General Medicine for the Optometrist

Dr Russell Watkins

Anaemia Not a single disease state, anaemia

results from a precipitating pathological process

It is defined as a reduction in the concentration of circulating haemoglobin Defective Hb synthesis Diminished RBC production Excessive RBC destruction Blood loss

Anaemia Ocular features of anaemia due to any

cause Pale conjunctivae Retinal haemorrhages Roth spots Dilated retinal veins

Sickle Cell Disease Caused by the presence of one or more

abnormal haemoglobins RBCs adopt abnormal “sickle” shape

under conditions of hypoxia & acidosis Sickled RBCs cause hypoxia by blocking

arterioles multi-tissue & multi-organ damage

Sickle Cell Disease

AS (sickle cell trait): requires hypoxia or abnormal conditions to produce sickling

SS (sickle cell disease): severe systemic complications, mild ocular disease

SC (sickle cell HbC disease): severe ocular disease

Sthal (sickle cell Hb with thalassaemia): severe systemic & ocular disease

Sickle Cell Disease Ocular features (anterior segment)

“Comma-shaped” vascular segments seen on conjunctivae

Focal ischaemic atrophy of iris; occasional hyphaema & rarely rubeosis

Sickle Cell Disease Posterior segment involvement

Venous tortuosity Peripheral choroidoretinal scars (black

sun-bursts) Salmon patch haemorrhages “Silver-wiring” of peripheral arterioles Retinal breaks Angioid streaks

Sickle Cell Disease Posterior segment involvement (cont.)

Vascular occlusions C/BRAO and C/BRVO

Sickle retinopathy produces “sea-fan” pattern neovascularisation eventually causing vitreous haemorrhage & traction retinal detachment

Demyelinating Disease A group of diseases in which the main

abnormality is damage to the CNS myelin The most important condition is multiple or

disseminated sclerosis MS is an immune-mediated disease of

uncertain aetiology Relapsing episodes of demyelination within

the CNS Episodes separated in time & space Demyelination leads to failure of axonal

function producing neurological defects

Demyelinating Disease Demyelination occurs in the brain & spinal

cord Areas of demyelination are called plaques

Histology (acute stage) = lymphocyte cuffing around small vessels; lipid-laden foamy macrophages & enlarged astrocytes are seen around the plaque

Most axons spanning a plaque are preserved thought there is evidence that there is some axonal loss

Histology (later) = few inflammatory cells; astrocytes occupy plaques

Demyelinating Disease Epidemiology

Onset most often at age 20-40 yrs Said to more common in middle class

women More common in northern climes RBN more commonly occurs in the

spring Associated with HLA-DR2

Demyelinating Disease Diagnosis is based on

History Examination Investigations

Electrophysiology MRI scans Cerebrospinal fluid examination

Demyelinating Disease Ocular features

Retrobulbar & optic neuritis Eye movement disorders

Nerve palsies incl. ptosis INO Nystagmus

AAU

Tumours of the Nervous System

Primary neoplasia are an important cause of death in young people - ~10% of cancer deaths in those aged 15-35yrs

Most common neoplasm in the brain is metastasis

Others Meningiomas Gliomas Lymphomas

Clinical Features of ICP In slowly developing lesions, symptoms

& signs may develop slowly In rapidly progressive lesions, symptoms

& signs can develop within minutes There may be vomiting, headache and

papilloedema When more advanced, there may be a

‘blown pupil’, bradycardia, hypertension and dyspneoa (due to neurogenic pulmonary oedema)

Cerebrovascular Disease The third most common cause of death

in Western countries Most frequent manifestation is the

sudden onset neurological deficit known as “stroke”

Stroke can be due to infarction or haemorrhage (85%:15%)

Cerebrovascular Disease Stroke occurs in about 2 per 1000

population The clinical spectrum of the

cerebrovascular accident Stroke Reversible ischaemic neurological

deficit (RIND) Transient ischaemic attack (TIA)

Cerebrovascular Disease Definitions

Stroke is a sudden onset, non-traumatic focal neurological deficit which causes death or lasts longer than 24 hrs

A RIND is when function returns after a period of time (usually defined as 7 days)

TIAs are defined as non-traumatic focal loss of cerebral or visual function lasting less than 24 hrs

Cerebrovascular Disease Glutamate receptor activation

Ischaemic damage causes activation of the NMDA subtype of glutamate receptors

Calcium ions pour into the neurons causing cell death

This process is termed excitotoxicity & is also believed to be implicated in the optic neuropathy of open angle glaucoma

Cerebrovascular Disease Sub-arachnoid haemorrhage is most

often due to rupture of a berry aneurysm (present in about 2% of population)

“Thunderclap” headache Associated with subhyaloid

haemorrhage

Site of aneurysm

Seronegative Arthropathies Characterised by

Spinal & sacroiliac joint involvement Asymmetrical oligo- or monoarthritis

of large joints Strong HLA associations Extra-articular manifestations

(including ocular)

Seronegative Arthropathies Ankylosing spondylitis Reiter’s syndrome Behçet’s disease Psoriatic arthropathy Enteropathic arthropathies (Juvenile chronic arthritis)

Ankylosing Spondylitis Progressive spinal fusion with loss of

mobility; pulmonary fibrosis; aortic regurgitation; colitis

M>F; 90% HLA-B27 positive Prevalence 1 in 2000 Associated with uveitis, scleritis,

episcleritis

Reiter’s Syndrome Triad of conjunctivitis/iritis/keratitis,

arthritis & urethritis/dysenteric disease M>>F; 70% HLA-B27 positive; 30% AAU Arthritis affects knees, sijs, ankles Plantar fasciitis Keratoderma blenorrhagica on feet &

hands Circinate balanitis Painless mouth ulcers

Behçet’s Disease Triad of oral ulceration, genital

ulceration, inflammatory eye lesions M>F esp Japan & Mediterranean

(Turkey) Increased prevalence of HLA-B5

Behçet’s Disease Ocular features

Severe AAU (often with hypopyon) Conjunctivitis Keratitis Episcleritis Retinal vasculitis & infarction BRVO Neovascularisation with vitreous

haemorrhage Retinal & macular oedema & exudates

Psoriatic Arthropathy Increased prevalence of HLA-B17 &

HLA-B27, associated with Conjunctivitis AAU Dry eyes

Enteropathic Arthropathy Ulcerative colitis & Crohn’s disease

Inflammatory bowel diseases with systemic manifestations

Ocular features Conjunctivitis, KCS,

keratoconjunctivitis, episcleritis, scleritis, AAU, retinal oedema, orbital cellulitis, optic neuritis

Juvenile Chronic Arthritis A multisystem seronegative disease

that also has ocular manifestations Chronic anterior uveitis Secondary glaucoma Cataract Band keratopathy