Hemichorea associated with gabapentin therapy with hypoperfusion in contralateral basal ganglion - a case of a paraplegic patient with neuropathic pain

Gabapentin-Associated Movement Disorders: A Literature Review

BACKGROUND

Gabapentin (GBP)-induced movement disorders (MDs) are under-recognized adverse drug reactions. They are commonly not discussed with patients, and their sudden occurrence can lead to misdiagnosis. This literature review aims to evaluate the clinical-epidemiological profile, pathological mechanisms, and management of GBP-associated MD.

METHODS

Two reviewers identified and assessed relevant reports in six databases without language restriction between 1990 and 2023.

RESULTS

A total of 99 reports of 204 individuals who developed a MD associated with GBP were identified. The MDs encountered were 135 myoclonus, 22 dyskinesias, 7 dystonia, 3 akathisia, 3 stutterings, 1 myokymia, and 1 parkinsonism. The mean and median ages were 54.54 (SD: 17.79) and 57 years (age range: 10-89), respectively. Subjects were predominantly male (53.57%). The mean and median doses of GBP when the MD occurred were 1324.66 (SD: 1117.66) and 1033 mg/daily (GBP dose range: 100-9600), respectively. The mean time from GBP-onset to GBP-associated MD was 4.58 weeks (SD: 8.08). The mean recovery time after MD treatment was 4.17 days (SD: 4.87). The MD management involved GBP discontinuation. A total of 82.5% of the individuals had a full recovery in the follow-up period.

CONCLUSIONS

Myoclonus (GRADE A) and dyskinesia (GRADE C) were the most common movement disorders associated with GBP.

Diagnostic Uncertainties: Chorea

Chorea is a hyperkinetic movement disorder with a multitude of potential etiologies, both acquired and inherited. Although the differential diagnosis for new-onset chorea is extensive, there are often clues in the history, exam, and basic testing that can help to narrow the options. Evaluation for treatable or reversible causes should take priority, as rapid diagnosis can lead to more favorable outcomes. While Huntington's disease is most common genetic cause of chorea, multiple phenocopies also exist and should be considered if Huntington gene testing is negative. The decision of what additional genetic testing to pursue should be based on both clinical and epidemiological factors. The following review provides an overview of the many possible etiologies as well as a practical approach for a patient presenting with new-onset chorea.

Deep brain stimulation in critical care conditions

Some neurological conditions require admission to an intensive care unit (ICU) where deep sedation and mechanical ventilation are administered to improve the patient's condition. Nevertheless, these treatments are not always helpful in disease control. At this stage, deep brain stimulation (DBS) could become a viable alternative in the treatment of critical neurological conditions with long-lasting clinical benefit. The value of deep brain stimulation has been investigated in the treatment of patients who had undergone surgical electrode implants as an emergency procedure to treat acute life-threatening conditions requiring admission to neurological ICU (NICU). A before-and-after perspective study was examined of seven patients who were treated with DBS for status dystonicus (SD) and post-stroke severe hemiballismus. Bilateral globus pallidus internus (GPi) DBS was performed in five SD patients and unilateral ventralis oralis anterior and posterior (Voa/Vop) nucleus of the thalamus DBS in two post-stroke hemiballismus patients. Bilateral GPi-DBS allowed SD resolution in a time lapse varying from 1 week to 3 months. No clear improvements compared to the baseline clinical condition were observed. Unilateral Voa/Vop-DBS intervention controlled hemiballismus after 10 h, and the patient was discharged in 2 days. The other patient was transferred from the NICU to the neurosurgery ward after 13 days. No surgical complications were observed in any of the above procedures. Neurostimulation procedures could represent a valuable choice in critical care conditions, when involuntary movements are continuous, life-threatening and refractory to intensive care procedures. DBS is feasible, safe and effective in selected cases.

Hemiballismus

Hemiballism is a relatively rare hyperkinetic movement disorder characterized by involuntary, violent, coarse and wide-amplitude movements involving ipsilateral arm and leg. Although classically related to lesions in the subthalamic nucleus, in clinical-radiological series of hemiballism most patients had lesions outside this nucleus, involving mainly other basal ganglia structures. It has been suggested that abnormal neuronal firing patterns in the internal segment of the globus pallidus may be related to the pathogenesis of hemiballism. Stroke is the most common cause, but in recent years an increasing number of patients with hemiballism associated with nonketotic hyperglycemia or with complications of human immunodeficiency virus (HIV) infection have been reported. Contrarily to what was stated in older literature, hemiballism has, in general, a relatively good prognosis. Depending on the underlying causes, many patients may experience spontaneous improvements or remissions. Treatment should be directed to the cause of hemiballism. Symptomatic treatment includes the use of drugs, particularly blockers of striatal D2 dopamine receptors and tetrabenazine. Surgical treatment, especially pallidotomy, is a therapeutic option for the minority of patients with severe persistent disabling hemiballism.

Methylprednisolone worsening neuropathic pain in non-traumatic thoracic myelopathy

Methylprednisolone (MP) is the only neuroprotective medication currently in widespread use for the treatment of spinal cord injury. Increasingly, published studies challenge its clinical effects in view of its serious side-effects including wound infection, pneumonia, sepsis and steroid myopathy. Most cases with spontaneous spinal epidural haematoma (SSEH) need emergency evacuation, and typically show good neurologic recovery. Some patients with SSEH given preoperative or postoperative MP within hours of the onset of symptoms, and have had good motor recovery, although no mention was made of sensory function. Severe, intractable neuropathic pain has not been reported in patients with SSEH. We present a case of SSEH treated with a high-dose MP 16 h after onset of symptoms. Surgical decompression was performed 1 h after MP treatment. Motor recovery was good; however, intractable neuropathic pain developed 5 weeks postoperatively. We discuss the factors contributing to intractable pain. We speculate that the severe, intractable pain might be due to misuse of large-dose steroids in this case of non-traumatic spinal myelopathy, and not because of the injury per se.