LESIONS

A Guide to Localisation in Neurology

Case 9. Weakness and tingling

Outcome

The patient was admitted. A CT head showed advanced small vessel disease relative to the patient's age (51), though no acute lesions were evident.

An MRI was then performed. This revealed an acute diffusion-restricting lesion in the posterior limb of the internal capsule - consistent with a lacunar stroke in the territory perfused by the small perforating arteries.

There was also evidence of severe small vessel disease changes and chronic clinically-silent lacunar infarcts, seen on the sagittal FLAIR sequence below.

She was given a combination of medications - an antiplatelet, a statin, and blood-pressure reducing agents - as well as having a short period of inpatient rehabilitation.

No other causes were identified to cause stroke - such as carotid artery disease or arrhythmia - and the lesion was attributed to cerebral small vessel disease.

The patient was discharged after a short admission and made a good recovery, though several weeks later still experienced ongoing partial sensory disturbance in the right arm and leg.

Acute hemibody sensorimotor disturbance due to lacunar infarction in the posterior limb of the internal capsule - sparing the corticobulbar fibres at the genu - in the context of severe, treatment-refractory hypertension and accelerated small vessel disease.

1. Knowledge of the motor and sensory fibres enables accurate localisation - in this case to the internal capsule. Facial weakness and sensory disturbance are not always present even in capsular lesions - they are further forward at the genu
2. Strokes tend to cause purely negative symptoms - the exception is tingling, which is relatively common in lacunar infarctions
3. When patients wake up with symptoms it is difficult to know the onset. what happens in the following period is also informative regarding the lesion type