LESIONS

A Guide to Localisation in Neurology

Case 16 - Involuntary movements

Outcome

CT head showed a small hyperdense lesion in the subthalamic nucleus, consistent with acute haemorrhage.

The distribution was in keeping with small vessel disease, associated with her vascular risk factors (particularly hypertension). Blood tests showed normal coagulation parameters and platelet count and she was not on any blood-thinning medicines that could have provoked this haemorrhage.

She was treated with blood-pressure lowering therapy. She was also given risperidone to treat the hyperkinetic movements by blocking dopamine receptors (essentially switching off the two pathways to attempt to reduce motor output). This helped to reduce the movements' intensity but did not give complete resolution.

She required several days in hospital, being nursed in a bed with padded sides to protect against physical injury by hitting her limbs against the rails or a limb becoming stuck between them and dislocated. Her skin became quite red from rubbing, so care was taken to prevent skin breaks and ulceration.

After a few days in hospital with some rehabilitation she was able to resume walking and the movements had reduced to a manageable minimal level, allowing her to return home independently. At follow up in 3 months she was back to normal.

Acute basal ganglia haemorrhage affecting the subthalamic nucleus, causing contralateral hemichorea-hemiballismus - reduced with risperidone.

1. Movement disorder phenomenology is important - we can classify movements according to various characteristics, which helps us think about causes and treatments
2. The basal ganglia circuits are complex but essentially activate movements via the direct pathway and inhibit unwanted ones via the indirect pathway
3. Hemichorea-hemiballismus is disabling and is most often due to stroke or hyperglycaemia, although rarer causes exist