INSTRUCTION

Examine this patient's eyes.

Test the patient's eye movements.

SALIENT FEATURES

History

· Obtain history regarding cerebellar syndrome: multiple sclerosis, alcohol, etc. (p. 143).

· Ear infections (vestibular involvement).

· Horizontal nystagmus with fast components to right or left side (when eliciting nystagmus take care to keep your finger at least

2 feet away from the patient and avoid going laterally beyond the extent of binocular vision).

Proceed as follows:

· Look for other cerebellar signs (see p. 144).

· Tell the examiner that you would like to do the following: -Examine the fundus for optic atrophy (multiple sclerosis). -Take a

history of vertigo (vestibular nystagmus).

Note. Remember that if the patient has vertical nystagmus in addition to horizontal nystagmus it is more likely to be vestibular

nystagmus or brainstem disease.

DIAGNOSIS

This patient has a jerky nystagmus with optic atrophy (lesion) due to multiple sclerosis (aetiology). I would like to examine her

neurological system to evaluate the disability (functional status).

QUESTIONS

What do you understand by the term 'nystagmus'?

Nystagmus is a series of involuntary, rhythmic oscillations of one or both eyes. It may be horizontal, vertical or rotatory.

ADVANCED-LEVEL QUESTIONS

What is pendular nystagmus?

In pendular nystagmus, the oscillations are equal in speed and amplitude in both directions of movement. It may be seen on central

gaze when the vision is poor, as in severe refractive error or macular disease.

What do you understand by the term 'jerky' nystagmus?

Jerky or phasic nystagmus is a condition in which eye movement in one direction is faster than that in the other. This is usually seen

in the horizontal plane and is brought out by lateral gaze to one or both sides. It is seen with lesions of the cerebellum, vestibular

apparatus or their connections in the brainstem.

What is dissociated nystagmus?

Dissociated or ataxic nystagmus is irregular nystagmus in the abducting eye. It is bilateral in multiple sclerosis, brainstem tumour or

Wernicke's encephalopathy. It is unilateral in vascular disease of the brainstem. It is due to a lesion in the medial longitudinal

fasciculus (which links the sixth nerve nucleus on one side to the medial rectus portion of the third nerve on the other).

Where is the lesion in vestibular nystagmus?

It may be in one of two locations:

· Peripheral (labyrinth or vestibular nerve), as in labyrinthitis, Meniere's syn-drome, acoustic neuroma, otitis media, head injury.

· Central (affecting vestibular nuclei), as in stroke, multiple sclerosis, tumours, alcoholism.

What do you know about 'downbeat' and 'upbeat' nystagmus?

Downbeat nystagmus is associated with brainstem lesions, meningoencephalitis and hypomagnesaemia. Upbeat nystagmus is

caused by lesions of the anterior vermis of the cerebellum.

K. Wernicke (1848-1904) graduated from Poland; although aware that a toxic factor was important in the aetiology, he did not

realize that this syndrome was due to a nutritional deficiency.

R Meniere (1799-1862), French ear, nose and throat specialist.