Hypertrophic Olivary Degeneration Research Articles

Bilateral Hypertrophic Olivary Degeneration and Holmes Tremor without Palatal Tremor: An Unusual Association.

BackgroundLesions in the Guillain–Mollaret triangle or dentate-rubro-olivary pathway may lead to hypertrophic olivary degeneration (HOD), a secondary trans-synaptic degeneration of the inferior olivary nucleus. HOD is usually associated with palatal tremor and rarely with Holmes tremor. Bilateral HOD is a very unusual condition and very few cases are reported.Case ReportWe report here two cases of bilateral HOD after two different vascular lesions located at the decussation of superior cerebellar peduncles, thus impairing both central tegmental tracts and interrupting bilaterally the dentate-rubral-olivary pathway. Interestingly, both developed bilateral Holmes tremor but not palatal tremor.DiscussionLesions in some of the components in the Guillain–Mollaret triangle may develop Holmes tremor with HOD and without palatal tremor. Magnetic resonance imaging is an invaluable tool in these cases. Better understanding of the pathways in this loop is needed.

MRI and neurological presentation of hypertrophic olivary degeneration

Background and purposeHypertrophic olivary degeneration (HOD) is a rare transsynaptic degeneration that usually appears at around 3–4weeks following an injury to the Guillain–Mollaret triangle, resulting in three possible patterns. Our purpose was to describe those MRI features linking them to their corresponding neurological manifestations and possible prior location of brain insults based on our own experience compared to the review of the literature. MethodsSix patients with clinically evident new neurological symptoms not explained by the initial brain insult were included. All patients were subjected to complete neurological assessment by neurologist or neurosurgeon accordingly. Review of their prior and recent MRI studies as well as CT if available was carried out by two neuroradiologists who picked up the different but classical patterns of HOD on the latest imaging studies. ResultsThe 6 patients had old brain insults including old hematomas (1 patient), old infarctions (3 patients) and hemorrhagic vascular malformation (2 patient) involving the afferent components of the Guillain–Mollaret triangle with development of new movement disorders including ataxia (4 patients), palatal myoclonus (4 patients), tremors (1 patient) and nystagmus (2 patients). MRI clearly showed the nature of the initial lesions. High T2 signal intensity was noticed at the inferior olivary nucleus (ION) in all patients representing olivary degeneration. The size of the ION was enlarged with rounded configuration in 5 cases thus considered hypertrophic, while the size of the ION was shrunken in one case and considered atrophic. The examined ION showed no restricted diffusion excluding recent infarction, blooming on T2∗ excluding hemorrhage or post contrast enhancement excluding inflammation or neoplasm. Unilateral HOD was seen in 3 cases involving the contra-lateral ION while bilateral HOD was seen in 3 cases. ConclusionHOD is an infrequent neurological pathology, sequel to Guillain and Mollaret triangle affection that involves a wide range of symptomatology. It manifests as enlargement of the ION with high T2 and FLAIR signal without enhancement, restricted diffusion or blooming on T2∗ or SWI.

Hypertrophic olivary degeneration: A clinico-radiologic study

IntroductionThe frequency and causes of hypertrophic olivary degeneration (HOD) are unknown. We compared the clinical and radiological characteristics of unilateral HOD and bilateral HOD. MethodsWe performed a search of a radiologic report database for patients who were radiologically diagnosed as having HOD. This database includes the patients examined at the Mayo Clinic in Florida and Arizona. We used the search terms “hypertrophic olivary degeneration”, “HOD”, and “olivary” in the reports recorded from 1995 to 2015. Pertinent medical records and magnetic resonance imaging (MRI) scans of the brain for those with HOD were reviewed retrospectively. ResultsWe identified 142 MRI studies on 95 cases who had radiologically proven HOD, 39 cases had unilateral HOD and 56 with bilateral HOD. In symptomatic cases, the most common symptom was ataxia. Palatal tremor was observed in almost half of all HOD cases. While cerebrovascular diseases were the most frequent etiology in both types of HOD (n = 24, 62% in unilateral; n = 17, 30% in bilateral), more than half of bilateral HOD cases had an unknown etiology (52%, n = 29), whereas only 13% (n = 5) of the unilateral cases had an unknown etiology (χ2 test, P < 0.001). The lesions of unilateral HOD had a tendency to improve radiologically over time, whereas those associated with bilateral HOD were likely to worsen (χ2 test, P < 0.05). ConclusionsOur study showed that bilateral HOD is more common than unilateral HOD. Half of bilateral HOD cases had no obvious cause and some worsened over time. This may implicate a possible primary neurodegenerative process.

