Cherry-Red Spot: Difference between revisions
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== Etiology == | == Etiology == | ||
The causes of cherry-red spot in the macula can be categorized into | The causes of cherry-red spot in the macula can be categorized into 6 groups, according to etiological factors: | ||
==== '''<big>Vascular</big>''' ==== | ==== '''<big>Vascular</big>''' ==== | ||
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== History == | == History == | ||
* Medical history of cardiovascular disease, thromboembolic disorders | |||
* Smoking | |||
* Family history of lipid/lysosomal storage disorders or metabolic disease | |||
== Physical examination == | == Physical examination == | ||
Line 118: | Line 121: | ||
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 | 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 or other cardiac disease. | |||
Echocardiography 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 | |||
Carotid doppler ultrasound ordered and 2 D echocardiogram n | |||
Carotid Doppler Ultrasonography | |||
Carotid ultrasonography may be used to evaluate for atherosclerotic plaque; this appears to be more sensitive than carotid ultrasonography with Doppler, which determines only the flow. | |||
Magnetic resonance imaging | |||
Approximately 20% of patients with a CRAO also have cerebral ischemia; therefore, magnetic resonance imaging (MRI) of the brain may reveal concurrent cerebral ischemia in patients without accompanying neurological symptoms. [23] Magnetic resonance angiography (MRA) of the head and neck may be more accurate in detecting vascular occlusive disease. Computerized tomography (CT) or computerized tomography angiography (CT/CTA) or MRI/MRA of the neck may be needed for carotid dissection. | |||
* Fundus autofluorescence : in the acute phase, fundus autofluorescence in ischemic areas is decreased because of retinal edema blocking the normal RPE. Eventually, this could return to normal baseline or may be associated with increased autofluorescence owing to a window defect created by the thinned-out inner retinal layers. | |||
* Fluorescein angiography may be a prognostic test. Poor perfusion on fluorescein angiography has been associated with lower vision than exudative and mixed perfusion. This finding does not influence therapy. Normal choroidal filling begins 1-2 seconds before retinal filling and is complete within 5 seconds of dye appearance in healthy eyes. A delay of 5 or more seconds is seen in 10% of patients. Consider ophthalmic artery occlusion or carotid artery obstruction if choroidal filling is significantly delayed. Delay in arteriovenous transit time (reference range, < 11 seconds) | |||
Delay in retinal arterial filling | |||
Arterial narrowing with normal fluorescein transit after recanalization | |||
* Spectral-domain optical coherent tomography (OCT) has been proposed as one modality that might be used to diagnose and monitor CRAO. In CRAO, there is an observed increase in intensity of inner retinal layers compared with age-matched controls, and it corresponds to the layers supplied by central retinal arteries. Chen et al showed that optical intensity on OCT can be correlated with visual prognosis. [26] Incomplete CRAO shows minimal retinal architectural disruption and inner layer hyper-reflectivity without retinal edema. Subtotal CRAO demonstrated inner macular thickening and loss of organization of the inner retina, and total CRAO demonstrated marked inner retinal thickening and subfoveal choroidal thinning. [27, 28] In the chronic phase, there is a corresponding thinning of the inner retinal layers. | |||
* Optical coherent tomography angiography is a novel noninvasive technique that eliminates the need for dye injection to evaluate the retinal microvasculature. It is based on the principle that static and nonstatic structures (ie, blood flowing through vessels) generate different signal amplitudes on repeated B scans from the same cross-sections. OCTA provides structural and functional (blood flow) information at a fixed point; however, it is not useful to appreciate leakage from vessels. [29] OCTA shows decreased vascular perfusion in superficial and deep retinal plexus that corresponds to poor perfusion on fluorescein angiography. In patients with the cilioretinal artery–sparing variant, the deep capillary plexus retained perfusion. However, unlike fundus fluorescein angiography, OCTA cannot demonstrate a delay in transit time. [30] | |||
* Electroretinography shows a diminished b-wave corresponding to Muller and/or bipolar cell ischemia.F | |||
== Laboratory test == | == Laboratory test == | ||
* Complete blood count CBC (anemia, leukemia, polycythemia, platelet disorders) | |||
* urea and electrolytes | |||
* Erythrocyte sedimentation rate (ESR) to detect the remote possibility of giant cell arteritis in elderly patients | |||
* C-reactive protein | |||
