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In Parkinson's disease (PD) imaging of the brain is seldom cost-effective since the chance of detecting relevant structural abnormality as a cause of the symptoms is very low. However, brain imaging can provide diagnostic clues in young patients with atypical parkinsonian features.
A Chinese man aged 28 had experienced progressive slowness of movements, limb stiffness, generalized malaise and fatigue over the past eighteen months. Activities of daily living were ever more difficult. Family members noticed that his mental responses were slowing and his handwriting was becoming smaller. In addition, his speech was diminished in volume and slurred and his balance was poor, with a tendency to fall when turning or if pushed. He did not have swallowing difficulty, urinary or bowel complaints, memory loss or visual or hearing problems. There was no history of delay in his developmental milestones and no family history of parkinsonism or other neurological illness. There was also no history of any psychiatric illness, or of exposure to heavy metals and toxins.
On examination his mentation was slow and his speech hypophonic and slurred. Extraocular movements were full. There was moderately severe rigidity and bradykinesia in all four extremities with the right more affected than the left. Rest tremor was absent. In addition, he had mild bilateral dysmetria and dysdiadochokinesia. Power was full in his limbs. All his reflexes, including the jaw jerk, were brisk. There was no demonstrable clonus and his plantar responses were flexor. He had a mild stooped posture and a slow and shuffling gait, with decreased arm swing. His postural stability was poor. Investigations on blood included blood count, blood film, urea and electrolytes, liver function tests, thyroid and parathyroid function tests, vitamin E levels, calcium, phosphate, magnesium, iron, ferritin, caeruloplasmin, heavy metals and Venereal Disease Research Laboratory test. All were normal. DNA tests for trinucleotide repeat expansions for spinocerebellar ataxia 1,2,3,6 and 7 were negative. Slit lamp examination revealed no corneal Kayser—Fleischer rings or lens opacities. Somatosensory evoked and brainstem evoked potentials were normal but visual evoked potentials showed conduction abnormalities in the anterior visual pathways bilaterally. On neuropsychological testing his general intellectual abilities were of low average range; we could not determine whether there had been recent deterioration. Memory and attention abilities seemed unimpaired. MRI of the brain revealed diffuse white matter disease with extensive paramagnetic material in the basal ganglia, cerebellum, and subcortical regions (Figure 1a and b). A CT scan confirmed the gross calcifications in the dentate nuclei, basal ganglia and subcortical regions. His response to levodopa therapy was poor, and this was subsequently stopped.
The patient had four sisters and a brother. Two of the sisters were willing to have CT scans of the head, and these were normal.
This case illustrates how brain imaging can provide diagnostic clues in a young patient with parkinsonism. The investigation is especially useful if the parkinsonian features are associated with other neurological features such as pyramidal tract signs, cerebellar dysfunction, and cognitive impairment2. MRI may demonstrate abnormal deposition of minerals such as iron, calcium, and copper or structural lesions in basal ganglia. It is a useful diagnostic tool in the differential diagnosis of parkinsonism5. MRI can also help distinguish some of the parkinson-plus syndromes, such as multiple system atrophy, from PD4. In our patient, the imaging study was warranted by the absence of limb tremor, the poor response to levodopa, the rapid progression of his symptoms and the presence of other neurological signs.
Calcifications of the brain are found in about 0.3 to 1.5% of individuals undergoing routine CT examination, most commonly in the basal ganglia and sometimes in the cerebellar dentate nucleus4,5. Neurological symptoms are usually absent. Hypoparathyroidism and pseudohypoparathyroidism are common aetiologies. Idiopathic calcification of the basal ganglia is often called Fahr's disease6 but some prefer the term bilateral striatopallidodentate calcinosis. Idiopathic calcification of the basal ganglia is usually sporadic but an autosomal dominant mode of inheritance is also seen. There is a slight preponderance in men, with presentation usually between 30 and 50 years of age. Calcifications generally precede the onset of symptoms by many years and the course is typically slow and progressive. Mental deterioration, extrapyramidal signs, and cerebellar ataxia are the three predominant manifestations, resulting in gait and speech disturbance6. Pyramidal signs, psychiatric symptoms, urinary incontinence, and epilepsy occur in some patients. To date, there is no effective therapy.