A Case of a Blinding Sneezing Attack. A Case Report on a Central Retinal Artery Occlusion By: Erica L. Touhill O.D. Resident at the Battle Creek Veteran Administration Abstract: A 60 year old white male presents with a sudden painless unilateral loss of vision in his right eye after a sneezing attack. A dilated fundus examination reveals a central retinal artery occlusion. Case History: A 60 year old white male presented to the clinic with a chief complaint of a sudden onset of vision loss in his right eye after a sneezing attack he had 4 days ago. The patient reported having flashes of light and subtle right temporal pain before the vision loss. The patient was previously seen in urgent care for photopsia and a referral was made to the eye clinic to evaluate for a retinal detachment. The patient’s significant medical history includes coronary artery disease, hyperlipidemia, peripheral vascular disease, hypertension, and multiple carotid/femoral stent surgeries. His current medications are amlodipine, combivent, divalproex, ezetimibe, fluticasone nasal spray, formoterol nebulizer, gabapentin, guaifenesin, hydrocodone/apap, IBU, lisinopril, lorazepam, metoprolol, mometasone MDI, morphine sulfate, sublingual nitroglycerin, omeprazole, rosuvastatin, and trazodone. Case Data: initial evaluation Patients best corrected visual acuity is hand motion OD and 20/25+ OS. Pupils measured to be 4mm OU and right APD. Intraocular pressures were 14mmHg OD and 17mmHg via Goldmann tonometry. The C/D ratio was .3 round OU with pink, perfuse rim tissue. A cherry red spot was noted with a pale appearance of the surrounding posterior pole and a Hollenhorst plaque at the third bifurcation in the inferior temporal arcade (figure 1). According to his previous primary care records, a carotid Doppler hasn’t been performed in a couple of years. Therefore, the patient was sent out for a carotid Doppler to be completed before next office visit. Figure 1 Case Data: one month follow‐up The patient's vision improved in the right eye to count fingers at 2 feet. Slit‐lamp evaluation with gonioscopy was performed on the right eye which revealed no neovascularization of the iris (NVI) or of the angle (NVA). Intraocular pressures via NCT were 13 OD and 16 OS. A dilated fundus examination revealed two small splinter hemorrhages on the optic disc inferior temporal (figure 2). However, no neovascularization of the disc (NVD) or papilledema was noted. Erythrocyte sedimentation rate (ESR) and C‐reactive protein (CRP) was ordered. The ESR result was 7 and the results of the carotid Doppler ordered 3 weeks ago and the CRP are still pending. A Humphrey’s Visual Field 24‐2 was performed on the right eye which showed a severely depressed field. The patient had a difficult time fixating during the test causing an increase in fixation losses. Therefore, the test has a low reliability. Figure 2 Differential Diagnosis: There are a couple of differential diagnoses that can be made based on sudden vision loss and/or the cherry red spot alone. The leading differential diagnosis that should be considered in this case is a central retinal artery occlusion (CRAO), followed by acute ophthalmic artery occlusion, and Tay‐sachs disease. If a CRAO is a possibility, then it is extremely important to rule out giant cell arteritis (GCA) as the primary etiology for the CRAO. With an acute ophthalmic artery occlusion the whole retina becomes white and an absence of a cherry red spot.1 To differentiate a metabolic cherry red spot from a cherry red spot associated with a CRAO is the white retina has a halo appearance and is thinner in the metabolic disorders, acute loss of vision does not occur in the metabolic disorders and the cherry‐red spot is always binocular in metabolic disorders and monocular in retinal occlusion.2 As previously indicated, the patient presented with a monocular cherry red spot, Hollenhorst plaque, and retinal whitening. Diagnosis and discussion: The final diagnosis made at the initial visit was a CRAO because he presented with the classic signs (unilateral cherry red spot, associated retinal whitening, and APD). The most likely etiology of a CRAO in general and to this case is a cholesterol embolus (Hollenhorst plaque). Hollenhorst plaques are typically refractile and orange and located