* Hypercoagulable state evaluation (eg, factor V Leiden, prothrombin mutation, homocysteine levels, fibrinogen, antiphospholipid antibodies, prothrombin time/activated partial thromboplastin time [PT/aPTT], serum protein electrophoresis, among others) | |||
* Fasting blood sugar, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease | |||
* Homocysteine levels | |||
* Plasma protein electrophoresis (sickle-cell anemia) | |||
* Blood cultures to evaluate for suspected bacterial endocarditis and septic emboli | |||
* Antibodies | |||
* Genetic testing, molecular analysis of cells or tissues, and enzyme assays to investigate possible lipid-storage disorders in younger patients | |||
== Differential diagnosis == | == Differential diagnosis == | ||
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== Medical therapy == | == Medical therapy == | ||
==== IOP reducing | ==== IOP reducing pharmacological agents ==== | ||
* IV acetazolamide | * IV acetazolamide | ||
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* Topical antiglaucoma medications | * Topical antiglaucoma medications | ||
==== | ==== Vasodilation agents ==== | ||
* Pentoxifylline | * Pentoxifylline | ||
Line 163: | Line 205: | ||
==== Thrombolytic therapy to dissolve clot ==== | ==== Thrombolytic therapy to dissolve clot ==== | ||
* IV or intra-arterial recombinant tissue plasminogen activator (rt-PA) is delivered through the supraorbital artery and can | * IV or intra-arterial recombinant tissue plasminogen activator (rt-PA) is delivered through the catheterization of the ophthalmic artery or supraorbital artery and can reach the CRA in doses 100 times greater than by systemic administration. Vision improvement is noted in 50% of the patients. | ||
==== IV methylprednisolone ==== | ==== IV methylprednisolone ==== | ||
Line 196: | Line 238: | ||
These acute measures may provide benefit, however, there is no clear evidence at this point that these measures improve the patient's final visual acuity | These acute measures may provide benefit, however, there is no clear evidence at this point that these measures improve the patient's final visual acuity | ||
= References | Vision loss is permanent due to infarct of inner retina n Irreversible damage to sensory retina after 90100 minutes of complete CRAO Vision of 20/400 or worse in 66% of cases n Complications n Iris neovascularization occurs in 18% of eyes n Less than five percent develop neovascular glaucoma n | ||
= References = | |||
Add text here | Add text here |
Revision as of 15:36, May 30, 2021
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Cherry red spot is a significant fundoscopic finding in the macula, observed in central retinal vein occlusion (CRAO) and a variety of lipid storage disorders.
Disease Entity
Disease
Cherry-red spot (CRS) at the macula is a clinically significant sign observed on fundus examination in a variety of pathological conditions[1], including retinal infarction, retinal ischemia. as well as a variety of lysosomal storage disorders.[2] The term refers to the appearance of a red-tinted region at the center of the macula surrounded by retinal opacification[2], and it consists a clinical sign usually present within the context of thickening and loss of transparency in the posterior pole of the retina.[3] The fovea being the thinnest part of the retina and devoid of ganglion cells, retains relative transparency, due to which the color of the choroids shines through.[3] The appearance of a cherry red spot can result from retinal edema most commonly due to central retinal artery occlusion or traumatic retinal ischemia, which cause the perimacular tissue of the retina to appear pale, while the fovea maintains its normal color[4], as it receives its blood supply from the choroid, supplied by the long and short posterior ciliary arteries.[5]In the case of lipid storage diseases, the lipids are stored in the ganglion cell layer of the retina, giving the retina a white appearance. As ganglion cells are absent at the foveola, this area retains relative transparency and contrasts with the surrounding retina.[3] Cherry-red spot is an important fundoscopic sign, when clubbed with key clinical features and a good history, it often guides one to the diagnosis of the disease.[1] It should be noted that as a condition resolves or evolves over the course of time, the appearance of a cherry-red spot diminishes and may not be present, therefore absence of a cherry red spot does not indicate that a disease is not present.[2]
History
The term “cherry-red spot” was first by American neurologist Bernard Sachs in 1887, when describing the fundus appearance of a child with "amaurotic familial idiocy" in his publication on “arrested development with special reference to its cortical pathology”. [4] The patient was confirmed upon neuropathologic examination to have lipid storage in the brain. [6] Bernard Sachs acknowledged that his patient had also been examined by ophthalmologist Herman Joseph Knapp, who practiced in both New York and Berlin, and described the striking retinal findings at an ophthalmology meeting in Heidelberg, and had first used the term “cherry red color” to describe the fovea.[4] . Knapp had initially believed that the cherry red spot was a benign fundoscopic finding, but later on realized its grave implications. [4]
