Anatomy Flashcards
What sensory modality is most likely to be damaged in acceleration/deceleration (MVA) injuries to the brain?
The sense of smell. Olfactory bulbs and nerve lie underneath the frontal lobe and are often damaged in these accidents.
( Olfaction is also the only modality that bypasses the thalamus and anosmia can be a sign of early parkinsons)
Where is the lesion in a patient that presents with marked ptosis, dilated pupil and the eye deviated downwards and outwards.
Occulomotor nerve (Innervates all of the eye muscle except for the lateral rectus and the superior oblique. It also controls the levator palpebrae superioris, contains parasymp. fibers that constrict the pupil)
A third nerve palsy can be a symptoms of an aneurysm of what vascular structure?
Ipsilateral Posterior Communication Artery
Patient present with double vision with head tilted to one side, where is the pathology localized to ?
Trochlear nerve ( Innervates the superior oblique and when damaged causes vertical diplopia and patient compensate by tilting the head towards the shoulder on the unaffected side)
This nerve is most commonly damaged when there increased intracranial pressure
Abducens nerve ( Innervates lateral rectus. Patient cannot abduct when this nerve is damaged. When damaged due to a brainstem lesion often presents with facial weakness)
A patient with an inability to move left eye associated with a fixed dilated pupil and ptosis, numbness on the upper and middle part of the his face points to a lesion where?
Cavernous sinus ( CN III, IV, VI, V1 , V2 and the internal carotid artery all pass through the cavernous sinus. Can be caused by mucormycosis in diabetics, Tolosa-Hunt syndrome is a idiopathic granulomatous disease of the cavernous sinus)
What are some symptoms associated with pineal gland tumors ?
- Can be clinically silent until they affect the midbrain and cause visual symptoms, primary disturbance of upgaze, and at times disruptions of circadian rhythms.
When someone has a stroke affect the left frontal lobe their eyes will deviate to which side?
The left side ( Strokes look at the Same Side. In this case the left frontal eye field is infarcted and not functional, so there is unopposed action of the right frontal eye field which cause the eyes to deviate to the left)
When a patient has a seizure focus originating in their left frontal lobe which side will their eyes deviate to?
The right side ( Seizures look at the opposite side. In this case the seizure = hyperactivity of the left frontal eye field which will drive the eyes to the right)
What are the hallmarks of a horner’s syndrome ?
- Mild Ptosis, Miosis ( constricted pupil) and anhydrosis ) It is due to a lesion in the sympathetic pathway and is common in carotid artery dissection due to the fact that the sympathetic fibers run along the carotid, also seen in Wallenberg syndrome)
What is an internuclear opthalmoplegia? Where does the lesion localize to? In what condition is this most commonly seen?
INO: characterized by a failure to adduct one eye while having nystagmus in the opposing abducted eye. This is due to a lesion in the medial longitudinal fasciculus on the same side as the eye that cannot adduct. This is most commonly seen in Multiple Sclerosis. MLF connects the abducens nerve on side with the occulomotor nerve on the other side which allows for simultaneous activation of the medial and lateral rectus and preserves conjugate gaze.
Blurry vision and pain with eye movement are symptoms of what disease process ? Treatment?
-Optic neuritis ( Patients can loss color vision particularly color red.)
- Steroids ( solumedrol) is used to help patients with optic neuritis recover more rapidly
relapses can be treated with plasmaphoresis.
Explain an afferent pupillary defect.
An afferent pupillary defect is cause when there is a dysfunction in the CN2. Usually when light is swung from one eye to the other, both pupils will constrict. In afferent pupillary defect, due to the patient’s inability to perceive light in the affected eye, when light is shone in that eye it paradoxically dilates instead of constricts but when light is swung to the unaffected eye both eyes will constrict. In regularly lighted room, both pupils are equal.
What is the risk of developing MS most closely correlated with?
The number of lesions in the brain MRI. ( Older lesions on T1 are hypointense and appear as black holes and are evidence of axonal damage.
MS is associated with a deficiency in what vitamin ?
Vitamin D ( also associated with worsening symptoms in the heat, and with decrease incidence as you get closer to the equator)
What is the diagnostic criteria for MS?
Having 2 or more attach with clinic evidence or supportive evidence including typical MRI or oligoclonal bands in the CSF.
What are the DMD used to treat MS?
- Inteferons: Avonex, Rebif, Betaseron. ( injection)
- Glatiramer Acetate : Copaxone
- Natalizumab: Tysabri ( monthly infusion, monoclonal antibody prevents T-cell from crossing BBB. associated with PML)
- Fingolimod: Gilenya : Oral med
- Teriflunimode : Aubagio : Oral
- Dimethyl Fumerate : Tecfidera.
Neuromyelitis optica
- Devic’s disease: A demyelinating illness characterized by optic neuritis ( often b/l), transverse myelitis with MRI evidence of a contiguous spinal cord lesion 3 or more segments in length, brain MRI non-diagnostic for MS and NMO-IgG seropositivity. The IgG is directed against astrocytes on BBB and is generally more severe than MS
- may have intractable hiccups due to lesions in area postrema in medulla
Tx for NMO
- oral immunosuppression. Not MS tx: may make this worse
Bitemporal hemianopsia is caused by lesion where?
- Optic chiasm ( eg pituitary tumor compressing)
Where does monoccular blindness localize to?
- Optic nerve of that eye
Where does a homonymous hemiamposia localize to?
- Optic tract.
- right homonymous hemianopsia = left optic tract and vice versa
