Introduction :
Chronic post-hypoxic myoclonus is a rare complication that occurs in chronic phase after successful cardiopulmonary resuscitation. Symptom of the post-hypoxic myoclonus is characterized by the action myoclonus. In our previous case report, we explored the neural network known to be related with myoclonus using diffusion tensor imaging (DTI) in order to understand its underlying pathophysiological mechanism. In this case report, we aimed to find out the neural correlates that induced the long-term changes in functional outcome by 3 years of follow-up using DTI.
Case report :
A sixty-nine years old male patient was transferred to a university hospital after he found on the street in cardiac arrested status on December 2016. After 9 minute of CPR, his sinus rhythm returned. Since the ICU admission period, intermittent myoclonic jerky movements were observed and continued. On first admission in our hospital on June 12, 2017, although his muscle power was good grade on manual muscle test, he was unable maintain his sitting posture as well as unable to walk due to jerky movement and balance problem. After discharge in our hospital, he continued rehabilitation treatment and pharmacological management for 3 years in different rehabilitation center. He was readmitted to our hospital on May 19, 2020. His myoclonic movements were significantly decreased and his balance control, gait function and cognitive function were also improved. The Berg balance test score, which was 9 points at the first visit, improved to 35 points. And the time to walk 10-meters has been improved from minimal assist gait with 81 seconds duration to 30 seconds of independent walking. The Korean Mini-Mental Status Examination score has been improved from 22 to 27, especially in memory domain. The dose of drugs related to myoclonus control were reduced. The diffusion metrics on the region-of-interests (ROIs), such as red nucleus, thalamus and subthalamic nucleus, frontal wither matter, internal capsule, cerebellum and peduculopontine nucleus, the fractional anisotropy (FA) value was significantly lower than healthy controls of the same age (4 controls, average age: 69.5 ± 3.3, M:F=2:2) (uncorrected p < 0.001) in bilateral pedunculopontine nucleus, which was normalized on the follow up. The mean diffusivity (MD) values showed significantly higher initially in right red nucleus, left pedunculopontine nucleus, left subthalamic nucleus and right thalamus than control group, which was normalized in the red nucleus on the follow up.
Conclusion :
Comprehensive rehabilitation including gait and cognitive training improved gait and cognitive function in this case. The DTI metrics change might indicate some improvement in the integrity of the mesencephalic locomotor center (pedunculopontine nucleus) and red nucleus. This would be the first study showing the changes in neural network integrity as improvement of functional outcome of patient with chronic post-hypoxic myoclonus. |
