Visual cortex
Fiona Rowe in Visual Fields via the Visual Pathway, 2016
The nerve fibres of the optic radiations terminate in layer 4 of the primary visual striate cortex which is located on the medial aspect of the occipital lobe, superior and inferior to the calcarine fissure. The most anterior part of the visual cortex represents the extreme nasal periphery of the retina corresponding to the monocular temporal crescent of the visual fields. Pathologies causing unilateral and/or bilateral visual field loss include migraine, trauma, primary and secondary tumours and vascular abnormalities. Visual field loss may be caused by tumour compression of the visual cortex but visual field loss may result from surgery to remove the tumour. Unilateral lesions produce colour loss in the contralateral visual hemifield and patients are less aware of colour loss than those with achromatopsia. Optic atrophy is generally absent in patients with visual cortex lesions unless there is other pathology such as papilledema due to raised intracranial pressure.
Cheryl
Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner in The Integrated Nervous System, 2017
The assessment is that Cheryl has bilateral papilledema , which is considered an emergency and requires an immediate consultation. Physical examination reveals a wide-awake boy who also has bilateral papilloedema and no other neurological findings. Although vascular disease processes usually produce acute-onset symptoms, bleeding from veins draining the brain may occur over a prolonged period of time in the form of chronic subdural hematoma; again, this is a space-occupying lesion, which might give rise to headache and raised intracranial pressure (ICP). An intraventricular colloid cyst could be considered a space-occupying lesion if it obstructed the outflow of cerebrospinal fluid (CSF) from the lateral ventricles into the third ventricle or from the third ventricle into the aqueduct thereby causing increased ICP. Cheryl was soon back on the road and arrived home safely. Her mother, hearing the story, insisted that she seek immediate medical attention and Cheryl is now in the emergency room (ER) at local community hospital, the morning following the incident.
Headache
Sherif Gonem, Ian Pavord in Diagnosis in Acute Medicine, 2017
Headache therefore arises from the various pain-sensitive structures of the head and neck, namely the meninges, blood vessels, muscles, sinuses, eyes, teeth and gums. Headache, like other forms of pain, may also be neuropathic in origin. Raised intracranial pressure most probably causes headache as a result of traction on the meninges and intracranial blood vessels. The causes of headache may be conveniently classified into the following five categories: vascular; infectious; inflammatory; miscellaneous; and extracranial disease. Headache is an extremely common symptom, and although most cases are managed entirely in primary care, a minority represent serious pathology that demands urgent investigation and treatment. Signs of meningeal irritation include neck stiffness, Kernig's sign and Brudzinski's sign. Fundoscopy may reveal papilloedema, which is a sign of raised intracranial pressure. Subhyaloid haemorrhage may accompany subarachnoid haemorrhage.
Do Optic Canal Dimensions Measured on CT Influence the Degree of Papilloedema and Visual Dysfunction in Idiopathic Intracranial Hypertension?
Published in Neuro-Ophthalmology, 2019
Nicholas T. Skipper, Mark S. Igra, Revelle Littlewood, Paul Armitage, Peter J. Laud, Susan P. Mollan, Basil Sharrack, Irene M. Pepper, Ruth Batty, Daniel J. A. Connolly, Simon J. Hickman
A recent study found that increased optic canal area on magnetic resonance imaging was associated with worse papilloedema in idiopathic intracranial hypertension (IIH). We repeated this study using more accurate computerized tomography derived measurements. Optic canal dimensions were measured from 42 IIH patients and 24 controls. These were compared with papilloedema grade. There was no correlation between any of the optic canal measurements and papilloedema grade and no significant difference in optic canal measurements between patients and controls. Our results cast doubt on the existing literature regarding the association between optic canal size and the degree of papilloedema in IIH. CT delineates bony anatomy more accurately than MRI and our CT-derived optic canal measurements cast doubt on the existing literature regarding the association between optic canal size and the degree of Papilloedema in IIH.
Papilloedema and Increased Intracranial Pressure as a Result of Unilateral Jugular Vein Thrombosis
Published in Neuro-Ophthalmology, 2015
Abhishek Thandra, Bokkwan Jun, Miguel Chuquilin
Intracranial hypertension and papilloedema are known to develop secondary to cerebral sinus or bilateral jugular vein thrombosis. However, in rare cases, unilateral jugular vein thrombosis may lead to increased intracranial pressure and papilloedema with resultant headache and vision changes. We describe a 45-year-old patient with squamous cell carcinoma of the larynx that developed right jugular vein thrombosis after chemoradiation therapy with cetuximab. This was later complicated by intracranial hypertension and papilloedema. The normal cerebral venous drainage, the potential role of chemoradiation therapy on the aetiology of jugular vein thrombosis, and the mechanism of increased intracranial pressure secondary to unilateral jugular vein occlusion are discussed.
Papilloedema associated with dural venous sinus thrombosis
Published in Clinical and Experimental Optometry, 2014
Tara Leigh O'rourke, W Scott Slagle, Meghan Elkins, Daniel Eckermann, Angela Musick
Papilloedema is a diagnostic term used exclusively to describe optic disc oedema associated with increased intracranial pressure. Septic cerebral venous sinus thrombosis has become an increasingly rare cause of papilloedema because of the widespread availability of antimicrobial agents; however, it is imperative for optometrists to maintain vigilance for this pathologic process. Presented is a case of a 77‐year‐old Caucasian male with a complaint of blurred vision and non‐specific, diffuse headache. He had a right sixth cranial nerve palsy and bilateral disc oedema. Raised intracranial pressure was confirmed by lumbar puncture. Neuroimaging, including magnetic resonance imaging and magnetic resonance venography in conjunction with cytological assessment of the cerebral spinal fluid led to a probable diagnosis of mastoiditis causing multiple dural venous sinus thrombi of the superior sagittal and right transverse sinuses. Sequential evaluation of this complex case is displayed along with pertinent differential diagnoses for optic disc oedema and a review of current standards for diagnosis and management of papilloedema from dural sinus thrombosis.
Related Knowledge Centers
- Eye
- Intracranial Pressure
- Optic Disk
- Optic Nerve Diseases
- Optic Atrophy
- Ophthalmoscope
- Visual Field