A Case of Progressive Supranuclear Palsy-like Syndrome: Aetiology Revealed.

In 2015, we published an enigmatic case in Neuro-Ophthalmology regarding an 18-year-old woman who underwent an initially uneventful ascending aortic aneurysm repair. After 48 h, she developed a progressive supranuclear palsy-like syndrome with no findings on magnetic resonance imaging (MRI), MRI tractography, or functional MRI which correlated with this syndrome. After following our patient over the ensuing years, it became clear that the likely aetiology of these neurologic deficits was the profound deep hypothermia associated with her aortic aneurysm repair.

Disorders of the Fourth Cranial Nerve.

ABSTRACT: This review of disorders of the fourth cranial nerve includes discussion on anatomy, examination techniques, congenital and acquired etiologies, differential diagnosis, and management options. The findings of the superior oblique muscle on orbital MRI in patients with fourth nerve palsy have had a major impact on our understanding of this cranial neuropathy. In addition, briefly reviewed are rare disorders of the fourth nerve: superior oblique myokymia, Brown syndrome, and ocular neuromyotonia. It behooves the clinician to have a clear understanding of the role that the fourth cranial nerve plays in a variety of neuro-ophthalmic conditions.

Intraparenchymal Schwannoma: A Rare Entity.

A 60-year-old woman noted headaches, transient visual obscurations and pulsatile tinnitus. She had Frisén grade 4 papilloedema. Brain magnetic resonance imaging showed a large subfrontal cystic mass with ring enhancement. Tumour pathology was in-keeping with an intraparenchymal schwannoma. This uniquely rare tumour is discussed.

Erythropsia and Chromatopsia: Case Study and Brief Review.

A 65-year-old woman presented with erythropsia (red-tinged vision) in the right eye from a subfoveal macula dehaemoglobinised intraretinal haemorrhage. Erythropsia is a type of chromatopsia, a condition in which objects appear to be abnormally coloured or tinged with colour. This manuscript provides a brief review of colour vision abnormalities including chromatopsia, and additionally we discuss dyschromatopsia and achromatopsia defined as deficiency and absence of colour vision respectively, both of which may be congenital or acquired. We theorise that the mechanism of the chromatopsia may be selective damage of ganglion cells involved in colour opponency.

The Visual Agnosias and Related Disorders.

BACKGROUND: There are many disorders of higher visual processing that result from damage to specific areas of the cerebral cortex that have a specific role in processing certain aspects (modalities) of vision. These can be grouped into those that affect the ventral, or "what?", pathway (e.g., object agnosia, cerebral achromatopsia, prosopagnosia, topographagnosia, and pure alexia), and those that affect the dorsal, or "where?", pathway (e.g., akinetopsia, simultanagnosia, and optic ataxia). EVIDENCE ACQUISITION: This article reviews pertinent literature, concentrating on recent developments in basic science research and studies of individual patients. RESULTS: An overview of the current understanding of higher cerebral visual processing is followed by a discussion of the various disorders listed above. CONCLUSIONS: There has been considerable progress in the understanding of how the extrastriate visual cortex is organized, specifically in relation to functionally specialized visual areas. This permits a better understanding of the individual visual agnosias resulting from damage to these areas.

Pituitary Ring Sign Plus Sphenoid Sinus Mucosal Thickening: Neuroimaging Signs of Pituitary Apoplexy.

Two magnetic resonance imaging (MRI) signs of pituitary apoplexy are the "pituitary ring sign" and "sphenoid sinus mucosal thickening". The occurrence of both these MRI signs together in patients with ischaemic pituitary apoplexy was investigated. A literature review searching the terms "pituitary ring sign" and "sphenoid sinus mucosal thickening" in the context of pituitary apoplexy from 1990 until present was performed. To be included in the study, each case had to have ischaemic pituitary apoplexy defined as acute expansion of a pituitary adenoma or, less commonly, in a non-adenomatous gland, from infarction without haemorrhage or very little haemorrhage and a T1-weighted MRI of the brain with contrast that displayed both "sphenoid sinus mucosal thickening" and a "pituitary ring sign" either on an actual study (the author's cases) or in a figure in an article from the literature that could be reviewed and clearly illustrate these two signs. Twelve cases of ischaemic pituitary apoplexy were found, all with MRI images that showed both of these signs. Ten cases from the literature (3 of which were published by this author) plus an additional 2 recently evaluated in our hospital, totalled the 12 cases. Thus, 5 of the total 12 cases were evaluated by this author. Of these 12 patients, both headache and visual loss were present in 5 patients, headache alone was indicated in 5 patients (10 of the 12 presented with headache), and no initial symptoms identified in 2 patients (incidentally found non-functioning pituitary adenomas on MRI). These findings indicate that each sign ("pituitary ring sign" and "sphenoid sinus mucosal thickening") may exist alone with or without pituitary apoplexy, yet both signs together in the appropriate clinical context is a strong predictor of pituitary apoplexy.