Hypertrophic Olivary Degeneration After Pontine Hemorrhage: A Case Report

Introduction: Hypertrophic olivary degeneration (HOD) is a rarely neurologic disease, occurring after damage to the dentato-rubro-olivary pathway. Case presentation: A 50-year-old hypertensive man suffered pontine hemorrhage resulting in numerous neurological deficits. Neurologic examination 4 months after the hemorrhage showed mild to moderate improvement. 8 months after the hemorrhage, the patient developed truncal and limb tremors, unsteady gait and dysarthria. Magnetic resonance showed increasing bilateral hypertrophic olivary degeneration. Administration of clonazepam and levodopa were ineffective for symptom relief. Conclusion: This case was presented in order to describe the clinical manifestations of HOD and to recognize the possibility of hypertrophic olivary degeneration after the pontomesencephalic stroke.

A clinicoradiologic study of hypertrophic olivary degeneration

Objectives: To study the frequency and causation of hypertrophic olivary degeneration (HOD) reported in a radiologic database of the Mayo Clinic Florida and Arizona. HOD usually occurs following lesions involving the dento-rubro-olivary pathway. There are two types of HOD, unilateral and bilateral. Current literature suggests bilateral HOD is less frequent. The epidemiology and etiology of HOD are unknown, particularly bilateral HOD.

Hypertrophic Olivary Degeneration: A Neurosurgical Point of View

Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration characterized by hypertrophy of the inferior olivary nucleus situated in the olivary body, part of the medulla oblongata, representing a major source of input to the cerebellum. HOD typically results from focal lesions interrupting connections from the inferior olive within the dentato-rubro-olivary pathway, a region also known as the triangle of Guillain-Mollaret (TGM) (red nucleus, inferior olivary nucleus, and contralateral dentate nucleus). Clinically, HOD presents classically as palatal tremor and can include dentatorubral tremor and/or ocular myoclonus. The pathologic changes associated with HOD feature radiologic changes with the inferior olivary nucleus appearing larger and increasing its T2-weighted signal intensity on magnetic resonance images. HOD is commonly managed with pharmacotherapy but may require surgical intervention in extreme cases. HOD has been found to develop as a consequence of any injury that disrupts the TGM pathways (e.g., pontine cavernoma).These findings highlight the critical importance of a thorough knowledge of TGM anatomy to avoid secondary HOD. We present a patient who developed HOD secondary to resection of a tectal plate cavernous malformation and review the literature with an emphasis on the current knowledge of this disorder.

Magnetic resonance imaging of hypertrophic olivary degeneration

ObjectiveTo review the pathophysiologic mechanisms involved in hypertrophic olivary degeneration, with attention to epidemiological and clinical aspects and especially to imaging findings. Material and methodsWe reviewed 5 patients diagnosed with hypertrophic olivary degeneration at our center from 2010 through 2013, analyzing relevant clinical, epidemiological, and radiological findings. ResultsIn all cases, a hyperintensity was seen in the inferior olivary nuclei in FLAIR and T2-weighted sequences. No signal alterations were seen on T1-weighted sequences, and no enhancement was seen after intravenous injection of contrast material. In the cases studied by diffusion-weighted imaging, no significant alterations were seen in these sequences. Olivary hypertrophy was seen in all patients except in one, in whom presumably not enough time had elapsed for hypertrophy to occur. The alterations were bilateral in two of the five cases. Only one case exhibited the typical clinical manifestations. ConclusionGiven that patients may not present clinical manifestations that can be attributed to hypertrophic olivary degeneration, it is important to recognize the characteristic radiologic signs of this entity.

Identifying quantitative imaging features of posterior fossa syndrome in longitudinal MRI.

