01Approach to the Critical Patient/attcp57

Immediate priorities

›Vision loss and ischemic threats

›Sudden painless visual loss or amaurosis fugax

›Ophthalmologic emergency requiring immediate action

›Risk of bilateral blindness without treatment

›Diplopia or RAPD on exam

›Impending permanent vision loss indicator

›Urgent ophthalmology consultation

›If active vision loss, IV methylprednisolone 1 g/day x 3 days

›Do not delay for biopsy

›Class I recommendation for vision-threatening GCA

›Cerebrovascular and vascular threats

›TIA or stroke symptoms

›GCA causes stroke in approximately 7% of confirmed cases

›Urgent neurology and vascular assessment

›Asymmetric blood pressures or absent pulses

›Large-vessel involvement pattern

›Consider aortic imaging

›Chest or back pain with GCA diagnosis

›Aortitis or aortic aneurysm concern

›CT angiography aorta consideration

Monitoring and targets

›Monitoring bundle

›Visual acuity checks at presentation and after steroid initiation

›Document baseline VA both eyes

›Repeat after 24 to 48 hours

›Bilateral blood pressure measurements

›Asymmetry >10 mmHg suggests large-vessel involvement

02History/hx66

Core symptoms

›Headache pattern

›New-onset headache in patient age 50 or older

›Present in approximately 2/3 of patients

›Typically temporal, unilateral or bilateral

›Boring or throbbing quality

›Often constant rather than episodic

›Distinct from prior headache patterns

Alarm features

›Vision changes

›Amaurosis fugax

›Transient monocular vision loss

›Often precedes permanent loss

›Sudden painless permanent visual loss

›Arteritic anterior ischemic optic neuropathy most common cause

›Central retinal artery occlusion less common

›Diplopia

›Cranial nerve III, IV, or VI involvement

›Associated with higher ischemic complication risk

›Jaw and tongue claudication

›Jaw pain with chewing resolving with rest

›Positive likelihood ratio 4.90 for GCA diagnosis

›One of the most specific symptoms

›Tongue claudication or dysphagia

›Rare but associated with higher complication risk

›Scalp necrosis rare but pathognomonic

Constitutional symptoms

›Systemic features

03Physical Exam/exam59

Vital signs and general

›Vital sign assessment

›Temperature

›Low-grade fever in subset

›Normal temperature does not exclude active disease

›Bilateral blood pressure in both arms

›Asymmetry >10 mmHg indicates large-vessel involvement

›Document at initial assessment

›Heart rate and respiratory rate

›Tachycardia may indicate aortic involvement or severe disease

›Baseline hemodynamic stability

Temporal artery and head exam

›Temporal artery palpation

›Tenderness on palpation

›Positive likelihood ratio 2.60 for GCA

›Bilateral palpation required

›Thickening or nodularity

›Positive likelihood ratio 4.70

›Compare side to side

›Loss of temporal artery pulse

›Positive likelihood ratio 3.25

›Occluded vessel sign

›Prominence of temporal artery

›Visible tortuous course

›May be associated with normal or reduced pulse

›Scalp tenderness

›Tenderness on scalp palpation

›Positive likelihood ratio 3.14

04Differential Diagnosis/ddx55

Life-threatening mimics

›Vascular emergencies

›Aortic dissection

›ICD-10 I71.0

›Chest and back pain with BP asymmetry

›Central retinal artery occlusion from atherosclerosis

›ICD-10 H34.1

›Typically lacks systemic inflammation

›Vertebrobasilar TIA or stroke

›ICD-10 G45.0 to G45.9

›Posterior circulation visual symptoms

›Non-arteritic anterior ischemic optic neuropathy

›ICD-10 H47.01

›Visual loss without systemic inflammation

›Typically younger with cardiovascular risk factors

›Normal ESR and CRP

Vasculitis and inflammatory conditions

›Other vasculitides

›ANCA-associated vasculitis

›ICD-10 M31.3

›Renal and pulmonary involvement

›Positive ANCA serology

›Takayasu arteritis

›ICD-10 M31.4

›Similar large-vessel pattern but age typically less than 50

›Different ethnic distribution

›Primary CNS angiitis

›ICD-10 I67.7

05Laboratory Tests/lt47

Inflammatory markers

›Erythrocyte sedimentation rate

›Westergren method ESR

›Sensitivity approximately 80% for GCA

›Typically greater than 50 mm/hr

