Which of the following produce a rapidly evolving dementia with neurological features?
B. Creutzfeldt–Jakob disease (CJD) is a prion disease that presents with rapidly evolving dementia with multiple neurological features. Prions are virus-like transmissible agents but without any nucleic acid. They are simple, mutated proteins originating from the normal human prion protein gene (PRNP), which is located on the short arm of chromosome 20. When mutant PrPSc is formed it is partially protease-resistant with a capacity to change further normal PrP to PrPSc, initiating a cascade. CJD presents non-specifically with fatigue and fl u-like symptoms with rapid development of neurological findings such as aphasia, cerebellar signs, myoclonus, apraxia with emotional lability, depression, delusions, hallucinations, or marked personality changes. The disease is rapidly progressive with dementia, akinetic mutism, coma, and death occurring within few months of onset.
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Prion dementia is caused by all of the following EXCEPT:
D. Sporadic onset accounts for 85% of cases with CJD, while 10% result from genetic mutation. The remaining 5% result from iatrogenic transmission during transplant surgery of dura and corneal grafts, and pituitary growth hormone. vCJD is a variant form of human CJD that is transmitted by eating contaminated meat of an animal with bovine spongiform encephalopathy. Peritoneal dialysis does not involve foreign tissue.
The probability of developing Korsakoff’s syndrome is related to which of the following features?
B. Wernicke–Korsakoff syndrome is considered to be a nutritional illness seen in alcoholics. Thiamine deficiency can occur secondary to gastrectomy, carcinoma stomach, anorexia, haemodialysis, hyperemesis gravidarum, prolonged intravenous hyperalimentation, and alcoholism. This produces neuronal damage with small vessel hyperplasia and occasional haemorrhages especially in diencephalic structures such as mamillary bodies and medial dorsal thalamus. There is no clear correlation between amount, type, or duration of alcohol consumption and incidence of Korsakoff’s syndrome. It is thought that patients who develop Korsakoff’s may have abnormal transketolase enzyme, involved in thiamine metabolism.
Korsakoff’s syndrome is characterized by all EXCEPT:
B. In Korsakoff’s syndrome recent memory tends to be affected more than is remote memory. Confabulation, apathy, and executive dysfunction are prominent. The length of retrograde amnesia is variable. Working memory and attention are preserved. The implicit emotional learning and procedural memory are preserved, facilitating rehabilitation; 75% of these patients show some degrees of improvement, whilst 25% show no change.
Which of the following best describes the triad characteristic of normal pressure hydrocephalus?
E. Normal pressure hydrocephalus or NPH is a syndrome of cerebral ventricular dilatation with normal CSF pressure. The changes are prominent in the third ventricle, affecting the pyramidal tract representing legs. This leads to a triad of: dementia, gait ataxia, and urinary incontinence. The dementia is reversible if NPH is treated promptly with shunt or repeated lumbar puncture.
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