Limb weakness Flashcards
What is ataxia
A clumsy limb
Sudden onset (Seconds to minutes) limb weakness implies what cause?
Trauma (e.g. displaced fractures) or vascular insults (e.g. stroke/TIA)
Subacute onset (hours to days) limb weakness implies what cause?
Progressive demyelination (e.g. Guillain-Barre syndrome, multiple sclerosis) or a slowly expanding haematoma
Chronic onset (weeks to months) limb weakness implies what cause?
Slow growing tumour or MND
Speech or visual disturbance indicates that the problem is where?
In the brain (not peripheral nerve or spine)
Headaches are uncommon in TIA. A sudden onset headache that is terrible may indicate?
SAH
A unilateral headache before limb weakness may indicate?
Hemiplegic migraine
Gradual onset headache preceding limb weakness may indicate?
Subdural haemorrhage
Guillan-Barre syndrome often is accompanied by pain where?
Back pain
If there is neck or back pain, aside from Guillain-Barre syndrome, what else can we suspect?
Spontaneous disc prolapse or traumatic injury to the spine
Describe the signs of an UMN lesion
Increased tone, reflexes, upgoing plantar (Babinski positive), clonus (sometimes)
Describe the signs of a LMN lesion
Decreased tone, reflexes, wasting, fasciculations (sometimes)
Language defects suggest pathology in the dominant hemisphere (usually left). Describe receptive and expressive dysphasia
Receptive dysphasia = problems in Wernickes area, can speak fluently but cannot comprehend
Expressive dysphasia = patient can comprehend speech and follow instructions. Cannot find words or speak fluently
Attention deficits (e.g. ignoring half of their sensory world), where is the lesion?
Parietal cortex
Complete blindness in one eye indicates a lesion where?
Optic nerve (e.g. optic neuritis)
Homonymous hemianopia. Where is the lesion.
Lesion between optic chiasm and visual cortex
NB homonymous hemianopia may present similarly to visual neglect due to parietal cortex lesions
If the eye deviates away from the weak side, where is the lesion?
If the eye deviates towards the weak side, where is the lesion?
Eye deviates away from weak side = cortical lesion
Eye deviates towards weak side = brainstem lesion
In facial nerve palsy, how can you distinguish UMN lesion from LMN lesion
If forehead wrinkling and blinking is spared, this is an UMN
What are the ddx for lesions in a cerebral cortex
Stroke (infarct or haemorrhage)
Cerebral mass (Eg tumour, abscess)
Hemiplegic migraine
Hypoglycaemia
What does the anterior cerebral artery supply?
What about MCA
ACA = foot and leg
MCA = everything else (including face and arms)
Lesion to the posterior parietal cortex can cause?
Contralateral hemineglect
If someone presents with a suspected stroke within 4.5 hours of onset of symptoms, what should be done?
Non-contrast CT head.
4.5 hours = thrombolysis window
Ischaemic strokes are more common than haemorrhagic strokes. How do you treat an ischaemic stroke?
If within 4.5 hour window of thrombolysis: Thrombolysis and anti-platelet therapy (aspirin)
If outside 4.5 hour window of thrombolysis: anti platelet (aspirin), VTE prophylaxis (LMWH & stockings), stroke unit
On the stroke unit, what second line investigation should be done in a patient who has had a suspected (ischaemic) stroke?
Carotid doppler US: ?carotid artery atheroma cause of emboli
Echocardiogram: identified cardiac source of thrombus
Which drug prophylaxis may benefit patients who have suffered from ischaemic stroke?
Daily antiplatelet (e.g. clopidogrel),daily statin and daily ACEi or diuretic
When do you use anticoagulants and when do you use antiplatelets?
Anticoagulants (warfarin/rivaroxaban)- red clots - i.e. deep veins or fibrillating atria (VTE/AF)
Antiplatelets (aspirin/clopidogrel)- white clots - MI/primary ischaemic strokes
If you suspect cord compression (bilateral weakness and sensory loss in legs), what should you do
Spinal MRI to confirm
If a patient has bilateral weakness in legs, as well as eye problems, over a gradual time course - what could this suggest?
MS - it is a gradual demyelinating disorder of neurons
Consider doing a lumbar puncture, MRI and visually evoked potentials
In spinal cord lesion, what functions are lost ipsilaterally and what functions are lost contralaterally
Ipsilaterally - power, vibration, proprioception and fine touch
Contralaterally - pain and temperature
Proximal muscle weakness (in 1/2/3/4 limbs) may indicate NMJ weakness. Which conditions could this indicate?
Myasthenia gravis, Eaton-Lambert syndrome
