What is Causing this Woman’s Tunnel Vision

Question 1

A 36-year-old woman has tunnel vision in which she reports the same size area of perception regardless of how far from the testing screen the examination is performed. This history often indicates which of the following?

1. Retinitis pigmentosa

2. Neurosyphilis

3. Sarcoidosis

4. Chorioretinitis

5. Conversion disorder

Answer to Question 1

The answer is e, Conversion disorder.[1]

Tunnel vision must be distinguished from concentric constriction. In the latter, the area perceived enlarges as the test screen is moved farther away from the patient, but the overall visual field is always smaller than the normal visual field. Concentric constriction associated with optic atrophy may develop with neurosyphilis. Tunnel vision, on the other hand, is characterized by the patient reporting the same size field even as the test screen is removed farther away. Tunnel vision is not a physiologic pattern of visual loss, and should suggest either conversion disorder or malingering. Significant spiraling of the visual field, in which repeat testing of the same part of the visual field during the same examination leads to a successively smaller field each time, similarly may reflect conversion or malingering, although stress or panic may lead to mild effects of this sort.

Question 2

A young man with multiple sclerosis (MS) exhibits paradoxical dilation of the right pupil when a flashlight is redirected from the left eye into the right eye. Swinging the flashlight back to the left eye produces constriction of the right pupil. Which of the following is the most likely diagnosis?

1. Early cataract formation in the right eye

2. Occipital lobe damage on the left

3. Oscillopsia

4. Hippus

5. Optic atrophy

Answer to Question 2

The answer is e, Optic atrophy.[2]

The test performed is usually called the swinging flashlight test, and the pupillary finding is a Marcus Gunn, or afferent pupillary, defect. It commonly develops in persons with MS as a sequela of optic neuritis. Damage to the optic nerve reduces the light perceived with the affected eye. If the other eye has less or no optic atrophy, the consensual response of the pupil to light perceived by the better eye will constrict the pupil in the atrophic eye, even though direct light to the injured eye does not elicit a strong pupillary constriction.

Question 3

A 23-year-old woman has 2 days of visual loss associated with discomfort in the right eye. She appears otherwise healthy, but her family reports recurrent problems with bladder control over the prior 2 years, which the patient is reluctant to discuss. On neurologic examination, this young woman exhibits dysmetria in her right arm, a plantar extensor response of the left foot, and slurred speech. Which of the following would be the most informative ancillary test?

1. Visual evoked response (VER) testing

2. Sural nerve biopsy

3. Electroencephalography (EEG)

4. Magnetic resonance imaging (MRI)

5. Computed tomography (CT)

Answer to Question 3

The answer is d, Magnetic resonance imaging (MRI).[3]

This young woman almost certainly has MS. Her visual loss can be explained by optic neuritis, and her bladder problems may be due to demyelination of corticospinal tract fibers. Many patients are reluctant to discuss minor problems with bladder, bowel, or sexual function with a physician of the opposite sex. The positive Babinski sign, focal dysmetria, and apparent dysarthria all support the diagnosis of a multifocal CNS lesion. Multiple lesions disseminated in time and space are typical of MS. With MRI, the multifocal areas of demyelination should be apparent. Many more lesions may be evident on MRI than are suggested by the physical examination

Related Keyword terms:

,neurosyphilis,conversion disorder vision loss,neurosyphilis mri,neurosyphilis pictures,concentric tunnel like blindness conversion disorder,neurosyphilis visual field constriction