Eye (1990) 4, 464-468 The Investigation of Patients with Retinal Vascular Occlusion ELIZABETH M. GRAHAM London Summary The investigation of patients with retinal artery occlusion, retinal vein occlusion and cotton wool spots is discussed. The majority are due to either emboli or atheroma and occur in elderly patients. A full clinical history and examination remain the essential part of the investigation but the ophthalmologist must select patients in whom further investigation is warranted. The recent recognition of the importance of antiphospbolipid antibodies and natural anticoagulant deficiency states in the pathogenesis of thrombosis has identified a group of young people in whom specific therapy may be indicated. Every ophthalmologist encounters the unfor­ examination accompanied by a thorough oph­ tunate patient with sudden visual loss due to a thalmic examination frequently identify the recent retinal vascular occlusion. Two cause of the occlusion without resorting to immediate questions arise: Firstly, can any­ special investigations. Salient features in the thing be done to improve or preserve vision? history are age, general health, family history Secondly, what was the cause of the occlusion of vascular disease, diet, drug and smoking and are any practical precautions available to habits. General examination should include prevent a further attack? In the majority of measurement of pulse, blood pressure in both cases substantial visual recovery is unusual arms, auscultation of the heart and carotids and therefore the second question is vitally and urinalysis for sugar and protein. important. The ophthalmologist who firstsees _ The eye examination is often diagnostic and such a patient is responsible for identifying important things to look for are: the cause of the occlusion, and consequently (i) evidence of local ocular disease, eg, arranging appropriate referral for further episcleritis or scleritis, anterior seg­ management. This paper addresses the inves­ ment inflammation, arteriolar loop, tigation of patients presenting to the ophthal­ drusen of the optic nerve. mologist with either retinal artery occlusion, (ii) evidence of generalised retinal vascular retinal vein occlusion or an isolated cotton disease, hypertensive or diabetic wool spot. retinopathy. (iii) presence of emboli and the nature of Retinal Artery Occlusion the embolus-white and calcific, The majority of both central retinal artery refractile (cholesterol) or pale fibrin occlusions and branch retinal artery occlu­ platelet plaques. sions are due to either emboli or atheroma Special investigations are directed towards and occur in patients with generalised arteri­ the cause of the vascular disease and the func­ osclerosis and hypertension. tion of the heart (Table I). Essential tests in all A pertinent general medical history and patients are a full blood count, ESR, blood Correspondence to: Dr. E. M. Graham, Medical Eye Unit, St Thomas' Hospital, London SE1 7EH. THE INVESTIGATION OF PATIENTS WITH RETINAL VASCULAR OCCLUSION 465 Table Ia Investigation of embolic retinal artery occlusion Table Ib Investigation of non embolic retinal artery TYPE OF CALCIFIC FIBRIN PLATELET CHOLESTEROL occlusion EMBOLUS Pulse ORIGIN aOr!ic or hear! valve or neck vessels Blood pressure mitral valve neck vessels Carotid bruit ! Smoking habits / � Urinalysis ! Pulse WHAT TO DO Pulse Blood glucose Blood Pressure in both arms Blood lipids Blood Pressure ESR Carotid Bruit VDRL TPHA Auscultation Ophthalmodynometry Echocardiogram Blood Lipids Electrocardiogram ! Smoking Cardiology Referral ! Consider Neurology Referral Consider Digital Subratction Angiography Trial of Aspirin glucose and lipid screen. Several points are Isolated Cotton Wool Spot worth remembering. Calcific retinal emboli Cotton wool spots are commonly seen as part originate from either the aortic or mitral of a diabetic or hypertensive retinopathy. An valve. 1,2 An urgent opinion from a cardiol­ isolated cotton wool spot is unusual, and even ogist should be sought as frequently early though it is often an incidental finding it may valve replacement is the best treatment. herald severe systemic disease. The cotton In young patients retinal artery occlusions wool spot is produced by occlusion of the pre­ are often due to emboli from the heart, capillary arterioles and is a reflection of the although mitral valve prolapse has been breakdown of retrograde and orthograde axo­ 3 incriminated in the past. A recent study of plasmic flow: the axoplasmic debris accumu­ amaurosis fugax and retinal artery occlusion lates at the junction of healthy and anoxic in people under 45 years of age found the inci­ retina and causes a dense white fluffy appear­ dence of mitral valve prolapse was 6·5% in ance. 7,s The presence of a cotton wool spot both the patient group and in the general therefore indicates blockage of a retinal arte­ population4 casting doubt upon the previous riole which may be due to abnormalities of the assumption that mitral valve prolapse is of vascular endothelium, blockage by abnormal pathogenetic significance. erythrocytes or unusual emboli (see Ta ble II). In elderly patients giant cell arteritis must The macroscopic and microscopic features of never be forgotten as 20% of patients who a cotton wool spot are always the same lose vision do so from central retinal artery regardless of its cause. 