Syndromes Flashcards
Uncal herniation
Supratentorial mass may cause downward displacement and herniation of uncus across tentorial edge (compresses nerve). Patient usually AMS.
Cavernous sinus syndrome
With or without CN3,4,5, sympathetic plexus, optic nerve or chiasm
Orbital syndrome
CN3 divides into superior and inferior division as it enters orbit- involvement of orbit –> paresis of structures innervated by either of these divisions
Looking for CN4 palsy in setting of complete CN3 palsy
Patient is instructed to look down while the examiner looks for intorsion (based on conj blood vessels). If ABSENT, then CN4 paresis
light induced amaurosis
Light-induced amaurosis is a very characteristic finding of ocular ischemic syndrome.
Dx studies to order in evaluation: FA, carotid dopplers, CTA, or MRA.
Ophthalmodynamometry (low, unlike CRVO)
FA: delayed arm to eye time and would highlight any areas of possible retinal / optic nerve neovascularization.
SLE/DFE: hypotony, mid-peripheral dot blot heme (often more asymmetric between eyes and peripheral than typical dot blot heme seen in diabetes), K edema, rNVE, and prominent anterior chamber flare.
Rx: if significant carotid stenosis, carotid endarterectomy
Balint syndrome
Due to bilateral parieto-occipital lesions.
Classic triad:
optic ataxia
acquired ocular motor apraxia
simultagnosia
The underlying etiology is usually either bilateral strokes or cortical dysfunction from a variant of Alzheimer’s disease which predominately affects the parieto-occipital region known as posterior cortical atrophy (or the visual variant of Alzheimer’s disease).
differentiating orbital apex vs cavernous sinus
Cavernous sinus and the orbital apex share many of the same nerve components including cranial nerves 3, 4, V1, and 6 along with third order sympathetic neurons. Often need MRI to distinguish.
Optic neuropathy = orbital apex.
ON does not pass through the cavernous sinus.
However, the same process in theory could also extend posteriorly to involve the cavernous sinus.
V2 is present in the POSTERIOR portion of the cavernous sinus before exiting the skull base via the foramen rotundum. Since an anterior cavernous sinus and an orbital apex lesion both would spare V2, the presence of absence of V2 involvement is not a great localizing sign (but if V2 impairment is present it could be helpful).
Ocular apraxia
Ocular apraxia is difficulty initiating saccades.
Optic ataxia
Optic ataxia is essentially acquired poor hand-eye coordination caused by a disconnect between vision and motor functions. There are many other causes of poor hand-eye coordination so this is not that helpful in making a diagnosis of Balint syndrome.
Simultagnosia
Simultagnosia = most prevalent component of the Balint syndrome triad and is also arguably the most useful sign to look for on examination.
Def: failure to understand the entire meaning of a picture despite retaining the ability to recognize isolated objects within the picture.
can not “see the forest through the trees.”
Tested for by using the “cookie theft picture” and asking the patient to give an account of what is happening in the picture. A patient with simultanagnosia may describe one item in the picture but will be unable to provide a complete interpretation of the scene.
Similarly, Ishihara plates are actually complex images. A patient with simultanagnosia will have intact color vision but will be unable to identify the number within the pattern. Inability to identify color plates in an elderly patient should raise suspicion for PCA.
Object agnosia
Object agnosia is the inability to visually recognize objects despite being able to recognize objects based on touch or description.
Chromatopsia
Chromatopsia is the illusion of vision exhibiting an abnormal color. Digoxin toxicity-related chromatopsia is usually described as a yellow (i.e. “xanthopsia”) or yellowish green hue throughout the visual field. It is typically reversible with cessation or decreased dose of the drug.
These visual effects can occur despite “normal” serum level of digoxin on lab testing. ERG may reveal cone dysfunction in these patients.
Sildenafil (Viagra) has been reported to result in a blue chromatopsia and this illusion may be a harbinger of an underlying risk in certain individuals for more serious ocular pathology such as non-arteritic anterior ischemic optic neuropathy (NAION) due to Sildenafil (and related erectile dysfunction (ED) drugs). The exact association between ED drugs and NAION is still quite controversial.
Photopsias
Photopsias associated with cancer associated retinopathy, MEWDS, AZOOR, birdshot chorioretinopathy, and PVD are all simple, unformed hallucinations because they do not arise from distortion of an object in reality.
Micropsia
Micropsia is the illusion that objects appear smaller than they should and is indicative of macular pathology, parietal lobe pathology, or an unusual migraine headache related phenomenon known as the “Alice in Wonderland” effect
Pulfrich phenomenon
The Pulfrich phenomenon is the illusion that an object moving perpendicular to a person’s line of sight is actually moving toward them or away from them. Theoretically, it could be seen in any disease affecting the conduction of visual information in one optic nerve more than the other. It is usually described in patients who have partially recovered following a bout of optic neuritis.
Heterochromia - peds
Neuroblastoma and birth trauma-related brachial plexus* injuries both cause Horner syndrome.
left Horner syndrome: heterochromia with a lighter colored left iris, anisocoria with a smaller left pupil, and a smaller palpebral fissure on the left
The narrowing of the palpebral fissure from a combination of subtle upper eyelid ptosis and lower eyelid inverse ptosis is more prominent than upper eyelid ptosis.
Sympathetic innervation=required for normal melanocyte development within the iris. In kids, iris on the affected side is often hypopigmented in comparison to the normal contralateral iris.
*(i.e. shoulder dystocia) is a very common cause of congenital Horner syndrome. Another associated feature of brachial plexus injury is arm weakness.
Heimman - Bielschowsky phenomenon
monocular vertical pendular nystagmus - poorly seeing eyes (often in kids). can be 2/2 low-grade pediatric ON gliomas, amblyopia, trauma, and many other causes of vision loss. B/c of possibility of ON glioma, any child with monocular nystagmus should have neuro-imaging performed.
Tolosa Hunt syndrome
idiopathic sterile inflammation of cavernous sinus. Severe ipsilateral periorbital pain along with any deficits of any or all nerves passing through the affected cavernous sinus (CN 3, 4, V1, V2, 6 and the sympathethics). Dx of exclusion (exclude infection/inflammation, lymphoma, carcinoma).
Miller Fisher syndrome
Areflexia, ataxia, ophthalmoplegia
Variant of Guillain-Barre syndrome (oculomotor predominant; EOM affected 1st)
Signs? bilateral ptosis facial diplegia (b/L facial paralysis) respiratory supression swallowing difficulties
CSF?
Elevated protein, normal cell count
Autoantibodies?
GQ1b