at a bifurcation. They arise from ulcerated atheromas from the carotid arteries.1 The presence of a retinal embolus is associated with a 56% mortality rate over 9 years compared to 27% in patients without arterial emboli.3 These deposits get trapped within a vessel decreasing perfusion to the tissues causing a whitening effect to the surrounding retina and a cherry red spot. Another likely etiology in this case could have been GCA due to the presence of two splinter hemes at the optic disc. However, the ESR that was ordered at the follow‐up visit points away from diagnosis of GCA. GCA is an inflammation of medium‐large size vessels. The symptoms associated with GCA are ipsilateral jaw claudication, tenderness of scalp, enlarged and tender ipsilateral temporal artery. This patient presented with the classic signs and symptoms of a CRAO and denies any symptoms of GCA. The patient experienced the sudden vision loss after sneezing which in itself is unique. However, it’s logical that if he has an extensive history of atherosclerosis and heart disease that a powerful sneeze would cause some of the plaque to dislodge and travel up stream. If the plaque were to continue up towards the brain, it could have lead to a cerebrovascular accident. Research has indicated, the life expectancy of patients with central retinal artery occlusion (CRAO) is 5.5 years compared to 15.4 years for an age‐matched population without CRAO.3 Treatment and management: Extensive patient education was given regarding the severity of the situation, in addition to an explanation of stroke symptoms. The patient was also informed of the possible poor visual prognosis associated with this vascular anomaly. At this point it is highly unlikely this patient has GCA given the normal ESR. However, close monitoring is still warranted for NVI and NVA. Therefore, the patient is scheduled for a follow‐up in 2‐4 weeks. Neovascularization of the iris occurs in 20% of patients at an average of 4‐5 weeks after the event and neovascularization of the disc occurs in 2‐3% of patients.3 In addition to a Doppler, an electrocardiography (ECG) could be used for cardiac evaluation if not already performed and a magnetic resonance angiogram (MRA) to localize the obstruction. Transcorneal stimulation is a new form of treatment for a CRAO that is still undergoing clinical trials. This procedure uses a biphasic bipolar waveform to attempt to restore vision.4 Conclusion: It is very important in CRAO cases that GCA is immediately ruled out. In this particular case, waiting until the one month follow‐up to order an ESR or CRP is taking a risk. These labs should have been ordered at the initial visit. Therefore, with any CRAO diagnosis a carotid Doppler, ESR and CRP should be ordered all together at the same time. In general, a CRAO is a very serious situation with a poor visual prognosis. Therefore, extensive patient education is also important. The most important first steps that should be taken are requesting the appropriate lab work (ESR, CRP, prothrombin time) and ordering a carotid Doppler. It’s important to keep in mind that the survival rates in these patients are reduced and the main cause of mortality is cardiac. Therefore, a referral to a cardiologist is imperative. Bridging the gap between health care disciplines (i.e. cardiologist, primary care physician, laboratory personnel, and eye care specialists) is very important, especially in cases like this. References 1. Ehlers, Justis P., and Chirag P. Shah. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. Philadelphia: Lippincott Williams & Wilkins, 2008. Print. 2. "The Eyes Have It." Kellogg Eye Center‐University of Michigan‐Ann Arbor MI‐Ophthalmology. Web. 01 Sept. 2010. <http://www.kellogg.umich.edu/theeyeshaveit/index.html>. 3. Graham, Robert H. "Central Retinal Artery Occlusion: Follow‐up ‐ EMedicine Ophthalmology." EMedicine ‐ Medical Reference. 12 Feb. 2009. Web. 01 Sept. 2010. <http://emedicine.medscape.com/article/1223625‐followup>. 4. "The Effect of Transcorneal Stimulation in Cases of Central Retinal Artery Occlusion Using a New Waveform ‐ Full Text View ‐ ClinicalTrials.gov." Home ‐ ClinicalTrials.gov. Dec. 2008. Web. 01 Sept. 2010. <http://www.clinicaltrials.gov/ct2/show/NCT00802698?term=central retinal artery occlusion&rank=1>. .