›ESR greater than 40 mm/hr

›Negative likelihood ratio 0.18 when normal

›Normal ESR substantially reduces but does not exclude diagnosis

›Marked elevation greater than 100 mm/hr

›Increases diagnostic probability

›Monitor during taper

›C-reactive protein

›CRP elevated in approximately 96% of biopsy-proven GCA

›Higher sensitivity than ESR alone

›CRP greater than or equal to 2.5 mg/dL associated with diagnosis

›Negative likelihood ratio 0.38 when below threshold

›Combined normal ESR and CRP found in only 3 to 4% of confirmed GCA

›Tocilizumab suppresses CRP making it unreliable for monitoring on therapy

Complete blood count

›CBC findings

›Thrombocytosis

›Platelets greater than 400 x 10 to the 9th per litre

›Positive likelihood ratio 3.75 for GCA

›Normocytic anemia

›Anemia of chronic inflammation pattern

›Hematocrit commonly reduced

›Leukocytosis

›May be present but less specific

06Diagnostic Tests/dt100

Scoring Systems

›2022 ACR/EULAR Classification Criteria for GCA

›Weighted criteria scoring system

›Age 50 years or older required at entry

›Applies when GCA on differential

›Positive criteria and their weighted scores

›Morning stiffness in shoulders or neck: +2

›Sudden visual loss: +3

›Jaw or tongue claudication: +2

›New temporal headache: +2

›Temporal artery abnormality on exam or imaging: +5

›Biopsy showing GCA histology: +5

›Halo sign on temporal artery ultrasound: +5

›Score of 6 or more classifies as GCA

›Sensitivity 87%, specificity 95% in validation cohorts

›Classification criteria not diagnostic criteria

›Likelihood ratios for clinical features

›Individual symptom and sign LR data

›Limb claudication LR+ 6.01

›Temporal artery thickening LR+ 4.70

›Jaw claudication LR+ 4.90

›Combined probability assessment

›Multiple positive features substantially increase pre-test probability

›Normal ESR and CRP together substantially reduce probability

MRI

›MRI and MRA of cranial vessels

›Vessel wall imaging

›Concentric vessel wall thickening and enhancement in GCA

›High-resolution vessel wall MRI emerging technique

›Temporal artery MRI

›Sensitivity 78%, specificity 90% in selected populations

›Operator and field strength dependent

›MRA for large-vessel assessment

›Subclavian, axillary, carotid involvement mapping

›Stenosis and aneurysm detection without contrast in some protocols

›Brain MRI indications

›Stroke or TIA symptoms attributable to GCA

›DWI sequences for acute ischemia

›T2/FLAIR for subacute infarct

›Posterior fossa and visual pathway assessment

›Occipital infarction pattern in vertebrobasilar GCA

›Visual cortex involvement

›MRI aorta

›Aortitis and aortic aneurysm assessment

›Aortic wall thickening and enhancement

›Long-term surveillance role in large-vessel GCA

›Contraindications

›Pacemaker or non-MRI compatible implants

›Severe claustrophobia

›Acute hemodynamic instability

CT

›CT angiography for large-vessel involvement

›Indications

›Suspected aortitis or aortic aneurysm

›Limb claudication or asymmetric pulses

›CT angiography of thorax and abdomen

›Luminal narrowing, wall thickening, aneurysm detection

›Sensitivity reported up to 100% for aortic GCA involvement in selected studies

›CT angiography of neck and intracranial vessels

›Carotid and vertebral artery involvement

›Intracranial extension assessment

›FDG-PET CT

›Indications

›Large-vessel GCA suspected without localizing signs

›Fever of unknown origin workup with GCA suspicion

›High sensitivity for active large-vessel inflammation

›Sensitivity 80 to 90% for large-vessel involvement

›Not useful for cranial vessel assessment due to brain uptake

›Limitations

›Steroids reduce FDG uptake within days

›Perform before or within 72 hours of starting steroids

›Temporal artery biopsy pathology context

›Not a CT finding but essential diagnostic test

›Segment at least 2 cm recommended

›Skip lesions require longer segment

›Histology findings

›Granulomatous inflammation with giant cells

›Intimal hyperplasia and internal elastic lamina disruption

›Negative biopsy does not exclude GCA in high clinical probability

Ultrasound

