Prevalence of intracranial lesions in children initially diagnosed with disconjugate nystagmus (spasmus nutans)

Eye oscilations with neurological implications in pediatric age

INTRODUCTION

Eye oscillations, both nystagmic and non-nystagic, can occur from birth. Most correspond to infantile nystagmus that dubates in the first six months of life, which include idiopathic, sensory, latent, or overt latent motor nystagmus. Those associated with neurological diseases or syndromes correspond to approximately 33%, their identification and correct evaluation being important given the potential visual and vital complications.

MATERIAL AND METHODS

We made a systematic review of the literature on supranuclear gaze control mechanisms and the main ocular oscillations with possible neurological implications, both in childhood. With this, we intend to assess if there are already established clinical-anatomical associations, and to propose a protocol on the complementary studies to be carried out in these cases.

RESULTS

There are still anatomical pathways involved in supranuclear gaze control that are not fully clarified and understood. Besides, except in the case of nystagmus in seesaw and upbeat, we did not find anatomical explanations for their pathogenesis. The need for complete neuro-ophthalmological physical examinations and the request for additional tests in children who present ocular oscillations with neurological characteristics are clear.

CONCLUSIONS

Supranuclear gaze control follows a complex neurological network that still needs to be studied better. With a better dissection of the same we could try to understand why the ocular oscillations that we studied have these specific forms of presentation. As for the complementary requests, the request for neuroimaging tests is practically constant, making the others according to the specific case before which we find ourselves.

Long-Term Follow-up of Spasmus Nutans

PURPOSE

Spasmus nutans is an acquired form of nystagmus that is classically associated with torticollis and titubations of the head, often presenting in the first year of life and spontaneously resolving within the next 2 years. The purpose of our study was to record and characterize the long-term prognosis of children diagnosed with spasmus nutans.

METHODS

All patients under the age of 21 years with a diagnosis of spasmus nutans were included. Parameters of age, nystagmus symmetry and quality, presence of titubations, torticollis, and strabismus, and findings on CT or MRI were recorded.

RESULTS

Our 22 patients had an average age of onset of 9.8 and a follow-up of 62.6 months. Nystagmus was unilateral in 5 children, asymmetric in 5, symmetric in 10, and inapparent in 2. Titubations were identified in 10 and torticollis in 7. Nystagmus persisted in 16 of 20 children, titubations in 3, and torticollis in 6. Neuroimaging, performed on 17 of the 22 children, was negative for any space-occupying lesions.

CONCLUSION

In conclusion, we are reluctant to assure parents of children who have even the most typical spasmus nutans that their child will be normal after a predictable interval. Instead, we advise them that many children do well, assuming normal imaging, but that nystagmus, torticollis, and even titubations may persist. Follow-up, especially for strabismus and amblyopia, should be continued throughout childhood.

Magnetic resonance imaging findings in children with spasmus nutans

BACKGROUND

Spasmus nutans (SN) is a rare pediatric ophthalmologic syndrome characterized by nystagmus, head bobbing, and abnormal head positioning. Historically, SN has been associated with underlying optic pathway gliomas (OPG); however, evidence of this association is based primarily on a small number of isolated case reports. Prior retrospective analyses have found the rate of OPG to be <2%, but these studies only intermittently used neuroimaging with computed tomography, which has limited sensitivity for detection of small lesions in the optic pathway. The purpose of this study was to investigate the association of SN with intracranial abnormalities, particularly OPG, using magnetic resonance imaging of the brain and orbits.

METHODS

Neuroradiology databases at three institutions spanning January 2010 to May 2016 were queried for examinations ordered for evaluation of SN; MRI examinations of the brain and/or orbits were included and evaluated for OPG and other structural abnormalities. Medical records were reviewed to confirm a diagnosis of SN, presence of other underlying neurological disease, or preexisting diagnoses.

RESULTS

A total of 40 patients with eligible MRI examinations were identified. None had optic nerve pathway gliomas. Two children had optic nerve hypoplasia; no other patients had optic pathway abnormalities. None had intracranial or orbital masses. MRI examinations were normal in 25 patients.

CONCLUSIONS

This series represents the largest collection of MRI examinations for SN in the literature to date and shows no association between OPG and SN. In children presenting with SN but no other findings suggesting OPG or neurological abnormalities, neuroimaging may not be required.

