Test 22 (neuro-ophthalmology)

 

Refer to this picture for question 1.

1. The following signs may occur in this patient:

a. 

b. 

c. 

d. 

e. 

Answera.T   b.F  c.T  d.F  e.F
The picture shows a patient with up-gaze palsy.
Note the patient has to elevate his chin to look
upgaze and the eyes remain in the primary position.
This occurs in patient with mid-brain lesion such as Parinaud's syndrome.
Signs of this include light-near dissociation (a.) and convergence retraction nystagmus (c.)
b. shows a patient with latent nystagmus.
d. is upbeat and e. downbeat nystagmus.

 

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Refer to this picture for question 2

2. Condition that can give rise to this picture include:

a. 

b. 

c. 

d. 

e. 

Answera.T   b.T   c.F  d.F  e.F
The patient has a complete right ptosis which can result from a third nerve palsy. 
Aneurysm that causes third nerve palsy
is typically found in either the posterior communicating artery or within the cavernous sinus.
a. shows a posterior communicating artery aneurysm. 
b. carotid cavernous fistula.
c. is an anterior cerebral artery aneurysm d. a posterior cerebral artery aneurysm 
e a basilar artery aneurysm.

 
 
 
 

... The two pictures (before and after treatment) were taken  about 20 years apart.

3. The following are true:

a. craniotomy scar is likely to be present

b. abdominal scar is likely to be present

c. if he fails to take his medication, 
    hypotension and hyperkalaemia will occur.

d. bitemporal hemianopia may be present

e. junctional scotoma may be seen

Answera.F   b.T  c.T  d.T  e.T
The first picture shows the patient with clinical features of Cushing's syndrome characterized by moon face and buffalo hump. The second picture shows the same but older patient with increased pigmentation but without the features of Cushing's syndrome. Increased pigmentation can result from excess ACTH secretion.
He had Cushing's syndrome which was treated by bilateral adrenalectomy. This resulted in an increased ACTH secretion. Overtime, ACTH adenoma may occur ie. Nelson's syndrome. If large the tumour can cause bitemporal hemianopia or junctional scotoma depending on the location of the optic chiasm in relation to the pituitary gland.
If he failed to take his medication which is a combination of gluco and mineralocortisols, Addisonian crisis can occur with hypotension and hyperkalaemia.
 

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Refer to the picture above for question 4.

4. The right pupil is dilated and the result of the swinging
    light test is as shown above. The following may 
    account for the findings:

a. the examination is normal 

b. the patient may have a right optic atrophy

c. the patient may have a left optic atrophy

d. the patient may have advanced left
   glaucoma

e. the patient may have a right macular hole

Answera.F  b.T  c.F  d.F   e.F
RAPD (relative afferent pupillary defect) can still be demonstrated even though one pupil 
is dilated. The observation is focused on the non-dilated eye. In this patient, dilation of the
left pupil when the light is shown into the right eye suggests the right eye is abnormal.
For right RAPD to occur there must be optic nerve dysfunction or extensive nerve fibre lost. 
Macular hole does not cause RAPD.

 

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Refer to this picture for question 5.

5. Drugs which can precipitate myasthenia gravis include:

a. 

b. 

c. 

d. 

e. 

Answera.T   b.T  c.T  d.F   e.T
The referring picture shows optic atrophy.
a. is retinitis pigmentosa which in advanced cases can produce optic atrophy.
b. shows an internal carotid aneurysm at the junction of the ophthalmic artery. This can cause compressive optic neuropathy.
c. is a blood film showing hypersegmentation of the neutrophil. This occur in vitamin B12 
deficiency which can cause subacute combined degeneration of the cord and optic atrophy.
d. shows left occipital infarction. Infarction of the visual cortex does not cause optic atrophy.
e. shows Lisch's nodules. Neurofibromatosis type I is associated with optic nerve glioma and meningioma.

 
 

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