Which of the following is a monogenic ischaemic stroke syndrome?
A. CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is an autosomal dominant familial trait linked in several families to a mutation in the Notch 3 gene on chromosome 19. It presents as recurrent small-vessel strokes, beginning in early adulthood, leading to extensive symmetric white matter changes similar to Binswanger’s disease and progressive dementia. The genetic nature of the syndrome may not be fully apparent because of the low penetrance. Approximately 40% of patients have migraine with aura. CADASIL is the only monogenic ischaemic stroke syndrome described. Genetic testing is available.
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Which of the following is NOT a feature of Stage I Alzheimer’s dementia?
E. According to Cummings, Alzheimer’s disease progresses through three stages. In the first stage, the patient has anomia, defective visuospatial skills and calculation ability along with an indifferent personality. Examination of the motor system and EEG may be relatively normal, although some medial temporal atrophy may be noted in a structural brain scan. In the second stage of dementia, the patient has fluent aphasia and further deterioration in memory, visuospatial skills, and personality. In addition, there may be motor restlessness on examination. EEG may show background slowing and a structural brain scan may show temperoparietal atrophy. In the third and fi nal stage, there is severe impairment in intellectual function and speech disturbances characterized by palilalia, echolalia, or mutism. In addition, there is sphincter disturbances, diffuse slowing on EEG and diffuse atrophy on structural scan.
Which of the following is NOT a feature of Binswanger’s disease?
A. Binswanger’s disease is a slowly progressive dementia associated with subacute progression of focal neurological deficits in chronically hypertensive patients. These deficits could involve pseudobulbar, pyramidal, and parkinsonian features. Incontinence and fluctuating cognition may be seen. The periventricular area shows white matter demyelination, especially resulting from diffuse ischaemic damage. Lacunar infarcts are frequently absent. In patients thought to have multi-infarct dementia, leucoaraiosis is found in at least three quarters.
Which of the following is true regarding frontotemporal dementia (FTD)?
C. Forty per cent of cases of FTD are familial, mainly autosomal dominant. Mutations in the tau gene were first found in FTD with parkinsonism linked to chromosome 17 (FTDP-17). Histologically FTD consist of fi ve types. The motor neuron type with inclusions reactive for ubiquitin but not for tau is the most frequent type. The second most common is a corticobasal degeneration type that is tau positive but with ubiquitin-negative inclusions. The third is Pick’s disease with neuronal loss, widespread gliosis, and inflated neurons with inclusions positive for both tau and ubiquitin. The familial pattern has tau-positive inclusions in neurons and glial cells. Clinically frontal lobe variant accounts for the most common presentation (70%). They present with symptoms suggestive of frontal lobe dysfunction. Temporal variants are of two types: semantic and progressive aphasic. Semantic dementia accounts for about 15% of the presentation. They show progressive loss of word meaning and object or face identity. Ten per cent of cases are of the progressive aphasic type.
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HIV-induced cognitive deficits have been proposed to be due to:
E. All of the given mechanisms have been proposed to be the aetiopathogenesis behind cognitive deficits in HIV infection. In the process of binding to a CD4+ receptor-containing cells, HIV gp120 binds to a calcium channel and increases intracellular free calcium. This also leads to an alteration in glucose metabolism, leading to brain dysfunction. Further, the viral genome is incorporated into the host genome, which leads to the release of more injurious compounds. These include substances such as quinolinic acid, superoxide anions, and other pro-inflammatory cytokines. These products, especially quinolinic acid, act as NMDA agonists, leading to excitotoxicity and cell death. TNF-alpha, one of the pro-inflammatory cytokines, is also known to trigger apoptosis or programmed cell death.
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