General Medicine for the Optometrist


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General Medicine for the Optometrist

  1. 1. General Medicine for the Optometrist Dr Russell Watkins
  2. 2. Anaemia <ul><li>Not a single disease state, anaemia results from a precipitating pathological process </li></ul><ul><li>It is defined as a reduction in the concentration of circulating haemoglobin </li></ul><ul><ul><li>Defective Hb synthesis </li></ul></ul><ul><ul><li>Diminished RBC production </li></ul></ul><ul><ul><li>Excessive RBC destruction </li></ul></ul><ul><ul><li>Blood loss </li></ul></ul>
  3. 3. Anaemia <ul><li>Ocular features of anaemia due to any cause </li></ul><ul><ul><li>Pale conjunctivae </li></ul></ul><ul><ul><li>Retinal haemorrhages </li></ul></ul><ul><ul><li>Roth spots </li></ul></ul><ul><ul><li>Dilated retinal veins </li></ul></ul>
  4. 5. Sickle Cell Disease <ul><li>Caused by the presence of one or more abnormal haemoglobins </li></ul><ul><li>RBCs adopt abnormal “sickle” shape under conditions of hypoxia & acidosis </li></ul><ul><li>Sickled RBCs cause hypoxia by blocking arterioles  multi-tissue & multi-organ damage </li></ul>
  5. 6. Sickle Cell Disease <ul><li>AS (sickle cell trait): requires hypoxia or abnormal conditions to produce sickling </li></ul><ul><li>SS (sickle cell disease): severe systemic complications, mild ocular disease </li></ul><ul><li>SC (sickle cell HbC disease): severe ocular disease </li></ul><ul><li>Sthal (sickle cell Hb with thalassaemia): severe systemic & ocular disease </li></ul>
  6. 7. Sickle Cell Disease <ul><li>Ocular features (anterior segment) </li></ul><ul><ul><li>“Comma-shaped” vascular segments seen on conjunctivae </li></ul></ul><ul><ul><li>Focal ischaemic atrophy of iris; occasional hyphaema & rarely rubeosis </li></ul></ul>
  7. 8. Sickle Cell Disease <ul><li>Posterior segment involvement </li></ul><ul><ul><li>Venous tortuosity </li></ul></ul><ul><ul><li>Peripheral choroidoretinal scars (black sun-bursts) </li></ul></ul><ul><ul><li>Salmon patch haemorrhages </li></ul></ul><ul><ul><li>“ Silver-wiring” of peripheral arterioles </li></ul></ul><ul><ul><li>Retinal breaks </li></ul></ul><ul><ul><li>Angioid streaks </li></ul></ul>
  8. 9. Sickle Cell Disease <ul><li>Posterior segment involvement (cont.) </li></ul><ul><ul><li>Vascular occlusions </li></ul></ul><ul><ul><ul><li>C/BRAO and C/BRVO </li></ul></ul></ul><ul><ul><li>Sickle retinopathy produces “sea-fan” pattern neovascularisation eventually causing vitreous haemorrhage & traction retinal detachment </li></ul></ul>
  9. 16. Demyelinating Disease <ul><li>A group of diseases in which the main abnormality is damage to the CNS myelin </li></ul><ul><li>The most important condition is multiple or disseminated sclerosis </li></ul><ul><li>MS is an immune-mediated disease of uncertain aetiology </li></ul><ul><ul><li>Relapsing episodes of demyelination within the CNS </li></ul></ul><ul><ul><li>Episodes separated in time & space </li></ul></ul><ul><ul><li>Demyelination leads to failure of axonal function producing neurological defects </li></ul></ul>
  10. 17. Demyelinating Disease <ul><li>Demyelination occurs in the brain & spinal cord </li></ul><ul><li>Areas of demyelination are called plaques </li></ul><ul><ul><li>Histology (acute stage) = lymphocyte cuffing around small vessels; lipid-laden foamy macrophages & enlarged astrocytes are seen around the plaque </li></ul></ul><ul><li>Most axons spanning a plaque are preserved thought there is evidence that there is some axonal loss </li></ul><ul><ul><li>Histology (later) = few inflammatory cells; astrocytes occupy plaques </li></ul></ul>
