Bashed, Blind and Bulging

aka Ophthalmology Befuddler 033

A 35 year-old martial artist presents with loss of vision in his right eye after being on the wrong end of a spinning back fist.

Examination of the right eye reveals:

  • He is unable to detect light when the eyelids are passively opened.
  • There is a relative afferent pupillary defect affecting the right eye.
  • Extraocular movements are markedly reduced.
  • Tonometry reveals an intraocular pressure of 45 mmHg.
retrobulbar hemorrhage EYE trauma

Questions

Q1. What is shown and what is the likely diagnosis?
Answer and interpretation

The right eye appears proptosed with a dilated pupil, extensive subconjunctival hemorrhage and bloody chemosis, as well evidence of periorbital swelling and hematoma.

The likely underlying diagnosis is:

Retrobulbar hemorrhage due to trauma, resulting in acute orbital compartment syndrome.

Hemorrhage into the potential space within the rigid orbit and around the eye transmits pressure onto the optic nerve. Acute orbital compartment syndrome occurs when this results in a compressive optic neuropathy.

The main differentials are:

  • ruptured globe: proptosis and raised intraocular pressure are not consistent with this
  • orbital blowout fracture: raised intraocular pressure, RAPD and decreased visual acuity are not seen in this condition unless there is coexistent retrobulbar hemorrhage.

Q2. What are the clinical features of this condition on history?
Answer and interpretation

History:

  • Symptoms: pain, decreased vision, inability to open the eyelids due to severe swelling.
  • Cause: history of trauma or surgery to the eye or orbit, or retrobulbar injection.
  • Risk factors for spontaneous hemorrhage — bleeding disorder, anticoagulants and anti-platelet drugs, pregnancy.

Q3. What are the clinical features of this condition on examination?
Answer and interpretation

Examination:

  • Visual acuity and visual fields:  decreased with dyschromatopsia (signs of optic neuropathy)
  • External exam: Proptosis with resistance to retropulsion, diffuse subconjunctival hemorrhage, tight eyelids (rock hard) with echymosis and chemosis.
  • Extraocular eye movements: limited extraocular motility
  • Pupils: RAPD.
  • Tonometry: increased intraocular pressure (IOP)
  • Funduscopy: papilloedema from compressive optic neuropathy may be present, retinal artery or vein occlusion.

Q4. What investigation should be performed and what are the typical findings?
Answer and interpretation

Retrobulbar haemorrhage with acute orbital compartment syndrome is primarily a clinical diagnosis.

CT orbit (axial and coronal views) can confirm the diagnosis — but if vision is threatened treat first!

Usual findings on CT:

  • diffuse, increased reticular pattern of the intraconal orbital fat rather than a discrete hematoma.
  • teardrop or tenting sign is ominous — it occurs when the optic nerve is at maximum stretch and distorts the back of the globe into a teardrop shape.

Q5. What is the treatment of this condition?
Answer and interpretation

Admit to hospital and treat with aggressive decompression.

Therapy depends on whether there is compressive optic neuropathy or severely raised IOP:

  • Evidence of optic neuropathy or severely raised IOP (>40 mmHg): lateral canthotomy and cantholysis should be performed immediately (ideally by an ophthalmologist); use procedural sedation in the ED if it does not cause a delay.
  • No evidence of optic neuropathy but IOP is raised (e.g. >30 mmHg): treat with agents used to lower IOP (e.g. topical timolol, acetazolamide, mannitol; see acute glaucoma).

McInnes and Howes suggest the DIP-A CONE-G mnemonic for remembering the indications and contra-indications for this procedure:

Primary indications:

  • Decreased visual acuity
  • Intraocular pressure > 40 mm Hg
  • Proptosis

Secondary indications:

  • Afferent pupillary defect
  • Cherry red macula
  • Ophthalmoplegia
  • Nerve head pallor
  • Eye pain

Contraindications:

  • Globe rupture

Q6. How is a lateral canthotomy/ cantholysis performed?
Answer and interpretation

The main steps in emergency canthotomy/ cantholysis are:

  • use local anesthetic but warn the patient that they may feel pain
  • Perform the canthotomy:
    • place the scissors across the lateral canthus and incise the canthus full thickness
  • Perform cantholysis:
    • Grasp the lateral lower eyelid with toothed forcepsPull the lower eyelid anteriorlyPoint the scissors toward the patient’s nose, place the blades either side of the lateral canthal tendon, and cut.

Cantholysis is done more by feel than by visual identification of landmarks — the lower eyelid will come completely away from the globe once the tendon has been completely severed.

Good overview from Ballard et al: Emergency lateral canthotomy and cantholysis: a simple procedure to preserve vision from sight threatening orbital hemorrhage.

Emergency lateral canthotomy and cantholysis: a simple procedure to preserve vision from sight threatening orbital hemorrhage.


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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