›Temporal artery ultrasound

›Halo sign

›Dark hypoechoic halo around temporal artery lumen

›Sensitivity 77%, specificity 96% versus biopsy per Cochrane review 2024

›Compression sign

›Non-compressible halo on direct pressure

›Distinguishes from edema or artifact

›Bilateral temporal artery assessment

›Both superficial temporal arteries and branches

›Frontal and parietal branches inclusion

›Axillary artery ultrasound

›Large-vessel GCA pattern

›Axillary halo sign

›Intima-media thickness measurement

›Combined temporal and axillary ultrasound

›Increases sensitivity for GCA diagnosis

›Recommended when cranial symptoms absent but GCA suspected

›Ultrasound as fast-track diagnostic

›Available within hours of presentation

›ACEP equivalent to biopsy in high-probability settings per emerging evidence

›Reduces time to diagnosis in specialized units

›Operator and equipment dependent

›High-frequency probe 15 to 22 MHz required

›Specialist training required for accurate interpretation

07Disposition/dispo43

Admission indications

›Hospital admission criteria

›Active vision loss or amaurosis fugax

›IV methylprednisolone initiation

›Ophthalmology inpatient assessment

›Stroke or TIA symptoms attributable to GCA

›Stroke unit or monitored bed

›Antiplatelet therapy review

›Suspected aortitis or aortic dissection

›Urgent CT angiography

›Vascular surgery consultation

›Significant comorbidities complicating steroid initiation

›Poorly controlled diabetes

›Active infection requiring treatment

›Inability to ensure close follow-up

›Social supports inadequate

›Unreliable adherence concern

Discharge with close follow-up

›ED discharge criteria

›No visual symptoms and stable exam

›Normal visual acuity and fields

›No RAPD

›Oral steroids initiated

›Prednisone 40 to 60 mg per day started

›Written instructions provided

›Reliable patient with adequate supports

›Understands vision loss warning signs

›Has reliable transportation for urgent return

08Treatment/t81

Glucocorticoid therapy

›Initial steroid dosing

›Uncomplicated cranial GCA without vision loss

›Prednisone 40 to 60 mg per day orally

›Class I recommendation per ACR 2021 guidelines

›Vision loss or imminent vision-threatening disease

›IV methylprednisolone 1 g per day for 3 days

›Transition to oral prednisone 1 mg/kg/day after pulse

›Continue until symptoms resolve and inflammatory markers normalize

›Typically 2 to 4 weeks at initial dose

›ESR and CRP guide response assessment

›Steroid taper protocol

›Initial taper

›Reduce by 10 to 20% per month while monitoring ESR and CRP

›Taper more slowly when dose below 20 mg per day

›When dose below 10 mg per day

›Reduce by 1 mg per month

›Accelerate taper if tocilizumab added

›Total treatment duration 1 to 5 years

›Aim for 0 to 5 mg per day by 12 months when possible

›Relapse requires dose increase to prior effective dose

Glucocorticoid-sparing agents

›Tocilizumab (IL-6 receptor inhibitor)

›Subcutaneous tocilizumab 162 mg weekly

›FDA-approved for GCA

›Conditionally recommended with glucocorticoids as initial therapy per ACR 2021

›Alternative dosing 162 mg every other week

›For new diagnosis or lower-risk features

›Discuss with rheumatology

›Intravenous tocilizumab 8 mg/kg every 4 weeks

›Alternative route for selected patients

›Maximum dose 800 mg per infusion

›Monitoring on tocilizumab

›CRP unreliable for disease activity monitoring on therapy

›Lipid panel, LFTs, CBC monitoring

›Contraindications and precautions

›Active infection or high infection risk

›Diverticulosis or diverticulitis history

›GI perforation risk

›Upadacitinib (JAK inhibitor)

›Upadacitinib 15 mg orally daily

›Recently FDA-approved for GCA

›Glucocorticoid-sparing option

›Monitoring

›Infection surveillance including reactivation of latent TB and herpes zoster

›Cardiovascular and thromboembolic risk assessment

›Preferred over tocilizumab when

›Subcutaneous injection not feasible

›Diverticular disease present

›Methotrexate (alternative)

›Methotrexate 7.5 to 15 mg orally once weekly

›Alternative steroid-sparing agent if tocilizumab or upadacitinib contraindicated

