Weakness

Question 1

What associated features should you ask about?

Answer 1

• Blackout, seizures
• Headaches (explore)
• Visual problems
• Balance / hearing / vertigo and dizziness
• Speech and swallowing
• Chest pain and SOB
• Weight loss, appetite change, fever, fatigue, sweats
• Joint pain, back pain, hip pain
• Incontinence, anaesthesia
• Muscle wasting
• Funny sensations, numbness, tingling

Question 2

What PMH should you specifically enquire about?

Answer 2

Diabetes

Spinal pathology

Question 3

What medications should you specifically enquire about?

Answer 3

LT corticosteroids

Question 4

What FHx should you specifically enquire about?

Answer 4

Muscular Dystrophy

Autoimmune disorders

Question 5

What are the features of Myopathy vs Neuropathy?

Answer 5

Myopathy

• Gradual onset
• Proximal muscles affected
• Selective muscles
• DTR preserved

Neuropathy

• Acute rapid onset
• Numbness and tingling
• Autonomic dysfunction, bladder problems
• Paraesthesia
• Distal weakness

Question 6

What are the features of Duchenne’s muscular dystrophy?

Answer 6

Presents @ 4 years old

• Problems standing up
• Clumsy walking
• Respiratory failure

CK >40x the normal

Question 7

What are the features of polymyositis and dermatomyositis?

Answer 7

This is a rheumatological condition

• Slow onset and progressive
• Bilateral Myalgia & Arthralgia
• Dysphagia & Dysphonia
• Fever

Question 8

What is the treatment for poly/dermatomyositis?

Answer 8

Prednisolone 1mg/kg/day

Question 9

What is myasthenia gravis?

Answer 9

An autoimmune condition affecting AChR of the postsynaptic membrane at the skeletal muscle, resulting in muscle weakness and fatiguability.

Question 10

What muscles does myasthenia gravis tend to affect (in order) and what symptoms does this result in?

Answer 10

Extraoccular - Double vision
Levator Palpebrae - Ptosis
Bulbar muscles - Chewing and swallowing
Face and neck muscles - Drooping

Question 11

What are some associations of myasthenia gravis that you should ask about when taking a history?

Answer 11

Other autoimmune conditions

• Thyrotoxicosis
• Diabetes
• Rheumatoid Arthritis
• Thymoma

Question 12

What investigations should be carried out for myasthenia gravis?

Answer 12

Tinsilon test: Injection of edrophonium improves strength

Vital capacity
Chest CT or MRI

Antibodies

• AChR receptor antibody present in more than 90%
• MuSK receptor antibody if seronegative

EMG
- Decremental muscle response on repeated stimulation

Plasma thyroxine to rule out associated thyroid disorder

Question 13

What is the treatment for myasthenia gravis?

Answer 13

Anticholinesterase e.g. Pyridostigmine up to 6x a day

Question 14

What immunosuppressants may be indicated for myasthenia gravis, and what must be administered on top as prophylaxis?

Answer 14

Prednisolone on alternating days due to side effect of muscle weakness

Give osteoporosis prophylaxis

Can also give azathioprine on top

Question 15

When may thymectomy be indicated in myasthenia gravis?

Answer 15

If

• Onset <50 years
• Not improved with anticholinesterase

Question 16

What is the danger in a myasthenia crisis and what is the immediate treatment?

Answer 16

Respiratory depression

Immediate artificial ventilation
Plasma exchange
IV Ig

Question 17

What is Lambert-Eaton syndrome?

Answer 17

Myasthenic disorder

Can be paraneoplastic, result of small cell lung cancer, or can be autoimmune

NO Bulbar or Extra-occular manifestations…
Therefore SPARES THE EYES

Loss of DTR

Weakness is usually truncal and proximal muscles, especially of the pelvic girdle and thighs.

Weakness and loss of DTR IMPROVES WITH EXERCISE!

EMG is diagnostic.

Question 18

What is the management of muscular dystrophy?

Answer 18

• Supportive
• Genetic counselling
• Orthosis (brace/splint) and prednisolone may help prolong ambulatory phase

Question 19

What question should you ask if you suspect infection or encephalitis as a cause of weakness?

Answer 19

Recent overseas travel

Question 20

What are the key elements in the history of MS?

Answer 20

Visual disturbance in one eye
Peculiar sensory phenomenon
Fatigue
Foot dragging or slapping
Leg cramping
Urinary frequency
Bowel dysfunction
20-40 years old

Question 21

What are the key findings of examination of MS?

Answer 21

Top to toe

Incorrect response to Ishihara plates, desaturation
Pale optic disc
Abnormal eye movements (Intranuclear ophthalmoplegia)

Spasticity
Increased muscle tone
Increased DTR
Motor weakness and plegia

Question 22

What are the key findings on investigation of MS?

Answer 22

MRI head - White matter hyperintensities

MRI spinal cord - demyelinating lesions especially C-spine

LP - oligoclonal bands

EP - prolongation of conduction, asymmetrical visual EP

Question 23

What are the key elements in the history of GBS?

Answer 23

Often there is a PRECEDING VIRAL / BACTERIAL INFECTION

PROGRESSIVE, ASCENDING, SYMMETRICAL muscle WEAKNESS

FLACCID PARALYSIS of LOWER EXTREMITIES before upper extremities

PROXIMAL muscles before distal affected
with
PARAESTHESIA of HANDS and FEET

accompanied by BACK or LEG PAIN

RESPIRATORY DISTRESS if chest involved

Question 24

What are the key findings on examination in GBS?

Answer 24

AREFLEXIA

OROPHARYNGEAL WEAKNESS
FACIAL WEAKNESS

SPEECH PROBLEMS

OPTHALMOPLEGIA

Dysautonomia (sinus tachy, labile BP, posturoal hypo, urinary retention, ileus)

Question 25

What are the key findings on investigation in GBS?

Answer 25

LP - PROTEIN IS >1g/L
Spirometry - reduced VC
Nerve conduction studies - PROLONGED DISTAL LATENCIES

Question 26

What are the key findings on investigation in MG?

Answer 26

Serum Anti-AchR antibody
Anti-MuSK antibody

MG Crisis - Reduced FVC

CT Chest - Thymic enlargement