Arteritic Anterior Ischemic Optic Neuropathy and Giant Cell Arteritis
Giant cell (temporal or cranial) arteritis (GCA) is an inflammatory vasculopathy of the elderly that affects medium- to large-sized arteries. GCA may present with numerous systemic and ocular manifestations (Aburahma, 1992, 1996; Aiello, 1993; Astion, 1994; Barton, 1991; Berlit, 1992; Buchbinder, 1992; Cid, 1998; Clearkin, 1992b; Diamond, 1991, 1993; DiBartolomeo, 1992; Evans, 1993; Gabriel, 1995; Gaynes, 1994; Glutz von Blotsheim, 1997; Grosser, 1999; Hayreh, 1991, 1998b,c; Heathcote, 1999; Hellman, 1993; Hunder, 1990a; Kachroo, 1996; Kattah, 1999; Kyle, 1993; Matzkin, 1992; Mizen, 1991; Myles, 1992; Nordborg, 1990; Postel, 1993; Pountain, 1995; Rousseau, 1994; Salvarani, 1995; Schmidt, 1994; Siatkowski, 1993; Sonnenblick, 1994; Stevens, 1995; Weinberg, 1994). Here we concentrate on the ocular manifestations, diagnosis, and treatment of GCA. Less emphasis is placed on nonocular involvement by GCA.
What Clinical Features Suggest Giant Cell Arteritis?
GCA usually causes visual loss due to anterior ischemic optic neuropathy (AION). All patients older than age 50 years with AION should be suspected of having GCA. The index of suspicion is greater with increasing numbers of typical features of GCA listed in Table 5–1 (Aburahma, 1992,1996; Aiello, 1993; Astion, 1994; Barton, 1991; Berlit, 1992; Buchbinder, 1992; Clearkin, 1992b; Diamond, 1991, 1993; DiBartolomeo, 1992; Evans, 1993; Gabriel, 1995; Gaynes, 1994; Glutz von Blotsheim, 1997; Goh, 2000; Hayreh, 1991, 1998b,c; Hellman, 1993; Hunder, 1990a; Kachroo, 1996; Kyle, 1993; Liu, 1994; Matzkin, 1992; Mizen, 1991; Myles, 1992; Nordborg, 1990; Postel, 1993; Pountain, 1995; Rousseau, 1994; Salvarani, 1995; Siatkowski, 1993; Sonnenblick, 1994; Stevens, 1995; Weinberg, 1994).
Age greater than 50 years (median 75 years) Acute, often severe, visual loss (usually anterior ischemic optic neuropathy [AION]) Unilateral or bilateral visual loss (higher incidence of bilateral than nonarteritic [NA]-AION) Pallid swelling of the optic nerve (may be “chalk white”) Optic atrophy eventually (usually in 6 to 8 weeks) often with end-stage optic disc appearance of cupping with pallor and loss of neuroretinal rim (Danesh-Meyer, 2001; Hayreh, 1998c, 2001) Constitutional signs and symptoms Headache (4–100%) Scalp or temporal artery tenderness (28–91%) Weight loss (16–76%) Jaw claudication (4–67%) (Lee, 1995) Anorexia (14–69%) Fever (low grade) and diaphoresis (Fife, 1994) Proximal muscle aches or weakness (28–86%) Polymyalgia rheumatica Morning stiffness lasting 30 minutes or more Proximal joint pain (e.g., shoulders, hips, neck, or torso) Fatigue and malaise (12–97%) Leg claudication (2–43%) Elevated erythrocyte sedimentation rate (usually > 50 mm per hour by Westergren method) Temporal artery biopsy positive |
Is the Clinical Suspicion for GCA High?