Etiology
The causes of cherry-red spot in the macula can be categorized into 6 groups, according to etiological factors:
Vascular
- Central retinal artery occlusion (CRAO) - This disease entity characteristically presents as a sudden onset of painless, unilateral visual loss in elderly patients, most commonly caused by an embolism, which blocks the central retinal artery.[2] The embolus may be composed of cholesterol, fibrin-platelet, or calcium and usually originating from the carotid plaque and less commonly from the heart or the aorta. Inflammatory conditions like giant cell arteritis (GCA), may also cause CRAO. Other causes of CRAO n include myxoma or vegetations of the cardiac valves, thrombophilic disorders, and retinal migraine.. Cherry-red spot has been found to be present on the initial examination in 90% of permanent CRAO cases.[2]
- Acute occlusion of the choroidal circulation causing outer retinal whitening and a cherry-red spot at the macula following cataract surgery (phacoemulsification)
- Intraorbital hemorrhage or mass may compromise the choroidal and retinal circulation and lead to a cherry-red spot at the macula
- Macular infarction due to various causes
Metabolic Storage Diseases
- Tay-Sachs disease (GM2 gangliosidosis type 1, infantile amaurotic familial idiocy, B variant GM2 gangliosidosis)- This is the most common type of gangliosidosis due to deficiency of the alpha subunit of hexosaminidase A on chromosome 15q23. The disease has an onset of the symptoms in the infancy. There is an abnormal accumulation of gangliosides in the brain and ganglion cell layer of the retina. A cherry-red spot is present in approximately 90% of the patients affected with the disease.
- GM2 gangliosidosis type 2 or Sandhoff disease
- Niemann-Pick disease - Type A, B, C, D disease
- GM1 gangliosidosis type 1 (Generalized gangliosidosis or Landing disease), in which a cherry-red spot in the macula occurs in around 50% cases.[6] There are three variants:
- Sialidosis or mucolipidosis type 1 is a lysosomal storage disease cause by alpha-neuraminidase deficiency and presents with ataxia, movement disorders, nystagmus, and myoclonic seizures. Intellect is usually normal, and somatic features are generally not seen. Two types have been described according to the age of onset and severity of the disease: Sialidosis type I or cherry-red spot myoclonus syndrome is characterized by onset in the 2nd or 3rd decade, gait disturbances, myoclonus, ataxia, tremor, a cherry-red spot at the macula, and seizures. The intellect and life expectancy are usually not affected, though the patient eventually needs wheelchair assistance with time. Almost all the patients have the cherry-red spot at the macula.[7]
- Farber disease (Farber lipogranulomatosis) is a rare autosomal recessive (AR) disorder characterized by Ceramidase or acid ceramidase (chromosome 8p22) deficiency . The typical triad consists of painful swollen joints, subcutaneous nodules (lipogranulomas), and weak cry or hoarse voice due to laryngeal nodules. Other features include a developmental delay, visceromegaly, respiratory involvement, and neurological features, including quadriplegia, seizures, and myoclonus.
- Metachromatic leukodystrophy is another rare (AR) lysosomal storage disorder described by arylsulfatase A or deficiency, resulting in abnormal collection of sulfatides in myelin-producing cells that leads to progressive destruction of white matter (leukodystrophy). A cherry-red spot at the macula is occasionally a finding in fundoscopy along with progressive decline in intellectual and motor functions, peripheral neuropathy resulting in diminished sensations, hearing loss, incontinence, loss of speech and mobility, blindness, unresponsiveness, and eventual death.
- Galactosialidosis (Goldberg Cotlier syndrome or neuraminidase deficiency with beta-galactosidase deficiency or cathepsin A deficiency) is an AR disorder due to a mutation in the CTSA gene coding for cathepsin A. Ocular features include a cherry-red spot at the macula, corneal clouding, and conjunctival telangiectasia.
Inflammation
- Retinitis involving the central retina, including progressive outer retinal necrosis, subacute sclerosing panencephalitis. [2]
Drug Toxicity
- Quinine
- Carbon monoxide
- Dapsone poisoning associated with hemolytic anemia and peripheral neuropathy
- Methanol
- Intravitreal gentamicin
Trauma
- Commotio retinae - Acute retinal opacification following blunt trauma, also known as Berlin's edema, can cause a pseudo-cherry red spot, as a result of peripheral whitening of the retina that involves the macula.
