MCQ's in Neurology

Not long afterwards his friends noticed he had an unusual facial appearance. In that he could not smile, close his left eye or wrinkle his forehead on the left.

[Photo from: William F. Hoyt Neuro-Ophthalmology Collection]

You also notice that she has a VI^th nerve palsy.

Here is his CT scan:

Examination reveals weakness on right shoulder abduction (4/5) and right elbow flexion (4/5). Reflexes in her right arm are all absent apart from triceps. There are no sensory findings. The remainder of the examination is normal.

What do you diagnose?

Answers Case 1:

1.1: (e) Erythema nodosum

1.2: (b) Sarcoidosis

Discussion:

This patient presents with painful red lesions on his shins together with a facial palsy.

The facial appearance represents a VII^th nerve palsy, in this instance a lower motor neurone VII^th.

The key to this question is linking conditions that cause a VII^th nerve palsy with painful skin lesions on the legs.

Acute onset of painful red lesions on anterior shins is almost characteristic of erythema nodosum.

Some causes of unilateral VII^th nerve palsy:

• Bells palsy
• CPA tumour
• Mononeuritis - sarcoid, diabetes, lyme
• Ramsay Hunt syndrome
• Parotid tumour
• Pontine lesion - vascular/demyelinating

Some causes of erythema nodosum:

• Sarcoidosis
• Streptococcal infection
• Drugs (OPC)
• Inflammatory bowel disease
• TB
• Pregnancy
• Rheumatic fever

A few clinical features of sarcoidosis (Many - multi-system disorder!!):

• Unilateral or bilateral VII^th nerve palsy (though really any cranial nerve palsy)
• Bilateral hilar lymphadenopathy
• Erythema nodosum
• Polyarthralgia

Answers Case 2:

2.1: (c) Papilloedema

2.2: (d) CT scan

2.3: (e) Benign intracranial hypertension

Discussion:

The retinal photograph demonstrates raised intracranial pressure, as shown by the papilloedma, with evidence of a pink disc, blurred margins and haemorrhages.

All of the mentioned investigations are appropriate here, though given the papilloedema, a space-occupying lesion must first be excluded. This is easily done with a CT scan. Though in clinical practice a CTV (CT venogram) may also be required to exclude the possibility of a venous sinus thrombosis.

Benign intracranial hypertension, the brain imaging is normal in the vast majority. In some instances there may be slight venricular dilation.

Note - that the VI^th nerve palsy here is a false localising sign of raised intracranial pressure.

Potential causes of benign intracranial hypertension:

• Raised BMI
• OCP use
• Antibiotics - tetracyclines

Answers Case 3:

3.1: (a) Urinary incontinence

3.2: (d) Normal Pressure Hydrocephalus

Discussion:

CT scan or MRI will demonstrate ventricular dilation.

This is a potentially treatable cause of dementia. The treatment option in the first instance is lumbar puncture. If a clinical improvement is shown with lumbar puncture then the patient may benefit from VP shunt.

Answer Case 4:

(c) Brachial neuritis

Discussion:

A CVA, would cause upper motor neurone signs.

Cervical myelopathy could cause this picture if the lesion was at C5-C6. Though upper motor neurone signs would be expected below the level of the lesion. Remember that a spinal cord lesion can cause lower motor neurone signs at the level of the lesion due to compression of nerve roots and upper motor neurone lesion below the level of the lesion.

A radial nerve palsy, causes wrist drop resulting from weakness of wrist extensors, finger extensors, supinator and extensor carpi radialis. Classically occurs as a "Saturday night palsy" (patient falls asleep with arm hanging over back of chair), in which the nerve is compressed against middle third of humerus. Only if the nerve is compressed in the axilla, will weakness of triceps occur (C7) together with loss of the triceps reflex.

A frozen shoulder causes stiffness and painful restriction of all shoulder movements, felt to be due to an adhesive capsulitis and responds to intra-articular steroids injections and physio.

Answer Case 5:

(d) Left VI^th nerve palsy

Discussion:

Answers Case 6:

6.1: (b) Smell testing

6.2: (e) Salbutamol

6.3: (d) Gabapentin

Discussion:

In contrast Parkinsons disease is initially an asymmetric condition, characterised by rest tremor, bradykinesia and rigidity.

Many tremors can have action and resting components to them and they do not always fit the textbook description.

Alcohol can relieve all tremors though it is classically said that it characteristically eases benign essential tremor.

Recent research has demonstrated that sense of smell is lost in Parkinsons disease. On direct questioning patients deny this though it can be accurately tested for and be a good discriminating test in distinguishing benign tremor from Parkinsons disease.

A DAT scan may be helpful in distinguishing the two conditions, as it outlines dopamine deplete areas.

B2 agonists like Salbutamol can cause tremulousness as an unwanted side-effect.

Treatment options usually are nothing or Beta-blockers. However Beta-blockers are contra-indicated here as this gentleman suffers from asthma and COPD!

Other alternative options include, Gabapentin, Pregabalin, Topiramate and Levitaracetam.

Answers Case 7:

7.1: (c) Café-au-lait spots

7.2: (b) Neurofibromatosis type I

7.3: (c) Chromosome 17

Discussion:

Important to distinguish it from tuberous sclerosis, which will present with learning difficulties, decreased IQ and a different set of skin lesions. Tuberous sclerosis is also mainly autosomal dominant like neurofibromatosis.

Epilepsy is common in both conditions and so knowledge of the skin lesions can often be helpful in obtaining a diagnosis.

Answers Case 8:

8.1: (d) Right homonymous hemianopia

8.2: (b) Right parietal lobe

8.3: (e) Constructional apraxia

Discussion:

Clinical signs expected would be a right homonymous hemianopia, right upper motor neurone VII^th nerve palsy, right hemiplegia - with increased tone, reflexes and an extensor plantar on the right.

The second man, is also right handed so therefore left hemisphere dominant. He has a left visual field defect, therefore right sided brain pathology in his parietal lobe. A temporal lobe lesion would give a superior quadrantanopia.

As this gentleman has a lesion in his non-dominant parietal lobe, constructional or dressing apraxia may be seen. All the other features are dominant parietal lobe signs.

Answer Case 9:

9.1: (b) Migraine

9.2: (c) None

9.3: (e) Beta-blockers

Discussion:

The key to this case is the fact that this is not an isolated episode. It has happened previously with no neurological sequeli.

However if this was his first episode he would of course warrant investigation for subarachnoid haemorrhage. Which would include a CT brain followed by a lumbar puncture if the CT scan was normal.

Migraine associated with vigourous exercise and with sexual intercourse can be very disabling and does warrant treatment. Prophlaxis with Beta-blockers is generally recommended, despite the obvious side-effect of impotence!!

Answer Case 10:

10.1: (a) Right VI^th palsy

10.2: (d) Cerebellopontine angle

Discussion:

The corneal reflex will be lost first.

Other potential causes include a meningioma.