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Title: Transient Cortical Blindness Following Cerebral Angiography in a 34 year old male Abstract: A 34 YO male with a subarachnoid hemorrhage underwent cerebral angiography to rule out an aneurysm. Neurotoxicity to the contrast agent led to acute encephalopathy, headache, cerebral infarcts, and cortical blindness that recovered in days. I. Case History •Patient demographics: 34 year old white male •Chief complaint: The patient experienced lightheadedness and presyncope at the gym while doing squats. He presented to the ER later that week with left retrobulbar headache and was found to have a subarachnoid hemorrhage in the left frontal-parietal lobe. A four vessel catheter-based cerebral angiography with the contrast agent Ultravist, was performed to rule out an aneurysm. Upon completion of the procedure and within minutes, the patient became bilaterally blind, with associated headache and disorientation. •Ocular history: o o o o Myopia OU h/o contact lens wear many years ago No ocular trauma OU No ocular surgery OU •Medical history o Non-aneurysmal Subarachnoid hemorrhage in the left frontal-parietal convexity with valsalva •Medications o Acetaminophen tablet 650 mg po Q4H prn for headache II. Pertinent findings •Clinical Initial examination by optometry took place in the angiography suite after a stat page from the neurology department. Immediately upon completion of a cerebral angiography, the patient complained of vision changes. The neurology resident performed confrontation fields and found the patient to be full to finger count in both eyes. However, over the following 30 minutes, the patient reported progressive visual deterioration, which culminated in complete bilateral blindness. Upon optometry’s arrival to the scene, the patient was disoriented, and thrashing about with a severe headache. The patient was not able to cooperate with testing but maintained a brisk pupillary response to light in each eye, had no afferent pupillary defect, no purposeful gaze, and his eyes would roll back when being manually opened for testing. There was no verifiable response to the OKN tape for either eye. Vision was unable to be quantified. However, IOP was normal and fundoscopy was unremarkable with flat, pink discs OU with a well-perfused posterior pole OU. The angiography failed to show aneurysm. The patient was sedated, given Calcium channel blockers to control vasospasms and lower blood pressure, and an MRI was performed. Unfortunately, there was motion artifact of the imaging but another MRI was performed the next morning with improvement of image quality. The MRIs were negative for new hemorrhaging but were positive for an acute infarct within the right cerebellum with a smaller infarct in the right temporal lobe. The strokes were not cause for the cortical blindness as they were not in a location to cause such symptoms. The patient was intubated and sedated for next two days. Two days later the patient was extubated and was examined bedside in intensive care. The patient recalled feeling “pressure in my head” during the angiography and confirmed that his vision was not blurry but was black. Upon awakening from sedation, the patient was symptomatic for blur but admitted that his vision had been improving throughout the day. He was having trouble reading the keys on his cell phone with his current spectacles. A persistent headache with a severity of 1/10 was also present. The patient had not been previously examined by an optometrist through the VA but had an eye exam 2 years prior was with no health concerns. A corrected, distance Snellen equivalent acuity of 20/30 OD and OS was obtained. Resolution of smaller letters may have been possible at that time but vision was quantified to the fullest extent of a bedside exam with a Feinbloom chart at 7 feet. Near acuities were 20/20 in each eye. Confrontation fields revealed a questionable inferior-temporal defect OD as the patient had more difficulty in this quadrant. All other quadrants were FTFC OD and OS and no visual extinction was noted. Facial amsler was grossly normal. Snowflake Amsler, done to pick up a small paramacular scotoma, was full in each eye. Red cap desaturation was of equal color and brightness in each eye. Pupils remained briskly responsive to light, equal, and round with no APD. Extraocular motilities were full range of motion in both eyes with no diplopia or pain. A questionable right beat nystagmus was observed. However, the patient seemed to have more difficulty with this gaze that may account for the finding. There was no nystagmus on up or down gaze. Color vision with Ishihara was 4/11 OD and 5/11 OS. The patient denied knowledge of prior color vision defect, and the patient’s mother, who was present during the exam, confirmed “he was always able to correctly identify crayon colors as a child”. Anterior segment was unremarkable and IOPs were 15 mmHg OD and 18 mmHg OS. On dilated fundus exam, several vitreous floaters were noted in the periphery of both eyes and over the optic nerve in the right eye. There was a foveal light reflex in both eyes, a clear macula OU, normal vasculature with no emboli, and a intact and perfused retina. Optic nerves appeared healthy, flat, and pink, with a spontaneous venous pulsation in both