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Frontotemporal Dementia Initially Misdiagnosed As Psychotic Disorder: A Case Report

Resident in Psychiatry, Carilion Clinic Virginia Tech, Carilion School of Medicine Psychiatry Residency Program, Roanoke, Va

Reena Thomas, MD

Resident in Psychiatry, Carilion Clinic Virginia Tech, Carilion School of Medicine Psychiatry Residency Program, Roanoke, Va

First published in Psychiatry Weekly, Volume 7, Issue 2, January 23, 2012

Introduction

Frontotemporal dementia (FTD) is an early-onset, rapidly progressive neurodegenerative disorder that affects the frontal lobe of the brain, or the anterior temporal lobes, or both. It is the second most common early-onset dementia after Alzheimer’s disease.¹ Behavioral and personality changes are early features of FTD, which is more common in middle-aged patient populations. Diagnosis of FTD can become particularly complicated when psychotic symptoms are present.¹ We describe an elderly patient with possible FTD, who presented with psychotic symptoms, hallucinations, personality changes, and nonfluent aphasia.

Case Report

A 74-year-old man was found wandering on the hospital campus and was brought to the emergency department by a visitor. He was initially evaluated for delirium workup, which was negative, and was admitted to the acute psychiatry inpatient unit with provisional diagnosis of psychotic disorder not otherwise specified and questionable elements of cognitive impairment.

Mental status examination upon admission showed an alert gentleman who was oriented to self with evidence of moderate psychomotor agitation. He was anxious, and at times engaged in rapid, uninterrupted speech with no provocation. He described his mood as “unhappy,” but could not elaborate further. His speech was interspersed with the stock phrase, “I am not mental.” There was some paranoid ideation about treatment team, previous doctors, mental health, and family members, but no delusions were reported. Mini-Mental State Examination (MMSE) on admission was scored as 20/30. The patient had a family history of paranoid schizophrenia, but no family history of neurologic illness, and no history of drug and alcohol use. His blood work, including electrolytes, liver/renal function tests, thyroid-stimulating hormone, rapid plasma reagin, B12, folic acid, and blood counts were noncontributory. His head CT, done as part of a first-episode psychosis and delirium workup, showed no acute intracranial pathology.

If psychotic features dominate the presenting picture, FTD is likely to be misdiagnosed as psychotic disorder NOS or schizophrenia-like psychosis in the early years of its presentation.

The patient had been hospitalized for similar complaints around a year prior and was then treated as psychotic disorder not otherwise specified. During that acute inpatient psychiatric hospitalization, he continued to show symptoms of paranoia with poverty of thoughts. He was easily irritable, reclusive, felt conspired against, and claimed his mother was speaking to him from heaven.

During that same hospitalization, neuropsychology evaluation diagnosed the patient with cognitive disorder not otherwise specified with possible dementia of mixed type. His abnormal behavior was treated with divalproex sodium extended release 2,000 mg at bedtime, with donepezil 5 mg at bedtime for cognitive impairment due to possible mixed dementia. After being transferred to the long-term psychiatric care unit, the patient had an episode of questionable transient ischemic attack due to dizziness. Neurology ruled out the possibility of a transient ischemic attack or stroke.

Follow-Up Presentation

Six months after the patient’s initial emergency room visit, where our account begins, his MMSE score was 6/30—much lower than his admission MMSE of 20/30. A speech pathology consultation suggested non-fluent aphasia. Differential diagnosis at this point included amyotropic lateral sclerosis and FTD. The patient did not have tongue fasciculations or muscle atrophy, which clinically rules out amyotrophic lateral sclerosis. Neurology recommended EEG to rule out amyotropic lateral sclerosis, but the patient was not cooperative; MRI was not performed because he had pacemaker.

The patient was evaluated with PEG-FDG scan, revealing markedly reduced metabolic activity and perfusion in the left temporoparietal cortex and left frontal lobe with mild reduced metabolism in the right temporoparietal cortex, which was consistent with his memory impairment, non-fluent aphasia, and psychotic symptoms. Based on the typical clinical presentation meeting the consensus criteria for FTD and the neuroimaging and cognitive findings, he was diagnosed with FTD and treated with divalproex sodium extended release 1,500 mg at night (valproate level 46 mg/liter), reduced from the initial earlier dose of 2,000 mg at bedtime. His earlier dose of donepezil 5 mg at bedtime was continued. His psychotic symptoms remitted completely on this combination, but he continued to display the intermittent agitation, nonfluent aphasia, indifference, and lack of insight.

Discussion

Some of the qualifers of FTD—insidious onset and gradual progression, early decline in social interpersonal conduct, early impairment in regulation of personal conduct, early emotional blunting, and early loss of insight—also apply to schizophrenia. If psychotic features with negative symptoms dominate the presenting picture, FTD is likely to be misdiagnosed as psychotic disorder not otherwise specified, schizophrenia, or schizophrenia-like psychosis in the early years of its presentation.² In many cases, FTD is diagnosed several years after an initial diagnosis of a psychotic disorder. The social disinhibition and facile euphoria of FTD can also be misconstrued as bipolar disorder with psychotic features.² Hallucinations are considered rare in patients with FTD and are not included in its diagnostic criteria,^3,4 but they were evident in our patient.

The language subtypes of frontotemporal lobar degeneration (semantic dementia and progressive nonfluent aphasia) can be regionally dissociated by imaging approaches in vivo.⁵ Consensus criteria for FTD and neuropsychological measures lacked sensitivity for FTD.⁶ However, neuroimaging, especially functional neuroimaging such as PET-FDG in our case, increases the sensitivity of diagnosing FTD, but this may not be available everywhere. There is therefore an emerging need to develop more neurocognitive tools that can help distinguish this diagnosis at an early stage.

Disclosure: Dr. Sharma and Dr. Thomas report no affiliations with, or financial interests in, any organization that may pose a conflict of interest.

References:

1. Haberland C. Frontotemporal dementia or frontotemporal lobar degeneration--overview of a group of proteinopathies. Ideggyogy Sz. 63(3-4):87-93.

2. Waddington JL, Youssef HA, Farrell MA, Toland J. Initial ‘schizophrenia-like’ psychosis in Pick’s disease: case study with neuroimaging and neuropathology, and implications for frontotemporal dysfunction in schizophrenia. Schizophr Res. 1995;18:79-82.

3. Lopez OL, Gonzalez MP, Becker JT, et al. Symptoms of depression and psychosis in Alzheimer’s disease and frontotemporal dementia. Neuropsychiatry Neuropsychol Behav Neurol. 1996;9:154-161.

4. Brun A, Englund B, Gustafson L, et al. Clinical and neuropathological criteria for frontotemporal dementia. The Lund and Manchester Groups. J Neurol Neurosurg Psychiatry. 1994;57:416-418.

5. Schroeter ML, Raczka KK, Neumann J, von Cramon DY. Neural networks in frontotemporal dementia--a meta-analysis. Neurobiol Aging. 29:418-426.

6. Mendez MF, Shapira JS, McMurtray A, Licht E, Miller BL. Accuracy of the clinical evaluation for frontotemporal dementia. Arch Neurol. 2007;64:830-835.

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