CNS

Question 1

Dementia is the acquired and persistent loss of higher neurological functions such as intellect, reason, and personality with associated diminished consciousness

Answer 1

Dementia is the acquired and persistent loss of higher functions which had previously been displayed by an individual. However, there is no associated loss of consciousness.

Question 2

Alzheimer’s disease is associated with plaques and neurofibrillary tangles and these can be visualised on high resolution MRI

Answer 2

Incorrect, the answer is False

Alzheimer’s disease is associated with βA4-amyloid plaques, and tau-2+ve neurofibrillary tangles. However, these are histological features, so would only be seen on microscopic evaluation of affected brains.

Question 3

Epidemiological studies of individuals with Downs’s syndrome have underlined a possible genetic factor in the aetiology of Alzheimer’s disease

a) True
b) False

Answer 3

Correct, the answer is True

Patients with Downs’s syndrome develop the clinical and histopathological features of Alzheimer’s disease, with increased β-amyloid, before the age of 40 years. The gene for the amyloid precursor protein is located on chromosome 21, so Downs patients have an extra copy of the gene, and presumably excess protein.

Question 4

Huntington’s disease is caused by an x-linked recessive genetic deficit

a) True
b) False

Answer 4

Correct, the answer is False

Huntington’s disease is a movement disorder, caused by neurodegeneration, which is inherited as an autosomal dominant disorder.

Question 5

Parkinsonism is a movement disorder that may be caused by toxins, post infection, trauma, and Wilson’s disease

a) True
b) False

Answer 5

Correct, the answer is True

Parkinsonism refers to the clinical syndrome of movement disorder, characterised by bradykinesia, rigidity, and tremor. This can be caused by Parkinson’s disease, or by other conditions, including drug treatment, trauma, or post infection.

Question 6

Causes of dementia may be transmitted from individual to individual iatrogenically

a) True
b) False

Answer 6

Incorrect, the answer is True

Dementia due to prion disease, such as Creutzfeld-Jacob disease, can be transmitted from person to person, usually as a result of medical interventions such as corneal transplantation, pituitary hormone administration, or use of neurosurgical instruments which are insufficiently sterilised.

Question 7

The human prion gene, which is associated with Creutzfeld-Jacob disease, is found on chromosome 21

a) True
b) False

Answer 7

Correct, the answer is False

The gene for the human prion gene is found on chromosome 20. It codes for a protein, prion protein, which is 254 amino acids long.

Question 8

Name and describe the disease

Answer 8

This is a gross photograph of the substantia nigra. The lower image shows pallor, due to decrease in pigmented neurons in the substantia nigra. This results in a relative deficiency of dopamine, which acts as an inhibitory neurotransmitter. The clinical sign and symptoms are due to lack of fine coordination between the components of the motor system.

Question 9

What are the CSF findings in MS

Answer 9

Majority of pts will have inc protein in CSF (60%) and 40% will have inc levels of IgG - this supports immune aetiology for disease

Question 10

MS is a progressive neurological disorder which affects the central and peripheral NS

Answer 10

MS only affects the CNS. It is progressive but the are different rates of progression.

Question 11

2o demyelination may occur as a result of axonal injury

Answer 11

True

Damage to a neuron, resulting in its death, will also cause demyelination of the axon which is then not used for electrical transmission

Question 12

Progressive multifocal leukoencephalopathy is a progressive disease of the white matter seen in patients with immunosuppression

Answer 12

True

PML is a multifocal disease caused by a papovavirus-like DNA virus known as the John Cunniingham (JC) virus. It causes discrete foci of demyelination at the grey-white junction of the cerebral hemispheres and brain stem.

Clinically, it causes dementia, weakness, visual loss, and death within 6 months.

Question 13

In MS what is the major immune cells involved in the pathogenesis

Answer 13

In MS, the major inflammatory cells involved in the pathogenesis of the disease are the lymphocytes, which are perivascular, and the macrophage

Question 14

What part of the brain is shown? What abnormality is seen here? Which alcohol associated lesion is characteristic of this appearance?

Answer 14

The image is of the mammillary bodies. There are petechial haemorrhages seen, which are characteristic of Wernicke’s disease.

Question 15

What are the effects of alcohol misuse on the CNS?

Answer 15

The effects of alcohol on the brain are caused by a combination of the direct toxic effects of alcohol, and the poor nutrition which often co-exists with alcohol dependence.

The main lesion are Wernickes Syndrome, cortical atrophy, central pontine myelinolysis and atrophy of the cerebellar vermis.
Wernickes Syndrome is due to thiamine deficiency, and leads to disorders of the hypothalamus and mamillary bodies.It is associated with Wernicke-Korsakoff syndrome, where disordered memory is compensated for by confabulation. Cerebral atrophy, cerebellar regions and central pontine myelinolysis are probably due to a combination of alcohol toxicity, malnutrition and other factors, but these are unclear.

However, a large number of alcohol related admissions to hospital are due to trauma, fights and road traffic accidents.

Question 16

What is the Glasgow Coma Scale?

Answer 16

The Glasgow coma scale is a grading system for coma associated with head injury. The score is the sum of three scores, for eye opening, motor response and verbal response. The top or “normal” score is 15/15.

Question 17

JF, a man in his 60s, is a regular attendee of A&E. He is a down and out, with a long history of alcohol abuse. On this occasion, he is escorted into casualty by the police. He has been “creating a disturbance” in Shaftesbury Square and may have got into a fight.

In view of the history of trauma you order a Skull x-ray; and arrange for JF to be admitted for neurological observation. The skull X-ray does not show any evidence of skull fracture.

JF becomes more irascible and troublesome while in the A&E department, and takes his own discharge, against medical advice.

Two days later, JF is brought in by ambulance. The accompanying history is vague; he was found collapsed near a hostel.

On neurological examination, he is drowsy, and irritable. He complains of a headache.

His GCS is now 5/15

What is the likely diagnosis? What factors in JFs presentation suggest this diagnosis?

Answer 17

The likely diagnosis is subdural haematoma.
This is suggested by JFs alcohol abuse, with the associated cortical atrophy leading to stretching of the intracranial veins across the subdural space, and an increased likelihood of rupture and haemorrhage.

Question 18

Describe the gross findings.

Answer 18

The dura is reflected to show an area of blood clot, which has an irregular inner contour. It closely follows the shape of the underlying brain. The blood has gathered in the subdural space and is therefore a subdural haematoma.