›Folic acid 1 mg daily to reduce toxicity

›Monitoring

›CBC and LFTs every 4 to 8 weeks

›Renal function monitoring

›Avoid in significant hepatic or renal impairment

›Agents to avoid

›Infliximab should NOT be used in GCA

›Associated with worse outcomes in controlled trials

›Class III harm designation

Supportive and preventive measures

›Steroid-associated complication prevention

›Proton pump inhibitor for GI prophylaxis

›Omeprazole 20 mg daily or equivalent

›Continue while on high-dose steroids

›Calcium and vitamin D supplementation

›Calcium 1000 to 1500 mg per day

›Vitamin D 800 to 1000 IU per day

›Bone density monitoring

›DEXA scan at baseline

›Bisphosphonate consideration per osteoporosis risk

›Glucose monitoring

›Fasting glucose or HbA1c at baseline

›Home glucose monitoring if elevated

›Aspirin therapy consideration

›Low-dose aspirin 81 mg daily

›Consider for ischemic risk reduction in high-risk features

›Evidence limited but used in clinical practice for patients with prior ischemic events

›Weigh GI bleeding risk

›Pneumocystis jirovecii prophylaxis

›Trimethoprim-sulfamethoxazole 80/400 mg daily or 160/800 mg three times per week

›Consider with prolonged high-dose prednisone above 20 mg per day

›Continued for duration of high-dose steroid exposure

09Special Populations/sp54

Pregnancy

›Pregnancy considerations

›GCA extremely rare in reproductive age

›Age requirement of 50 years virtually excludes pregnancy overlap

›Consider other vasculitides if young patient

›If GCA occurs in perimenopause

›Prednisone preferred initial therapy

›Avoid methotrexate in pregnancy

›Teratogenic

›Contraindicated

›Tocilizumab in pregnancy

›Limited safety data

›Crosses placenta in third trimester

›Avoid unless benefit clearly outweighs risk

›Steroid effects in pregnancy

›Gestational diabetes risk increased

›Preeclampsia risk

›Fetal monitoring when viable gestation

Geriatric

›Geriatric-specific features

›GCA is predominantly a disease of older adults

›Peak incidence 70 to 75 years

›Steroid side effects more severe in this population

›Steroid complications magnified

›Osteoporosis fracture risk markedly elevated

›Delirium and neuropsychiatric effects

›Glucose intolerance and diabetes

›High rates of steroid-induced hyperglycemia

10Background/b83

Epidemiology

›Incidence and prevalence

›Most common primary vasculitis in adults

›Incidence 10 to 30 per 100,000 persons age 50 or older per year

›Higher rates in Scandinavian populations

›Northern European descent highest risk

›Swedish and Norwegian populations most affected

›Lower rates in Asian and African populations

›Female predominance

›Women to men ratio approximately 2:1

›Hormonal factors suspected but unproven

›Risk of complications

›Vision loss in 15 to 20% of untreated or undertreated patients

›Arteritic AION most common cause of permanent vision loss

›Bilateral vision loss possible within days without treatment

›Stroke in approximately 7% of confirmed GCA cases

›Vertebrobasilar distribution most common

›Associated with significantly worse prognosis

›Aortic aneurysm risk 17 times higher than age-matched controls

›Long-term surveillance required

›Often asymptomatic until complication

›Relapse epidemiology

›Approximately 50% of patients experience at least one relapse

›Most common during steroid taper

›Minor relapses PMR symptoms in approximately 75%

›Major relapses ischemic symptoms in approximately 25%

Pathophysiology

›Immunologic mechanisms

›Immune-mediated granulomatous vasculitis

›CD4+ T-helper cell activation in vessel wall

›Macrophage and giant cell recruitment

›IL-6 and IL-17 pathways central to inflammation

›Rationale for tocilizumab (IL-6 receptor blockade)

