Examination Findings

Question 1

Clinical Manifestations suggestive of MS

Answer 1

Internuclear ophthalmoplegia
Optic neuritis 
RAPD (Marcus Gunn pupil) 
Upper motor nueurone weakness
Cerebellar signs 
Posterior column sensory loss 
Faecal/urinary incontinence 
Lhermitte's sign 
Uhthoff's phenomenon

Question 2

Lhermitte’s sign and causes

Answer 2

Electric shock like sensation in limbs or trunk following neck flexion
Caused by: MS and other disorders of cervical spinal cord - cervical spondylosis, cervical cord tumours, subacute combined degeneration of the cord, foramun magnum tumours, nitrous oxide abuse, mantle irradiation

Question 3

Uhtoff’s phenomenon and causes

Answer 3

Worsening of symptoms with hear (fever) and exercise

Common in MS - also seen in peripheral disorders like myasthenia gravis

Question 4

Internuclear ophthalmoplegia - site of lesion and description of sign

Answer 4

Lesion of medial longitudinal fasciculus
Looking away from site of lesion - failure of adduction eye ipsilateral to side of lesion, abduction of CL eye with nystagmus
Commonly seen in MS - bilateral INO in young person nearly always MS
Vascular causes are potential culprits in older people

Question 5

Differential diagnosis of peripheral neuropathy

Answer 5

Drugs - isoniazid, vincristine, phenytoin, nitrofurantoin, cisplatin, heavy metals, amiodarone
Alcohol abuse
Metabolic - DM, CKD
Guillain-Barre
Malignancy - carcinoma of lung - paraneiplastic neuropathy, leukaemia, lymphoma, or chemo (vincristine, cisplastin, etoposide, paclitaxel
Vitamin deficiency (B12) or excessive B6
Connective tissue disease or vasculitis (PAN, SLE)
Hereditary (hereditary motor and sensory neuropathy)
Other (amyloidosis, HIV)
Idiopathic

Question 6

Differential diagnosis of predominant motor neuropathy

Answer 6

Guillain-Barre 
Chronic inflammatory polyradiculopathy 
Hereditary motor and sensory neuropathy 
Diabetes 
Other - acute intermittent porphyria, lead poisoning, diphtheria, multi focal motor neuropathy with conduction block

Question 7

Causes of painful peripheral neuropathy

Answer 7

Diabetes
Alcohol 
B12 or B1 deficiency 
Carcinoma 
Prophyria 
Arsenic or thallium poisoning

Question 8

Causes of upper motor neurone lesions

Answer 8

Vascular disease - thrombosis, embolism, haemorrhage
Compressive and infiltrative lesions _ note can get false localising signs in raised ICP e.g. unilateral or bilateral sixth nerve palsy (nerve has long intracranial path)
Demyelination (MS)
Infection - HIV

Question 9

Features of lateral medullary syndrome (Wallenburg)

Answer 9

Ipsilateral cerebellar signs
Ipsilateral Horner’s
Ipsilateral IX, X
Ipsilateral loss of pain and temperature to face
Contralateral arm and leg loss of pain and temperature
No upper motor neurone weakness

Arises from occlusion of the vertebral or poserior inferior cerebellar or lateral medullary arteries

Question 10

Signs of upper motor neurone lesions

Answer 10

Weakness in all muscle groups - in upper limb more marked in extensor and abductor groups, lower limb flexor and abductor groups
Little muscle wasting
Spasticty - may be clasp knife, may be associated with clonus
Increased reflexes except for superficial (abdominal) which are absent
Extensor plantar response

Question 11

Signs of lower motor neurone lesions

Answer 11

Weakness more obvious distally - flexors and extensors equally involved
Prominent wasting
Reduced reflexes, normal or absent plantar response
Fasciculations

