Contralateral ictal ptosis

PRACTICAL IMPLICATIONS

Unilateral ptosis may be seen in focal seizures and should be actively sought for during video-EEG (scalp and intracranial) evaluations. Further studies are needed to confirm its lateralizing value, but it was contralateral to seizure onset in this case.

We report a rare finding of transient unilateral ptosis occurring during a seizure and discuss its potential lateralizing value. The patient is a 17-month-old girl with epilepsy, onset at 3 months, who was diagnosed with 2q31.2-q32.3 deletion that includes SCN1A and SCN2A genes. She had focal seizures with behavioral arrest and myoclonic seizures. One of the focal seizures originating from right temporal region is shown in video 1. Clinically, the patient was seen to arouse from sleep and stare, had oral automatisms, did not react to stimulation, and with ongoing seizure developed left ptosis; toward the end of the seizure there was oxygen desaturation to below 80% (video 1, figure, B and D). On EEG, sharply contoured 6 Hz rhythmic theta was seen maximally over the right temporal but also right frontal region (F8/T8/Fp2>F4). This evolved in morphology and frequency to 1–1.5 Hz spike and wave discharges. Diffuse slowing was seen postictally. Heart rate increased from 120 to 150 seconds during the seizure (figure, A and C).

Figure. Seizure evolution.

(A) EEG in bipolar montage showing seizure onset in right temporal region. (B) Clip of patient video a few seconds into seizure onset showing staring with both eyes wide open (no ptosis). (C) EEG in bipolar montage showing seizure evolution in right temporal and frontal regions. (D) Clip of patient video showing left eye ptosis with seizure evolution. EEG shown at: LFF 1 Hz, HFF 70 Hz, Notch off, sensitivity: 7 uV, Timebase: 15 seconds.

Video 1

Video showing arousal, behavioral arrest, staring (no ptosis) with seizure onset, and development of left eye ptosis with seizure evolution. EEG in bipolar montage showing right temporal seizure as described.Download Supplementary Video 1 ^{(15.2MB, mp4)} via http://dx.doi.org/10.1212/000690_Video_1

Discussion

Ptosis is a common neurologic sign, most commonly resulting from weakness of levator palpebrae superioris. Lesions of the third cranial nerve often result in complete ptosis, whereas a lesion within the sympathetic component of the nerve (innervating Müller muscle) or central sympathetic pathways typically results in a mild, partial ptosis affecting the upper and lower lids. Partial ptosis can occur in isolation but is more commonly a component of Horner syndrome, which may result from a central or a peripheral pathology. The central pathway includes cerebral cortex¹ (especially the insula), amygdala, hypothalamus, parabrachial nucleus, nucleus of tractus solitarius (because of reciprocal connections with hypothalamic nuclei involved in sympathetic pathways), and ventrolateral medulla. From here, the signals relay in the intermediolateral horn of the eighth cervical and upper 2 to 3 thoracic segments of the spinal gray matter and terminate in the superior cervical ganglion. Postganglionic neurons from the superior cervical ganglion terminate in the orbit and the skin of the face, head, and neck. This pathway was classically described as being ipsilateral¹; however, a study of 15 patients with cerebral lesions and ptosis (“cerebral ptosis”) reported contralateral ptosis in 6, bilateral but more prominent contralaterally in 3, bilateral but more prominent ipsilaterally in 2, ipsilateral in 2, and ipsilateral as part of Horner syndrome with carotid occlusion in 2. Thus, contralateral ptosis was more common than ipsilateral with a cortical lesion. In the contralateral cases, the infarcts were in variable vascular territories.²

Ptosis as a result of seizures is rare. However, it may be missed because it is not readily observed on video 1. There has been 1 previous report of ictal ptosis in a 14-year-old child with right temporal lobe epilepsy,³ observed in the left eye during a clinical focal seizure with impaired awareness, similar to our case. The second patient described in that report had ptosis in the setting of febrile illness and new-onset seizures and was ipsilateral to a smaller left temporal lobe. This was, however, not described as an ictal phenomenon and could have been an encephalitic illness with other mechanisms for the abnormalities on neurologic examination.

The mechanism of ictal ptosis with temporal lobe seizures is likely activation of the central autonomic network in the amygdala or via spread to the hypothalamus. The medial temporal lobe and hypothalamus are well connected via the fornix, the stria terminalis, the medial forebrain bundle, and the ventral amygdalofugal tract.⁴ Autonomic symptoms are commonly seen in association with temporal lobe seizures, attributed to activation of central autonomic network. These have been observed to occur more commonly with nondominant temporal lobe seizures due to asymmetric representation of the central autonomic network.^5–7 Some examples are peri-ictal water drinking, coughing, spitting, vomiting, and urinary urgency. Other ocular manifestations due to autonomic activation such as unilateral mydriasis have been reported. Mydriasis has been reported as an ipsilateral and a contralateral finding.⁸ Contralateral mydriasis was seen with frontal lobe stimulation and ipsilateral mydriasis was seen with occipital lobe stimulation in animals and humans.^9,10

We suspect that the presence of unilateral ictal ptosis may suggest seizure activity affecting the nondominant temporal lobe because our patient (similar to the prior report³) had a right temporal seizure, and nondominant temporal seizures are more likely to cause activation of the central autonomic network as discussed above. In addition, it is possible, and perhaps even likely, that this occurs contralateral to the hemisphere of seizure onset. Most descriptions of the sympathetic pathways describe ipsilateral representation without crossing, starting in the hypothalamus. However, as mentioned above, cortical dysfunction can cause strictly contralateral or asymmetric bilateral ptosis.^2,3 The mechanisms and pathways of this are not well understood. Further reports, preferably with intracranial studies, are needed for better evaluation of lateralizing and localizing significance of this finding.

Appendix. Authors

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