In 1990 the American College of Rheumatology (Hunder, 1990a) analyzed 214 patients with GCA (196 proven by positive temporal artery biopsy) and compared them with 593 patients with other forms of vasculitis. In their analysis of 33 criteria, the highest sensitivity criteria for GCA were the following:
1. Age >50 years (mean age 69 years, 90% >60 years)
2. Westergren erythrocyte sedimentation rate (ESR) >50 mm/hour
3. Abnormal temporal artery biopsy (TAB)
The highest specificity clinical criteria were the following:
1. Jaw and/or tongue claudication
2. Visual abnormalities (e.g., AION, amaurosis, optic atrophy)
3. Temporal artery abnormalities (e.g., decreased pulse, tenderness, or nodules)
If at least three or more criteria of the following five were met, the specificity of diagnosis was 91.2% and the sensitivity was 93.5%:
1. Age >50 years
2. New headache (localized)
3. Temporal artery abnormality (see above)
4. Elevated ESR ( >50 mm/hour)
5. Abnormal temporal artery biopsy (e.g., necrotizing arteritis, multinucleated giant cells)
One of these diagnostic criteria (positive temporal artery biopsy) makes the diagnosis with high specificity and is the “gold standard” for diagnosis. Fernandez-Herlihy increased the specificity for diagnosis of GCA by defining symptom clusters, for example, jaw claudication with any of the following (Fernandez-Herlihy, 1988):
1. Recent headaches and scalp tenderness
2. Scalp tenderness and ESR >50 mm/hour
3. Visual symptoms and ESR >50 mm/hour
A specificity of 90 to 100% could be obtained if the cluster included elevated ESR, scalp tenderness, jaw claudication, recent visual changes, polymyalgia rheumatica, and a good response to steroid therapy. A 94.8% sensitivity and 100% specificity were obtained if the symptom cluster included new-onset headache, jaw claudication, and abnormal temporal artery examination (Mizen, 1991). Vilaseca et al found that simultaneous jaw claudication, abnormal temporal arteries on exam/and new headache had a specificity of 94.8% for positive TAB (Vilaseca, 1987). Chmelewski et al compared the initial clinical features of 30 patients with positive TAB and 68 with negative TAB (Chmelewski, 1992). TAB-positive patients had significantly increased incidence of headache (93% vs. 62%) and jaw claudication (50% vs. 18%). Jaw claudication had a specificity of 56% as a differentiating feature, but the specificity of headache was low (40%). Hayreh et al reported that jaw claudication (p = 0.001) and neck pain (mostly in the occipital and back parts of the neck; p = 0.0003) were significant indicators of a positive TAB independent of ESR and age, and that these clinical signs were more highly correlated to a positive TAB than anorexia, weight loss, fever, and scalp tenderness (Hayreh, 1997). Hayreh et al felt that the odds of a positive TAB were 9.0 times greater with jaw claudication, 3.3 times greater with neck pain, 3.2 times greater with a C-reactive protein (CRP) >2.45 mg/dL, 2.1 times greater with an ESR of 47 to 107 mm/hour, 2.7 times greater with an ESR >107 mm/hour, and 2.0 times greater when the patient was greater than 75 years old (compared with age below 75 years). The typical features of GCA are listed in Table 5–1.
Acute visual loss is reported in 7 to 60% (average 36%) of patients with GCA. Although the usual cause of visual loss in GCA is AION or central retinal artery occlusion (CRAO) (Charness, 1991; Clearkin, 1992a; Liu, 1994), cilioretinal artery occlusion, ocular ischemic syndrome, posterior ischemic optic neuropathy (PION), choroidal ischemia, or rarely occipital lobe ischemia may also occur (Miller, 1991; Sadda, 2001). In a prospective study of 170 patients with biopsy-proven GCA, 85 (50%) presented with ocular involvement (Hayreh, 1998b). The ocular findings in this study are outlined in Table 5–2.
Although visual loss and AION in GCA tends to be more severe than that seen in NA-AION (Hayreh, 1998b), the lack of severe visual loss is not a differentiating feature. Patients with AION in GCA may have little or no visual loss. On the other hand, very severe visual loss with AION is a “red flag” for GCA. In a study by Hayreh et al, 54% of patients with arteritic AION had initial visual acuity of counting fingers to no light perception (compared to 26% of patients with NA-AION). Light perception was present in 29% and no light perception in 4% of AION due to GCA (Hayreh, 1998c). Therefore, massive early visual loss in AION is suggestive of GCA. Up to 25% of GCA patients have visual acuities of 20/40 or better and 20% of NA-AION patients have initial visual acuities of counting fingers or worse (Hayreh, 1990). The clinical features favoring arteritic AION over NA-AION are listed in Table 5–3. Other less common ocular features of GCA are listed in Table 5–4.
Finding | Number of Patients (%) |
|---|---|
Ocular symptoms | |
Visual loss of varying severity | 83 (97.7%) |
Amaurosis fugax | 26 (30.6%) |
Diplopia | 5 (5.9%) |
Eye pain | 7 (8.2%) |
Ocular signs | |
Arteritic AION | 69 (81.2%) |
Central retinal artery occlusion | 12 (14.1%) |
Cilioretinal artery occlusion | 12 (14.1%) |
Posterior ION | 6 (7.1%) |
Ocular ischemic syndrome | 1 (1.2%) |
n = 85 with ocular involvement.
