Considering this neurological finding, a comprehensive neurological consultation was promptly requested to further assess the patient’s condition.
As part of the neurological evaluation, a non-contrast computed tomography (CT) scan of the brain was ordered to rule out any intracranial pathology that could potentially be contributing to the patient’s strabismus. The CT scan would provide valuable information regarding the structural integrity of the brain, including any evidence of methadone-induced neurotoxicity, cerebral edema, or other abnormalities that may have developed secondary to the methadone overdose.
Upon further evaluation of the patient’s neurological status, a comprehensive eye examination was performed to assess the extent and nature of the strabismus and to rule out any other ocular abnormalities related to the methadone poisoning. The patient’s visual acuity was measured at 20/25 in the right eye (OD) and 20/30 in the left eye (OS). The pupillary examination revealed pupils that were equal in size and reactive to light bilaterally, with no evidence of a relative afferent pupillary defect (RAPD).
Extraocular motility testing demonstrated a full range of motion in all directions of gaze in the left eye. However, the right eye exhibited a restricted adduction, with a full range of motion in all other directions. A 30-prism diopter right exotropia was noted in primary gaze, consistent with the patient’s reported symptom of diplopia. Confrontation visual fields were full to finger counting in all quadrants bilaterally.
Slit-lamp examination of the anterior segment was unremarkable, with normal lids, lashes, conjunctiva, sclera, cornea, anterior chamber, iris, and lens in both eyes. Intraocular pressure was measured at 14 mmHg in the right eye and 15 mmHg in the left eye, both within normal limits.
A dilated fundus examination was performed to assess the posterior segment of the eye. The vitreous was clear bilaterally, and the optic nerves appeared normal with sharp margins and no signs of edema. The cup-to-disc ratio was 0.3 in both eyes. The macula exhibited a normal foveal reflex without any signs of edema, and the vasculature was of normal caliber with no evidence of occlusion or hemorrhage. The peripheral retina was flat and intact in both eyes.
The comprehensive eye examination confirmed the presence of a significant left exotropia, measuring 30 prism diopters, which was consistent with the patient’s reported diplopia. The restricted adduction in the left eye further supported the diagnosis of lateral strabismus.
The emergence of strabismus in the context of methadone poisoning is a relatively uncommon neurological manifestation. However, it is crucial to thoroughly investigate any neurological signs or symptoms in patients presenting with opioid toxicity, as they may be indicative of more severe central nervous system dysfunction. By promptly recognizing and evaluating the patient’s strabismus, the medical team aimed to identify any underlying neurological complications and provide appropriate management to prevent further deterioration and ensure the best possible outcome for the patient.
The patient’s methadone toxicity was managed with intravenous naloxone and supportive care, including mechanical ventilation. The patient’s altered mental status and respiratory depression resolved with treatment on hospital day 3.
The patient’s strabismus was managed conservatively with observation and serial ophthalmological examinations. Over the course of her hospital stay, the right exotropia gradually improved, with a residual deviation of 10 prism diopters at the time of discharge on hospital day 7. The patient was advised to follow up with ophthalmology as an outpatient for further monitoring and management of her residual strabismus.