Waheeda, R., et. al. “Giant Cell (Temporal) Arteritis: An
Overview and Update,” Survey of Ophthalmology, Sept- Oct, 2005.
(Selected Quotes and In-context Paraphrases)
- “ the exact etiology of the condition, to date, remains unclear.”
- "Maintenance of a high index of clinical suspicion
is essential to institute prompt adequate treatment, especially
in atypical cases.”
- “A wider recognition of the disease will minimize the prevalence
of irreversible vision loss among patients with giant cell
arteritis.”
- “The disease commonly occurs in the Caucasian population,
and rarely occurs in Asians and blacks. Women are affected
twice as often as men, with a mean age at presentation of 71
years.”
- “Focal arteritic lesions causing ischemia lead to a variety
of systemic manifestations and rapid, progressive loss of vision.”
- “Giant cell arteritis commonly affects the superficial temporal,
occipital, vertebral, ophthalmic (which can cause CRAO), and
posterior ciliary arteries (which can result in ischemic optic
neuropathy).”
- “Headache of new-onset, characteristically temporal and lancinating
in quality is attributed to the stimulation of sensory fibers
within inflamed extracranial arteries. It is the most common
symptom occurring in up to 90% of patients and tends to be
located over the temporal or occipital areas.”
- "Fever, usually low-grade, is seen in about 15% of
cases. Jaw claudication due to arteritis of the maxillary
artery causing ischemia of the muscles of mastication, is
the classic symptom of GCA.”
- "Pain may also be felt in the face, behind the ears
(associated with vertigo and deafness), and may affect the
tongue, gums, and throat causing diagnostic confusion.”
- “The most common and serious ophthalmic presentation is permanent
visual loss in one or both eyes, which occurs in 20% of patients
with GCA. Patients may present with transient visual loss,
which is generally unilateral.”
M & T Commentary:
Any older person complaining of transient unilateral vision
loss merits strong consideration of two diagnostic tests:
carotid ultrasound to rule out carotid atheromatous disease,
and an erythrocyte sedimentation rate (“sed rate”) to help
stage the risk for GCA and/or the need for a temporal artery
biopsy. These should generally be done within 24 hours.
- “Visual loss is sequential in the majority of cases and results
due to occlusion mainly of the posterior ciliary arteries,
occasionally of the central retinal artery, and rarely of
the ophthalmic artery. Amaurosis Fugax can occur in as many
as 31% of patients with GCA, commonly caused by transient
ischemia of the optic nerve head.”
- “The most common cause of visual loss (81%) in GCA is due
to arteritic-anterior ischemic optic neuropathy (A-AION) resulting
from occlusive inflammation in the posterior ciliary arteries
causing infarction of the optic nerve head. A-AION may be
partial or complete depending on the number of occluded ciliary
arteries supplying the nerve.”
- “Diplopia and ocular motor imbalance occurs in 2-15% of GCA
patients due to ischemia of the extraocular muscles, ocular
motor nerves, or brain stem.”
- “Risk factors for non-arteritic-AION include a small crowded
optic disc, smoking, hypertension, diabetes mellitus, hyperlipidemia,
and migraine. There is no effective treatment for N-AION.”
- Regarding the ESR (sed rate), “Readings above 30mm/hr are
regarded as significant. An empiric formula designed by Miller,
et. al., uses age divided by 2 in men, and age + 10 divided
by 2 in women to calculate the normal thresholds of the ESR
in the setting of GCA. A normal or low ESR may be found in
5-30% of patients with biopsy-proven GCA. The ESR is a useful,
simple test for the diagnosis and management of GCA, but in
isolation, is non-specific.”
- “A positive temporal artery biopsy (TAB) confirms the diagnosis,
but a negative result does not exclude it.”
- “With fluorescein angiography, massive choroidal non-profusion
is seen if there is A-AION.”
- “MRI imaging has no practical use in the diagnosis of GCA.”
- “Polymyalgia rheumatica (PMR) and GCA are closely related
disorders thought to be two ends of a spectrum of disease.
PMR is characterized by morning stiffness and pain in the muscles
of the cervical region, shoulder and pelvic joints. PMR may
later progress to GCA and is considered by some to be more
severe variant of PMR.”
- “Treatment should be implemented in advance of the biopsy
procedure in order to decrease the possibility of further visual
loss.”
M & T Commentary:
This is the situation where a patient presents with AION
which is suspected to be arteritic. Though it is always
desirable to have a firm diagnosis prior to initiating therapy,
“presumptive” treatment is wise in the potential setting
of GCA to attempt to prevent further unilateral (or bilateral)
visual loss. Such proactive oral prednisone therapy will
not alter the validity of a subsequent biopsy.
- “General treatment guidelines have been established, but
there is no standardized protocol. However, patients with
suspected GCA are usually started on oral prednisolone of
1mg/kg/day. Higher doses (80-100mg/day) are advocated for
patients with ocular or cerebrovascular symptoms of GCA.
Interestingly, there is no evidence that intravenous high-dose
steroid therapy is more effective than high-dose oral steroid
therapy in improving vision or preventing visual deterioration
due to GCA. However, it has been recommended to give IV high-dose
corticosteroids in patients who present with a history of
amaurosis fugax, complete or marked loss of vision in one
eye, or early signs of involvement of the second eye.”
- “Gradual tapering of the steroid dose is recommended to reach
a maintenance dose of 10mg prednisolone by 6-9 months, and
5-7.5mg within one year. It must be individualized, guided
by ESR and CRP levels.”
- “Gastric protection with H2 blockers or proton pump inhibitors
is advisable until prednisolone doses are reduced below 10mg/day.”
- “Permanent visual loss is more frequent in patients with transient
visual loss, transient diplopia, or jaw claudication. The
best predictors of permanent visual loss were amaurosis fugax,
cerebral vascular accidents, or jaw claudication.”
- “Patients usually retain their initial vision when appropriate
treatment is promptly initiated and if no further loss of vision
is reported within the first week of therapy.”
- “A high level of clinical suspicion must be maintained and
an immediate and adequate steroid treatment provides the best
chance for preservation of vision and quality of life.”
M & T Commentary:
This is an excellent review and update article. It is so
conclusive that we find little need for further commentary.
When in doubt, at the very least, get a sed rate to help
guide your workup. As always, we recommend reading the entire
article.
End
|