The differential diagnosis for these ocular conditions (especially unexplained diplopia, retinal or choroidal ischemia, central retinal artery occlusion without visible emboli, or transient visual loss) should include GCA. Goldberg reviewed the literature in 1983 on ocular motor paresis in GCA and found ocular muscle involvement was reported in 59 patients (Goldberg, 1983). The duration of symptoms was transitory to several months. Many cases had other signs to suggest GCA (e.g., headache, scalp tenderness, optic nerve, or retinal involvement). The diplopia was often transient, variable, and sometimes not associated with motility examination abnormalities. The optic nerve or central retinal artery involvement followed within several days in many patients. Graham described 10 GCA patients with ophthalmoplegia (four pupil-sparing third nerve palsies, four sixth nerve palsies, and two multiple ocular motor nerve palsies) (Graham, 1980). Bondeson described a patient with pupil-sparing third nerve palsy secondary to GCA (Bondeson, 1997). Brilakis and Lee reviewed 18 previous reports (81 patients) of diplopia with GCA (Brilakis, 1998). Of these 81 patients, 60 (74%) had other signs and symptoms of GCA and 21 (26%) had insufficient clinical information to determine if other signs and symptoms of GCA were present.
Elderly patients with constitutional symptoms (especially scalp tenderness or jaw claudication) Polymyalgia rheumatica Elevated erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) Amaurosis fugax—likely transient optic nerve ischemia rather than retinal ischemia (Hayreh, 1998b; Liu, 1994; Ronchetto, 1992) Ocular findings (Hayreh, 1990, 1997, 1998b,c; Sadda, 2001): Posterior ischemic optic neuropathy (PION) Cup to disc ratio greater than 0.2 in fellow eye Early massive or bilateral simultaneous visual loss Markedly pallid optic disc edema (chalky white in 68.7%) End-stage optic disc appearance of cupping (seen in 92% of eyes with arteritic AION vs. 2% of eyes with NA-AION) (Danesh-Meyer, 2001) Fluorescein angiography findings of choroidal nonperfusion or delayed choroidal filling (indocyanine green angiography provides no additional information) (Hayreh, 1990; Mack, 1991; Segato, 1990; Siatkowski, 1993; Valmaggia, 1999) AION associated with choroidal nonfilling Simultaneous AION with nonembolic cilioretinal artery occlusion (CRAO) Simultaneous AION with choroidal or retinal infarction |
Visual loss Transient visual loss (Hayreh, 1998b; Liu, 1994; Thystrup, 1994) Alternating transient visual loss (Finelli, 1997) Alternating transient visual loss induced by bright light (Galetta, 1997b) Posture related retinal ischemia Bilateral transient visual loss with change in posture due to vertebrobasilar involvement (Diego, 1998) Bilateral transient visual loss with change in posture due to impending AION (Diego, 1998) Nonembolic branch or central retinal artery occlusion (Fineman, 1996; Glutz von Blotsheim, 1997; Hayreh, 1998b; Liu, 1994; Miller, 1991; Wein, 2000) Combined central retinal artery and vein occlusion Ophthalmic artery occlusion Ophthalmic artery microembolism (Schauble, 2000) Choroidal or retinal ischemia (Glutz von Blotsheim, 1997; Quillen, 1993; Slavin, 1994) Cotton wool spots (Hayreh, 1998b; MacLeod, 1993; Melberg, 1995; Thystrup, 1994) General anesthesia induced ischemic optic neuropathy Pre- and perichiasmal ischemia and visual field defects Postchiasmal ischemic visual field defects (rare) Anterior segment ischemia (Birt, 1994) Episcleritis and scleritis Iritis Panuveitis (Rajesh, 2000) Conjunctivitis Glaucoma (e.g., acute angle closure glaucoma) Uveitic glaucoma (Tomsak, 1997) Transient bilateral corneal edema Acute hypotony Marginal corneal ulceration (Tomsak, 1997) Autonomic pupil abnormalities Tonic pupil Light-near dissociation Horner syndrome (Pascual-Sedano, 1998) Miosis Mydriasis Diplopia Orbital ischemia Ophthalmoplegia (Goadsby, 1991) due to ischemia to cranial nerves III, IV, and/or VI (Bondeson, 1997; Diamond, 1991; Killer, 2000) Brainstem ischemia (rare) Internuclear ophthalmoplegia (Ahmed, 1999; Askari, 1993; Eggenberger, 1998; Johnston, 1992; Trend, 1990) Internuclear ophthalmoplegia with facial nerve palsy (“eight-and-a-half syndrome”) (Eggenberger, 1998) One-and-a-half syndrome (Galetta, 1997b) Nystagmus Subjective diplopia by history Transient diplopia with or without ptosis (Hayreh, 1998b; Liu, 1994) Divergence insufficiency (Jacobson, 2000) Transient oculomotor synkinesis Laboratory measures of ischemia Color Doppler hemodynamics (Ho, 1994) Decreased ocular pulse Decreased ocular pulse amplitudes Orbital involvement Orbital pseudotumor (Chertok, 1990; de Heide, 1999; Laidlaw, 1990; Lee, 2001; Looney, 1999) Orbital infarction (Borruat, 1993; Chertok, 1990; Laidlaw, 1990) Ocular ischemic syndrome (Casson, 2001; Hamed, 1992; Hayreh, 1998b; Hwang, 1999); may be bilateral (Casson, 2001) Reversible bruit Optic nerve enhancement on MR imaging (may help in differentiation from NA-AION) (Lee, 1999a) |
Liu et al noted that transient monocular blindness (18% of patients) and transient diplopia (15% of patients) were the most common premonitory visual complaint in GCA (Liu, 1994). Hayreh also described transient diplopia in 5.9% of patients with GCA (Hayreh, 1998b) and noted that all of the extraocular muscles and the levator palpebrae superioris are supplied by more than one and up to five vascular branches of the ophthalmic artery, except for the inferior oblique (with only one branch). This collateral vascular supply may explain the usual transient nature of diplopia in GCA, which is thought due to ischemia of one or more of the extraocular muscles due to arteritic occlusion of one or more of the muscular arteries (Hayreh, 1998a).
We do not routinely obtain an ESR on patients with transient or persistent diplopia without systemic signs of GCA in whom there is a clear alternative etiology (e.g., other vasculopathic risk factors). Nevertheless, we consider the diagnosis of GCA in all patients over 55 years with unexplained diplopia (class III, level U). It is our current practice to evaluate for GCA in elderly patients with diplopia that is ill defined or transient or if there are other signs or symptoms of GCA (class III, level U).
Caselli and Hunder reviewed the neurologic aspects of GCA and emphasized the often underrecognized fact that GCA affects the aortic arch and its branches, not just the superficial temporal arteries. Although GCA does not cause a widespread intracranial vasculitis, it may involve the cervicocephalic arteries including the carotid artery and vertebral arteries (Caselli, 1993). Less commonly recognized findings of GCA are listed in Table 5–5.
Is the ESR Always Elevated in GCA?
Although the ESR is often elevated in GCA (Brittain, 1991; Weinstein, 1994), patients with biopsy-proven GCA may have a normal ESR (2–30%) (Brigden, 1998; Brittain, 1991; Glutz von Blotsheim, 1997; Grodum, 1990; Hayreh, 1997; Jundt, 1991; Litwin, 1992; Liu, 1994; Neish, 1991; Salvarani, 2001; Wise, 1991; Zweegman, 1993). Cullen found an average ESR of 84 mm/hour in TAB proven GCA (Cullen, 1967).
What Is the Normal Value for an ESR?
The ESR rises with increasing age. The Westergren method is preferred over the Wintrobe method because of the more limited scale of the Wintrobe ESR. Boyd and Hoffbrand reported a Westergren ESR normal of 40 mm/hour for persons over age 65 years (Boyd, 1966). Bottiger and Svedberg felt that 30 mm/hour for women and 20 mm/hour for men was a reasonable limit (Bottiger, 1967). Hayreh concluded that a patient with an ESR >40 mm/hour should be considered to “suffer from temporal arteritis, unless proven otherwise.”
Miller et a1 measured Westergren ESR in 27,912 adults aged 20 to 65 years (Miller, 1983). None of the subjects were anemic. A series of curves of ESR versus age were derived for men and women with maximum values for 98% of the population. An empiric formula (98% curve) for deriving the maximum ESR normal is listed as follows (Miller, 1983; Sox, 1986): for men, age divided by 2; for women, age +10 divided by 2.