›JAK-STAT signaling pathway targeted by upadacitinib

›HLA-DRB1 04 alleles associated with GCA susceptibility

›Genetic predisposition identified

›Northern European genetic background

›Vessel involvement pattern

›Medium and large vessel tropism

›Temporal arteries classic involvement

›Ophthalmic artery and posterior ciliary artery vision supply

›Large-vessel GCA subtype

›Aorta, subclavian, axillary arteries

›Clinically distinct but may overlap with cranial GCA

›Ischemic complications mechanism

›Intimal hyperplasia causes luminal occlusion

›Internal elastic lamina disruption

›Platelet aggregation at inflamed vessel wall

›Triggering factors

›Infectious triggers suspected

›Mycoplasma and Chlamydia pneumoniae implicated but unproven

›Varicella-zoster virus arterial tropism studied

›Age-related immune senescence

›Dendritic cell dysregulation in vessel adventitia

›Reduced regulatory T-cell function

Therapeutic Considerations

›Steroid dependency and taper

›High-dose steroids required initially for ischemic protection

›Inflammatory cascade suppression within 24 to 72 hours

›Symptom response guides taper pace

›Long taper required due to relapse risk

›Average treatment duration 2 to 3 years

›Taper guided by ESR and CRP when not on tocilizumab

›Tocilizumab allows faster steroid taper in GiACTA trial

›56% sustained remission at 52 weeks versus 14 to 18% placebo

›Steroid cumulative dose substantially reduced

›Monitoring strategy

›Inflammatory markers guide activity assessment when not on IL-6 inhibitor

›ESR and CRP monthly initially then quarterly

›Rising markers with symptoms signal relapse

›Imaging for large-vessel surveillance

›CT or MRI of chest and abdomen every 1 to 2 years

›Even after disease remission for aortic aneurysm detection

›Ophthalmology monitoring

›Baseline and periodic visual field testing

›Any new visual symptoms warrant urgent assessment

›Treatment failure and refractory disease

›True refractory GCA uncommon

›Reassess diagnosis if no response to steroids within 72 hours

›Alternative diagnoses must be considered

›Biologic switch if tocilizumab fails

›Upadacitinib as alternative mechanism

›Rituximab off-label in selected refractory cases

›Infliximab contraindicated based on evidence

›Associated with worse outcomes in GCA trials

›Class III harm per rheumatology guidelines

11Patient Discharge Instructions/pdi48

copy discharge instructions

›Giant cell arteritis (GCA) home care instructions

›Take prednisone exactly as prescribed every morning with food

›Do not stop or reduce the dose without talking to your doctor first

›Stopping suddenly can be dangerous

›Take your stomach protection medication (proton pump inhibitor) daily

›Take calcium and vitamin D supplements as prescribed

›Check blood sugar as instructed if you have diabetes or your doctor recommends it

›Warning signs that require immediate return to the emergency department

›Any change in vision in either eye

›Blurring, darkening, loss of part or all of vision

›Double vision

›New or worsening headache that is severe

›Especially if different from your usual headache

›Any sudden severe headache

›Pain in the jaw when chewing

›Or difficulty opening the mouth fully

›Stop eating and seek care immediately

›Weakness or numbness in face, arm, or leg

›Difficulty speaking or understanding speech

›These may be signs of stroke

›Chest pain, back pain, or arm pain with activity

›May indicate blood vessel involvement in chest

›Seek emergency care immediately

›Scalp pain or tenderness that suddenly worsens

›Especially with any skin color change

›Follow-up appointments

›Rheumatology within 1 to 2 weeks

12References/r35

Guidelines and key sources

›Primary guideline references

›2021 ACR/Vasculitis Foundation Guideline for Management of Giant Cell Arteritis and Takayasu Arteritis

›Maz M et al. Arthritis Care and Research 2021

›Tocilizumab conditional recommendation for initial therapy with glucocorticoids

›2022 ACR/EULAR Classification Criteria for Giant Cell Arteritis

›Ponte C et al. Arthritis and Rheumatology 2022

›Weighted criteria system with imaging incorporated

›Landmark trials and systematic reviews

›GiACTA Trial tocilizumab in GCA

›New England Journal of Medicine 2017

›56% sustained remission with weekly subcutaneous tocilizumab

›Cochrane Review halo sign versus biopsy 2024

›Pouncey AL et al. Cochrane Database of Systematic Reviews

›Sensitivity 77%, specificity 96% for temporal artery ultrasound halo sign

›Diagnostic accuracy systematic review

›van der Geest KSM et al. JAMA Internal Medicine 2020

›Likelihood ratios for symptoms, signs, and laboratory tests

›Population-based inflammatory marker performance

›Castillejo Becerra CM et al. American Journal of Ophthalmology 2025

›Both ESR and CRP normal in 3 to 4% of biopsy-proven GCA

›Key review articles

›Large-Vessel Vasculitis. Lancet 2025

›Cacoub P et al.

›Comprehensive review including upadacitinib approval

›Giant Cell Arteritis. Annals of Internal Medicine 2026

›Kermani TA

›Current evidence summary with relapse data

Evidence & Review