Presentation
A married professional woman with new visual hallucinations and declining occupational function was referred to a community mental health service. When initial investigations were reported as normal, a provisional diagnosis of schizophrenia was made and low dose risperidone was commenced. 18 months later she was referred for sub-specialist review with further occupational decline, impoverished speech and marked parkinsonism.
Patient Data
Not available
No large territory established infarction.
No loss of grey / white matter differentiation.
No hydrocephalus.
No acute intracranial hemorrhage demonstrated.
No surface collection, mass lesion or midline shift.
Unremarkable bones.
COMMENTS:
No acute intracranial abnormality demonstrated.
No large territory established infarction.
Admission investigations
Bloods: FBE, UEC, LFT, TFT and serology unremarkable
LP: MCS, glucose and protein unremarkable
Examination Findings
Stood at bedside throughout assessment. Mild utilization behaviors.
Bland and apathetic affect, except when occasionally fatuous.
Impoverished and non-spontaneous speech with considerable latency but without agrammatism or anomia.
No disorganization of thought. No hallucinations. Encapsulated beliefs about a ghost living in her home.
Marked paucity of speech and movement associated with bilateral rest tremor, cog-wheel rigidity, normal brisk reflexes and normal power.
Normal range of eye movements on smooth pursuit but delayed saccades with hypometria and gaze perseveration.
Bilateral palmo-mental reflexes. No grasp or glabellar tap. Downing plantars.
Alert and well-oriented without anosognosia.
Neuropsychological profile
Severe impairment of verbal fluency and executive function
Relatively well-preserved naming, grammar, memory, and praxis
MRI on admission +18 months
There is probable mild bilateral frontal selective cortical volume loss (atrophy) with slight prominence of the bilateral frontal sulci. No significant volume loss of the hippocampi or the temporal lobes.
No significant signal changes in the brain parenchyma. No intracranial mass lesion or collection. There is developmental venous anomaly in the right parietal lobe medially. No hydrocephalus. No acute ischemic lesion. There is no evidence of prior intracranial hemorrhage.
Impression:
There is probable mild bilateral frontal cortical volume loss (atrophy) which raises the possibility of frontotemporal dementia. Correlation with PET imaging would be helpful.
Cardiac 123I-MIBG SPECT
Normal cardiac sympathetic innervation is maintained which makes a diagnosis of a Lewy body cluster disorder (such as idiopathic Parkinson’s disease or diffuse Lewy body disease) highly unlikely.
Case Discussion
This patient's presentation was atypical for schizophrenia, and her hallucinations and neuroleptic sensitivity raise early differential diagnoses of dementia with Lewy Bodies (DLB) and idiopathic Parkinson disease (IPD).
Her course was subsequently marked by a progressive impairment in communication that was by far her most prominent and disabling clinical feature,.
Structural neuroimaging gave the impression of fronto-temporal lobar degeneration, while cardiac MIBG suggested that synucleinopathy (DLB or IPD) was unlikely; in addition, the clinical parkinsonism resolved with the withdrawal of neuroleptic medication. The visual hallucinations, which were undistressing and only occurred in the patient's home, were eventually attributed to a firmly held but encapsulated belief in ghosts associated with misperception.
Neuropsychology assessment strongly favored a diagnosis of logopaenic aphasia, with severe impairment of verbal fluency and executive function but relatively well-preserved naming, grammar, memory, and praxis.
While the clinical presentation and neuroimaging findings in logopaenic aphasia supports its categorization as a language variant of front-temporal lobar degeneration (FTLD), the underlying pathology is characterized by the amyloid plaques and neurofibrillary tangles typical of Alzheimer disease. A careful neuro-cognitive assessment is required to differentiate the language variants of FTLD clinically.