Occult Acute Macular Neuroretinopathy.

A 19-year-old Caucasian woman developed an upper respiratory infection, took a cold formulation containing 5 mg of phenylephrine, and developed a very rare and unusual form of acute macular neuroretinopathy (AMN) that could not be detected on fundoscopic examination, visual fields, nor electrophysiological testing. Spectral-domain optical coherence tomography (SD-OCT) revealed a lesion limited to the fovea. This case illustrates the value of SD-OCT, in light of otherwise normal testing, in a variant of AMN the authors call "occult AMN".

Functional Magnetic Resonance Imaging (MRI) and MRI Tractography in Progressive Supranuclear Palsy-Like Syndrome.

An 18-year-old woman underwent an uneventful ascending aortic aneurysm repair then developed progressive supranuclear palsy-like syndrome. Extensive neuroimaging including contrasted fat-suppressed cranial and orbital magnetic resonance imaging (MRI), MRI tractography, and functional MRI (fMRI) revealed no clear radiographic involvement except for a single tiny hypoechoic midbrain dot on the T2*-weighted gradient-echo imaging, which is not considered sufficient to account for the patient's deficits. This case attests to the occult nature of this rare and devastating syndrome.

Peripheral cone dystrophy: a diagnostic improbability?

A 19-year-old man reported bilateral peripheral visual field loss, hemeralopia, and photophobia. Examination and testing was in keeping with peripheral cone dystrophy. This rare entity is discussed.

Mechanical oscillopsia after lower eyelid blepharoplasty with fat repositioning.

Blepharoplasty with fat repositioning is a technique used to fill the tear trough in the aging lower eyelid. We describe a patient who underwent transcutaneous lower eyelid blepharoplasty with fat repositioning who subsequently developed mechanical oscillopsia in the right eye exacerbated by facial movement. Surgical exploration revealed cicatrix between the inferior oblique muscle and the anterior superficial musculoaponeurotic system. Excision of the scar bands led to immediate amelioration of symptoms. When performing blepharoplasty with fat repositioning, it is essential to be aware of the anatomic location of the inferior oblique in the anterior inferomedial orbit to avoid incarceration of this muscle.

Susac syndrome. A differential diagnosis for demyelination.

Susac syndrome is a microangiopathy of unknown origin, probably autoimmune, affecting capillaries and precapillary arterioles of the brain, retina, and inner ear. It is often misdiagnosed as acute disseminated encephalomyelitis or multiple sclerosis. We report the case of a 25-year-old male with Susac syndrome who developed the clinical triad of encephalopathy, visual and hearing problems over the course of a year. The characteristic MRI findings including central corpus callosal involvement and brain infarctions were supported by branch retinal arterial/arteriolar occlusions on fluorescein retinal angiography. Most patients with Susac syndrome will not have the complete clinical triad initially. A very high index of suspicion is required by the clinician and radiologist in patients with any component of the clinical triad so as not to misdiagnose the MRI findings for demyelination. Even if initial ophthalmologic examinations are normal, these patients should be followed up for later development of branch retinal artery occlusions.

Delta-8 gummies causing visual snow: a case report.

A 26-year-old man developed visual snow syndrome (VSS) after consuming a little less than half of a delta-8 gummy (estimated at 4 mg of delta-8 tetrahydrocannabinol). Secondary VSS and hallucinogen-persisting perception disorder (HPPD) are discussed, and clinicians who evaluate patients with VS and VSS should ask about delta-8 gummies as an etiology of secondary VSS.