Retinal Arterial Obstructions
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Transcript of Retinal Arterial Obstructions
Retinal Arterial ObstructionsRetinal Arterial Obstructions
DR.SHAH-NOOR HASSAN FCPS,FRCS Assistant Professor Vitreo-Retina Unit Dept. of Ophthalmology BSMMU
Introduction Introduction Retinal arterial obstructive diseases can
manifest in different clinical forms.Classification:
1. Central retinal artery obstruction (57%)2. Branch retinal artery obstruction (38%)3. Ciioretinal artery obstriction (5%)4. Combined CRAO and CRVO5. Cotton-wool spots
HistoryHistory
Von Graefe 1859: Embolic CRAO in patients with endocarditis
Sweiger 1864: Histopathological description
Mauthner 1868: Spasmodic contractions could lead to retinal arterial obstruction
Loring 1874: Focal obstructive disease within retinal vessels as the cause
AetiologyAetiology
Intramural◦ Emboli◦ Thrombus
Mural◦ Luminal narrowing
Extra-mural◦ External compression
Intra-mural- EmboliIntra-mural- EmboliMost common cause of retinal arterial
occlusionsVisible in 20-40% of arterial occlusionsSystemic implications◦ 9 year mortality-56% with emboli
27% without emboliTypes:◦ EXOGENOUS◦ ENDOGENOUS
Endogenous emboliEndogenous emboliCholesterol emboli◦ Glistening yellow◦ Small peripheral asymptomatic block
Fibrin-platelet emboli◦ Dull, grey, elonagetd, multiple◦ Fills the entire lumen
Calcific emboli◦ Larger, more severe obstruction◦ Single, white, near the disc
Endogenous emboliEndogenous emboli
Fat emboli Long bones
Amniotic fluid emboli Complications of pregnancy
Tumor emboli Atrial myxoma
Erythrocyte aggregation Sickle cell disease
Leuko-emboli
Exogenous EmboliExogenous EmboliAir emboli◦ Trauma or surgery
Talc◦ IV drug abuse impurities
Corticosteroid◦ Intralesional Rx
Synthetic material◦ Valves, catheters, prosthesis
Luminal narrowingLuminal narrowingAtherosclerosis with thrombosis◦ Commonly seen with CRAO
Haemorrhage into the atheromatous plaque
VasospasmVasculitis
Atherosclerosis-related thrombosis at the level of the lamina cribrosa is by far the most common underlying cause of central retinal artery occlusion (CRAO), accounting for about 80% of cases. Atherosclerosis is characterized by focal intimal thickening comprising cells of smooth muscle origin, connective tissue and lipid-containing foam cells .
Blood VesselBlood Vessel
External compressionExternal compressionDisc oedema◦ Papillitis◦ Papilledema◦ AION◦ CRVO
RB injectionOcular Compression◦ During surgery
Retinal HypoperfusionRetinal HypoperfusionSystemic hypotensionOcular hypertensionBlood dyscrasias
Central retinal artery occlusionCentral retinal artery occlusion
Introduction Introduction Blockage within the optic nerve
substance-CRAOBlockage distal to lamina-BRAO
Incidence and DemographyIncidence and Demography1:10,000 of outpatient visits57% of the arterial occlusionsOlder adultsEarly sixtiesM>F1%-2% bilateral: consider cardiac valvular
disease, giant cell arteritis and other vascular inflammations
Clinical featuresClinical features
Sudden onset painless visual loss occurring over several seconds
Preceding history of amaurosis fugaxAfferent pupillary defect develops
secondsAnterior segment:◦ Initially normal
Cont… Cont… Vision◦ 90% cases: CF to PL◦ No PL: choroidal or optic nerve damage◦ 10% cilioretinal artery spares foveola
VA>20/40 in 80% over 2 weeks Small island of central vision
Clinical features: posterior segmentClinical features: posterior segment
