syndromes

Question 1

Vertigo

Answer 1

sensation of turning or rotation in space in the absence of actual rotation. Often accompanied by nausea, vomiting, and gait ataxia.

Peripheral vestibular lesions often arise from debris from the otolithic membrane in the saccule and utricle accumulating at the ampulla of the posterior semicircular canal and making it more sensitive to angular movement. This usually is intermittent and is always accompanied by unidirectional nystagmus.

Question 2

Frontal Eye field damage

Answer 2

Responsable for saccadic movements.

Lesions in this area cause gaze preference toward the lesion.

This is due to a imbalance in the PPRF on one side.

Question 3

accommodation reflex

Answer 3

This reflex consists of:

1) convergence of the eyes mediated by medial rectus innervation via CN III;
2) accommodation of the lens mediated by ciliaris and its parasympathetic innervation by CN III;
3) pupillary constriction mediated by sphincter pupillae and its parasympathetic innervation by CN III.

Question 4

Internuclear ophthalmoplegia

Answer 4

Lesion in the MLF

Eye does not adduct on affected side.

nygstamus on opposite eye

Question 5

One and a half syndrome

Answer 5

One eye can move only one way laterally

The other eye can’t move laterally at all.

Both the PPRF and the MLF are damaged on one side

Pontine issues….

Question 6

Parinaud’s syndrome (dorsal midbrain syndrome)

Answer 6

Caused by compression of the tectum by mass near the posterior commisure or the pineal region.

Results in:

upward gase palsy

pupillary light-near reflex dissociation - no light response, only neer objects.

abscence of convergence