Transcript This patient with idiopathic Parkinson’s Disease (PD) shows:

931-4
Convergence Insufficiency
History
A 73-year old man with known PD for 10
years, complained of horizontal double
vision for 18 months. He could see the
images move apart and refocus a single
image by blinking. Diplopia was most
marked reading, driving and watching TV.
Three ophthalmologists gave him 3 separate
sets of glasses. Past hx –ve for strabismus or
prism glasses.
Presenting Symptoms
Difficulty walking
Generalized rigidity
Tremor of the hands at rest
Diplopia reading
Ocular Motor Signs
Impaired convergence
Slow hypometric saccades
Saccadic substitution for smooth pursuit
Poor visual suppression of the
vestibular ocular reflex
Decreased spontaneous blink rate
Glabella tap positive
Neurological Signs
Rigidity of the neck, head flexed and tilted
Mild head tremor
Mask-like face
Slow (akinetic) head and neck
movements
Convergence Insufficiency
Three factors:
Age
Parkinson’s disease
Medications (Sinemet)
Etiology of Slow Saccades
Spinocerebellar Ataxias (SCA),
especially SCA2 (olivopontocerebellar
atrophy)
Huntington’s Disease
Progressive Supranuclear Palsy
Parkinson’s (advanced cases) and
related diseases.
Lytico-Bodig disease
Slow Saccades
Whipple’s Disease
Wilson’s Disease
Amyotrophic Lateral Sclerosis (some
cases)
Drug intoxications: anticonvulsants,
benzodiazepines
Courtesy of Mendez F. Cummings JL. Dementia: A Clinical
Approach. Third Edition. Butterworth Heinmann 2003.
The following illustrations of
The brain MRI
Pathology of the midbrain
Lewy body
are taken from the case of an elderly
woman with Parkinson’s Disease.
Figure 1 Axial T2WI through the midbrain shows the normal
pars compacta, the space between the substantia nigra and
red nuclei.
Figure 2: Axial T2WI in a patient with PD shows the midbrain is atrophic
Figure
2 Axial T2WI in a patient with PD shows the midbrain
and the red nuclei and substantia nigra almost touch each other because
is atrophic
the red
andreduced.
substantia nigra almost touch
the parsand
compacta
is greatly
each other because the pars compacta is greatly reduced.
Courtesy Anne Osborn, MD
Figure 3 Axial gross autopsy in patient with PD shows striking
reduction of the pars compacta, especially well seen on the right
side where the red nucleus and substantia nigra are actually
touching
Figure PD_Lewy body
Section of the brain showing cytoplasmic
inclusion body within a surviving neuron with an eosinophilic core
Figure
4 Section
ofhalo.
theThe
brain
showing
cytoplasmic
surrounded
by a clear
lewy body
is not entirely
specific, but inclusion
it is
highly sensitive
marker forneuron
PD.
bodyawithin
a surviving
with an eosinophilic core
surrounded by a clear halo. The Lewy body is not entirely
specific, but it is a highly sensitive marker for PD
Parkinson’s Disease
Due to dopaminergic cell death
leading to dopamine deficiency
Defective gene for  synuclein on
Chr. 4q
Second locus on Chr. 2p
http://library.med.utah.edu/NOVEL/Wray/