Yellow-white opacified retina :◦ Ischaemic necrosis affecting the inner half
of the retina◦ Less in areas outside the macular area
Cloudy swellingCherry red spot at the foveola:◦ Extremely thin foveal retina◦ View of underlying RPE and choroid◦ Nourished underlying choroid
Clinical featuresClinical featuresAttenuated retinal arteriesRetinal veins: can be thin, dilated or even
normal in appearanceSegmentation or “boxcarring” of the
blood column: in severe obstruction
Later stagesLater stagesOpacification vanishes in 4-6 weeksPale disc Narrowed retinal vesselsVisible absence of nerve fiber layer in the
region of optic discPigmentary changes: choroidal circulation
is involved
Clinical featuresClinical featuresPresence of emboli: poor prognosis
Emboli seen in 20%-40% of CRAO◦ Hollenhorst plaque (Cholesterol emboli)◦ Calcific emboli
Cholesterol emboliCholesterol emboli Hollenhorst plaque Most common variant Glistening, yellow coloured Small Usually do not obstruct the complete lumen Origin
atherosclerotic deposits in the carotid arteries Aortic arch Ophthalmic artery Proximal central retinal artery
Calcific emboliCalcific emboliLess commonLarger and cause more severe
obstructionOriginate from cardiac valves
Neovascularization Neovascularization 20 % acute central retinal artery
obstructionMean time of 4-5 weeks (range 1 to 15
weeks)NVD 2%-3%If NVI and NVD already present at the
time of acute CRAO- suspect underlying carotid artery obstruction
InvestigationsInvestigations
Fluorescein AngiographyFluorescein Angiography
Delay in the retinal arterial filling (most specific)
Delay in the arterio-venous transit time(most sensitive)
Late staining of the optic disc
Complete lack of filling of retinal arteries-2% cases
FAFA
FAFAChoroidal filling is usually normal◦ Prolongation of choroidal filling in presence of
cherry-red spot s/o ophthalmic or carotid artery obstruction
FA reverts back to normal at later stages as the circulation re-establishes
ERGERG Decrease in the amplitude of
b-wave a-wave is unaffected May be normal in some eyes
in spite of less vision because of re-establishment of retinal blood flow
Visual fieldsVisual fieldsRemaining temporal island-choroid
nourishing corresponding temporal retinaSmall island of central vision-patent cilio-
retinal artery
OCTOCT
Diffuse thickening of the neurosensory retina. Increased reflectivity was noted from the inner retinal layers corresponding to retinal ischemia and decreased backscattering was observed from the retinal photoreceptors.
OCT SpectralisOCT Spectralis
PathologyPathology Site: Lamina cribrosa or its posterior aspect First week:
Inner layer intracellular oedema
Pyknosis of the ganglion cell nuclei
Ischaemic necrosis Posterior pole:thick NFL and ganglion cells
Chronic: Diffuse inner retinal atrophy Homogenous scar formation
Pathology Cont..Pathology Cont..
Systemic associationsSystemic associations90% have systemic disease2/3rd of patients have HTN1/4th have DM45% show Carotid atherosclerosisIncreased thrombogenecityCardiac valvular disease
List of systemic causes…..List of systemic causes….. Arterial hypertension Carotid atherosclerosis Cardiac valvular disease Rheumatic mitral valve prolapse Mural thrombus after MI Cardiac myxoma Tumours IV drug abuse Lipid emboli Pancreatitis Purscher’s retinopathy
Loiasis Radiologic studies Carotid angiography Lymphangiography Hysterosalpingography Head & neck corticosteroid
inj Retrobulbar injections Trauma Orbital # repair Anaesthesia Drug or alcohol induced
