Download olivary nucleus

Bilateral Injuries to the
Triangle of Guillain-Mollaret
Daniel Chow, MD
Jared Narvid, MD
William Dillon, MD
Disclosures
The authors have no disclosures.
Background
The Triangle of Guillain-Mollaret
The triangle of Guillian-Mollaret, also known as the
myoclonic triangle, is feedback circuit for
regulating spinal cord motor activity.
Injury to triangle is associated with stereotypical
palatal myoclonus
(involuntary soft palatal musculature rhythmic movements)
Background
Triangle of Guillain-Mollaret Pathway
The three corners of the triangle:
1. Ipsilateral red nucleus
2. Ipsilaterla inferior olivary nucleus
3. Contralateral dentate nucleus
Red Nucleus
Red Nucleus
Dentate Nucleus
Inf. Olivary Nucleus
Central
Tegmental
Tract
Inf. Olivary Nucleus
Superior
Cerebellar
Peduncle
Dentate Nucleus
Inferior
Cerebellar
Peduncle
Background
Purpose
We report a unique case of
injuries to the dentatorubro-olivary
pathway bilaterally in a single
patient with both:
Red Nucleus
Dentate Nucleus
Inf. Olivary Nucleus
1. Hypertrophic olivary
2. Deafferentation changes in the
dentate.
Case Report
Presentation
A 63-year-old male with past
medical history significant for
prior right pontine hemorrhage
was referred to our institute for
follow-up imaging.
Evaluation of MR imaging at time
of the hemorrhage demonstrated
a right pontine hemorrhage in
the region of the right:
1. Central tegmental tract
2. Superior cerebellar peduncle
Axial susceptibility-weighted MRI
demonstrates a right pontine hemorrhage
Case Report
Follow-up (4 months)
MRI obtained 4 months later, revealed both:
1. Hypertrophy of the right olivary nucleus
2. Atrophy and high signal of the right dentate nucleus
Case Report
Comparison to prior imaging
Coronal T2 image at time of
hemorrhage demonstrates
normal appearing inferior
olivary nucleus and dentate
Follow-up MRI 4 months later reveals new ipsilateral
hypertrophy of the right inferior olivary nucleus as well as
atrophy and T2 hyperintense signal of the right dentate
Discussion
Pathway for Hypertrophic Olivary Denervation
Injury to the pathway
resulting in hypertrophic
olivary denervation is well
established:
1.
Injury to efferent central
tegmental tract may result in
hyperexcitation
2.
Subsequent hypertrophy of
the ipsilateral inferior olivary
nucleus.
Discussion
Pathway for Atrophy of the Contralateral Dentate
In our case however, a
heretofore underappreciated
change also was seen
consisting of abnormal signal
and atrophy of the ipsilateral
dentate nucleus:
1. Injury to afferent superior
cerebellar peduncle tract
2. Subsequent atrophy of
the ipsilateral dentate
nucleus.
Discussion
Summary
Familiarity with these pathways are important for the neuroradiologist for accurate diagnosis.
References
1. Kitajima M, Korogi Y, Shimomura O, et al. Hypertrophic olivary degeneration:
MR imaging and pathologic findings. Radiology. 1994; 192:539-43
2. Kim SJ, Lee JH, Suh DC. Cerebellar MR changes in patients with olivary
hypertrophic degeneration. AJNR Am J Neuroradiol. 1994; 15:1715-9