  11. 18. Demyelinating Disease <ul><li>Epidemiology </li></ul><ul><ul><li>Onset most often at age 20-40 yrs </li></ul></ul><ul><ul><li>Said to more common in middle class women </li></ul></ul><ul><ul><li>More common in northern climes </li></ul></ul><ul><ul><li>RBN more commonly occurs in the spring </li></ul></ul><ul><ul><li>Associated with HLA-DR2 </li></ul></ul>
  12. 19. Demyelinating Disease <ul><li>Diagnosis is based on </li></ul><ul><ul><li>History </li></ul></ul><ul><ul><li>Examination </li></ul></ul><ul><ul><li>Investigations </li></ul></ul><ul><ul><ul><li>Electrophysiology </li></ul></ul></ul><ul><ul><ul><li>MRI scans </li></ul></ul></ul><ul><ul><ul><li>Cerebrospinal fluid examination </li></ul></ul></ul>
  13. 20. Demyelinating Disease <ul><li>Ocular features </li></ul><ul><ul><li>Retrobulbar & optic neuritis </li></ul></ul><ul><ul><li>Eye movement disorders </li></ul></ul><ul><ul><ul><li>Nerve palsies incl. ptosis </li></ul></ul></ul><ul><ul><ul><li>INO </li></ul></ul></ul><ul><ul><ul><li>Nystagmus </li></ul></ul></ul><ul><ul><li>AAU </li></ul></ul>
  14. 25. Tumours of the Nervous System <ul><ul><li>Primary neoplasia are an important cause of death in young people - ~10% of cancer deaths in those aged 15-35yrs </li></ul></ul><ul><ul><li>Most common neoplasm in the brain is metastasis </li></ul></ul><ul><ul><li>Others </li></ul></ul><ul><ul><ul><li>Meningiomas </li></ul></ul></ul><ul><ul><ul><li>Gliomas </li></ul></ul></ul><ul><ul><ul><li>Lymphomas </li></ul></ul></ul>
  15. 26. Clinical Features of  ICP <ul><li>In slowly developing lesions, symptoms & signs may develop slowly </li></ul><ul><li>In rapidly progressive lesions, symptoms & signs can develop within minutes </li></ul><ul><li>There may be vomiting, headache and papilloedema </li></ul><ul><li>When more advanced, there may be a ‘blown pupil’, bradycardia, hypertension and dyspneoa (due to neurogenic pulmonary oedema) </li></ul>
  16. 32. Cerebrovascular Disease <ul><li>The third most common cause of death in Western countries </li></ul><ul><li>Most frequent manifestation is the sudden onset neurological deficit known as “stroke” </li></ul><ul><li>Stroke can be due to infarction or haemorrhage (85%:15%) </li></ul>
  17. 33. Cerebrovascular Disease <ul><li>Stroke occurs in about 2 per 1000 population </li></ul><ul><li>The clinical spectrum of the cerebrovascular accident </li></ul><ul><ul><li>Stroke </li></ul></ul><ul><ul><li>Reversible ischaemic neurological deficit (RIND) </li></ul></ul><ul><ul><li>Transient ischaemic attack (TIA) </li></ul></ul>
  18. 34. Cerebrovascular Disease <ul><li>Definitions </li></ul><ul><ul><li>Stroke is a sudden onset, non-traumatic focal neurological deficit which causes death or lasts longer than 24 hrs </li></ul></ul><ul><ul><li>A RIND is when function returns after a period of time (usually defined as 7 days) </li></ul></ul><ul><ul><li>TIAs are defined as non-traumatic focal loss of cerebral or visual function lasting less than 24 hrs </li></ul></ul>