stupor Coagulopathies Sickle cell disease
List continues…List continues… Homocystinuria Oral contraceptives Platelet and factor
abnormalities Pregnancy Prepapillary arterial
loops Optic disc drusen Increased IOP Collagen-vascular
diseases SLE PAN
GCA Ventriculography Fabry’s disease Sydenham’s chorea Migraine Hypotension Fibromuscular
hyperplasia Optic neuritis Orbital mucormycosis
Differential diagnosisDifferential diagnosisBilateral◦ Cardiac valvular disease◦ Giant cell arteritis◦ Vascular inflammations
Aminoglycoside toxicityPurtscher’s retinopathy
Management Management Ocular emergency Irreversible damage – 90 to 100 mins Aim: is to restore the circulation Recovery noted to occur till 3 days after the event Give ocular treatment if patient is seen within 24
hours
Modalities: Ocular massage Carbogen Anterior chamber paracentesis Fibirinolytic agents Other modalities
Transluminal Nd:YAG laser embolysis has been advocated for BRAO or CRAO in which an occluding embolus is visible; shots of 0.5–1.0 mJ or higher are applied directly to the embolus using a fundus contact lens. Embolectomy has been said to occur if the embolus is ejected into the vitreous via a hole in the arteriole. The main complication is vitreous haemorrhage
Ocular massageOcular massageIn and out movement with three-mirror
(Goldmann)contact lens or digital massage
Can dislodge an obstructing embolus-rare
Increase pressure for 10-15 secs followed by sudden release
Produces arterial dilatation improving retinal perfusion
86% increase in volume of flow
Oxygen and COOxygen and CO2 2 (Carbogen) (Carbogen)
95% O2 and 5 % CO2
CO2:◦ Vasodilator ◦ Increases retinal blood flow
100% O2
◦ Vasoconstriction◦ Normal pO2 through diffusion from choroid
◦ Improves visual function in CRAORebreathing in the paper bag
AC paracentesisAC paracentesisCauses sudden decrease in the IOPPerfusion pressure behind the
obstruction pushes the obstructing embolus
Fibrinolytic agentsFibrinolytic agentsDelivered via injection through
supraorbital arteryReaches CRA in doses 100 times greater
than by systemic administrationVision improvement noted in 50% of the
patients
Other treatment modalitiesOther treatment modalitiesRetrobulbar or systemic vasodilators:
papaverine or tolazolineSublingual nitroglycerineSystemic anticoagulants
Systemic EvaluationSystemic Evaluation
Many patients will have a history of vascular disease.
Enquiry should be made about smoking.
Symptoms of GCA should be kept in mind in older age group
Pulse particularly to detect atrial fibrillation.
Blood pressure
Carotid examination.
ECG to detect arrhythmia and other cardiac disease.
Erythrocyte sedimentation rate and C-reactive protein to detect the remote possibility of GCA.
Other blood tests include FBC, random glucose, lipids, urea and electrolytes.
Carotid duplex scanning is a non-invasive screening test involving a combination of high-resolution real-time ultrasonography with Doppler flow analysis. If significant stenosis is present, surgical management may be considered.
Special testsSpecial testsEchocardiography Usually performed
if there is a specific indication such as a history of rheumatoid fever, known cardiac valvular disease.
Chest X-ray - Sarcoidosis, tuberculosis, left ventricular hypertrophy in hypertension
Additional blood testAdditional blood test
Fasting plasma homocysteine level Thrombophilia screen
Plasma protein electrophoresis
Autoantibody
Blood cultures.
