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:
Sudden-onset (seconds to minutes)
Subacute onset (hours to days)
Chronic onset (weeks to months)
- Sudden-onset (seconds to minutes)
Vascular problem (e.g. stroke, TIA)
Trauma (e.g. disc herniation, subarachnoid haemorrhage) - Subacute onset (hours to days)
Progressive demyelination (e.g. MS, Guillain-Barre syndrome)
Slowly expanding haematoma (e.g. subdural haematoma) - 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.
- Brain: Stroke: Ischaemic and Haemorrhagic TIA Hemiplegic migraine Todd’s paresis Hypoglycaemia
- Spinal Cord
Spinal disc prolapse
Others: spinal cord transection/infarction - Nerve Root
Spinal disc prolapse
Vertebral fracture - Peripheral Nerve
Acute limb ischaemia
Traumatic nerve injury
List some causes of subacute onset limb weakness based on the location of the lesion.
- Brain Multiple sclerosis Haematoma Tumour - Spinal Cord Multiple sclerosis Tumour Transverse myelitis - Nerve Root Guillain-Barre syndrome Poliomyelitis - Neuromuscular Junction Botulism Tetanus
List some causes of gradual-onset limb weakness based on the location of the lesion.
- Brain
Tumour
Motor neurone disease - Spinal Cord
Spinal canal stenosis
B12 deficiency (subacute combined degeneration of the spinal cord) - Peripheral Nerve
Diabetes mellitus
Vasculitides - Neuromuscular Junction
Myasthenia gravis
Lambert-Eaton syndrome - 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)
List the pattern of symptoms/signs seen in:
Upper motor neurone lesions
Lower motor neurone lesions
- Upper motor neurone lesions Hypertonia Hyperreflexia Clonus Upgoing plantars - Lower motor neurone lesions Hypotonia Hyporeflexia Fasciculations Wasting
Describe the pattern or symptoms/signs in the acute phase of an upper motor neurone lesion.
Reduced tone and reduced reflexes
State two types of language defects and the area of the brain affected.
1) Receptive Dysphasia
Patient speaks fluently (words may be jumbled) but cannot comprehend language
Damage to Wernicke’s area
2) Expressive Dysphasia
Patient can comprehend language and follow instructions
Patient cannot find words and speak fluently
Damage to Broca’s area
A lesion in which part of the brain causes hemispatial neglect?
Posterior parietal cortex
Which part of the visual pathway is damaged in:
Complete blindness in one eye
Homonymous hemianopia
- Complete blindness in one eye Optic nerve Globe itself - Homonymous hemianopia Between the optic chiasm and the lateral geniculate nucleus