Abducens nucleus syndrome due to pontine haemorrhage

Complete Horizontal Gaze Paresis Due to Medial Pontine Haemorrhage

We report a case of bilateral horizontal conjugate gaze palsy due to a dorsal median pontine haemorrhage. The development of horizontal gaze palsy has been attributed to lesions in the pontine tegmentum, and in this case, has occurred in conjunction with other features as part of Foville's syndrome. Complete horizontal gaze palsy is a rare clinical manifestation as bilateral involvement is unusual. Our case provides further insight into the intricacies of the brainstem neuroanatomy through a description of the involved neural pathways and nuclei accounting for complex neurological manifestations in one patient.

Bilateral paramedian pontine infarcts: a rare cause of bilateral horizontal gaze palsy

A 73-year-old man presented to accident and emergency with headache and diplopia. Examination of the eye movements revealed a bilateral complete horizontal gaze palsy. On admission, a CT scan of the brain was performed, which was unremarkable. An MRI of the brain was then performed, which confirmed tiny acute infarcts involving the pons and the right cerebellum. This man was promptly treated with aspirin 300 mg one time per day, as per the stroke pathway. Further diagnostic workup later revealed atrial flutter. This man was therefore commenced on apixaban. The differential diagnoses for bilateral gaze palsy include the following: multiple sclerosis, infarction, haemorrhage and space occupying lesion. Bilateral gaze palsy is often associated with other neurological symptoms.

Sixth Cranial Nerve Palsy and Vertigo Caused by Vertebrobasilar Insufficiency

A 38-year-old woman presented with a week’s history of binocular horizontal double vision and acute vertigo with gaze-induced nystagmus. We considered a diagnosis of one of the six syndromes of the sixth cranial nerve and evaluated several causes. She had history of severe anemia, vitamin B12 deficiency, and hypertension. Magnetic resonance imaging with angiography showed stenosis of the right vertebral artery and hyperintensity on both basal ganglia. As we describe here, we should consider vertebrobasilar insufficiency as a cause for sixth cranial nerve palsy if a patient has high risk for microvascular ischemia, even in the absence of acute brain hemorrhage or infarction.

Delayed Trigeminal Motor Denervation after Pontine Hemorrhage

Pontine hemorrhage is a life-threatening emergency which may result in high mortality and devastating disability. Trigeminal denervation is usually caused by neoplasms and trauma but rarely occurs after pontine hemorrhage. Herein, we present a patient with delayed trigeminal motor denervation who presents with progressive atrophy of the right temporalis and masseter muscles 1 year after pontine hemorrhage. Details of the pathogenesis and correlation between clinical, electrophysiological, and radiological findings are addressed.

[Quantitative analysis of vascular network of oculogyric nerve nuclei]

INTRODUCTION

Nuclei of oculogyric nerves (principal oculomotor nucleus, trochlear nucleus and abducens nucleus) are densely vascularized brainstem structures. The aim of this study was to determine quantitative characteristics of the vascular network of these nuclei.

MATERIAL AND METHODS

The study was done on 30 adult brainstems, both male and female, without diagnosed neurological disturbances. Three-millimetre-thick stratums were taken in transversal plane and cut in 0.3 micrometer semi-serial sections stained with Mallory method. The images of studied nuclei were taken with "Leica" DM 1000 microscope and "Leica" EC3 digital camera under 400x magnification, and analyzed by ImageJ software with A 100 grid. The statistical analysis was performed by Statistical Package for the Social Sciences software with 5% level of significance.

RESULTS

A statistically significant difference was found in the volume and surface density between principal oculomotor nucleus and trochlear nucleus, and between trochlear nucleus and abducens nucleus. No difference was found in the length density.

DISCUSSION

The results of this research match the results of studies on characteristics of vascular network of oculogyric nerve nuclei, while the comparison of vascular networks of these nuclei, substantia nigra, vestibulocochlear nuclei and precentral gyrus illustrates differences in quantitative characteristics of blood vessels in these structures.

CONCLUSION

Blood vessels of principal oculomotor nucleus and abducens nucleus have similar dimensions and approximately the same arborization pattern, while vessels of trochlear nucleus have significantly smaller dimensions and density.