Acute cortical blindness due to posterior reversible encephalopathy

Generalized anosognosia, anosodiaphoria, and visual hallucinations with bilateral enucleation after severe bifrontal brain injury: a case report describing similarities with and differences from Anton syndrome

Visual anosognosia, associated with confabulations and cortical blindness in the context of occipital lobe injury, is known as Anton syndrome. Patients with this syndrome strongly deny their vision loss and confabulate to compensate for both visual loss and memory impairments. In this article, we present a case of a patient with some similarities to Anton syndrome, however, with several differences in clinical presentation. Bifrontal brain injury, bilateral enucleation, affective indifference (anosodiaphoria), generalized anosognosia, and the conviction that vision will resume mark clear clinical differences with Anton syndrome. Differentiating these findings from Anton syndrome will help occupational therapists, neuropsychologists, speech-language pathologists, physical therapists, and physicians when assessing frontal lobe brain injury with total and partial visual loss. This case demonstrates that visual anosognosia and confabulations can occur without occipital lobe dysfunction or cortical blindness.

Temporary Visual Loss Due to Posterior Reversible Encephalopathy Syndrome in the Case of an End-Stage Renal Disease Patient

Posterior reversible encephalopathy syndrome is a clinical phenomenon associated with headache, altered mental status, seizures, and visual disturbances along with radiographic acute cerebral oedema. Several conditions are correlated with posterior reversible encephalopathy syndrome, with acute hypertension, eclampsia, and cytotoxic agents being the most common. This report presents a case of posterior reversible encephalopathy syndrome in a 45-year-old male with multiple underlying conditions, including hypertension, diabetes, and end-stage renal disease. Sudden onset of bilateral visual loss with mild systemic feature of dizziness was noted on presentation. Radiologic findings showed characteristic findings of posterior reversible encephalopathy syndrome. Following prompt control of hypertension and haemodialysis, resolution of symptoms was noted.

MRI in the Evaluation of Acute Visual Syndromes

Acute visual symptom emergencies occur commonly and present a challenge to both clinical and radiologic facets. Although most patients with visual complaints routinely require clinical evaluation with direct ophthalmologic evaluation, imaging is rarely necessary. However, there are highly morbid conditions where the prompt recognition and management of an acute visual syndrome (AVS) requires an astute physician to probe further. Suspicious symptomatology including abrupt visual loss, diplopia, ophthalmoplegia, and proptosis/exophthalmos require further investigation with advanced imaging modalities such as magnetic resonance imaging and magnetic resonance angiography. This review will discuss a variety of AVSs including orbital apex syndrome, cavernous sinus thrombosis, cavernous carotid fistula, acute hypertensive encephalopathy (posterior reversible encephalopathy syndrome), optic neuritis, pituitary apoplexy including hemorrhage into an existing adenoma, and idiopathic intracranial hypertension. A discussion of each entity will focus on the clinical presentation, management and prognosis when necessary and finally, neuroimaging with emphasis on magnetic resonance imaging. The primary purpose of this review is to provide an organized approach to the differential diagnosis and typical imaging patterns for AVSs. We have provided a template for radiologists and specialists to assist in early intervention in order to decrease morbidity and provide value-based patient care through imaging.

Anton's Syndrome due to Bilateral Ischemic Occipital Lobe Strokes

We present a case of a patient with Anton's syndrome (i.e., visual anosognosia with confabulations), who developed bilateral occipital lobe infarct. Bilateral occipital brain damage results in blindness, and patients start to confabulate to fill in the missing sensory input. In addition, the patient occasionally becomes agitated and talks to himself, which indicates that, besides Anton's syndrome, he might have had Charles Bonnet syndrome, characterized by both visual loss and hallucinations. Anton syndrome, is not so frequent condition and is most commonly caused by ischemic stroke. In this particular case, the patient had successive bilateral occipital ischemia as a result of massive stenoses of head and neck arteries.