Infantile and acquired nystagmus in childhood

Nystagmus is an involuntary, periodic eye movement caused by a slow drift of fixation which is followed by a fast refixation saccade (jerk nystagmus) or a slow movement back to fixation (pendular nystagmus). In childhood most cases are benign forms of nystagmus: idiopathic infantile, ocular or latent nystagmus. They arise at the age of 3 months, without oscillopsia and show the absence of the physiologic opto-kinetic nystagmus. A full ophthalmologic evaluation is all that is needed in most cases: albinism, macular or optic nerve hypoplasia and congenital retinal dystrophies are the most common forms of ocular nystagmus. Idiopathic infantile nystagmus can be hereditary, the most common and best analyzed form being a mutation of the FRMD7 gene on chromosome Xq26.2. The mutation shows a mild genotype-phenotype correlation. In all female carriers the opto-kinetic nystagmus is absent and half had mild nystagmus. Latent nystagmus is part of the infantile esotropia syndrome and shows the unique feature of change of direction when the fixing eye changes: it is always beating to the side of the fixing eye. There is no cure for infantile nystagmus but therapeutic options include magnifying visual aids or eye muscle surgery at the age of 6-8 y in patients with head turn. Less than 20% of childhood nystagmus are acquired and need further neurological and imaging work-up. Alarming signs and symptoms are: onset after the age of 4 months, oscillopsia, dissociated (asymmetric) nystagmus, preserved opto-kinetic nystagmus, afferent pupillary defect, papilloedema and neurological symptoms like vertigo and nausea. The most common cause is due to pathology of the anterior optic pathway (e.g. optic nerve gliomas). It shows the same clinical feature of dissociated nystagmus as spasmus nutans but has a higher frequency as in INO. Other forms of acquired nystagmus are due to brainstem, cerebellar or metabolic diseases.

Spasmus Nutans-Like Nystagmus is Often Associated With Underlying Ocular, Intracranial, or Systemic Abnormalities

BACKGROUND

There is uncertainty as to whether spasmus nutans (SN) is an isolated idiopathic entity or whether there are underlying conditions that could cause or be associated with the nystagmus. We undertook this study to determine the frequency of ocular, intracranial, and systemic conditions in patients with nystagmus having characteristics of SN.

METHODS

We performed a chart review of 22 consecutive patients examined from 2000 through 2005 at the Dean McGee Eye Institute and Children' Hospital of Oklahoma with nystagmus consistent with SN. We collected information related to gender, age at presentation and age at final visit, visual acuity, refractive error, laterality of nystagmus, presence of head nodding and torticollis, pattern of strabismus, neuroimaging and electroretinography results, and other associated clinical findings.

RESULTS

Visual acuity was reduced in 75% of eyes at presentation and 58% of eyes at last visit. Eight patients had significant refractive error. Seven patients had strabismus. Two patients had chiasmal gliomas. Four patients had cone or rod/cone dystrophy. Only three patients had no associated ocular, intracranial, or systemic conditions.

CONCLUSIONS

A substantial proportion of patients presenting with SN-like nystagmus have important underlying ocular, intracranial, or systemic abnormalities that may require evaluation and management.

Medical Imaging in Pediatric Neuro-Ophthalmology

This article provides an outline of the congenital and acquired conditions encountered in the practice of pediatric neuro-ophthalmology. Although some entities can be effectively evaluated clinically, CT and MR imaging studies may prove instrumental in many instances for detailed evaluation, narrowing of the differential diagnosis, or exclusion of underlying central nervous system pathologic findings.

Electroretinography is necessary for spasmus nutans diagnosis

The purpose of the present study was to determine whether that which clinically appeared to be spasmus nutans could actually represent retinal sensory deficits diagnosable by electroretinography. Eight patients clinically thought to have spasmus nutans underwent electroretinography according to international standards. Five had normal electroretinograms and represented cases of true spasmus nutans. Three patients had abnormal electroretinograms, indicating that they did not have spasmus nutans. The clinical findings used to diagnose spasmus nutans can be simulated by retinal dystrophies. A normal electroretinogram is needed to confirm the diagnosis of spasmus nutans.