Question 12

Features of motor neurone disease

Answer 12

Combination of upper and motor neurone signs - changes in anterior horn cells, motor nuclei of medulla and descending tracts
Fasciculations almost always present
Rarely objective sensory changes (15-20% of patients report sensory symptoms)

Prognosis 3-5 years at diagnosis
Mode of death - progressive respiratory failure and aspiration pneumonia

Question 13

Guillain-Barre syndrome features

Answer 13

Often 7-10 days following an infective illness e.g. campylobacter jejuni
Flaccid proximal and distal muscle paralysis ascends from lower to upper limbs
Reflexes reduced or absent
Back pain common - radiculitis
Cranial nerves can be affected (and disease confined to these)
Sensory loss common but frequently patchy on testing
Sphincter’s unaffected
Respiratory muscle weakness - regular FEV1/FVC
HIV can cause a similar syndrome

Question 14

Mononueritis multiplex causes and definition

Answer 14

The separate involvement of more than one peripheral nerve (or less often cranial nerves) by a single disease

Acute causes: usually vascular
PAN
DM
Connective tissue disease (RA, SLE)

Chronic: multiple compressive neuropathies, sarcoidosis, acromegaly, HIV, leprosy, Lyme disease, others - carcinoma (rare)

Question 15

Causes of demyelinating polyneuropathy

Answer 15

Guillain barre
CIDP 
Paraproteinaemia
Hereditary motor sensory neuropathy
Refsum's disease
HIV infection
Amiodarone

Question 16

Causes of axonal polyneuropathy

Answer 16

Diabetes
Alcohol
Vasculitis
Vitamin deficiencies

Question 17

Causes of small pupils

Answer 17

Horner's syndrome
Old age
Argyll-Robertson pupil
Pontine haemorrhage
Drugs - opioids

Question 18

Notes on pupillary examination anatomy

Answer 18

• Parasympathetic innervation by Edinger-Westphal nucleus of third nerve -> pupillary constriction
• Sympathetic innervation - hypothalamus -> spinal cord, lots of synapses until third order neurones with carotid artery reach eye (mydriasis)

Pupillary reflex:
- When light shone in an eye -> afferent fibres from optic nerve -> superior colliculus -> Edinger-Westphal nucleus in midbrain -> third nerve causes constriction

Question 19

Extraocular muscles are nerve supply

Answer 19

• All suppled by 3rd nerve except
• 1. Superior oblique - fourth nerve
     
     2. Lateral rectus - sixth nerve

Question 20

Causes of RAPD/Marcus Gunn pupil

Answer 20

Optic atrophy or reduced visual acuity of any cause

Question 21

Causes of an intact accommodation reflex and absent light reflex

Answer 21

• Argyll Robertson pupil (syphilis)
• Adie’s pupil (ciliary ganglion lesion)
• Parinaud’s syndrome

Question 22

Classification of eye movements

Answer 22

1. Pursuit - controlled by cerebellum and brainstem
2. Saccadic - controlled from frontal lobe, brainstem, cerebellum
3. Convergence - controlled from midbrain
4. Vestibul-ocular reflex - used to compensate for movements of the head and enable fixation to be maintained e.g. keeping your eyes on target while moving your head - controlled by vestibular organs and cerebellar and vestibular nuclei

Question 23

Notes on nystagmus

Answer 23

**Jerky horizontal nystagmus
**Vestibular lesion (to the side of the lesion, usually increases in intensity as the eye is moved away from side of lesion)
Cerebellar lesions - Bidirectional i.e. beats left looking left, right looking right. Cerebellar nystagmus often worsens with fixation
Toxins e.g. phenytoin, alcohol
INO

**Jerky vertical nystagmus
**Cerebellar or brainstem lesion
Upbeat sugests midbrain or floor of fourth ventricle, downbeat suggests foramen magnum lesion

**Pure torsional nystagmus
**Always a central cause

**Pendular nystagmus
**Present when nystagmus phases are equal in duration
Retinal (decreased macular vision), or congenital