Inspired by a patient
Kartal A. Paroxysmal Tonic in Children: Three Case Reports and a Review of . Emerg Care. 2019 Apr;35(467-e69. : 10.1097/PEC.0000000000001327. PMID: 29095389.
Background: In clinical practice, nonepileptic paroxysmal events during infancy and childhood are common reasons for parents and caregivers to medical advice. These events are mostly unrecognized and considered as an epileptic seizure because of the clinical features resembling an epileptic seizure. Paroxysmal tonic , which consists of recurrent episodes of sustained upward deviation of the eyes and incomplete downward saccades, and normal horizontal eye movements without impairment of consciousness, is a diagnostic challenge for the pediatrician and pediatric neurologist. In general, the entity was defined as an apparently benign phenomenon with normal investigations and eventual complete resolution of the symptoms, although some authors reported on patients with associated neurologic signs, such as ataxia, developmental delay, and abnormal brain magnetic resonance imaging finding.
Methods: The patients were 3 children (1 boy and 2 girls) who were between 5 and 18 months old experiencing rapid ocular movements with sustained conjugate upward deviation of the eyes. Their attacks, which were recorded using a video or electroencephalogram system, were also investigated comprehensively, including neurologic examination, electroencephalograms, brain magnetic resonance imaging, and metabolic tests. Paroxysmal tonic attacks have decreased in number or disappeared in 2 patients, but 1 patient exhibited mild abnormalities on magnetic resonance imaging and had relatives with epilepsy.
Conclusions: In conclusion, paroxysmal tonic is an apparently benign phenomenon with unclear pathophysiology of various proposed mechanisms such as genetic predisposition, immaturity of the brain stem, neurotransmitter depletion, or immune dysregulation. It is important to recognize the clinical presentation of paroxysmal tonic and distinguish the disorders from epilepsy for deciding the treatment and prognosis of the patients.
R, Billson F. Paroxysmal tonic of childhood--a review. Brain Dev. 2005 Apr;27(3):185-8. : 10.1016/j.braindev.2004.02.016. PMID: 15737699.
and Billson (1988) were apparently the first to describe this entity. In the four original cases, the clinical features were as follows: (1) onset usually under 1 year of age, (2) episodes of variably sustained conjugate upward deviation of the eyes, with neck flexion (chin down) apparently compensating for the abnormal eye position, (3) saccades in attempted downgaze, (4) normal horizontal eye movements, (5) diurnal fluctuation of symptoms, (6) frequent relief by sleep, (7) exacerbation with febrile illnesses, (8) varying degrees of ataxia, (9) neurological examination usually otherwise normal, (10) absence of deterioration during long-term follow-up, (11) eventual improvement, (12) usually negative investigations, including imaging, EEG and CSF neurotransmitters. As of 2002, 49 cases have been reported. factors have included autosomal dominant inheritance in four families, exposure to sodium valproate in three cases, and structural lesions in five (hypomyelination x 2, periventricular leukomalacia, Vein of Galen malformation, pinealoma). Only a few cases have responded to L-dopa. The pathophysiology is still not understood. The outcome appears to be good in about half the cases. Ataxia, borderline cognitive abilities and residual minor oculomotor disorders are seen in the remainder.
Ozbay OE. Idiopathic paroxysmal tonic upward gaze. Neurol. 2012 Oct;47(4):306-8. : 10.1016/j.pediatrneurol.2012.05.028. PMID: 22964448.
Paroxysmal tonic upward gaze constitutes a neuro-ophthalmologic syndrome characterized by episodes of sustained conjugate upward deviation of the eyes, normal horizontal gaze, and ataxia. Its pathogenesis is unknown, and the etiology is heterogeneous. The prognosis is variable. We present a case of "idiopathic paroxysmal tonic upward gaze" with a positive clinical course and spontaneous remission.