Posterior Reversible Encephalopathy Syndrome and Anti-Angiogenic Therapy

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological entity first described in 1996 by Hinchey et al, most commonly associated with hypertensive encephalopathy, eclampsia in pregnant women, immunosuppressants and cytotoxic agents. In recent years, anti-angiogenic agents as a novel class of anti-cancer therapies have become a standard of care for certain tumours. Correspondingly, there have been an emerging number of case reports documenting PRES associated with these anti-angiogenic therapies. As the manifestations of PRES are often non-specific, but could rarely lead to permanent neurological disability or even death, it is crucial that physicians are aware of PRES in relation to anti-angiogenic therapy to promptly institute appropriate management to achieve the best outcomes for patients.

Posterior reversible encephalopathy syndrome presenting as Balint syndrome

Balint syndrome is a disorder of inaccurate visually guided saccades, optic ataxia, and simultanagnosia that typically results from bilateral parieto-occipital lesions. Visual perception disturbances in the posterior reversible encephalopathy syndrome (PRES) include hemianopia, visual neglect, and cerebral blindness, but Balint syndrome had not been recognized. We report Balint syndrome associated with PRES in a 37-year-old woman with acute hypertension and systemic lupus erythematosus. Balint syndrome can be an initial presentation of PRES.

First description of posterior reversible encephalopathy syndrome as a complication of glycerolnitrate patch following open cardiac surgery

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) affects predominantly the parietal and occipital lobes. Frequent clinical features are epileptic seizure, altered mental status and visual disturbances.

CLINICAL PRESENTATION

We present the first case of a patient with pericarditis and mitral valve insufficiency, who developed PRES after application of a glycerolnitrate patch day three post-operatively and whose neurological deficits improved within 2 days after withdrawal of patch therapy.

CONCLUSION

The precise pathomechanism of PRES is unknown. The lower sympathetic innervation of the posterior circulation may be one explanation for its particular vulnerability to vasodilatation caused by glycerolnitrate.

Seizures in Women with Preeclampsia: Mechanisms and Management

Eclampsia is defined in the obstetrical literature as the occurrence of unexplained seizure during pregnancy in a woman with preeclampsia. In the Western world, the incidence of eclampsia is ~1 per 2000 to 1 per 3000 pregnancies, but the incidence is 10-fold higher in tertiary referral centers and undeveloped countries where there is poor prenatal care, and in multi-fetal gestations. Nearly 1 in 50 women with eclampsia die as do 1 in 14 of their offspring, and mortality rates are considerably higher in undeveloped countries. Eclampsia is also associated with significant life-threatening complications, including neurological events. Seizure acutely can cause stroke, haemorrhage, oedema and brain herniation and thus lead to epilepsy and cognitive impairment later in life.

Posterior Reversible Encephalopathy Syndrome and Anti-Angiogenic Agents: A Case Report

Posterior reversible encephalopathy syndrome is an increasingly recognised clinico-radiological entity, associated with several medical conditions (such as systemic arterial hypertension) and characterised by seizures, altered mental status, headaches, and visual symptoms. Magnetic resonance imaging is a key component in this diagnosis, with hyperintense foci in T₂-weighted images, corresponding to vasogenic oedema. The pathophysiology is not fully understood but probably involves loss of auto-regulation of cerebral vasculature or endothelial dysfunction or both. A 56-year-old male, suffering from a gastro-intestinal stromal tumour with hepatic metastasis resistant to imatinib, on therapy with sunitinib, came to the Emergency Department because of headaches, hallucinations, and loss of vision. There was no previous history of high blood pressure. A hypertensive crisis was diagnosed; ophthalmological examination on admission showed no light perception bilaterally. Brain imaging displayed bilateral parieto-occipital and frontal vasogenic oedema, consistent with the clinical diagnosis of posterior reversible encephalopathy syndrome. After treatment of hypertension and suspension of sunitinib, the patient recovered from his symptoms. Control imaging showed no oedema. Angiogenesis inhibitors, such as sunitinib and bevacizumab, can cause hypertension, one of the many medical conditions associated with the posterior reversible encephalopathy syndrome. This syndrome should be considered in cases of acute visual loss, particularly in view of its reversible nature when diagnosed and treated promptly.