Apneic Seizures in a Child with Achondroplasia

A 7-month-old female with achondroplasia (FGFR3 c.1138G > A), developmental delay, obstructive sleep apnea (OSA) diagnosed by sleep study, s/p tonsillectomy presented with apneic spells starting at 4 months. Initial electroencephalograms (EEG) were normal but failed to capture apneas. Eventually, a left temporal seizure was captured on video EEG characterized by apnea resulting in cyanosis, unresponsiveness, right-sided eye deviation, lip smacking, and tongue thrusting ([Fig. 1]). Magnetic resonance imaging (MRI) revealed foramen magnum stenosis consistent with stigmata of achondroplasia, frontotemporal atrophy, hippocampal inversion, and deep transverse sulcus ([Fig. 2]). The patient's seizures were treated with low-dose oxcarbazepine and apnea resolved.

Fig. 1 Electroencephalography tracings showing left temporal seizure. (A–D) Evolution of left temporal seizure that clinically resulted in right-sided eye deviation, lip smacking, tongue thrusting, cyanosis, and unresponsiveness.

Fig. 2 Magnetic resonance imaging with foramen magnum stenosis, frontotemporal atrophy, ventriculomegaly, hippocampal inversion, and deep transverse sulcus. (A) sagittal T2 short tau inversion recovery, arrow-foramen magnum stenosis with opisthion overgrowth, (B) coronal T2, solid arrow-incomplete folding with hippocampal inversion, dashed arrow-hippocampal inversion, dysgenesis (C) axial T1, arrow-deep transverse sulcus in the mesial temporal lobe.

Achondroplasia is an inherited autosomal dominant condition with incidence of 0.36 to 0.6 per 10,000 live births.[1] [2] [3] Although apnea in achondroplasia is frequently associated with OSA, craniocervical junction abnormalities, and/or brain stem compression causing central apnea,[1] [2] seizures should be considered as a possible treatable etiology for apneic events,[4] especially in the setting of abnormal neuroimaging. Temporal lobe seizures and temporal lobe abnormalities ([Table 1]) are reported in FGFR3-related disorders, including hypochondroplasia and achondroplasia.[3] [5] Therefore, this case highlights the importance of comprehensive neurological examination, testing with EEG and MRI, and multidisciplinary follow-up including neurology subspecialty services in children with achondroplasia.

Table 1 Brain imaging findings in achondroplasia

Ventriculomegaly

Megalencephaly

Atrophy

Abnormal temporal horns

Deep transverse sulcus

Sagittal cleft

Hippocampal inversion

Oversulcation

Loss of temporal gray-white matter differentiation

Publikationsverlauf

Eingereicht: 27. Oktober 2020

Angenommen: 10. Dezember 2020

Artikel online veröffentlicht:
12. Februar 2021

• References

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