BRAOBRAO
PresentationPresentationSeventh decadeSudden, painless loss of visionCorresponding visual field deficitH/O amaurosisH/O transient ischaemic attack or
strokes1/3rd have H/O carotid occlusive disease
or hypertension
Funduscopically Funduscopically Localized region of superficial retinal whiteningProminent at the posterior pole, along
distribution of obstructed vesselIntense whitening at the borders of
ischaemic areas: secondary to blockage of axoplasmic flow
90% involve temporal retinal arteries
Prognosis Prognosis Good if foveola is not surrounded by
retinal whitening80% improve to 20/40 or betterResidual visual field remainsPosterior segment neovascularizationIris neovascularizationArtery-artery collateral vessels –
pathognomic of BRAO
FFAFFADelayed or no filling of occluded branchHypofluorescence◦ Lack of perfusion◦ Blockage by edema
Retrograde filling of distal veinsFlow restored after dissolution of
obstruction
Cilio-retinal artery Cilio-retinal artery obstructionobstruction
Cilio-retinal arteryCilio-retinal arteryClinically 20%; Angiographically 32%Fill concurrently with choroidal
circulation 1-2 secs before retinal circulation
Papillo-macular retinal circulationSupplies foveola in 10% of cases
Presentation Presentation Sudden onset visual lossArea of superficial retinal whitening 3 clinical variants◦ Isolated◦ Associated with CRVO◦ Aoosciated with AION
Isolated cilio-retinal artery obstruction (40%):◦ Good visual prognosis◦ 90 % 20/40 or better◦ Intact superior and inferior NFL bundles
With CRVO (40%)◦ Seen in 5% of CRVO (non-ischaemic)◦ 70% >20/40◦ Low hydrostatic pressure in cilio-retinal
artery as compared to CRA◦ Swelling of the optic disc
Associated with AION (20%): ◦ Poor visual prognosis◦ 20/400 to no PL◦ Optic nerve damage◦ Hyperaemic or pale disc along with retinal
whitening Acute pale swelling s/o GCA
◦ Posterior ciliary insufficiency
Carotid artery Carotid artery obstructionobstruction
Presentation Presentation Visual loss (20/20 to No PL)Severe pain due to ischaemia or NVGDot-blot haemorrhages, narrowed
arteries, dilated veinsFFA:◦ Increase in the A-V transit time (95% cases)◦ Prolonged patchy choroidal filling (60%)
CourseCourseVisual improvement takes several weeks◦ poor visual prognosis
Optic atrophy, arteriolar attenuation, NVE
NVI in 2/3rd cases (NVG in half)
InvestigationsInvestigations Digital ophthalmodynamometry
Decreased ocular perfusion pressure Diminished or absent pulse of ipsilateral
cervical carotid artery Bruit if partial stenosis
Absent if complete stenosis Digital subtraction angiography, MRI,
Intra-arterial angiography
Management Management To prevent permanent vision loss and
strokeScreen for systemic illnessesAntiplatelet therapyAnticoagulantsCarotid end-arterectomy◦ Stenosis greater than 70%
Combined retinal artery Combined retinal artery and vein occlusionand vein occlusion
Presentation Presentation Retrobulbar injections-1/4th of cases Clinical features of CRVO & CRAO Sudden onset of painless loss of vision Fundus:
Superficial retinal opacification Cherry red spot
Dilated and tortuous retinal veins Retinal haemorrhages Swollen optic disc
Central retinal artery obstruction
Central retinal vein occlusion
Fluorescein Angiography◦ Severe retinal capillary non-perfusion◦ Sudden termination of mid-sized retinal vessels◦ Minimal leakage-shutdown of retinal vessels
Visual prognosis◦ Poor ◦ Within HM range◦ 80% develop rubeosis and NVG (6 weeks)◦ Aggressive PRP to prevent rubeosis (may fail)
Cotton-wool spotsCotton-wool spots
Cotton-Wool Spots (soft exudate)Cotton-Wool Spots (soft exudate)Yellow white lesion in superficial retina
with feathery margins
Less than 1/4th DD
Correspond to areas of retinal capillary non-perfusion or bordered by microaneurysmal abnormalities
CWSCWSDevelop secondary to obstruction of a
retinal arteriole and resultant ischaemiaHypoxia ->blockage of axoplasmic
transport within NFL -> deposition of intra-axonal organnels
Largely made of mitochondria and lipidLight microscopy: ◦ Cytoid bodies◦ Cellular appearing bodies with psedonucleus
CWSCWS Spots in the visual field may cause a small
scotoma Most resolve within 5-7 weeks May remain longer in diabetic pts. 95% cases have some systemic disease Even one cotton-wool spot in non-diabetics
warrants evaluation Common causes:
Diabetes Mellitus Systemic Arterial Hypertension
To conclude…..To conclude…..Retinal artery occlusion is an ocular emergency
Immediate intervention improves chances of visual recovery, but even then, prognosis is poor.
Follow up for ocular neovascularization needed
Although restoration of vision is of immediate concern, retinal artery occlusion is a harbinger for other systemic diseases that must be evaluated .
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