- Optic nerve avulsion
Neoplastic Disease
- Leukemic infiltrates of the optic nerve head may cause CRAO and cherry red spot
Risk Factors
Risk factors that predispose to developing cherry-red spot at the macula are CRAO-associated clinical conditions including cardiovascular disease, thromboembolic disorders, dyslipidemia, diabetes, hypertension, smoking, and pyoderma gangrenosum.
Pathophysiology
The macula is histologically characterized by an area consisting of more than one layer of ganglion cell layers, and the ganglion cell layer is thick at the macula. In disease entitiescausing loss of transparency (whitening or opacification) of the inner retina, the reddish color of the vascular choroid and pigmentation of retinal pigment epithelium (RPE) is not visible through the opacified retina. However, foveola is devoid of the inner retinal layer. The retinal layers present at the foveola are (from inside outwards)- internal limiting membrane, outer nuclear layer, external limiting membrane, photoreceptor layer, and RPE. Inner retinal layers are absent in mature foveola. The vascular supply of the fovea is from the choroid, and in the occlusion of retinal vessels, it does not get hampered. Thus foveola, the thinnest part of the central retina, does not lose its transparency in inner retinal ischemia.
Thus, when there is inner retinal opacification, the reddish color of the vascular choroid and the RPE remains visible through the foveola, which is surrounded by an area of the white/opacified retina, giving rise to the typical cherry-red spot. The size of the cherry-red spot depends on the size of the foveola. There are several causes for opacification of the inner layers of the retina, including from deposition of compounds as in storage diseases, or ischemia from vascular compromise involving the retina but not the underlying choroidal circulation.
As the color of choroid and RPE varies with racial variation, the color of foveola or the central dot may change according to race. A true cherry-red spot presents in Caucasian individuals. Variations of the red-cherry spot are observed in non-Caucasian patients; the color of foveola was brown, a cherry-brown spot has been described in a Canadian aboriginal child with Sandhoff disease, due to the brown color of the fovea, whereas a cherry-black spot was reported in a patient of East Indian descent with Sandhoff disease., as a result of the black fovea color. Thus, an alternate term of 'perifoveal white patch' has been suggested. Therefore for a cherry-red spot to be seen, the vascularity of choroid needs to be intact. In cases of ophthalmic artery occlusion, there is a compromise to the vascular supply to retina, choroid, and optic nerve head circulation. There is retinal opacification without a cherry-red spot and severe vision loss, which might cause no perception of light or inaccurate projection of rays.
Opacification of the inner retina can occur as a result of retinal ischemia due to occlusion of the central retinal artery . The retinal whitening is typically most prominent in the posterior pole, and the opaque retina obscures the details of the choroidal vessels. The whitening of the retina becomes less prominent a little peripheral to the arcades, which may be related to the reduced inner retinal thickness at the peripheral retina. There is a cessation of axoplasmic transport and then the opacification of both the ganglion cell and the nerve fiber layer in a CRAO.
A variety of lipid storage disorders can produce deposition / accumulation of material at the level of the ganglion cell layer can other lipid storage disorders (sphingolipidoses), leading to progressive abnormal excessive intracellular accumulation of various glycolipids/phospholipids in the ganglion cell layer, that cause opacification of the inner retina. The foveola is devoid of the ganglion cell layer and hence remains transparent and allows transmission of the color of the choroid and the RPE. However, with the increasing age, the damaged ganglion cells are lost, and the cherry-red spot becomes less prominent. In such cases, there is consecutive optic atrophy and pallor of the optic disc due to the degeneration of the ganglion cell layer and nerve fiber layer. Cherry-red spots of the macula are produced when ganglion cells filled with lipid degenerate, thereby exposing the vascular choroidal tissue behind these cells
Primary prevention
Prevention for retinal ischemia can include measures to reduce cardio or cerebrovascular diseases.
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Diagnosis
Ruling out serious life-threatening or sight-threatening conditions is of paramount importance in a patient with a cherry-red spot at the macula, thus requiring a thorough evaluation and management of such patients.[2] It highlights the role of interprofessional team members in collaborating to provide well-coordinated care and enhance patient outcomes. Acute loss of vision with a cherry red spot should raise concern of risk for a stroke occurring. Depending on the institution, initiating consultation with a stroke team or neurology is important. Also important is assessing blood pressure.A useful sign, when clubbed with key clinical features and a good history, it often guides one to the diagnosis of the disease.[1]
History
- Medical history of cardiovascular disease, thromboembolic disorders
- Smoking
- Family history of lipid/lysosomal storage disorders or metabolic disease
Physical examination
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Signs
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Symptoms
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Clinical diagnosis
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Diagnostic procedures
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 or other cardiac disease.
