Редкие танцевальные движения могут быть единственным признаком инсульта, при этом первые снимки часто выглядят нормально

Sudden Dance-Like Movements Can Be the Only Sign of a Stroke and Scans Often Look Normal at First A small fraction of strokes do the opposite. The patient's arm and leg on one side begin moving on their own, in irregular, flowing, unpredictable motions that observers often describe as dance-like. The person is fully awake, fully aware, and cannot stop it. The condition is called hemichorea, and when the movements become wide and forceful, it is called hemiballismus. It occurs in fewer than 1 percent of strokes, with published estimates ranging from 0.4 to 0.54 percent. It is rare enough that it gets mistaken for intoxication, a seizure, or a psychiatric problem, and rare enough that a normal first scan can send the patient home. The Textbook Explanation Keeps Failing For decades, the teaching was clean. Hemichorea meant a lesion in the subthalamic nucleus on the opposite side of the brain, a small structure deep in the basal ganglia that helps suppress unwanted movement. Damage the brake, and movement escapes. That rule keeps breaking. A case series in the Journal of Stroke and Cerebrovascular Diseases reported four patients whose hemichorea came from acute ischemic strokes confined to the parietal and insular cortex, the outer surface of the brain, with no involvement of the deep structures at all. The authors wrote that the pathophysiology of this cortical form remains unknown and suggested dysfunction in the pathways connecting those cortical regions to the basal ganglia. Reports since have widened the map further. Published cases have traced hemichorea to the temporal, frontal, and parietal lobes, the centrum semiovale, and the lenticular nucleus. The current framing is less about a single-culprit structure and more about a loop, the cortex-basal ganglia-thalamus-cortex circuit, that can be disrupted at multiple points. Location does appear to predict recovery. A review of post-stroke movement disorders cited a study in which 85 percent of patients with cortical lesions recovered completely, compared with 54 percent of those with basal ganglia lesions, and none of those with isolated subthalamic lesions. Imaging Can Be Clean at First The diagnostic problem is compounded by scanning. Non-contrast CT, the first-line study in most emergency departments, frequently misses small or deep infarcts, and MRI is not infallible either. The pattern shows up repeatedly in the case literature. In one report of hemichorea from a middle cerebral artery dissection, emergency CT excluded hemorrhage and the initial MRI revealed nothing diagnostic. Only a repeat MRI confirmed an infarct in the globus pallidus. In a case published last year, a 31-year-old man with no medical history developed sudden left-sided hemichorea alongside a visual field cut. MRI showed an acute infarct in the right lentiform nucleus. He improved markedly within 24 hours of starting antiplatelet therapy, and further workup found a patent foramen ovale, a hole between the upper chambers of the heart, as the likely source. That last case makes a point that gets lost in the neuroanatomy. The movements are the presenting sign, but the underlying event is a stroke whose cause needs to be found. The Look-Alike That Is Not a Stroke The condition most often confused with stroke-related chorea is metabolic rather than vascular. Non-ketotic hyperglycemia can produce hemichorea in people with poorly controlled diabetes, typically at markedly elevated blood glucose levels. On MRI, it produces characteristic changes in the basal ganglia. Both the movements and the imaging findings are usually reversible with treatment of the hyperglycemia. This matters because the treatments diverge completely. One patient needs antiplatelet therapy and a stroke workup. The other needs glucose control. Case reports have described patients in whom both problems had to be considered at once, which is why blood sugar is checked alongside imaging. Symptomatic treatment of the movements themselves, when they are disabling, generally involves drugs that block or deplete dopamine, such as haloperidol or tetrabenazine. These are prescribed by specialists and are not a substitute for treating the stroke. Why This Belongs in the Public Conversation The current AHA and ASA guideline on acute ischemic stroke, issued this year to replace the 2018 guideline and its 2019 update, is built around speed because reperfusion treatments work within narrow time windows. A presentation that does not look like a stroke costs time nobody has. Emergency physicians writing up these cases keep landing on the same conclusion. One report from a Singapore emergency department put it directly: recognizing stroke presenting as a movement disorder in the emergency department can help prevent delays in diagnosis and treatment. For the public, the useful version is not the neuroanatomy. It is that stroke does not always subtract. New, sudden, uncontrollable movements on one side of the body, arriving over minutes rather than days, are a reason to call emergency services rather than wait and see, particularly in someone with high blood pressure, diabetes, atrial fibrillation, or a prior stroke. The evidence here comes from case reports and small series, which describe what happened to individual patients and cannot establish frequency or best treatment. Anyone with concerns about their own risk should raise them with a clinician. Related MedicalDaily Coverage A Seizure at 16 Left Her Brain Flipping Words Backward, and It Never Switched Back A Flicker in Your Pupil Marks the Instant Your Brain Deletes an Outdated Assumption Key Questions Answered What is hemichorea? Irregular, flowing, involuntary movements affecting one side of the body, often described as dance-like. Hemiballismus is the version with wider, more forceful flinging motions. How often does stroke present this way? Rarely. Published estimates put hemichorea-hemiballismus at roughly 0.4 to 0.54 percent of strokes, and it is the most common hyperkinetic movement disorder after stroke. Why is it easy to misdiagnose? It produces additional movement rather than loss of function, so it does not fit the familiar stroke pattern, and non-contrast CT often fails to show the underlying infarct. Does it always come from deep brain structures? No. A case series documented four patients whose hemichorea came from strokes limited to the parietal and insular cortex, and other reports have implicated temporal and frontal regions. What else causes sudden one-sided chorea? Non-ketotic hyperglycemia in poorly controlled diabetes, which is usually reversible with glucose control and requires different treatment than a stroke. Do the movements go away? Often, though it depends on location. In one study 85 percent of patients with cortical lesions recovered completely, compared with 54 percent with basal ganglia lesions. Published by Medicaldaily.com