Cerebrovascular diseases are considered among possible causes of acute/subacute parkinsonism, representing up to 22% of secondary movement disorders. In cases of suspected vascular parkinsonism (VP), dopamine transporter SPECT has been highly recommended to exclude nigrostriatal dopaminergic degeneration. We report the case of a hemiparkinsonism related to a left midbrain infarct with focal lateralized putaminal abnormalities at 123I-FP-CIT SPECT imaging. The asymmetric uptake at dopamine transporter SPECT was different to findings commonly observed in typical PD pattern, because the ipsilateral striatum, in opposite to idiopathic PD, showed normal tracer binding. However, this selective parkinsonism after infarction of the midbrain was responsive to levodopa. In conclusion, we retain that there is a need of more functional imaging studies in VP addressed to a more consistent classification of its different clinical forms and to a better understanding of the adequate pharmacological management.
Parkinsonism with acute/subacute onset is uncommon and other conditions, different from a neurodegenerative process, should be considered in differential diagnosis. In this context, cerebrovascular diseases are considered among these possible causes of parkinsonism, representing up to 22% of secondary movement disorders [
We report the case of a hemiparkinsonism related to a left midbrain infarct with peculiar asymmetrical putaminal abnormalities at 123I-FP-CIT SPECT imaging.
A 69-year-old male patient come to our observation suffering from motor slowness and rigidity at right limbs which showed an acute onset. His medical history revealed diabetes and a previous psychiatric history of depression. Neurological examination showed severe bradykinesia and rigidity in his right hemibody, with inconstant mild rest tremor. The patient was mildly depressed, without significant cognitive impairment or other important nonmotor features. A brain MRI was performed two months before and revealed a lacunar infarct in the substantia nigra (Figure
Cranial MRI revealed a lacunar infarction localized in the left midbrain (arrow) appearing hyperintense in T2 sections.
123I-FP-CIT SPECT showed an absent ligand binding in the left putamen and a less marked reduction in the homolateral caudate (Figure
123I-FP SPECT showing a reduced tracer binding in the left striatum, with a more marked reduction in the putamen.
The term vascular parkinsonism (VP), firstly described by Critchley in 1929 [
Previous observations have described the occurrence of hemiparkinsonism following strategic infarcts affecting the basal ganglia, following contralateral lenticular [
Interestingly, a previous case with an isolated ischemic focal lesion located in the left cerebral peduncle and a homolateral SPECT abnormality has been described, although, different to our patient, dopaminergic treatment did not exert a definite positive response [
In our patient, the asymmetric uptake at dopamine transporter SPECT was different to findings commonly observed in typical PD pattern, because the ipsilateral striatum, in opposite to idiopathic PD, showed normal tracer binding. Moreover, the contralateral reduction in dopamine transporter uptake in the striatum at SPECT imaging was ipsilateral to this midbrain ischemic lesion, suggesting a probable involvement of the substantia nigra pars compacta.
In this regard, the selective vascular damage in the midbrain might have played a similar action observed in neurolesional animal models used in experimental settings.
This selective VP due to a midbrain lesion secondary was responsive to levodopa. This consideration is further supported by the evidence that also other conditions such as perivascular spaces in the midbrain can cause hemiparkinsonism and dopamine transporter SPECT abnormalities with documented dopamine response [
Correlation between VP and CIT SPECT is not a resolved issue. According to other previous study [
The authors declare that they have no conflict of interests.
Dr. Paolo Solla gratefully acknowledges Sardinia Regional Government for the financial support (P.O.R. Sardegna F.S.E. Operational Programme of the Autonomous Region of Sardinia, European Social Fund 2007–2013, Axis IV Human Resources, Objective l.3, Line of Activity l.3.1 “Avviso di chiamata per il finanziamento di Assegni di Ricerca”).