Posterior cortical atrophy (PCA) is a neurodegenerative disorder affecting the posterior cortical regions, manifesting as early visual dysfunction. This is a rare variant of Early Onset Alzheimer’s Disease, with only limited literature published
This is a case of a 54-year-old female, who presented with a 4-year progressive history of forgetfulness, visual changes, and eventually disruptions in her activities of daily living. Cranial MRI done showed prominent atrophy in the bilateral parieto-occipital areas.
PCA is often diagnosed late due to under recognition and there is a lack of existing and updated literature. A better understanding and awareness of this variant is important to improve early detection, diagnosis, and treatment.
INTRODUCTION
Posterior Cortical Atrophy (PCA) is a neurodegenerative disorder affecting the posterior cortical regions, manifesting as early visual dysfunction. The age of onset of PCA is usually between 50-65 years old, with undocumented prevalence due to its poor recognition.1
Posterior Cortical Atrophy (PCA) is a neurodegenerative disorder affecting the posterior cortical regions, manifesting as early visual dysfunction. The age of onset of PCA is usually between 50-65 years old, with undocumented prevalence due to its poor recognition.1
As defined in the Consensus Classification of Posterior Cortical Atrophy, “PCA is a clinico-radiological syndrome characterized by progressive decline in visual processing and other posterior cognitive functions, relatively intact memory and language in the early stages, and atrophy of posterior brain regions.”2 Its clinical symptoms mostly involve visual, visuospatial, literacy, praxic, and higher sensory functions; most of which have a great impact on their activities of daily living. Radiologically, noted abnormalities in the occipital, parietal, and/or occipito-temporo-parietal cortices are involved in PCA.
In this case report, we are presented with a case of a 55-year-old female, who presented with a 4-year history of forgetfulness, visual changes, with disruption in her activities of daily living.
CASE
Patient is a 55-year-old female, right-handed, with 9 years of education, sought consult due to forgetfulness since 2014. History started 2014, when husband noted memory lapses presenting as misplacing items and disorientation to date. No consult or any other interventions were done at this time. Around 2015, patient had difficulty managing her finances. Later that year, she already needed assistance on activities of daily living particularly on wearing her clothes. She also developed prosopagnosia. Due to persistence of above signs and symptoms, they eventually sought consult at the Neurology Outpatient Department. There was no history of head trauma, loss of consciousness, nausea, vomiting, previous infection. There were no family members who have had similar symptoms. She was a nonsmoker, nonalcoholic beverage drinker, without history of illicit drug use. On consult, vital signs were as follows: blood pressure was 100/60mmHg, heart rate of 82 beats per minute, respiratory rate of 19 cycles per minute, and was afebrile. Patient was ambulatory, with a disheveled appearance, and seemed anxious. She was alert, conversant, and can follow some simple commands. She was able to say her complete name but does not know her age nor her birthday. There was difficulty finding the right words when answering. On identifying three familiar objects; she cannot name, but she claimed she knew what they are for. There was difficulty repeating and writing simple and longer sentences. There was fair immediate recall, with poor recent and remote memories, forgetting what she recently ate and not remembering her birthday nor childhood address. Furthermore, she was able to do basic addition, with difficulty in basic multiplication and division. There was poor concentration, with finger agnosia and agraphesthesia. Stereognosis was intact. She was able to demonstrate how to brush teeth, comb hair, write using a pen; there was difficulty putting her clothes on. There was simultagnosia and visual apraxia. Dementia screening tests were done – Montreal Cognitive Assessment (MoCA) test revealed severe cognitive impairment, with a score of 7/30; the Mini Mental State Examination (MMSE) showed severe dementia, with a score of 1/30; and the Clinical Dementia rating (CDR) showed Moderate Dementia, with a score of 2. Dementia work-up was also done, which yielded a homozygous serum APOE-ε4. A cranial magnetic resonance imaging (MRI) with intravenous contrast was done and revealed a prominent atrophy in the bilateral parieto-occipital area.
Figure 1. Cranial MRI T1 in Axial Plane. A. Normal MRI. B. Note the prominent sulcal dilatation on both left and right frontal and parieto-occipital areas.
Figure 2. Cranial MRI in Sagittal Plane. Note the prominent atrophy in the posterior cingulate sulcus, parieto-occipital sulcus, and the precuneus gyrus.
DISCUSSION
Posterior Cortical Atrophy is a clinico-radiological syndrome coined by Dr. Frank Benson in 1988. In the literature, PCA has been described to be a rare, atypical variant of Early Onset Alzheimer’s Disease (EOAD). About 5-10% of cases diagnosed with EOAD may be of this variant.3 Since this is rare, the diagnosis of PCA is often delayed – where patients seek neurologic consult when other more apparent cognitive domains are already present.
PCA has been described to be a rare, atypical variant of Early Onset Alzheimer’s Disease (EOAD). About 5-10% of cases diagnosed with EOAD may be of this variant.3 Since this is rare, the diagnosis of PCA is often delayed – where patients seek neurologic consult when other more apparent cognitive domains are already present.
Most noted deficits in PCA are visuospatial and visuoperceptual impairments, with features of Balint’s syndrome (simultagnosia, oculomotor apraxia, optic ataxia) and Gertsmann syndrome (acalculia, agraphesthesia, finger agnosia, left-right disorientation). Patients present with at least one visual process, associated with the involvement of the occipital lobe.3 Radiologically, cranial MRI reveals supporting evidence of predominant occipital, parietal and/or occipitotemporal atrophy. Patient CP presented with 4-year progressive history of forgetfulness, with marked deficits in her visuospatial domain, as manifested by visual object agnosia, visual apraxia, simultagnosia. She also presented with incomplete Gertsmann syndrome (dyscalculia, finger agnosia, agraphesthesia). Furthermore, there is prominent atrophy in the bilateral parieto-occipital area, supporting the impression of PCA.
There are two subclassifications made: PCA-pure, those who only meet the criteria for PCA; and PCA-plus, patients who exhibit other manifestations consistent with other neurodegenerative disorders, such as Primary Progressive Atrophy (PPA) and Corticobasal Syndromes (CBS).4 Furthermore, there are also proposed stages for PCA: Prodromal/suspected/possible PCA, for those manifesting subtle deficits in posterior cortical functions but did not fulfill the PCA criteria. Next is PCA, consistent with the criteria of PCA, as previously mentioned. Thirdly, advanced PCA, described with further impairment in other cognitive functions.5 As with our patient, as of this writing, she may be classified into PCA-pure, at the stage of Advanced PCA, due to the involvement of other cognitive functions.
As with other neurodegenerative disorders, there is no proven treatment for PCA. There are no reports in use of acetylcholinesterase inhibitors but is still being used because Alzheimer’s Disease is most likely the underlying pathology. Some clinicians give anti-depressants or anti-Parkinson drugs for the concomitant signs and symptoms.6
CONCLUSION
PCA is a debilitating and underrecognized focal degenerative symptom, as it presents with significant cognitive impairments. With the latest Consensus Classification of Posterior Cortical Atrophy, this can help clinicians practice early recognition and improve interpretation of certain clinical findings. Better understanding and awareness of this variant is important to improve early detection, diagnosis, and treatment.
With the latest Consensus Classification of Posterior Cortical Atrophy, this can help clinicians practice early recognition and improve interpretation of certain clinical findings. Better understanding and awareness of this variant is important to improve early detection, diagnosis, and treatment.
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Our correspondent’s highlights from the symposium are meant as a fair representation of the scientific content presented. The views and opinions expressed on this page do not necessarily reflect those of Lundbeck.