eyes. Four days after the initial angiography event, the patient presented to the eye clinic for formal testing. He reported a subjective normalization of vision since the third day status post cerebral angiography and could now see his phone without difficulty. He experienced an intermittent headache that was relieved with Tylenol. Corrected, distance visual acuities were 20/20 in each eye. Pupils were equal, round, reactive to light, and with no APD. Confrontation fields were full in all quadrants OD/OS, and extraocular motilities were full range of motion OU with no diplopia, pain, or nystagmus. Color vision had normalized in both eyes with normal Ishihara and D15. Undilated fundus exam was unremarkable. Fundus photos were taken for photodocumentation and Humphrey Visual Fields were clean with no neurological defects in either eye. •Physical Decreasing vision within 30 minutes following the cerebral angiography was the first clue that a complication had occurred. The patient then complained of a headache with a rapid deterioration of cognition soon thereafter. He became disoriented and increasingly agitated. There were no other focal neurological deficits as the patient was able to move all four limbs spontaneously. Speech, although incoherent at times, was preserved. Blood pressure was on the lower side of normal. •Laboratory studies o o o o o Sickle cell anemia trait EGFR Creatinine Weight Height •Radiology studies o Non-contrast CT of head and neck o Small Left frontal subarachnoid hemorrhage without mass effect or midline shift. o MRI #1 ; before the angiography o FLAIR hyperintensity in the left frontopariental sulci, which are consistent with subarachnoid hemorrhage. o 4 Vessel Cerebral angiography with ULTRAVIST contrast o No brain aneurysm, AV Malformation, or dural AV fistula. o Focal vasospasm of vessels in near the left Middle Cerebral Artery and the SAH. o There are a few focal areas of moderate stenosis involving distal parietooccipital left middle cerebral artery (MCA) branches. These findings are suspicious for a vasculitis, or less likely, vasospasm related to known subarachnoid hemorrhage. No evidence of intracranial aneurysm. o MRI #2 ; immediately after angiography; sedated o Acute infarct within the right cerebellum and within the right temporal lobe. No evidence of hemorrhagic transformation was noted and the subarachnoid hemorrhage in left frotoparietal sulci remained unchanged. o MRI #3 ; one day s/p angiography, sedated o Acute infarct within the right cerebellum and right temporal lobe. o Unchanged subarachnoid hemorrhage in the sulci of the left frontoparietal convexity. No evidence of progressive reversible encephalopathy syndrome (PRES) in the current study. •Others o Humphrey Visual Field: 24-2 o OD/OS: clear with no defects o Fundus photos o OD/OS: unremarkable III. Differential diagnosis •Primary/leading o Neurotoxicity to the contrast agent, ULTRAVIST, which is used in catheter-based cerebral angiography. This condition is proposed to be on the same continuum as posterior reversible encephalopathy syndrome (PRES). •Differential Diagnosis of Cortical blindness o Bilateral Occipital lobe infarct o Ischemic o Hemorrhagic o Psychogenic blindness o OKN distinguishes this by having response o However, patient was confused and testing was inconclusive o Cerebral Vasoconstriction IV. Diagnosis and discussion •Elaborate on the condition High concentrations of hypertonic contrast agents used in cerebral angiography can disrupt the blood brain barrier, especially when the agent is repeatedly injected over several minutes. If the blood brain barrier is compromised, leakage of the contrast agent into the cerebrospinal fluid can occur. The contrast agent can then cause serious reactions, neurotoxicity, and electrolyte imbalance that can lead to encephalopathy (2). There is a predilection for the occipital lobe as there is less sympathetic vascular innervation, reduced ability to compensate for changes in blood pressure with vasodilation or vasoconstriction, and thereby worse auto regulation of the posterior vasculature (3). The endothelium becomes damaged by the agent, vasculature becomes overwhelmed, vasogenic edema builds in the occipital regions of the brain, and visual symptoms are experienced. Cortical blindness is characterized by a loss of vision secondary to a lesion affecting the geniculocalcarine visual pathway in the brain (1). Cortical blindness can be attributed to a variety of causes, with the most common being spontaneous ischemic stroke (32%), stroke secondary to cardiac surgery (20%), and cerebral angiography (12%) (1). Most patients have sudden onset of blindness but prior amaurosis, partial field loss progressing to complete field loss, and gradual decreases in vision were also reported (1). Proposed mechanisms of cortical blindness due to angiography are disruption of the blood-brain barrier, secondary toxicity, concurrent hypotension, embolism, cortical hemorrhage, or vasospasm. One study found that cortical blindness occurred in 0.8% of all vertebral angiographies (1). If the parietal lobe shows defects then it is usually associated with cognitive deficits without a significant vision reduction (1). Anton’s syndrome, the denial of cortical blindness, occurred but was very rare (1, 3). Absent OKN