rheumatica (PMR) - around 50% of patients will have features of PMR.
Epidemiology
- Incidence: 20.00 cases per 100,000 person-years
- Peak incidence: 70+ years
- Sex ratio: more common in females 3:1
| Condition | Relative incidence |
|---|---|
| Migraine | 250.00 |
| Polymyalgia rheumatica | 4.20 |
| Temporal arteritis | 1 |
| Fibromuscular dysplasia | 0.50 |
| Takayasu's arteritis | 0.01 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Aetiology
Risk factors
- increasing age: temporal arteritis is a disease of the elderly and it rarely affects those under 50-year-old
- sex women are twice more likely to develop the condition
Clinical features
Features
According to the American College of Rheumatology classification criteria, if 3 or more of the criteria are present below, the patient is highly suspected to have temporal arteritis
- typically patient > 60 years old
- usually rapid onset (e.g. < 1 month)
- headache (found in 85%)
- jaw claudication (65%)
- vision testing is a key investigation in all patients
- anterior ischemic optic neuropathy accounts for the majority of ocular complications. It results from occlusion of the posterior ciliary artery (a branch of the ophthalmic artery) → ischaemia of the optic nerve head. Fundoscopy typically shows a swollen pale disc and blurred margins
- may result in temporary visual loss - amaurosis fugax
- permanent visual loss is the most feared complication of temporal arteritis and may develop suddenly
- diplopia may also result from the involvement of any part of the oculomotor system (e.g. cranial nerves)
- tender, palpable temporal artery
- around 50% have features of PMR: aching, morning stiffness in proximal limb muscles (not weakness)
- also lethargy, depression, low-grade fever, anorexia, night sweats
According to the American College of Rheumatology classification criteria, if 3 or more of the criteria are present below, the patient is highly suspected to have temporal arteritis
- Age of onset≥50 years
- New onset of headache
- Temporal artery abnormality: tenderness, thickening or reduced pulsation of temporal artery
- ESR>50mm/hr
- Abnormal artery biopsy
Investigations
Investigations
Guidelines suggest investigations should be guided by the pre-test probability of temporal arteritis.
Treatment should not be delayed whilst investigations are carried out.
- raised inflammatory markers
- ESR > 50 mm/hr (note ESR < 30 in 10% of patients)
- CRP may also be elevated
- temporal artery biopsy
skip lesions may be present
- note creatine kinase and EMG normal
Guidelines suggest investigations should be guided by the pre-test probability of temporal arteritis.
- For a low clinical probability of temporal arteritis (<20%): order a temporal and axillary artery ultrasound scan.
- If the ultrasound result is positive (eg. detection of halo sign, stenosis/occluded vessel), arrange for a biopsy to confirm the diagnosis. It should be carried out within 14 days after commencing steroid therapy
- If the ultrasound result is negative, consider alternative diagnoses
- For a medium clinical probability of temporal arteritis (20–50%): ultrasound may be performed prior to biopsy to aid in diagnostic certainty in case the biopsy is negative
- For a high clinical probability of temporal arteritis (>50%): a positive ultrasound alone may be sufficient to make a diagnosis of temporal arteritis
- If an ultrasound scan is unavailable, patients should still have a temporal artery biopsy.
Treatment should not be delayed whilst investigations are carried out.
Differential diagnosis
As a general rule, we should always rule out common conditions and diseases that require urgent treatment before thinking of the rare diagnosis. Here, we should consider causes of sudden loss of vision as well as conditions that may present with worrying symptoms such as fever, weight loss and pain.
Possible differential diagnoses include:
Possible differential diagnoses include:
- Migraine:
- Similarities: severe headache
- Differences: No visual loss but only temporary visual disturbance experience such as photophobia, scotoma in the shape of a jagged crescent, hemianopia or jumbling of lines and dots, no muscle stiffness
- Central retinal artery occlusion:
- Similarities: sudden onset, loss of vision
- Differences: fundoscopy may reveal presence of cherry red spot with retinal whitening, no muscle stiffness
- Acute glaucoma
- Similarities: sudden onset, severe pain within/around the eye,associated headache, blurring of vision, loss of vision
- Differences: redness of eye, hazy cornea, nausea and vomiting
- Trigeminal neuralgia:
- Similarities: sudden onset, jaw pain
- Differences: No vision impairment
- Multiple sclerosis
- Similarities: sudden onset, loss of vision, diplopia, blurring of vision
- Differences: there is pain on eye movements, facial weakness, weakness of lower limb and autonomic dysfunction (eg. Urine incontinence)
- Polymyositis
- Similarities: fatigue, myalgia
- Differences: proximal muscle weakness in polymyositis which is not a feature of PMR, raised creatinine kinase, no visual impairment
Management
Treatment
- urgent high-dose glucocorticoids should be given as soon as the diagnosis is suspected and before the temporal artery biopsy
- if there is no visual loss then high-dose prednisolone is used
- if there is evolving visual loss IV methylprednisolone is usually given prior to starting high-dose prednisolone
- there should be a dramatic response, if not the diagnosis should be reconsidered
- urgent ophthalmology review
- patients with visual symptoms should be seen the same-day by an ophthalmologist
- visual damage is often irreversible
- other treatments
- bone protection with bisphosphonates is required as long, tapering course of steroids is required
- low-dose aspirin is sometimes given to patients as well, although the evidence base supporting this is weak
Complications
- anterior ischemic optic neuropathy (AION) → visual loss
- stroke
- steroid-related side effects