Echocardiography 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
Carotid doppler ultrasound ordered and 2 D echocardiogram n
Carotid Doppler Ultrasonography
Carotid ultrasonography may be used to evaluate for atherosclerotic plaque; this appears to be more sensitive than carotid ultrasonography with Doppler, which determines only the flow.
Magnetic resonance imaging
Approximately 20% of patients with a CRAO also have cerebral ischemia; therefore, magnetic resonance imaging (MRI) of the brain may reveal concurrent cerebral ischemia in patients without accompanying neurological symptoms. [23] Magnetic resonance angiography (MRA) of the head and neck may be more accurate in detecting vascular occlusive disease. Computerized tomography (CT) or computerized tomography angiography (CT/CTA) or MRI/MRA of the neck may be needed for carotid dissection.
- Fundus autofluorescence : in the acute phase, fundus autofluorescence in ischemic areas is decreased because of retinal edema blocking the normal RPE. Eventually, this could return to normal baseline or may be associated with increased autofluorescence owing to a window defect created by the thinned-out inner retinal layers.
- Fluorescein angiography may be a prognostic test. Poor perfusion on fluorescein angiography has been associated with lower vision than exudative and mixed perfusion. This finding does not influence therapy. Normal choroidal filling begins 1-2 seconds before retinal filling and is complete within 5 seconds of dye appearance in healthy eyes. A delay of 5 or more seconds is seen in 10% of patients. Consider ophthalmic artery occlusion or carotid artery obstruction if choroidal filling is significantly delayed. Delay in arteriovenous transit time (reference range, < 11 seconds)
Delay in retinal arterial filling
Arterial narrowing with normal fluorescein transit after recanalization
- Spectral-domain optical coherent tomography (OCT) has been proposed as one modality that might be used to diagnose and monitor CRAO. In CRAO, there is an observed increase in intensity of inner retinal layers compared with age-matched controls, and it corresponds to the layers supplied by central retinal arteries. Chen et al showed that optical intensity on OCT can be correlated with visual prognosis. [26] Incomplete CRAO shows minimal retinal architectural disruption and inner layer hyper-reflectivity without retinal edema. Subtotal CRAO demonstrated inner macular thickening and loss of organization of the inner retina, and total CRAO demonstrated marked inner retinal thickening and subfoveal choroidal thinning. [27, 28] In the chronic phase, there is a corresponding thinning of the inner retinal layers.
- Optical coherent tomography angiography is a novel noninvasive technique that eliminates the need for dye injection to evaluate the retinal microvasculature. It is based on the principle that static and nonstatic structures (ie, blood flowing through vessels) generate different signal amplitudes on repeated B scans from the same cross-sections. OCTA provides structural and functional (blood flow) information at a fixed point; however, it is not useful to appreciate leakage from vessels. [29] OCTA shows decreased vascular perfusion in superficial and deep retinal plexus that corresponds to poor perfusion on fluorescein angiography. In patients with the cilioretinal artery–sparing variant, the deep capillary plexus retained perfusion. However, unlike fundus fluorescein angiography, OCTA cannot demonstrate a delay in transit time. [30]
- Electroretinography shows a diminished b-wave corresponding to Muller and/or bipolar cell ischemia.F
Laboratory test
- Complete blood count CBC (anemia, leukemia, polycythemia, platelet disorders)
- urea and electrolytes
- Erythrocyte sedimentation rate (ESR) to detect the remote possibility of giant cell arteritis in elderly patients
- C-reactive protein
- Hypercoagulable state evaluation (eg, factor V Leiden, prothrombin mutation, homocysteine levels, fibrinogen, antiphospholipid antibodies, prothrombin time/activated partial thromboplastin time [PT/aPTT], serum protein electrophoresis, among others)
- Fasting blood sugar, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease
- Homocysteine levels
- Plasma protein electrophoresis (sickle-cell anemia)
- Blood cultures to evaluate for suspected bacterial endocarditis and septic emboli
- Antibodies
- Genetic testing, molecular analysis of cells or tissues, and enzyme assays to investigate possible lipid-storage disorders in younger patients
Differential diagnosis
A macular hemorrhage or hole, with resulting enhanced red contrast relative to the surrounding retina, may be confused with a cherry red spot.[4]
Management
General treatment
Cherry-red spot at the macula is a clinically significant fundoscopic finding, that is usually indicative of an ocular emergency, especially when observed in a patient who presents with sudden onset, painless, vision loss of one eye, and therefore requires a treatment plan .The general management of a cherry-red spot sign is determined by the underlying pathological condition that causes the appearance of the fundoscopic finding.