Up to 25% of children who undergo brain tumor resection surgery in the posterior fossa develop posterior fossa syndrome (PFS). This syndrome is characterized by mutism and disturbance in speech. Our hypothesis is that there is a correlation between PFS and the occurrence of hypertrophic olivary degeneration (HOD) in structures within the posterior fossa, known as the inferior olivary nuclei (ION). HOD is exhibited as an increase in size and intensity of the ION on an MR image. Longitudinal MRI datasets of 28 patients were acquired consisting of pre-, intra-, and postoperative scans. A semiautomated segmentation process was used to segment the ION on each MR image. A full set of imaging features describing the first- and second-order statistics and size of the ION were extracted for each image. Feature selection techniques were used to identify the most relevant features among the MRI features, demographics, and data based on neuroradiological assessment. A support vector machine was used to analyze the discriminative features selected by a generative k-nearest neighbor algorithm. The results indicate the presence of hyperintensity in the left ION as the most diagnostically relevant feature, providing a statistically significant improvement in the classification of patients ([Formula: see text]) when using this feature alone.

A case of hypertrophic olivary degeneration after resection of cavernomas of the brain stem and review of the literature

Hypertrophic olivary degeneration is a transsynaptic form of degeneration, which is also a result of primary or secondary lesion and can damage the dento-rubro-olivary pathway. The dento-rubro-olivary pathway was first described by Guillain and Mollaret and is referred to as “the triangle of Guillain and Mollaret”. Multiple factors can destroy the dento-rubro-olivary pathway, such as surgical operation, hemorrhage, tumor, trauma, inflammation, demyelination, degeneration, and radiation damage. All of the above factors can result in delayed hypertrophic olivary degeneration. Articles related to this disease cover etiology, clinical presentation, pathology changes, etc. However, to our knowledge, there has been no literature reporting the use of diffusion tensor imaging and diffusion tensor tractography to improve the diagnosis of hypertrophic olivary degeneration following resection of cavernomas in the brain stem. Herein, we report a case who was diagnosed with hypertrophic olivary degeneration following resection of cavernomas of the brain stem, verify the significance of diffusion tensor imaging and diffusion tensor tractography, and review previous literature. The development of imageology promotes and improves hypertrophic olivary degeneration diagnosis and differential diagnosis.

Postoperative posterior fossa syndrome: unraveling the etiology and underlying pathophysiology by using magnetic resonance imaging

Posterior fossa syndrome (PFS) is a severe, postoperative complication occurring in about 25 % of pediatric patients undergoing surgery for midline tumors in the posterior fossa. In recent years, MRI-based research elucidated the cause of PFS and shed new light on its putative pathophysiology. This review highlights the major advances arising from research of this topic. Postsurgical damage patterns in patients after posterior fossa surgery show that PFS results from bilateral surgical damage to the proximal efferent cerebellar pathways (pECPs). Surgical pECP disruption has other MRI-detectable effects that are more remote. Patients with PFS tend to develop global supratentorial cortical hypoperfusion, likely representing reversed, cerebello-cerebral diaschisis. Because this hypoperfusion is most prominent in frontal regions, cerebellar mutism may indicate a dominantly frontal lobe dysfunction, hence a peculiar form of speech apraxia. Injury to the pECP also leads to contralateral inferior olivary nucleus degeneration. When bilateral hypertrophic olivary degeneration (HOD) is observed after posterior fossa surgery, affected patients have clinical PFS. Therefore, it is suggested that bilateral HOD may be a sensitive and, in appropriate clinical settings, reliable a posteriori surrogate imaging indicator of bilateral disruption of the pECPs and consequently of PFS. Having such a "validation tool" presents new opportunities to develop better definitions for the phenotypes within the clinical spectrum of PFS. Anatomical and functional MRI techniques are suitable and valuable tools with which to detect structural changes and pathophysiological processes in the development and evolution of PFS and may be key, integral components of future clinical research endeavors.

MRI Findings in Nonlesional Hypertrophic Olivary Degeneration.

