Pathology Flashcards
What are the first and last muscles to be affected in Graves’ orbitopathy?
First - Inferior rectus
Last - Lateral rectus
In what condition would you find Dalrymple’s, Mobius and von Graefe signs?
Graves orbitopathy.
- Dalrymple’s: widening of palpebral fissure
- Mobius sign: Inability of eyes to maintain convergence
- Von Graefe’s sign: Lid lag
What is the main EOM affected in Duane’s syndrome?
Lateral rectus
What is Collier’s sign?
Lid retraction in midbrain lesion e.g. Parinaud’s syndrome
What should you check for in a patient with recurrent chalazions?
Sebaceous gland carcinoma
What is the causative organism in belpharitis acaria?
Demodex follicularum (mite)
What is the normal superior marginal reflex distance?
4mm
What is the Marcun Gunn jaw winking phenomenon?
Synkinesis between CN5 and CN3 - ptosis in primary position, opening mouth causes eyelid to jerk upwards. Congenital.
What is the procedure of choice for severe ptosis with poor LPS function?
Frontalis sling
How is congenital ptosis treated?
Resection (and strengthening) of LPS
What are 3 drugs that cause trichomegaly?
Phenytoin
Prostaglandins
Cyclosporins
What is the most common site of lid coloboma?
Medial half of upper lid
What is the most common tumour of the eyelid?
BCC
At what gestational age is lid disjunction complete?
7 months
What is Duane syndrome and what are the classic pathophysiological findings?
Absence of CN VI nuclei. Lateral rectus is innervated by CN III.
On attempted adduction, the eye retracts and may upshoot or downshoot.
In normal adduction, the ipsilateral MR contracts (CN3) and the LR (CN4) relaxes (Sherrington’s Law). In Duane’s syndrome, CN3 contracts both the LR and MR –> retraction of the eye. If the contraction is strong enough one or both of the recti may ‘slip’ causing an upshoot or downshoot.
What is the ‘disc at risk’ for non-arteritic anterior ischaemic optic neuropathy?
Small crowded optic discs (reduced cup-disc ratio <0.2) –> predisposition to microvascular flow blockage and ischaemia
What is the classic presentation of NAION?
Acute unilateral visual loss + RAPD
Patient: older, vasculopathic risk factors
Cup-disc ratio < 0.2
Disc oedema on examination of fundus
What is the cause of AION?
Arteritic anterior ischaemic optic neuropathy
Giant cell arteritis! Predilection for the small (10-20) posterior ciliary arteries supplying the optic nerve
What condition are Arlt’s line and Herbert’s pits seen in?
Trachoma
What is the treatment for onchocerciasis?
Ivermectin every 6 months until symptom free
What is Mazotti’s test for onchocerciasis?
Administration of microfiliaricidal DEC —> mass microfilaria death —> systemic symptoms
What is a Hissette Ridley fundus seen in?
End stage onchocercal chorioretinal atrophy - typically temporal to macula, with optic disc atrophy as well
In what disease can ‘eye worms’ be seen on gross inspection?
Loa loa - adult worms migrate through conjunctiva
What are the two most common infectious causes of blindness worldwide?
Trachoma and onchocerciasis
What is the causative organism and vector in onchocerciasis?
Onchocerca volvulus. Blackflies (Simulum genus)
What is the treatment for trachoma?
Single oral dose of azithromycin
Mutation of complement factor H is associated with?
Age related macular degeneration
In gene linkage analysis, genes that undergo recombination 1% of the time are how many centimorgans apart?
1 centimorgan apart
What percentage of retinoblastoma is inherited?
40%
What chromosome is the Rb gene located on?
Chromosome 13
What 2 other tumours are children with heritable retinoblastoma at risk for?
Trilateral disease:
- Bilateral retinoblastoma
- Pinealomas
- Osteosarcoma
What does the Hardy-Weinberg equation describe?
Relationship between genotypes and gene allele frequencies
What is the most common lacrimal gland tumour
Pleomorphic adenoma
What tumour classically has a Swiss cheese appearance
Adenoid cystic carcinoma
What are the genetic prognostic factors in uveal melanoma
Poor prognosis: Loss of chromosome 3, increased copies of chromosome 8q
Good prognosis: More copies of chromosome 6p
What is optic nerve glioma associated with
NF1
What is meningioma associated with? What other malignancies are associated with this disease
NF2
Bilateral schwannomas
High-grade and low-grade B cell lymphomas - an example of each
High-grade: Diffuse large B cell lymphoma
Low-grade: Follicular lymphoma
What are risk factors for a lesion being a choroidal melanoma rather than a choroidal naevus?
- Height > 2mm
- Orange pigmentation
- Subretinal fluid
What is the most common site for uveal melanoma
Choroid
What are common primaries for ocular metastasis
Breast
Lung
Prostate
Where does uveal melanoma metastasise to and what is the route of spread
Liver; haematogenous
Where does retinoblastoma metastasise to and what is the route of spread
Brain; via optic nerve
Orbit; trans-scleral