Hayreh et al suggested a cut-off criterion for an elevated ESR of 33 mm/hour for men and 35 mm/hour for women with a sensitivity and specificity of 92% (Hayreh, 1997). In addition, the ESR value at the time of diagnosis may not correlate with the clinical features or prognosis for visual loss in GCA. Other markers (e.g., CRP, von Willebrand factor) have also been proposed in the evaluation of GCA. Jacobson and Slamovits found an inverse correlation between ESR and hematocrit and felt that the “ESR may not reliably indicate active disease in a patient with a normal hematocrit” (Jacobson, 1987). Finally, it should be emphasized that the diagnosis of GCA is a clinical diagnosis, and reliance for such a diagnosis should not be placed on the ESR alone. If the clinical suspicion for GCA is high, a repeat ESR, TAB, and treatment with empiric prednisone should begin regardless of the initial ESR value.
Are There Other Hematologic Tests for the Diagnosis of GCA?
Another acute-phase reactant, CRP, has also been advocated as a marker for GCA (Hayreh, 1997). Hayreh et al felt that an elevated CRP (above 2.45 mg/dL) was more sensitive (100%) than the ESR (92%) for the detection of GCA, and that a CRP combined with an ESR gave the best specificity for diagnosis (97%) (Hayreh, 1997).
Other hematologic tests listed in Table 5–6 have been reported in association with GCA, but are of uncertain significance (e.g., serum amyloid, von Willebrand’s factor, plasma viscosity, antineutrophil cytoplasmic antibodies, and various human lymphocyte antigen [HLA] types). Anticardiolipin antibodies were present at the onset in 19 of 40 patients with GCA and polymyalgia rheumatica (Manna, 1998). In 56% of these patients, these antibodies disappeared during steroid treatment. Thrombocytosis occurred in 44% of 34 patients in one series and the platelet count was reduced by corticosteroid therapy (Gonzalez-Alegre, 2001). No association was found between the platelet count and ischemic complications of the disease.
Large vessel involvement (Butt, 1991; Lambert, 1996) Carotid siphon Bruits (Caselli, 1988) Facial artery (Achkar, 1995) Pain on palpation of external carotid artery (Gonzalez-Gay, 1998b) Occipital artery pain and occipital neuralgia (Jundt, 1991) Subclavian or axillary artery (Ninet, 1990) Aortitis or aortic rupture (Evans, 1995; Gersbach, 1993; Lagrand, 1996; Lie, 1995a; Liu, 1995; Mitnich, 1990; Richardson, 1996) Aortic aneurysm (Hamano, 1999) Limb claudication or gangrene (Desmond, 1999; Lie, 1995a; Walz-Leblanc, 1991) Upper or lower limb ischemia (Garcia Vazquez, 1999) Unilateral distal extremity swelling and edema (Kontoyianni, 1999) Raynaud’s phenomenon (Mallia, 1999) Neurologic features Central nervous system arteritis (Caselli, 1988,1990,1993; Hussein, 1990; Reich, 1990) Acute encephalopathy (Caselli, 1990; Tomer, 1992) Aseptic meningitis Cerebellar infarction (McLean, 1993) Diabetes insipidus Occipital infarction and cortical blindness Multifocal dural enhancement and enhancement of temporalis muscles on MR imaging (Joelson, 2000) Myelopathy (Caselli, 1988) Cervical radiculopathy (Rivest, 1995) Quadriplegia (Brennan, 1982) Transverse myelopathy Spinal cord infarction (Galetta, 1997a) Neuropsychiatric syndromes Hallucinations Depression Behavioral changes Psychosis and confusion Seizures Transient ischemic attacks (Caselli, 1988) Tremor Dysarthria precipitated by chewing or prolonged talking (Lee, 1999b) Numb chin syndrome (Genereau, 1999) Proximal muscle weakness with skeletal muscle vasculitis (Lacomas, 1999) Neuro-otologic symptoms (Caselli, 1988) Deafness (Caselli, 1988; Reich, 1990) Tinnitus Vertigo Brainstem (Dick, 1991; Gonzalez-Gay, 1998a) Ataxia, nystagmus, upgaze palsy Lateral medullary syndrome (Shanahan, 1999) Vertebrobasilar involvement (Sheehan, 1993) Acute confusional states (Caselli, 1988, 1990) Cluster headache (Jimenez-Jimenez, 1998) Peripheral neuropathies (Caselli, 1988) Sciatic neuropathy Carpal tunnel syndrome (Dennis, 1996) Vernet’s syndrome (affection of ninth, tenth, and eleventh cranial nerves due to ischemia of ascending pharyngeal artery) (Gout, 1998) Pain syndromes (headache, neck pain, backache) (Caselli, 1993) Respiratory tract (Gur, 1996; Rischmueller, 1996; Zenone, 1994) Cough (Lim, 1999; Olopade, 1997) Hoarseness Diaphragmatic weakness (Burton, 1999) Tongue ischemia (Caselli, 1988) Seronegative polyarthritis Coronary arteritis and myocardial infarction (Freddo, 1999) Visceral involvement Renal involvement (Lin, 1995) Visceral angiitis Liver involvement (Ilan, 1993; Killer, 2000) Small bowel infarction (Phelan, 1993) Tongue necrosis (Llorente, 1994) Submandibular swelling (Ruiz-Masera, 1995) Secondary amyloidosis (Altlparmak, 2001; Stebbing, 1999) Ischemic skin lesions (Hansen, 1995) and scalp necrosis (Botella-Estrada, 1999; Currey, 1997; Rudd, 1998) Association with parvovirus B19 infection (Gabriel, 1999; Straud, 1996) Mortality (Bisgard, 1991; Matteson, 1996) Myocardial infarction and mesenteric infarction |
Is a TAB Necessary in a Patient with a High Clinical Suspicion for GCA? Should a Unilateral or Bilateral TAB Be Performed?
Anticardiolipin antibodies (Kerleau, 1994; Manna, 1998; McHugh, 1990) Antineutrophilic antibodies (Bosch, 1991; McHugh, 1990) Mild to moderate normochromic, normocytic anemia (Weiss, 1995) Elevated white blood cell count and platelet count Thrombocytosis (Gonzalez-Alegre, 2001; Lincoff, 2000) Elevated acute-phase reactant proteins (e.g., fibrinogen, von Willebrand factor) (Pountain, 1994) Abnormal plasma viscosity (Gudmundsson, 1993; Orrell, 1993) Serum protein electrophoresis abnormalities Hepatic dysfunction Elevated endothelin-1 plasma levels (Pache, 2002) Multiple immunologic abnormalities (Bosch, 1991; Radda, 1981; Salvarani, 1991; Wawryk, 1991; Weyand, 1992, 1994, 1995, 1997) Immune complexes T-cell abnormalities Immunohistochemical abnormalities HLA-DR4 and -DR3 (Combe, 1998; Gros, 1998) |
Patients with a negative unilateral TAB in whom there is a strong clinical suspicion (see clinical features and symptom clusters, above) for GCA should be considered for a contralateral TAB (Coppetto, 1990; Hunder, 1990a). To minimize costs, some authors have advocated that a frozen section be performed on the symptomatic-side TAB and, if it is normal, proceed at the same sitting with a contralateral TAB (Hall, 1984).
Ponge et al analyzed 200 patients who underwent 200 bilateral TAB, all of which were preceded by Doppler flow studies. Forty-two TABs were positive, 20 bilaterally and 22 unilaterally (Ponge, 1988). In their analysis, they discovered that four patients with GCA would not have been diagnosed if only a unilateral TAB had been performed. Unilaterally positive TABs have been demonstrated in 8 to 14% of retrospective bilateral TAB series (Hall, 1984). Hall and Hunder retrospectively reviewed 652 TABs at Mayo Clinic (Hall, 1984). Of these, 234 (36%) revealed GCA, and 193 (82%) were positive on unilateral TAB. Bilateral TABs were performed in 41 cases (18%) because frozen section was normal on the first TAB. Of the 193 unilateral TABs, frozen section was abnormal in 188 and normal in 5. Thus, 86% of the 234 cases would have been diagnosed by unilateral TAB alone and 14% were diagnosed only because a TAB was performed on the contralateral side. Hayreh et al reported 76 of 363 patients who underwent a second TAB because of a strong clinical index of suspicion for GCA (Hayreh, 1997). Seven of these 76 patients had a positive contralateral TAB. Of the remaining 257 patients with a negative TAB, none developed signs of GCA on follow-up and these authors thought that this was indicative that a second TAB would not have been positive.
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