|Year : 2016 | Volume
| Issue : 3 | Page : 242-243
Facial colliculus syndrome
Rupinderjeet Kaur1, Paramdeep Singh2, Krishan Singh Kajal1, Simmi Aggarwal2
1 Department of Medicine, Guru Gobind Singh Medical College and Hospital, Baba Farid University of Health Sciences, Faridkot, Punjab, India
2 Department of Radiology, Guru Gobind Singh Medical College and Hospital, Baba Farid University of Health Sciences, Faridkot, Punjab, India
|Date of Web Publication||9-Jun-2016|
Department of Radiology, Guru Gobind Singh Medical College and Hospital, Baba Farid University of Health Sciences, Faridkot, Punjab
Source of Support: None, Conflict of Interest: None
A male patient presented with horizontal diplopia and conjugate gaze palsy. Magnetic resonance imaging (MRI) revealed acute infarct in right facial colliculus which is an anatomical elevation on the dorsal aspect of Pons. This elevation is due the 6th cranial nerve nucleus and the motor fibres of facial nerve which loop dorsal to this nucleus. Anatomical correlation of the clinical symptoms is also depicted in this report.
Keywords: Diplopia, facial colliculus, infarct, MRI, palsy
|How to cite this article:|
Kaur R, Singh P, Kajal KS, Aggarwal S. Facial colliculus syndrome. CHRISMED J Health Res 2016;3:242-3
A 75-year-old male presented in Emergency Department with acute-onset horizontal diplopia. Clinical examination depicted a conjugate gaze palsy, and the eyes could not be driven past midline to the right with fast head rotation, smooth pursuit, convergence, or saccades. However, bilateral pupils were normal in size with immediate direct light reflexes. He had facial weakness on the right (failure of forehead wrinkling, lower eyelid ectropion, inadequate eye blink, brow ptosis, flattened nasolabial fold, and a right mouth droop), which was suggestive of right peripheral facial palsy. No other deficits were present. On magnetic resonance imaging (MRI), a small area of diffusion restriction was seen in the right facial colliculus [Figure 1]. He was prescribed aspirin and ocular motility, and the seventh nerve function gradually improved. The patient was neurologically intact 3 months after initial presentation.
|Figure 1: Magnetic resonance imaging diffusion-weighted image (a) and apparent diffusion coefficient map (b) a punctate focus of acute infarct with restricted diffusion in the dorsal aspect of Pons on the right side at the floor of the fourth ventricle which corresponds to facial colliculus. The area of restricted diffusion is appearing hyperintense on diffusion-weighted image with the corresponding hypointensity on apparent diffusion coefficient map|
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The facial colliculus is an anatomical elevation in the floor of the fourth ventricle. The motor fibers of facial nerve loop dorsal to the 6 th cranial nerve nucleus before exiting the brainstem resulting in a bump at the floor of the fourth ventricle is known as facial colliculus [Figure 2]. The clinical signs and symptoms of the lesion in facial colliculus are determined by the structures that constitute it, especially the nucleus of the abducens nerve (cranial nerve VI), the facial nerve that loops around the abducens nucleus, the paramedianpontine reticular formation (PPRF) that is located near the abducens nucleus, and the medial longitudinal fasciculus (MLF). A pathology of the facial colliculus affects the facial nerve which leads to facial palsy affecting both the top and bottom of the face. This can often be mistaken as Bell's palsy, which is also a peripheral 7 th nerve palsy, but by definition is idiopathic. The abducens nerve innervates the ipsilateral lateral rectus muscle and, therefore, directly controls abduction in the ipsilateral eye. It also controls conjugate adduction of the contralateral eye through the MLF linkage to the oculomotor nucleus of the contralateral side. Therefore, any pathology in the abducens nucleus and PPRF would cause failure of abduction of the ipsilateral eye as well as loss of conjugate adduction of the contralateral eye. This is dissimilar from lesions of the abducens nerve, which would only cause failure of abduction in the ipsilateral eye. Underlying etiology of facial colliculus syndrome differs by age. While in young age group, tumor, demyelination, and viral infection may be the etiological factors whereas in elderly people, ischemia is a frequent causative factor. ,,,
|Figure 2: Axial magnetization-prepared rapid acquired gradient-echoes image at the level of the Pons demonstrates the facial colliculus seen as a small bump along the posterior aspect of the Pons. This is formed by the motor tracts of the facial nerve (magenta curved line) coursing around the abducens nucleus (green dot). Facial nucleus is depicted as blue dot|
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To summarize, the clinical presentation of facial colliculus syndrome is due to a lesion in the facial colliculus which comprises ipsilateral lower motor neuron pattern of facial nerve palsy, ipsilateral lateral rectus palsy, and frequently, conjugate gaze palsy due to an associated contralateral medial rectus palsy. The conjugate gate palsy may be either caused by a lesion involving the MLF or due to the involvement of interneurons at the level of abducens nucleus that continue into the MLF. Therefore, in a patient with peripheral facial nerve palsy, lateral rectus palsy, and conjugate gaze palsy, possibility of a pathology in facial colliculus must be considered, and MRI is the investigation of choice in depicting the exact site of the pathology.
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[Figure 1], [Figure 2]