Palinopsia as a Rare Presenting Symptom of Occipital Stroke “Case Report”

Palinopsia is the recurrence or persistence of visual images after cessation of the stimulus. Palinopsia has been associated with a wide variety of etiologies and mechanisms such as drug induced, seizures, migraine, psychiatric conditions, head trauma and structural lesions in the brain. We report a case of occipital stroke who presented with oscillating palinopsia. Sudden-onset pali-nopsia is a very rare symptom of stroke, but it must be recognized early as it is a highly time dependent, and potentially treatable condition. A 57-year-old woman with a history of poorly controlled type 2 diabetes, hyperlipidemia, and hypertension presented with sudden onset right sided palinopsia with images of her face and right forearm with hand, occurring several times in a day, lasting for a few minutes each time, and appearing in the same location each time. There are few case reports in literature secondary to stroke and what makes it interesting also is that she reported persistence of image even when her eyes are closed. Moreover, the sudden onset is not common in literature. The Magnetic Resonance Imaging (MRI) of the brain showed evidence of left Posterior Cerebral Artery (PCA) territorial (Fusiform gyrus) subacute ischemic infarction. Visual field assessment showed a right ho-monymous hemianopia. She was treated with aspirin and clopidogrel. The frequency and intensity of palinopsia reduced subsequently. The face image disappeared in the first week while the forearm image disintegrated gradually over the next few weeks. Palinopsia may be a rare presenting symptom of stroke. It is important for the clinician or emergency room doctors to be alert to the possibility of undiagnosed structural neurological lesions like occipital stroke and differentiate it from non-organic causes, as prompt management may reduce the risk of visual or motor disability.


Introduction
Visual perseveration or palinopsia is a term that describes multiple types of visual symptoms characterized by recurrence or persistence of visual images after cessation of the stimulus. This category of palinopsia represents a dysfunction in visual memory and is caused by posterior cortical lesions or seizures. It can be classified as hallucinatory and illusory palinopsia which can last for various durations. Sudden-onset palinopsia is a very rare symptom of stroke, but must be recognized as stroke, as it is a treatable condition, and the treatment is highly time dependent. This patient is unique in her sudden onset symptoms, vascular aetiology and persistence of image when eyes are closed.

Case Presentation
A 57-year-old, right-handed lady was referred to the neurology outpatient department (OPD) for evaluation with sudden onset visual symptoms. She had a history of poorly controlled diabetes mellitus, hypertension and dyslipidaemia.
There was family history of diabetes mellitus, hypertension and dyslipidaemia.
She had a stable psycho-social history. Four days prior to presentation at the neurology OPD, the patient had attended the emergency room for raised blood pressure (200/94mmHg). She had no symptoms at that point and her blood pressure was brought under control with medications. Computed tomography of the brain at that time did not reveal any pathological findings. She complained of blurring of vision the next morning. She underwent an ophthalmological examination which was unremarkable and patient was reassured and sent home.
However, on day 3, she noted that the blurring of vision had worsened. She further stated that she specifically saw her right hand and forearm on the left upper quadrant of the temporal field while her right upper limb was actually on her knee or over her chest. This occurred several times in a day, lasted for few seconds and the image was static, vivid and had clear contours. The image was visible even when her eyes were closed. Occasionally, she saw her face in the same area of the visual field. This was short lasting and the image was not distorted. She also noted that she was unable to see people standing in her right temporal field. The patient did not report any visual distortions or alterations in colours or micropsia, macropsia or metamorphosia. She also did not report any associated headaches, eye pain, impaired consciousness, or awareness and she was not on any new medications. The patient was very distressed by her symptoms and sought medical attention.
Her ophthalmological assessment showed that the best corrected visual acuity using the Snellen chart was 6/15 in the right eye and 6/30 in the left eye. The intra ocular pressure was normal in both eyes. Colour vision in both eyes was normal. Anterior segment examination revealed that the right pupil was mid-dilated with grade one relative afferent pupillary defect. There was no papilloedema.
Both fundi showed moderate non-proliferative diabetic retinopathy with macular edema. The ocular coherence tomography of the macula in both eyes showed     Her Visual field assessment showed a right homonymous hemianopia ( Figure   4). Visual evoked potentials were within normal limits.

