LETTERS TO THE EDITOR Year : 2022  |  Volume : 25  |  Issue : 6  |  Page : 1194-1196  

Upbeat and brun's nystagmus in cerebello-pontine tuberculoma

Anumeha Mishra, Sanjay Pandey
Department of Neurology, Govind Ballabh Pant Postgraduate Institute of Medical Education and Research, New Delhi, India

Date of Submission02-Jul-2022Date of Decision19-Aug-2022Date of Acceptance25-Aug-2022Date of Web Publication3-Dec-2022

Correspondence Address:
Sanjay Pandey
Department of Neurology, Academic Block, Room No 503, Department of Neurology, Govind Ballabh Pant Postgraduate Institute of Medical Education and Research, New Delhi - 110 002
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/aian.aian_577_22

  How to cite this article:
Mishra A, Pandey S. Upbeat and brun's nystagmus in cerebello-pontine tuberculoma. Ann Indian Acad Neurol 2022;25:1194-6

Dear Editor,

A 15-year-old girl presented with complaints of headache since 5 months, and decreased hearing in right ear since 2 months. She also had acute ataxia, sagging, and numbness of right side of the face associated with redness, excessive tearing, and binocular vertical diplopia that aggravated on downgaze and improved on lying down since the last 7 days. She also reported two consecutive episodes of left focal seizures, both occurring in a day, about one month back requiring oral levetiracetam (500 mg twice daily). Quite pertinently, she had received incomplete treatment for cervical tuberculous lymphadenitis six months ago.

On examination, she had facial puffiness and hirsutism. Her visual acuity in right and left eyes were bilaterally 6/6 with some blurring in the right eye. The right cornea of the patient appeared cloudy due to exposure keratopathy. Her pupils were bilaterally equal, normal in size, and well-responsive to light. Fundus examination did not show and choroid tubercles or papilledema. On examination of the eye movement, the patient has bilateral upbeat nystagmus with a fast-jerky component upwards. Bilateral upbeat nystagmus (more prominent on the left and aggravating while looking upwards) was present along with bilateral, but rather asymmetric, horizontal gaze-evoked Brun's nystagmus [coarse and slow low-frequency, large-amplitude nystagmus when looking towards right (the side of the lesion) coupled with rapid fine high-frequency, small-amplitude nystagmus when looking away from the lesion (towards left)] [See video]. However, nystagmus in the right eye is confounded by the abduction limitation in that eye because of right lateral rectus palsy. Touch and pinprick sensations were decreased by about 50% on the right half of the face. She had right lower motor neuron type of facial weakness and sensory-neural deafness in the right ear.

Mild dysmetria was noticed on performing the right finger and nose maneuver. Also, significant gait ataxia with a tendency to fall or veer towards right was seen. Tone of left upper and lower limb was decreased and motor power was 3+ (MRC scale) on the left, whereas tone and power were normal on the right side. Magnetic resonance images and spectroscopy of the brain were suggestive of tuberculoma in the right cerebello-pontine angle region [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e. Computerized tomography of chest was suggestive of focal cavitatory changes along with tree in bud pattern and peribronchial thickening suggestive of tubercular etiology.

Figure 1: Magnetic resonance images on T1-weighted (W) axial section (a) show heterogenous area of hypo-density surrounded by a rim of hyper-density in the area of right cerebello-pontine angle region. T1 post-gadolonium (b) axial images show multiple conglomerated ring enhancement at the areas on precontrast T1-weighted image. On T2W axial (c) and fluid-attenuated inversion recovery (FLAIR) coronal sequences (d) the corresponding area is showing heterogenous hyperintensity surrounding an area of hypointensity. (e) The magnetic resonance spectroscopy image is showing raised lipid/lactate peak within the lesion consistent with a diagnosis of tuberculoma

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Genexpert ultra on sputum sample was positive for Mycobacterium tuberculosis complex. Cerebrospinal fluid examination was not done due to tuberculoma in cerebello-pontine angle region. She was treated with five antitubercular drugs [Injection (intramuscular) Streptomycin 0.75 mg once daily, capsule Rifampicin = 450 mg, tablet Isoniazid = 300 mg, tablet Pyrazinamide = 1250 mg, tablet Ethambutol = 800 mg, and tablet Pyridoxine = 20 mg)].

Upbeat nystagmus is a type of central vestibular nystagmus that is usually transient and is less commonly encountered than downbeat nystagmus; it tends to increase with upward gaze and unlike downbeat nystagmus, it is not usually enhanced on lateral gaze and may even evolve into downbeat nystagmus with convergence.[1] Nystagmus with the fast phase jerking upward in primary position rarely may be congenital or reflect drug intoxication, but usually indicates acquired disease.[2] Although it has been reported in myriad conditions like infarctions, hemorrhages, tumors, multiple sclerosis, Wernicke's encephalopathy, epilepsy, brainstem encephalitis, Creutzfeldt-Jakob disease, Behçet syndrome, meningitis, Chiari malformation, and cerebellar degeneration, literature seems paltry when it comes to its causation by infectious space-occupying lesions like a tuberculoma seen in our patient.[1],[3] Encountered most commonly as a reflection of disease at the pontomesencephalic or pontomedullary junctions, it has also been reported with lesions of the perihypoglossal and inferior olivary nuclei, brachium conjunctivum, anterior cerebellar vermis, and more caudal parts of the medulla.[4] Brun's nystagmus, eponymously named after Ludwig Bruns, is the usual pattern of an extra-axial mass compressing the brainstem on the side of the slower nystagmus, can also be seen in our patient in the form of a gaze-evoked, coarse, slow nystagmus towards the side of the lesion and faster small-amplitude nystagmus towards the opposite side.[2]

Ethical compliance statement

The authors confirm that the approval of an institutional review board was not required for this work. We also confirm that the patient has given written informed consent for the publication of her video. We confirm that we have read the Journal's position on issues involved in the ethical publication and affirm that this work is consistent with those guidelines.

Author roles

Conception and design of the studyAcquisition and analysis of dataDrafting a significant portion of the manuscript and figures.

AM: 1, 2, 3.

AC: 1, 2, 3.

SP: 1, 2, 3.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

   References 
1.Kim JS, Yoon B, Choi KD, Oh SY, Park SH, Kim BK. Upbeat nystagmus: clinicoanatomical correlations in 15 patients. J Clin Neurol 2006;2:58-65.  
    2.Daroff RB, Troost BT. Upbeat Nystagmus. JAMA 1973;225:312.  
    3.Leigh RW, Zee DS. The vestibular-optokinetic system. In: Leigh RW, Zee DS, editor. The Neurology of Eye Movements. USA: Oxford University Press; 1999.  
    4.Janssen JC, Larner AJ, Morris H, Bronstein AM, Farmer SF. Upbeat nystagmus: Clinicoanatomical correlation. J Neurol Neurosurg Psychiatry 1998;65:380-1.  
    
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