Hypertrophic olivary degeneration-MRI
Case Report: 50 year old hypertensive with
prior history of stroke, presents with loss of fine voluntary movements. MRI
shows an ill defined, T2 low signal intensity foci in the lower pons suggesting
hemosiderin and ferritin deposits with relatively well defined T2 hyperintensity
and enlargement of the left anterior medulla in the inferior olivary nucleus
region with no restricted diffusion, suggesting possible hypertrophic olivary
degeneration (HOD) secondary to pontine haemorrhage.
Case submitted by Dr MGK Murthy, Mr Sentil & Mr Venkat
Teaching points :
- Is a form of trans-synaptic
degeneration. End result of the damage
of the neuronal connections between dentate nucleus , red nucleus &
inferior olivary nucleus (dentate-rubral-olivary pathway).
- Unique type
of degeneration in view of enlargement of the effected inferior olivary
neurons. Dentate nucleus is connected to contralateral red nucleus via ipsilateral inferior olivary nucleus and controls fine voluntary movement (called Gullain and Mollaret triangle).
neurons. Dentate nucleus is connected to contralateral red nucleus via ipsilateral inferior olivary nucleus and controls fine voluntary movement (called Gullain and Mollaret triangle).
- Red nucleus
of one side is connected to the ipsilateral inferior olivary nucleus via
different tract called central segmental tract. HOD can occur due to any focal lesion including ischaemia, demyelination & neoplasms.
different tract called central segmental tract. HOD can occur due to any focal lesion including ischaemia, demyelination & neoplasms.
- Typically
seen within 4 to 6 months of the primary brain stem insult. Olivary hypertrophy
usually resolves in 10 to 16 months, though T2 hyperintensity may persist for
years, and the clinical symptoms rarely improve.
- If the
primary lesion is in central tegmental tract, olivary hypertrophy is
ipsilateral. If the primary lesion is in dentate nucleus / superior cerebellar
peduncle, olivary
hypertrophy is contralateral. If the lesion involves both central tegmental tract and superior cerebellar peduncle, the olivary degeneration is bilateral.
hypertrophy is contralateral. If the lesion involves both central tegmental tract and superior cerebellar peduncle, the olivary degeneration is bilateral.
- Pathologically
is unusual vacuolar degeneration of cytoplasm leading to
enlargement and increased number of astrocytes. Palatal myoclonus / dentatorubral tremor / ocular myoclonus are unusual clinical syndromes. Presence of olivary lesion associated with contralateral dentate nucleus / superior cerebellar peduncle / ipsilateral red nucleus / pontine tegmentum makes any other diagnosis highly unlikely
enlargement and increased number of astrocytes. Palatal myoclonus / dentatorubral tremor / ocular myoclonus are unusual clinical syndromes. Presence of olivary lesion associated with contralateral dentate nucleus / superior cerebellar peduncle / ipsilateral red nucleus / pontine tegmentum makes any other diagnosis highly unlikely
Hypertrophic olivary degeneration-MRI
Reviewed by Sumer Sethi
on
Monday, October 28, 2013
Rating:
Reviewed by Sumer Sethi
on
Monday, October 28, 2013
Rating:
Sumer Sethi
Unique blend of academic excellence and entrepreneurship, heading leading firms in India- Teleradiology Providers, pioneering company providing teleradiology services and DAMS (Delhi Academy of Medical Sciences) Premier test preparation institute in India for MD/MS/MCI preparation. He has also been an invited faculty member at various conferences, including Teleradiology in IRIA 2008 and 2011, Hospital Build Middle East, Congress of the Brain Tumor Radiology in Neuro-oncology Society. Dr. Sethi is Editor-in-Chief of Internet Journal of Radiology. He has a keen interest in Web 2.0 technologies and in maintaining his famous radiology blog, which has been featured in multiple international journals.
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