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Basics

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Author:

Donald J.Lefkowits


Description!!navigator!!

Genetics

Genetic predisposition is linked to HLA-DR4 - 60% prevalence

Etiology!!navigator!!

Diagnosis

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Signs and Symptoms!!navigator!!

Essential Workup!!navigator!!

Diagnostic Tests & Interpretation!!navigator!!

Lab

  • Elevated ESR, often >100 mm/hr
    • ESR <40 is rare
  • C-reactive protein above 2.45 mg/dL
  • Complete blood count (CBC):
    • A mild normochromic anemia is typical
    • Thrombocytosis (often mild)
    • White cell count can be normal or slightly elevated and differential is usually normal
  • Liver function tests and prothrombin time may be elevated; creatine phosphokinase, tests of renal function, and urinalysis are generally normal
  • Elevation in interleukin-6 (IL-6) is seen during flares

Imaging

  • Color Doppler US:
    • Decreased blood flow in temporal, facial, and ophthalmic arteries
    • Presence of the “halo sign” is highly suggestive
  • MRI:
    • Indicated for exam of large arteries
  • Angiogram:
    • Smooth, tapered occlusions or stenosis

Diagnostic Procedures/Surgery

  • Temporal artery biopsy:
    • Multiple sections should be done as soon as feasible after initiation of steroid therapy
    • Gold stand ard for diagnosis
    • Contralateral biopsy is recommended if first is negative and index of suspicion high

Differential Diagnosis!!navigator!!

Treatment

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Prehospital!!navigator!!

Initial Stabilization/Therapy!!navigator!!

ED Treatment/Procedures!!navigator!!

Medication!!navigator!!

Follow-Up

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Disposition!!navigator!!

Admission Criteria

  • Patients with impending vascular complications or acute focal neurologic findings
  • Patients with associated acute visual loss or decrease in visual acuity

Discharge Criteria

  • Less symptomatic patients without evidence of end-organ involvement
  • Follow-up arranged within 1-2 d

Issues for Referral

  • Rheumatology
  • Ophthalmology if associated with visual symptoms
  • Neurology with acute focal neurologic findings

Follow-up Recommendations!!navigator!!

Pearls and Pitfalls

  • Permanent visual loss is the most feared complication of GCA
  • Do not delay initiation of steroid therapy to await biopsy if strong clinical suspicion for GCA exists or if visual changes are reported
  • Jaw claudication and amaurosis fugax, while often dramatic, are symptoms patients often neglect to report:
    • Query directly and specifically about them if TA/GCA is being considered
  • 25-50% of patients who present with acute loss of vision in 1 eye who go untreated will develop bilateral blindness

Additional Reading

See Also (Topic, Algorithm, Electronic Media Element)

Codes

ICD9

446.5 Giant cell arteritis

ICD10

SNOMED