You’re blind and your hair is a mess

aka Ophthalmology Befuddler 022

A 65 year-old man presents with sudden onset painless loss of vision affecting the lower half his right eye’s visual field. He says he skipped breakfast because it hurt to chew, and his hair is mess because it was too painful to comb. He has a low-grade fever and has been losing weight recently.

He can barely count fingers with his right eye, there is a relative afferent pupillary defect, he has a tender and palpable right temporal artery and on fundoscopy you see this:

Anterior ischemic optic neuropathy AION

Questions

Q1. What is the likely diagnosis?
Answer and interpretation

Anterior ischemic optic neuropathy (AION) due to giant cell arteritis

The history and examination is classic for giant cell arteritis, and papilloedema is evident on funduscopy.


Q2. What are the features on history?
Answer and interpretation

History:

  • visual loss: sudden and painless, can be severe and bilateral, may be preceded by amaurosis fugax. 1/2 unilateral, 1/3 sequential, 1/6 bilateral.
  • local symptoms: temporal headache, scalp tenderness (pain on combing hair), jaw claudication (pain with chewing)
  • systemic symptoms: fever and night sweats,  weight loss, malaise, anorexia
  • polymyalgia rheumatica: generalised muscle pain and weakness, predominatly affects the muscles of the limb girdles
  • age >50y (very rare younger than this, incidence rises with age)
  • assess for factors that may complicate steroid treatment – e.g. peptic ulcer disease, GI bleeding, poorly controlled diabetes, Tb.

Q3. What are the features on examination?
Answer and interpretation

Examination:

  • Visual acuity — poor e.g. CF only
  • Visual fields — defect may be present, respects the horizontal meridian (‘altitudinal’) or central
  • External examination — palpable and tender non-pulsatile temporal artery
  • Pupils — RAPD
  • Fundoscopy — papilloedema and flame-shaped hemorrhages may be seen, optic atrophy occurs late

Q4. Describe the investigation and management of this condition.
Answer and interpretation

Referral to ophthalmologist and arrange:

Immediate ESR/CRP (can be normal!)  – thrombocytosis may also be present

Urgent treatment with corticosteroids: start when the diagnosis is suspected, do not wait for confirmation.

  • use high-dose IV methyprednisolone initially — e.g. 250 mg IV q6h for 72 hours — more effective than oral prednisone in promoting recovery of vision and preventing the fellow eye from being affected; 1/3 with visual loss will recover.
  • follow with oral prednisolone ~ 1mg/kg until GCA ruled out, or until symptoms improve and ESR normalises — then a reducing dose over 6-12+ months is commonly used.
  • consider ulcer prophylaxis and risk of osteoporosis.

Temporal artery biopsy to confirm the diagnosis of GCA

  • perform within 1 week of symptom onset.
  • if negative on a 2cm biopsy but GCA is highly suspected, biopsy the other temporal artery
  • if negative stop treatment with prednisolone unless the presentation is classic and responded to steroid

Q5. What is the upper limit of normal for ESR?
Answer and interpretation

A guide to the upper limit of normal ESR is:

  • age/2 for men
  • (age + 10)/2 for women

Q6. What other types of ischemic optic neuropathy are there?
Answer and interpretation

In addition to arteritic ischemic neuropathy (which is commonly caused by GCA, but can occur in other forms of vasculitis), there is also:

  • Non-arteritic ischemic optic neuropathy: presents similar to arteritic ION but is usually less severe, and is without the systemic features or scalp/ facial symptoms. It is generally idiopathic, although may be linked to typical cardiovascular risk factors. The condition may be progressive or non-progressive and it is unclear if steroids are beneficial.
  • Postoperative ischemic optic neuropathy: occurs within 1 week of general anesthesia and is of uncertain etiology. It is associated with many different types of surgery, as well as head-down positioning and prolonged operative times. Correction of intra-operative hypotension and anemia may be beneficial.

Q7. What is the differential diagnosis of ischemic optic neuropathy?
Answer and interpretation
  • optic neuritis
  • other optic neuropathies — e.g. glaucoma, compressive optic neuropathy, radiation optic neuropathy, metabolic and toxic optic neuropathies
  • central retinal vein occlusion
  • central retinal artery occlusion
  • chiasmal and post-chiasmal visual loss

References

Ophthalmology Befuddler 700

CLINICAL CASES

Ophthalmology Befuddler

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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