responses were noted in almost every patient (1). This case report argues that neurotoxicity falls on a continuum and is related to PRES. Both conditions cause reversible neurological deficits. PRES is defined as a condition presenting with headache, increased confusion, visual changes, seizure, and characteristic radiological findings of posterior cerebral white matter vasogenic edema (3). The parieto-occipital region is typically involved (3). Predilection for white matter edema may be attributed to more densely packed matter in the cortex that opposes infiltration of edema (3). Findings that are found on imaging are focal areas of vasoconstriction that are consistent with impaired autoregulation, local hypoperfusion, vasogenic edema, and rare cerebral infarction (3). Vascular narrowing can be seen on catheter angiography or magnetic resonance angiography (MRA) (3). PRES can be differentiated from bilateral posterior cerebral infarction as calcarine and paramedical areas of the occipital lobe are usually spared with PRES (3). The cerebellum and brainstem are frequently affected (3). As the name suggests, clinical findings are reversible as are the radiological findings within days to weeks (3). There was an absence of seizures in a minority of patients who most often had milder disease (3). Ocular health is often unremarkable but hypertensive changes could be present as there is a higher incidence of PRES in patients with high blood pressure (3). Risk factors for neurotoxic reaction are significant fluid overload (>10% of baseline weight), mean blood pressure increase of >25% from baseline, and Creatinine of greater than 1.8 mg/dl (3). Dosing of the contrast agent for cerebral angiography should be 300 mg I/mL with a maximum dose for adults of 86 grams. However, dosage should be adjusted for age, body weight, vessel size, and rate of blood flow within the intended vessels (4). Single injection dosing for cerebral angiography for cerebral arteries should be between 3-12 mL and vertebral artery single dosing should be in the range of 4-12 mL (4). The contrast agent will increase the circulatory osmotic load and can cause hemodynamic disturbances in patients with cardiac, renal, or hepatic disease (4). Sickling can be induced by the contrast agent in patients with sickle cell disease but have not been noted in patients with sickle cell trait, such as our patient (4). In a study performed by the Ultravist company, 1142 patients underwent angiography to quantify adverse reactions. Adverse reactions were observed such as nausea (3.7%), abnormal vision (1.1%), headache (4%), vasodilation (2.6%), and a large variety of other complications. Incidence of adverse reaction was 24% of patients (4). •Expound on unique features A post approval adverse reaction to the contrast agent used in cerebral angiographies, Ultravist, is cerebral ischemia, infarction, vasospasm, and transient cortical blindness. Transient cortical blindness occurs in 0.3-1.0% of cerebral and vertebral angiographies (5). Complete cortical blindness is much more rare than incomplete blindness (1). Our patient received the correct dosage of the agent and did not have risk factors such as high blood pressure, older age, or reduced kidney function. V. Treatment, management •Treatment and response to treatment Neurotoxity to contrast agent is self-limiting, with the symptoms being caused by neurotoxicity to the contrast agent. Neuroimaging should be done to aid in diagnosis. Treatment of neurotoxicity involves facilitating clearance of contrast with hydration, sedation as required to accomplish imaging and to safeguard the patient, and blood pressure control. Diuresis to remove the agent has not been shown useful (5). Vision should recover to normal when the contrast has been eliminated from the system, within an average of 3 days (5). Visual recovery is gradual, beginning with light perception, followed by motion perception, and finally color vision recovery (5). •Bibliography, literature review encouraged 1. Aldrich, Michael S., Anthony G. Alessi, Roy W. Beck, and Sid Gilman. "Cortical Blindness: Etiology, Diagnosis, and Prognosis." Annals of Neurology Ann Neurol. 21.2 (1987): 149-58. Web. 2. Kocabay, G., and C. Y. Karabay. "Iopromide-induced Encephalopathy following Coronary Angioplasty." Perfusion 26.1 (2010): 67-70. Web. 3. Neill, Terry A. "Reversible Posterior Leukoencephalopathy Syndrome." Up to Date. Ed. Micheal J. Aminoff and Janet L. Wilterdink. N.p., 29 Apr. 2015. Web. 6 Aug. 2015. <www.uptodate.com>. 4. "Ultravist." RxList. N.p., 24 May 2012. Web. 12 Aug. 2015. <http%3A%2F%2Fwww.rxlist.com%2Fultravist-drug.htm>. 5. Yazici, Mehmet, Hakan Ozhan, Ozan Kinay, Baris Kilicaslan, Mustafa Karaca, Hasan Cece, Serdar Biceroglu, and Oktay Ergene. "Transient Cortical Blindness after Cardiac Catheterization with Iobitridol." Texas Heart Institute Journal (2007): 37375. Web. VI. Conclusion •Clinical pearls, take away points if indicated This case report highlights the potential for neurotoxicity to the contrast agent, which can occur immediately following catheter-based cerebral angiography. This condition can result in temporary cortical blindness, headache, encephalopathy, and possible seizures. Prognosis is good after clearance of the contrast agent, which generally takes about three days.