25. Limb Weakness Flashcards
What other symptoms may limb weakness be confused with?
Ataxia (clumsy limbs)
Reduced sensation in limbs
Painful limbs
What are the two most important factors to consider when establishing the cause of limb weakness?
Time course
Location of lesion
List some cause of limb weakness based on their time course:
a) Sudden-onset (seconds to minutes)
Vascular problem (e.g. stroke, TIA) Trauma (e.g. disc herniation, subarachnoid haemorrhage)
List some cause of limb weakness based on their time course:
b) Subacute onset (hours to days)
Progressive demyelination (e.g. MS, Guillain-Barre syndrome) Slowly expanding haematoma (e.g. subdural haematoma)
List some cause of limb weakness based on their time course:
c) Chronic onset (weeks to months)
Slow-growing tumour
Motor neurone disease
List some causes of sudden-onset limb weakness based on the location of the lesion.
i) Brain
Ischaemic stroke TIA Haemorrhagic stroke Hemiplegic migraine Todd’s paresis Hypoglycaemia
List some causes of sudden-onset limb weakness based on the location of the lesion.
ii) Spinal Cord
Spinal disc prolapse
Others: spinal cord transection/infarction
List some causes of sudden-onset limb weakness based on the location of the lesion.
iii) Nerve Root
Spinal disc prolapse
Vertebral fracture
List some causes of sudden-onset limb weakness based on the location of the lesion.
iv) Peripheral Nerve
Acute limb ischaemia
Traumatic nerve injury
List some causes of subacute onset limb weakness based on the location of the lesion.
i) Brain
Multiple sclerosis
Haematoma
Tumour
List some causes of subacute onset limb weakness based on the location of the lesion.
ii) Spinal Cord
Multiple sclerosis
Tumour
Transverse myelitis
List some causes of subacute onset limb weakness based on the location of the lesion.
iii) Nerve Root
Guillain-Barre syndrome
Poliomyelitis
List some causes of subacute onset limb weakness based on the location of the lesion.
iv) NMJ
Botulism
Tetanus
List some causes of gradual-onset limb weakness based on the location of the lesion.
i) Brain
Tumour
Motor neurone disease
List some causes of gradual-onset limb weakness based on the location of the lesion.
ii) Spinal Cord
Spinal canal stenosis B12 deficiency (subacute combined degeneration of the spinal cord)
List some causes of gradual-onset limb weakness based on the location of the lesion.
iii) Peripheral Nerve
Diabetes mellitus
Vasculitides
List some causes of gradual-onset limb weakness based on the location of the lesion.
iv) Neuromuscular Junction
Myasthenia gravis
Lambert-Eaton syndrome
List some causes of gradual-onset limb weakness based on the location of the lesion.
v) Muscle
Myositis
What’s Todd’s paresis?
Post-seizure paralysis
List some important features of the history that you should ask about.
Exact time of onset Speech or visual disturbance Headache Seizure or loss of consciousness Neck or back pain Trauma
Why is the exact time of onset of the symptoms important?
There is a 4.5 hour window (following the onset of symptoms) within which you have to thrombolyse patients with confirmed ischaemic stroke
Which causes of limb weakness are associated with causing headaches?
Hemiplegic migraine
Subarachnoid haemorrhage
Intracranial mass (e.g. subdural haemorrhage) causes a gradual-onset headache
List some causes of limb weakness that are associated with seizures and loss of consciousness.
Todd’s paresis
Hypoglycaemia
What would neck or back pain associated with limb weakness lead you to suspect?
Spinal pathology (e.g. disc prolapse, traumatic spinal injury) NOTE: Guillain-Barre syndrome can also cause some back pain
Why is it important to ask whether the patient has experienced any trauma to the head?
Head trauma can result in a slowly-expanding subdural haematoma, which causes symptoms days/weeks after the head injury
Which risk factors should you enquire about in a patient presenting with limb weakness?
Previous stroke/TIA
History of atrial fibrillation
Atherosclerotic risk factors (e.g. hypertension, hypercholesterolaemia)