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Cranial Nerves


February 15th, 2021
On this page:Extra Credit


When performing a cranial nerve examination, always ask to perform fundoscopy. This may provide valuable information regarding ocular or cranial nerve pathology, and reveals signs of diabetic or hypertensive nephropathy.
  • How to Perform

  • Dim the lights and examine the fundus using a traditional direct or PanOptic ophthalmoscope.
Dilate the eye if possible with tropicamide, atropine or phenylephrine eye drops.
  • Interpretation

  • Increased cup-disc ratio (>0.8, normally <0.5): the ratio of the size between the optic cup and the surrounding optic disc (entry point of the optic nerve and vessels)Glaucoma, giant cell arteritis, optic nerve compression / trauma / inflammation
  • Papilloedema: swelling of the disc with venous engorgement, cotton wool spots and haemorrhageRaised ICP, severe hypertension
  • Cotton wool spots: small white, cotton wool-like microinfarcts on the retinaHypertension, diabetes, HIV, anaemia, thrombocytopaenia, connective tissue disorders
  • Arteriovenous nicking: arteries displacing veins at points of crossingHypertension
  • Silver wiring: glistening bronze / silver arterial wallsHypertension
  • Retinal haemorrhages - e.g. small dots or flame-shapedDiabetes, leukaemia, pernicious anaemia, subarachnoid haemorrhage, DIC
  • Roth spots: haemorrhages with pale centresInfective endocarditis
  • Emboli: small white flecks over vessels, with distal narrowing.Generally cholesterol emboli from carotid artery disease

Extra Credit

  • Signs of Diabetic Retinopathy

  • Microaneurysms: tiny dot-like outpouchings
  • Cotton wool spots
  • Haemorrhages (small dots)
  • Macular oedema
  • Neovascularisation: formation of abnormal and fragile vessels
  • Signs of Hypertensive Retinopathy

  • Grade 1 - silver wiring
  • Grade 2 - arteriovenous nicking
  • Grade 3 - flame-shaped haemorrhages, cotton wool spots
  • Grade 4 - papilloedema
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