Cranial Nerves and Ophthalmology Flashcards
List 5 differentials for anosmia
- Ageing
- Traumatic brain injury
- Alzheimer’s
- Parkinson’s
- Tumour
What is the first step in assessing optic acuity (clarity of vision)
Use a Snellen chart
- 6 metres from chart, one eye at a time
- Record lowest line able to read with 2 or fewer mistakes
- Acuity is distance of chart as numerator over number of lowest line read as denominator
Give 5 symptoms of conjunctivitis
- Conjunctival hyperaemia
- Chemosis
- Crust and discharge
- “foreign body” sensation
- Photophobia
Give 4 ways to differentiate between bacterial and viral conjunctivitis.
Bacterial: Unilateral, thick discharge. reduced vision, urethritis/ vaginal discharge
Viral: Bilateral, watery discharge, normal vision, signs of viral infection
What type of hypersensitivity is allergic conjunctivitis? What 3 extra symptoms occur with allergic conjunctivitis?
- Type 1 hypersensitivity (IgE), Pollen, dust, chemical scents. Young adults.
- Itching
- Sneezing,
- Red, watery and oedematous eye
Give 5 signs of cataracts
- Painless
- Clouding of lens
- Visual impairment and glare
- Visual halos
- Reduced red reflex
What is glaucoma?
For an acutely red, painful eye, what must be ruled out?
- Vision loss resulting from optic nerve damage (retinal ganglion cells) and cupping of the optic disc. Normally due to increased intraocular pressure
- 2nd leading cause of blindness worldwide
Closed angle glaucoma must be ruled out.
Give 4 ways to differentiate open angle and closed angle glaucoma.
- Open angle: bilateral, progressive visual loss, initially asymptomatic, mild nonspecific symptoms. 90% of cases are open angle.
- Closed angle: unilateral, sudden onset, severely painful, N&V, cloudy cornea, headache, dilated pupil
Give 4 investigative techniques for glaucoma.
- Fundoscopy- may show disc cupping
- Gonioscope: enables you to look at angle of iris and determine closed or open angle
- Slit lamp allows closer examination of whole eye.
- Tonometry measures intra-ocular pressure
Which structures are involved in anterior and posterior uveitis respectively?
- Anterior: iris and ciliary body
- Posterior: vitreous body, choroid plexus, retina
Complete uveitis is everything.
Differentiate anterior and posterior uveitis by the following:
- Cause
- Pain
- Vision change-
- Other symptoms
Anterior:
- Autoimmune conditions
- Painful, ocular hyperaemia
- Blurry vision
- Increased lacrimation and photophobia
Posterior:
- Infective cause
- Painless
- Blurry vision
- Floaters and scotomata
Give two investigations for uveitis.
- Fundoscopy
- Slit lamp
Visual fields- What are the medical terms for the following visual field defects and where is the lesion:
- total vision loss in one eye
- loss of peripheral vision in both eyes
- Loss of half of vision on same side in both eyes
- Loss of upper/ lower quarter of vision on same side in both eyes
- Loss of half of vision on same side in both eyes apart from the centre.
- Monocular vision loss- optic nerve
- Bitemporal hemianopia- optic chiasm
- Contralateral homonymous hemianopia- optic tract
- Contralateral superior/ inferior quadrantinopia- optic radiations
- Contralateral homonymous hemianopia with macular sparing- occipital lobe
List 2 prechiasmal causes of vision loss.
List 2 chiasmal causes of vision loss.
- Ischaemia: TIA- amaurosis fugax: veil coming down over vision in one eye.
- Inflammation- MS, temporal arteritis
- Pituitary tumour, craniopharyngioma (compresses from top, not bottom)
What is neglect syndrome? What is it due to?
- Patients completely ignore left side of their world/ body. Patients only eat food on right side of plate/ shave right side of face.
- Due to damage to right parietal lobe.
What 4 optic reflexes are conducted in an exam?
- Direct pupillary
- Consensual pupillary
- Swinging light
- Accommodation
Which nerve is lesioned when there is a loss of consensual pupillary light reflex?
Which nerve is lesioned when there is loss of direct pupillary reflex?
- CN III
- CN II
What does the swinging light (relative afferent pupillary defect) test show?
How is it performed.
- Shows if there is a minor defect in afferent pathway of one eye.
- Swing torch from normal eye to damaged eye rapidly-
- Pupil in damaged eye appears to dilate as it doesn’t pick up as much light from the torch as a normal eye.
Give 3 symptoms of Horner’s syndrome
- Ptosis
- Miosis
- Anhidrosis
Loss of sympathetic stimulation.
Give 3 differentials for Horner’s syndrome
- Brainstem tumour: sympathetic supply originates from hypothalamus and passes down brainstem.
- Pancoast tumour: sympathetic nerve passes along apex of lung.
- Carotid artery dissection- nerve passes up carotid artery to eyes.
Give 3 investigations for the 3 different causes of Horner’s syndrome and when you would suspect each cause.
- CXR: Pancoast tumour- upper limb pain
- CT head: brainstem tumour
- MRI/ MR angiography: carotid dissection- ipsilateral face/ neck pain, trauma,
What 3 signs would be expected from oculomotor nerve palsy?
- down and out eye
- Ptosis
- Mydriasis
What is the difference in presentation between medical and surgical CN3 palsy?
Pupillary control is dorsal and peripheral part of CN3.
Surgical: Mydriasis first
Medical: down and out pupil first
- Surgical: compression on pia mater blood supply of nerve. Parasympathetic fibres affected first, which are more superficial in CN3. Mydriasis first.
- Medical: diabetes/ vasculitis cause CN3 palsy with pupillary sparing. Down and out pupil occurs before pupil dilation.
What sign would be seen in trochlear nerve palsy? What is the most common cause?
What is seen in abducens palsy? What is the most common cause?
Eye in and up.
- most common cause is trauma. May also result from diabetes/ atherosclerosis/ HTN.
Eye inwards- abducens has long nerve course in brain.
- Most commonly caused by stroke in adults and trauma in children.
