Midbrain Stroke Syndromes
- Blood Flow and Arterial Territories
- PCA[…] to tectum[…], ~75% of anterior tegmentum[…] - most lesions affect this distribution
- Pcomm[…] to ~25% of anterior tegmentum[…]
- SCA[…] to midline portion
- Benedikt[…] Syndrome
- @CN3[…] & EW[…] Nuclei > sx: ipsilateral Down/Out eye, Fixed/Dilated pupil, +Ptosis[…]
- @Red Nucleus[…] & Ventral Tegmental Decussation[…] > sx: contralateral ataxia[…]
- pathway: cerebellar hemisphere > contralateral red nucleus > thalamus > cortex
- @Crus Cerebri (Frontopontine / CST / CBT) Components[…] > sx: contralateral hemiparesis[…]
- pathway: medial (descending FP), middle (CST/CBT more of head/upper trunk) > decussates at medullary pyramid
- @Little of Substantia Nigra[…] > sx: athetosis[…] or mild tremors[…] up to more moderate sx like chorea[…]
- Weber[…] Syndrome
- @CN3[…] & EW[…] Nuclei > sx: ipsilateral Down/Out eye, Fixed/Dilated pupil, +Ptosis[…]
- @Crus Cerebri (Frontopontine / CST / CBT) Components[…] > sx: contralateral hemiparesis (face, arm, trunk)[…]
- Claude[…] Syndrome
- @CN3[…] & EW[…] Nuclei > sx: ipsilateral Down/Out eye, Fixed/Dilated pupil, +Ptosis[…]
- @Red Nucleus[…] & Ventral Tegmental Decussation[…] > sx: contralateral ataxia[…]
- Parinaud[…] Syndrome (ex: pinealoma)
- @tectum[…] at level of @superior colliculi[…] and @rostral interstitial nucleus of Cahal (vertical gaze center)[…] > sx pathway: cortex > sends inhibitory(-) fibers down to gaze center > out to eyeball; loss of inhibition = excess (+)stimulation of CN3
- BL eyelid retraction[…] aka "Collier's[…]" Sign
- due to excess stimulation ++++ of LPS[…] muscle
- Convergence-Retraction Nystagmoid[…] Reaction
- due to excess stimulation of SR, IR muscles which pull the eyelid back + MR contracting which causes the convergence
- Vertical Gaze[…] Palsy
- @pretectal nucleus[…] > sx: "Light-Near Dissociation[…]" of pupil aka "Argyll-Robertson[…]" Pupil > meaning shine light > pupils don't constrict; bring finger close to accommodate, pupils constrict[describe what this is]