Investigate the relative frequency of nonlesional versus lesional hypertrophic olivary degeneration (HOD) and potential explanations for nonlesional HOD. Our radiology report database was queried for "HOD" in all head MRI reports between 7/1/2002 and 7/1/2013 and identified 138 patients. Specific absence of HOD or cases with lesions within the dento-rubro-olivary pathway (DROP) or extending into the inferior olivary nuclei (ION) were excluded (22 in total). For included patients, 19 locations with the anatomic potential to connect to the ION or DROP were reviewed and grouped into embryological categories, along with the use of the drug metronidazole. A total of 51 of 116 (44%) HOD patients did not have a causative lesion in the DROP. The 27/51 (53%) of these patients had progressive ataxia with palatal tremor (PAPT). The 28/51 (55%) patients had one or more lesions outside of the DROP and one of these 28 patients used metronidazole. The remaining 23/51 (45%; 19% of total HOD cohort) patients had no additional lesions in the brain and 6 of these 23 patients did not have a clinical diagnosis of PAPT. Forty-four percent of patients with HOD did not demonstrate an MRI-identifiable lesion in the DROP, and 45% of those patients did not have identifiable brain lesions outside of the DROP. Thus, nearly a fifth of HOD cases may be truly idiopathic. A majority of patients without a DROP lesion had bilateral HOD and two-thirds were male.

Hypertrophic olivary degeneration resulting from posterior fossa masses and their treatments

PurposeCharacterize hypertrophic olivary degeneration (HOD) that develops from posterior fossa masses and their treatments. MethodsRetrospectively reviewed MR images and clinical data of 10 patients with posterior fossa masses and HOD. ResultsEight patients had cerebellar lesions, and two patients had pontine lesions. Lesions consisted of tumors, demyelination, and nonspecific necrosis. MRI showed T2 hyperintense signal in the inferior olive a median 86 days after the diagnosis of a posterior fossa lesion. HOD presented prior to surgery (n=2), after surgery (n=3), after surgery/radiation therapy (n=4), or without treatment (n=1). ConclusionsHOD may develop from posterior fossa masses and surgical and/or radiation therapy.

Vietnamese patient with progressive ataxia and palatal tremor syndrome

Background: We present clinical and MRI features of progressive ataxia and palatal tremor (PAPT). Case Report: A 67 year-old gentleman visiting from Vietnam presented with intermittent stroke-like episodes consisting of facial weakness, dysarthria, and osillopsia. He reported gradually worsening ataxia and dysequilibrium over 4 years. Examination revealed small amplitude nystagmus towards the right, impaired VOR to the left, palatal tremor, left-sided dysmetria, and an unsteady gait. MRI of the brain demonstrated increased T2/FLAIR signal within the inferior olive. Contrast enhanced and diffusion sequences were normal. MRA was normal. Electrocardiography, telemetry, and echocardiogram were normal. CSF was normal. Glial fibrillary acidic protein (GFAP) and vitamin E levels were normal. Genetic testing for hereditary forms of ataxia including spinocerebellar ataxia was not completed. Conclusion: Palatal tremor is commonly classified into symptomatic or essential subgroups. Symptomatic palatal tremor is frequently caused by a lesion in the triangle of Guillain and Mollaret leading to hypertrophic olivary degeneration. A subgroup of symptomatic palatal tremor form a syndrome of PAPT. Published details of cases of PAPT are sparse and the disorder appears to be mainly sporadic. Common features include progression of ataxia, olivary degeneration, gaze-evoked nystagmus, and internuclear ophthalmoplegia. There is no known effective treatment for progressive ataxia, which is the most disabling symptom of PAPT.

Imaging of Important Causes of Brain Stem Enlargement

The brain stem is a critical part of the central nervous system (CNS); it houses the cranial nerve nuclei and cardiopulmonary centers, and serves as a conduit for descending tracts into the spinal cord. The brain stem is located in the posterior fossa, and anatomically is composed of the midbrain (most rostral part of the brain stem), pons, and medulla. Gliomas are the most common cause of brain stem enlargement. However, a variety of other pathologic processes such as infection, metastasis, inflammation or demyelination, hemorrhagic lesions, posterior reversible encephalopathy syndrome, and hypertrophic olivary degeneration also may involve the brain stem, and occasionally cause diagnostic dilemmas. In some instances, combining the clinical presentation with the radiologic findings may even obviate the need for biopsy of this critical region of the central nervous system.

Inferior olivary nucleus involvement in pediatric neurodegenerative disorders: does it play a role in neuroimaging pattern-recognition approach?