In the acute setting of CRAO causes, treatment options are directed at resolving the CRAO and circulation, and thus maximizing visual outcome. Experimental studies suggest no detectable retinal damage in primate models with CRAO, if retinal blood flow is restored within 90 minutes. Subsequent partial recovery may be possible if ischemia is reversed within 240 minutes. However, occlusions lasting longer than 240 minutes produce irreversible damage. Treatment approach is attempted withing the first 24 hours.
For various storage diseases, the management requires a team of various specialties. Generalized pearls for the management of such patients include avoiding/reducing intake of specific molecules, enzyme replacement therapy, and symptomatic management.
Medical therapy
IOP reducing pharmacological agents
- IV acetazolamide
- IV mannitol
- Topical antiglaucoma medications
Vasodilation agents
- Pentoxifylline
- Inhalation of carbogen
- Sublingual isosorbide dinitrate
Thrombolytic therapy to dissolve clot
- IV or intra-arterial recombinant tissue plasminogen activator (rt-PA) is delivered through the catheterization of the ophthalmic artery or supraorbital artery and can reach the CRA in doses 100 times greater than by systemic administration. Vision improvement is noted in 50% of the patients.
IV methylprednisolone
(only in cases of arteritic CRAO)
Hyperbaric oxygen therapy
Increase blood oxygen tension Oxygen and COOxygen and CO22 (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 CRAO Rebreathing in the paper bag
Medical follow up
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Procedures / Surgery
- Ocular massage : it involves in and out movement with the use of a three-mirror (Goldmann) contact lens or digital massage, at an attempt to mechanically dislodge the obstructing embolus. Increase pressure should be applied for 10-15 seconds followed by sudden release. Ocular massage can cause arterial dilatation andi mprove retinal perfusion by an 86% increase in flow volume.
- Anterior chamber paracentesis : performing this procedure can provide sudden decrease in intraocular pressure, and aids the perfusion pressure behind the obstruction to dislocate the obstructing embolus.
- Transluminal Nd:YAG laser embolysis : the procedure has been advocated for CRAO or BRAO, in cases when the occluding embolus is visible an be performed to lyse or dislodge Shots of 0.5–1.0 mJ or higher are applied directly to the embolus using a fundus contact lens, in order to lyse or dyslodge the occluding embolus. 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.
- Pars plana vitrectomy : Surgical removal of the clot
Surgical follow up
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Complications
Neovascularization may occur in patients with CRAO. It may involve the retina, iris, or iridocorneal angle. There is a debate about the association of CRAO and the development of neovascular glaucoma. A prospective study of 33 patients established a temporal relationship between CRAO and neovascular glaucoma in 15% of cases.8 These results are corroborated by a retrospective study that showed a mean of 8.5 weeks from diagnosis to clinically evident neovascularization.9 However, a prospective study of 232 eyes found neovascularization in 2.5% of cases, and the authors found that there was no causal relationship.10
The development of neovascularization necessitates prompt panretinal laser photocoagulation to decrease retinal oxygen demand.
Prognosis
These acute measures may provide benefit, however, there is no clear evidence at this point that these measures improve the patient's final visual acuity
Vision loss is permanent due to infarct of inner retina n Irreversible damage to sensory retina after 90100 minutes of complete CRAO Vision of 20/400 or worse in 66% of cases n Complications n Iris neovascularization occurs in 18% of eyes n Less than five percent develop neovascular glaucoma n
References
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- ↑ Jump up to: 1.0 1.1 1.2 Suvarna J C, Hajela S A. Cherry-red spot. J Postgrad Med 2008;54:54-7
- ↑ Jump up to: 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Tripathy K, Patel BC. Cherry Red Spot. [Updated 2021 Feb 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539841/
- ↑ Jump up to: 3.0 3.1 3.2 General Practice Notebook
- ↑ Jump up to: 4.0 4.1 4.2 4.3 4.4 Leavitt, J. A., & Kotagal, S. (2007). The “Cherry Red” Spot. Pediatric Neurology, 37(1), 74-75 doi:10.1016/j.pediatrneurol.2007.04.011
- ↑ USMLE First AID 2010 page 417
- ↑ Leavitt, J. A., & Kotagal, S. (2007). The “Cherry Red” Spot. Pediatric Neurology, 37(1), 74–75. doi:10.1016/j.pediatrneurol.2007.04.011