9 occlusion; the remaining 80% suffering from The patient who presents with an isolated posterior ciliary artery occlusion,s In young patients with 'negative' history cotton wool spot requires the same general and examination a systemic vasculitis (PAN medical history and examination as the or SLE) should be suspected. Retinal artery patient with the retinal artery occlusion. occlusion associated with migraine is well However, the isolated cotton wool spot is documented. 6 However, the assumption that unlikely to be due to an embolic phenomenon migraine is the cause of the occlusion is but more likely to be due to arterial disease, dangerous and this diagnosis should stand particularly a systemic vasculitis. The inves­ only when all other possibilities have been tigations are summarised in Table III. Giant excluded. cell arteritis is usually easy to diagnose clini- 466 E. M. GRAHAM Table II Causes of cotton wool spots have vaso-occlusive retinopathy associated 2, with antiphospholipid antibodies. 1 13 Abnormalities of Arteriosclerosis The diagnosis of PAN is made on clinical vascular endothelium Diabetes mellitus Hypertension grounds and the pathological confirmationof a Systemic vasculitis vasculitis in the medium sized arteries with h!u­ (SLE, PAN, GCA, scleroderma) cocyte infiltration and fibrinoid necrosis. The Radiation retinopathy ESR is raised, autoantibodies are present in Human immunodeficiency virus Abnormal erythrocytes Haemoglobinopathies low titres and immunoglobulin levels are Unusual emboli Fat usually high. However none of these tests are Talc specific for PAN. Recently antineutrophil cytoplasmic antibodies (ANCA) have been cally and the diagnosis is supported by the ESR found in the sera of many patients with two dis­ and confirmed by the temporal artery biopsy. eases related to PAN, namely Wegener's The presence of cotton wool spots in these granulomatosis and microscopic polyarteritis patients means that the retinal circulation as nodosa.14 The latter is solely a renal disease well as the posterior ciliary circulation is and this test may therefore be useful in the involved in the disease progress and that investigation of the cause of an isolated cotton immediate treatment with systemic steroids is wool spot, particularly when associated with imperative to prevent further visual loss. hypertension or other ophthalmological fea­ The other systemic vasculitides associated tures such as scleritis or proptosis are also with cotton wool spots are systemic lupus presen!. erythematosus (SLE),10 polyarteritis nodosa In the majority of cases cotton wool spots are (PAN) and rarely scleroderma. The clinical due to abnormalities of the vascular endothe­ manifestations of these diseases are different: lium and this is secondary to an easily identified SLE commonly affects females particularly disease process such as diabetes mellitus West Indians, who present with rashes, mal­ (Table II). The question arises whether a local aise, arthritis and renal problems, whereas specific immune reaction against endothelial PAN afflicts middle aged men who develop cells can occur in isolation: antiendothelial cell asthma, hypertension, myalgia and neuro­ pathy. The simple investigations to support the antibodies have been demonstrated in the sera diagnosis of a systemic vasculitis remain the of patients with inflammatory vasculitis15 but ESR and antinuclear antibodies: the latter are their importance in the pathogenesis of the cot­ present in 90% of the sera of patients with ton wool spot or other retinal vascular disease SLE. Further classificationof these antibodies is not known. reveals that patients with SLE have antibodies The human immunodeficiency virus (HIV) against double stranded DNA whereas is known to infect endothelial cells directly16 patients with scleroderma and mixed connec­ and cotton wool spots are the most frequent tive tissue disease more frequently have anti­ manifestation of AIDS to be seen in the fun­ bodies against RNA. An important subgroup dUS.17 Interestingly, cotton wool spots are not of patients with SLE have recently been identi­ Table III Investigation of the isolated cottonwool