  19. 35. Cerebrovascular Disease <ul><li>Glutamate receptor activation </li></ul><ul><ul><li>Ischaemic damage causes activation of the NMDA subtype of glutamate receptors </li></ul></ul><ul><ul><li>Calcium ions pour into the neurons causing cell death </li></ul></ul><ul><ul><li>This process is termed excitotoxicity & is also believed to be implicated in the optic neuropathy of open angle glaucoma </li></ul></ul>
  20. 36. Cerebrovascular Disease <ul><li>Sub-arachnoid haemorrhage is most often due to rupture of a berry aneurysm (present in about 2% of population) </li></ul><ul><li>“ Thunderclap” headache </li></ul><ul><li>Associated with subhyaloid haemorrhage </li></ul>
  21. 37. Site of aneurysm
  22. 45. Seronegative Arthropathies <ul><li>Characterised by </li></ul><ul><ul><li>Spinal & sacroiliac joint involvement </li></ul></ul><ul><ul><li>Asymmetrical oligo- or monoarthritis of large joints </li></ul></ul><ul><ul><li>Strong HLA associations </li></ul></ul><ul><ul><li>Extra-articular manifestations (including ocular) </li></ul></ul>
  23. 46. Seronegative Arthropathies <ul><li>Ankylosing spondylitis </li></ul><ul><li>Reiter’s syndrome </li></ul><ul><li>Behçet’s disease </li></ul><ul><li>Psoriatic arthropathy </li></ul><ul><li>Enteropathic arthropathies </li></ul><ul><li>(Juvenile chronic arthritis) </li></ul>
  24. 47. Ankylosing Spondylitis <ul><li>Progressive spinal fusion with loss of mobility; pulmonary fibrosis; aortic regurgitation; colitis </li></ul><ul><li>M>F; 90% HLA-B27 positive </li></ul><ul><li>Prevalence 1 in 2000 </li></ul><ul><li>Associated with uveitis, scleritis, episcleritis </li></ul>
  25. 50. Reiter’s Syndrome <ul><li>Triad of conjunctivitis/iritis/keratitis, arthritis & urethritis/dysenteric disease </li></ul><ul><li>M>>F; 70% HLA-B27 positive; 30% AAU </li></ul><ul><li>Arthritis affects knees, sijs, ankles </li></ul><ul><li>Plantar fasciitis </li></ul><ul><li>Keratoderma blenorrhagica on feet & hands </li></ul><ul><li>Circinate balanitis </li></ul><ul><li>Painless mouth ulcers </li></ul>
  26. 54. Behçet’s Disease <ul><li>Triad of oral ulceration, genital ulceration, inflammatory eye lesions </li></ul><ul><li>M>F esp Japan & Mediterranean (Turkey) </li></ul><ul><li>Increased prevalence of HLA-B5 </li></ul>
  27. 55. Behçet’s Disease <ul><li>Ocular features </li></ul><ul><ul><li>Severe AAU (often with hypopyon) </li></ul></ul><ul><ul><li>Conjunctivitis </li></ul></ul><ul><ul><li>Keratitis </li></ul></ul><ul><ul><li>Episcleritis </li></ul></ul><ul><ul><li>Retinal vasculitis & infarction </li></ul></ul><ul><ul><li>BRVO </li></ul></ul><ul><ul><li>Neovascularisation with vitreous haemorrhage </li></ul></ul><ul><ul><li>Retinal & macular oedema & exudates </li></ul></ul>
  28. 59. Psoriatic Arthropathy <ul><li>Increased prevalence of HLA-B17 & HLA-B27, associated with </li></ul><ul><ul><li>Conjunctivitis </li></ul></ul><ul><ul><li>AAU </li></ul></ul><ul><ul><li>Dry eyes </li></ul></ul>
  29. 61. Enteropathic Arthropathy <ul><li>Ulcerative colitis & Crohn’s disease </li></ul><ul><ul><li>Inflammatory bowel diseases with systemic manifestations </li></ul></ul><ul><ul><li>Ocular features </li></ul></ul><ul><ul><ul><li>Conjunctivitis, KCS, keratoconjunctivitis, episcleritis, scleritis, AAU, retinal oedema, orbital cellulitis, optic neuritis </li></ul></ul></ul>
  30. 62. Juvenile Chronic Arthritis <ul><li>A multisystem seronegative disease that also has ocular manifestations </li></ul><ul><ul><li>Chronic anterior uveitis </li></ul></ul><ul><ul><li>Secondary glaucoma </li></ul></ul><ul><ul><li>Cataract </li></ul></ul><ul><ul><li>Band keratopathy </li></ul></ul>