The diagnostic work up of neurometabolic/degenerative disorders is complex. In such context, identification of neuroradiological features suggestive of specific diagnoses is useful to prompt further diagnostic tests. Involvement of the inferior olivary nucleus (ION) has been reported in several pathologic conditions, either as a primary manifestation of disease or secondary to hypertrophic olivary degeneration (HOD). In this study, we analyzed a cohort of 95 children with different neurometabolic/degenerative diseases involving the brainstem and cerebellum, with the aim to evaluate whether ION involvement plays a role in a neuroimaging-based pattern-recognition approach. A total of 13 patients (13.7%) showed bilateral high-signal intensity and enlargement of the ION on T2-weighted images, while 16 (16.8%) had ION T2-hyperintensity without olivary nucleus enlargement. Our study demonstrates that ION involvement is not rare in children with neurometabolic/degenerative disorders. Two main neuroradiological patterns, that is, "T2-hyperintense signal" and "T2-hyperintense signal with enlargement" are found. These patterns can be related to different etiologies, and do not suggest specific diagnoses. Primary ION lesion can be characterized by olivary swelling, and the differentiation from typical secondary HOD may be difficult.

Imagen por resonancia magnética en la degeneración olivar hipertrófica

ObjectiveTo review the pathophysiologic mechanisms involved in hypertrophic olivary degeneration, with attention to epidemiologic and clinical aspects and especially to imaging findings. Material and methodsWe reviewed 5 patients diagnosed with hypertrophic olivary degeneration at our center from 2010 through 2013, analyzing relevant clinical, epidemiologic, and radiologic findings. ResultsIn all cases, a hyperintensity was seen in the inferior olivary nuclei in FLAIR and T2-weighted sequences. No signal alterations were seen on T1-weighted sequences, and no enhancement was seen after intravenous injection of contrast material. In the cases studied by diffusion-weighted imaging, no significant alterations were seen in these sequences. Olivary hypertrophy was seen in all patients except in one, in whom presumably not enough time had elapsed for hypertrophy to occur. The alterations were bilateral in two of the five cases. Only one case exhibited the typical clinical manifestations. ConclusionGiven that patients may not present clinical manifestations that can be attributed to hypertrophic olivary degeneration, it is important to recognize the characteristic radiologic signs of this entity.

Hypertrophic Olivary Degeneration – A Report of Two Cases

Hypertrophic olivary degeneration (HOD) is seen following lesions in the Guillain–Mollaret triangle. This is unique because the inferior olivary nucleus hypertrophies following degeneration unlike the typical atrophy seen in other structures. We report two cases of HOD in two different clinical scenarios.

Hypertrophic olivary degeneration secondary to central tegmental tract injury.

. The main patient-related artifacts arecaused by motion during images acquisition and use of substanceson the skin.The present case illustrates the necessity of a strict mam-mographic image quality control and correlation with clinical find-ings for greater diagnostic accuracy. As already mentioned, theskin lesion led to simulation of a clustered pleomorphic microcalci-fications which would imply the necessity of biopsy. The activequest for prevention and detection of artifacts, in association witha continued quality control of imaging, processing, storage andimages analysis, reduces the incidence of misdiagnosis and costs,e should be the objective of any team involved in mammographyservices.

Hypertrophic olivary degeneration and holmes' tremor secondary to bleeding of cavernous malformation in the midbrain.

BackgroundHypertrophic olivary degeneration (HOD) is a rare phenomenon, probably related to transsynaptic degeneration of the inferior olivary nucleus. It usually occurs as a response to primary injury of dento-rubro-olivary pathways.Case reportA young man developed Holmes' tremor 7 months after a cavernous malformation bleed in the midbrain. Typical findings of HOD were observed in the magnetic resonance images: bilateral and asymmetric hypertrophy of the olivary nucleus with slight hypersignal in T2-weighted images. Because of the striking disability related to drug-resistant tremor, the patient underwent stereotactic thalamotomy (nucleus ventralis intermedius of the thalamus/zona incerta) with pronounced functional improvement over time.DiscussionDisruption of circuits in the Guillain–Mollaret triangle classically results in palatal myoclonus, however midbrain (Holmes') tremor can also occur, as we now describe.

Hypertrophic Olivary Degeneration and Holmes’ Tremor Secondary to Bleeding of Cavernous Malformation in the Midbrain

Hypertrophic Olivary Degeneration and Holmes’ Tremor Secondary to Bleeding of Cavernous Malformation in the Midbrain