Neurology PassMed

Question 1

Cranial nerve palsy responsible for ‘down and out’ motor deficit

Answer 1

Cranial nerve III

Question 2

Key causes of cranial nerve III palsy

Answer 2

Posterior communicating artery aneurysms and diabetic ophthalmoplegia

• the differentiating feature between the two is that posterior communicating artery aneurysms present with pupillary dilation first (due to compression of peripheral parasympathetic fibres) whilst diabetic ophthalmoplegia present first with motor deficits (i.e. ‘down and out’ pupil)

Question 3

Definition of a TIA

Answer 3

Updated guidelines: tissue based not time based

A transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction

Question 4

Mechanism of action: memantine

+ Use

Answer 4

NMDA antagonist

Use: second line treatment for Alzheimer’s disease

Question 5

Example of acetylcholinesterase inhibitors

Answer 5

Donepezil
Rivastigmine
Galantamine

Question 6

Thoracic outlet syndrome

Answer 6

Pathology: compression of the neurovascular bundle between the supraclavicular fossa and the axilla

Symptoms: nervous (90%), venous or arterial compression

Causes: congenital (e.g. presence of cervical rib), traumatic (e.g. following seatbelt trauma in car accident) or acquired (e.g. secondary to malignancy pressure effect).

Question 7

Contralateral homonymous hemianopia with macular sparing and visual agnosia

Answer 7

posterior cerebral artery

Question 8

Contralateral hemiparesis and sensory loss, lower extremity > upper

Answer 8

Anterior cerebral artery

Question 9

Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia

Answer 9

Middle cerebral artery

Question 10

Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity

Answer 10

Weber’s syndrome (branches of the posterior cerebral artery that supply the midbrain)

Question 11

Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus

Answer 11

Posterior inferior cerebellar artery (lateral medullary syndrome, Wallenberg syndrome)

Question 12

Symptoms are similar to Wallenberg’s (see above), but:
Ipsilateral: facial paralysis and deafness

Answer 12

Anterior inferior cerebellar artery (lateral pontine syndrome)

Question 13

‘Locked-in’ syndrome - artery?

Answer 13

Basilar artery

Question 14

Lacunar strokes

Answer 14

present with either isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
strong association with hypertension
common sites include the basal ganglia, thalamus and internal capsule

Question 15

Why do nerve lacerations have worse recovery than nerve crush injuries

Answer 15

Nerve lacerations cause neurotmesis (damage to the axon, myelin sheath and surrounding connective tissue). This leads to degradation of the axon distal to the site of injury - this usually occurs within 1-2 days of the injury.

nerve crush injuries cause axonotmesis (disruption to the axon but there is preservation of the myelin sheath). This leads to an improved likelihood of healing, albeit a slow recovery process.

Question 16

What is wallerian degeneration in nerve injury?

Answer 16

Axonal degeneration distal to the site of injury.
Typically begins 24-36 hours following injury.
Axons are excitable prior to degeneration occurring.
Myelin sheath degenerates and is phagocytosed by tissue macrophages.

Question 17

Where is oxytocin synthesised?

Answer 17

Paraventricular nucleus - secreted into the posterior pituitary gland

Question 18

Hypothalamus anatomy: Function of the anterior nucleus

Answer 18

Cooling by stimulation of parasympathetic nervous system

Question 19

Hypothalamus anatomy: lateral nucleus

Answer 19

Stimulation → increased appetite

Lesions → anorexia

Question 20

Hypothalamus anatomy: posterior nucleus

Answer 20

Heating (conservation and increased production) - damage results in poikilothermia

Stimulates sympathetic nervous system

Question 21

Nerve injury associated with mid-shaft humeral fractures

Answer 21

Radial nerve injury

Question 22

Which muscles does the ulnar nerve innervate?

Answer 22

M edial lumbricals
A dductor pollicis
F lexor digitorum profundus/Flexor digiti minimi
I nterossei
A bductor digiti minimi and opponens

Question 23

Sensory innervation of ulnar nerve

Answer 23

medial 1 1/2 fingers (palmar and dorsal aspects)

Question 24

Baclofen

Answer 24

GABAB agonist, that is used to treat muscle spasticity

Question 25

Ptosis differential diagnosis

Answer 25

3rd nerve - dilated
Horners - constricted

Question 26

Advantage of fentanyl over morphine

Answer 26

Faster onset

Question 27

Damage to which nerve would result in the inability to make an OK sign (thumb + index finger)

Answer 27

Anterior interosseous nerve (branch of median)

Question 28

Order of the three bones involved in transmitting sound waves to the eardrum

Answer 28

Malleus incus stapes

Question 29

Relative afferent pupillary defect

Nerve lesion?

Answer 29

Optic nerve lesion

Question 30

Level of nipple dermatome

Answer 30

T4

(T4 at the teat pore)

Question 31

Thumb and index finger dermatome

Answer 31

C6

Thumb + index finger together plus straight other fingers = 6

Question 32

Umbilicus dermatome

Answer 32

T10

BellybuT-TEN

Question 33

Inguinal ligament dermatome

Answer 33

L1

L (ligament) 1 (inguinal)

Question 34

Knee caps dermatome

Answer 34

L4

Down on aLL fours = L4

Question 35

Big toe dermatome

Answer 35

L5

Largest of the 5 toes

Question 36

Conduction aphasia affects which part of the brain

Answer 36

Arcuate fasciculus (connects Wernickes and Brocas i.e. speech is fluent but repetition is poor - aware of errors being made)