Discussion
We presented a patient with long standing risk factors for ischaemic stroke having repeated episodes of palinopsia as a major presenting symptom of stroke.
Palinopsia Palinopsia can occur as manifestation of epilepsy and seizures of the visual processing and memory centres of the brain might be the underlying cause of palinopsia [6]. Palinopsia may occur during a seizure aura, the ictal phase, and postictally and anticonvulsive therapy has also been found to reduce palinopsia in symptomatic patients [7]. Occasionally palinopsia may be the only symptom  [8].
Episodes of palinopsia may also occur due to disturbances of peripheral vestibular function. Stafuzza et al reported a patient with episodes of palinopsia after the functional loss of the 3 semicircular canals of the right ear with preservation of the otolithic function [9]. The abnormal temporal integration of the visual and vestibular inputs may result in palinopsia if there is a delay in the vestibular inputs [9]. The absence of vestibular symptoms and normal hearing function in our patient makes it unlikely to be a causal factor. Palinopsia has generally been described in reference to static afterimages. In our case too, the patient reported static images of her forearm and hand. Lahiri et al reported a case of kinetic palinopsia with images of a car moving backwards in his left visual field [10]. Similar to our case, their patient also had an associated field defect (left homonymous hemianopia) due to right occipital arteriovenous malformation (AVM) affecting the lingual gyrus and right occipital lobe. Palinopsia commonly occurs in the setting of posterior visual pathway deafferentation causing homonymous visual field deficits and it is most often hallucinatory palinopsia. This palinoptic mechanism is thought to be similar to visual release hallucinations (Charles-Bonnet syndrome), which are due to neuronal hyperexcitabiity, often from ocular vision loss [7]. Whereas hallucinatory palinopsia occurs due to focal cortical hyperexcitability from cortical visual loss. Visual release hallucinations can be distinguished from palinopsia by the content of the images (whether the formed image or scene actually occurred).
Palinopsia has been reported in Creutzfeldt-Jakob disease (CJD), Leber's Hereditary optic neuropathy, optic neuritis, perilesional hyperperfusion, multiple sclerosis, ceroid lipofuscinosis, Glycine receptor antibody syndrome, nonketotic hyperglycemia, tumors and leukemias [6] [7] [10] [11]. There were no associated neurodegenerative processes or other systemic diseases which may be a likely etiology for the palinopsia in our patient. There was no cognitive decline or ataxia as seen in palinopsia in ceroid lipofuscinosis [11]. Palinopsia usually results from a lesion in the dominant hemisphere in 25% of cases [9], as seen in our patient. Authors have reported a case of a glioblastoma tumor in the non-dominant occipito-temporal region, wherein the pattern of palinopsias was a complex scene of the family members and room contents [12]. In contrast, our patient had static palinopsia with afterimages of his own forearm and hand. Case Reports in Clinical Medicine Palinopsia has been found to be brought on by a variety of prescribed medications (Topiramate, clomiphene citrate, Zosuquidar, Nefazodone, Interleukin 2 therapy, trazodone) and illicit drugs (marijuana, mescaline, lysergic acid dyethilamide, 3,4-methylenedioxymethamphetamine [6] [7] [13] [14] [15] and most are illusory palinopsia. These symptoms typically occur during drug initiation or dose increase and resolve after drug discontinuation. Clomiphen citrate an infertility drug can result in palinopsia that may persist for years after use of the drug [13] [14]. The illusory palinopsia induced by drugs is mainly caused by its action on the serotonergic system and serotonin depletion leads to cortical hyperexcitability. In our case, a thorough history taking and inventory of medications, both past and present was done to rule out any influence of drug induced palinopsia. Also, the treatment for ischaemic stroke reduced the frequency and intensity of palinopsia. The face image disappeared in the first week while the arm image disintegrated gradually over the next few weeks. Palinopsia in our patient was also not associated with visual snow which is characterized by the perception of TV static-like "snow" in the entire visual field [16]. The absence of vestibular symptoms and normal hearing function of this patient makes it unlikely to be associated with vestibular dysfunction which may provoke palinopsia in few cases [9]. Selective intra cerebral stimulation of the right lateral fusiform gyrus may result in partial or superimposed palinopsia on other images (facial palinopsia) [17]. Involvement of fusiform gyrus in stroke may result in facial palinopsia, i.e. an individual face percept superimposed on the non-face stimulus. This might explain the face image observed by our patient.

Conclusion
Palinopsia may be a presenting symptom of stroke. It is important for the clinician or Emergency room doctors to be alert to the possibility of undiagnosed structural neurological lesions like occipital stroke and differentiate it from nonorganic causes, as prompt management may reduce the risk of visual or motor disability. Palinopsia is an unusual symptom with which many clinicians outside neurology may be unfamiliar and often requires interaction from multiple disciplines including neurology, eye care, and psychiatry. Those experiencing palinopsia often may be distressed and reluctant to describe their rather disturbing symptoms clearly to the attending physician. It is imperative for doctors to be aware of this condition, recognize associated factors and elicit the information by asking correct questions to the patient. In addition, it is important to address their concerns and reassure them that what they experience is a well-documented phenomenon and may be more common than it is perceived to be.

Consent for Publication
The consent for publication was obtained from both the patient and the University Hospital Sharjah ethical committee.

Availability of Supporting Data
The date is stored in the electronic database of the University Hospital Sharjah under the confidentiality act.

Authors Contributions
Dr