Systemic disease and the eye Flashcards
What is myotonic dystrophy?
Group of inherited conditions that show muscle weakness and myotonia (inability to relax after muscle contraction)
What are the 2 main types of myotonic dystrophy?
Classic dystrophia myotonica 1 (DM1)
Type 2 myotonic dystrophy (DM2)
What mutation causes classic dystrophia myotonica 1 (DM1)?
AD mutation in dystrophia myotonica protein kinase gene DMPK
What is type 2 myotonic dystrophy?
A milder version caused by a different mutation (abnormally expanded section in ZNF9 gene)
How does myotonic dystrophy present?
- Muscle wasting and weakness
- Mournful facial expression (facial wasting, loose jaw)
- Slurred speech (tongue/pharyngeal muscles involved)
- Frontal baldness in males
- In OSCE, would shake patients hand to show difficulty in releasing grip
What are some common ocular manifestations of myotonic dystrophy?
- Early onset cataract
- Pathognomonic: stellate posterior cortical catact
- Also ‘Christmas Tree’ (polychromatic) cataract (can also be age-related finding)
- Ptosis
- Hypermetrophia
What is shown?
Stellate posterior cortical cataract
What is shown?
Christmas tree (Polychromatic) cataract
What are some uncommon ocular manifestations of myotonic dystrophy?
- Mild opthalmoplegia
- Pupillary light-near dissociation
- Pigmentary retinopathy
- Optic atrophy
What are the 2 main ocular features of neurofibromatosis?
Optic glioma
≥ 2 Lisch nodules
What is optic glioma?
- Slow growing tumour of the optic nerve which causes fusiform enlargement, resulting in globe proptosis and an afferent pupillary defect
- Optic nerve may be swollen (or atrophic later)
- 30% have associated NF1
What is shown?
Optic glioma
What are Lisch nodules?
- Bilateral yellow or brown dome-shaped nodules
- Develop during 2nd-3rd decades, eventually present in 95% of cases
What is shown?
Lisch nodules
What are some non-ocular features of neurofibromatosis type 1?
- ≳6 cafe-au-lait macules
- ≳2 neurofibromas of any type, or one plexiform neurofibroma
- Axillary or inguinal freckling
- Distinctive osseous lesion e.g. sphenoid dysplasia or thinning of long bone cortex, with or without pseudoarthrosis
- First degree relative with NF1
What is thyroid eye disease?
Autoimmune disease caused by the activation of orbital fibroblasts by autoantibodies directed against thyroid receptors
What are some conditions that can cause thyroid eye disease?
Grave’s disease (90%)
Hypothyroidism (10%)
Describe the pathophysiology of thyroid eye disease
- Orbital fibroblasts activated by Graves’ disease-related autoantibodies, leading to an inflammatory response
- This results in enlargement of extra-ocular muscles, fatty and connective tissue volume
What are the 5 stages of thyroid eye disease?
- Soft tissue involvement
- Lid retraction
- Proptosis
- Optic neuropathy
- Restrictive myopathy (inflammation and fibrosis)
What are some symptoms of soft tissue involvement in thyroid eye disease?
Grittiness
Photophobia
Lacrimation
What are some signs of soft tissue involvement in thyroid eye disease?
Hyperaemia
Chemosis
Periorbital swelling
What is a possible complication of proptosis?
Could lead to exposure keratopathy → corneal ulceration
What is shown?
Thyroid eye disease
What are some management options in thyroid eye disease?
- Thyroid dysfunction control
- Stop smoking
- Selenium supplementation
- Lubricants
- Systemic steroids
- Radiotherapy
- Monoclonal antibody treatment
- Surgical decompression
- Eye muscle surgery
- Lid surgery
What is dermatomyositis?
Autoimmune condition that causes skin changes and muscle weakness
What are some causes of dermatomyositis?
- Systemic autoimmune
- Paraneoplastic phenomenon
- Drugs e.g. hydroyurea
What are some ocular features of dermatomyositis?
- Heliotrope rash on eyelids
- Systemic autoimmune disease - look for dry eyes, scleritis etc.
What is shown?
Dermatomyositis
What are some other features of dermatomyositis?
- Proximal muscle weakness
- Gottron’s papules on small joints of hands
What is Marfan syndrome?
Genetic connective tissue disorder
What causes Marfan syndrome?
Autosomal dominant mutation of the fibrillin-1 gene (FBN1)
What is an ocular feature of Marfan syndrome?
Disocated lens (ectopia lentis)
- Can be in any meridial, classically superotemporal
- Zonules still intact
What is shown?
Disocated lens (ectopia lentis)
What are some other features of Marfan syndrome?
- Tall, thin stature
- Disproportionately long limbs compared with trunk
- Arachnoidactoly
- Narrow high-arched (‘gothic’) palate
- Pectus excavatum
- Dilated aortic root
What is shown?
Gothic palate
What is shown?
Pectus excavatum
What are some signs of Marfan syndrome?
Wrist sign
Thumb sign
What are some ocular features of rheumatoid arthritis?
What are some ocular features of Sjögren’s syndrome?
- Dry eyes - gritty feeling
- Punctate epithelial erosions seen using fluorescein
What is shown?
‘Mutton-fat’ keratic precipitates - granulomatous anterior uveitis
What are some causes of granulomatous anterior uveitis (Mutton-fat keratin precipitates)?
- Sarcoidosis
- TB
- Syphilis
What is shown?
Posterior synechiae
What are some causes of posterior synechiae?
- HLA B27 anterior uveitis
- Idiopathic anterior uveitis
What is shown?
Posterior uveitis
What are some causes of posterior uveitis?
- Retinitis
- Vasculitis
- Optic neuritis
What is shown?
Vortex keratopathy
What are some drugs that can cause vortex keratopathy?
- Amiodarone
- Hydroxychloroquine
- Chlorpromazine
- Also caused by Fabry disease
What is shown?
Bull’s eye maculopathy
What are some drugs that can cause bull’s eye maculopathy?
- Hydroxychloroquine
- Chloroquine
What is shown?
Symblepharon
What are some causes of symblepharon?
- Stevens-Johnson (E.g. penicillins, sulfa drugs)
- Also caused by ocular cicatrical pemphigoid and chemical injury
What are some eye side effects of steroids?
- Rise in intra-ocular pressure (May be asymmetrical)
- Related to potency
- More marked in children or glaucoma patients
What are some infective causes of inflammatory eye disease?
- TB
- Herpetic (E.g. zoster, simplex)
- CMV
- Toxoplasmosis
- Syphilis
- Lyme disease
What are some non-infective causes of inflammatory eye disease?
- Idiopathic syndromes
- HLA-B27
- Juvenile arthritis
- Sarcoidosis
- Behcet’s disease
