Neurology Flashcards
(16 cards)
What are the causes of a peripheral neuropathy?
Remember also mechanical / compression as a cause
What are the typical findings in chronic inflammatory demyelinating polyneuropathy?
CIDP is an acquired, immune mediated demyelinating peripheral neuropathy (think: the acute form is GBS)
- Motor > sensory ivolvement (‘motor-predominant’ rather than ‘sensory-predominant’)
- If sensory - usually a loss of vibration/proprioception (think: demyelinating) rather than painful peripheral neuropathy
- If loss of proprioception: positive Rhomberg’s
- Usually symmetric
- Alost always areflexic, if not –> reconsider the diagnosis!
- Cranial and bulbar muscles may be involved (differential is Miller Fisher Syndrome / the acute variant).
- Miller Fisher Syndrome: ophthalmoplegia with ataxia and areflexia
- Antibodies against GQ1b (a ganglioside component of nerve) are present in 85 to 90% of patients with MFS
What are the causes of a paraparetic (instead of hemiparetic) spastic gait?
BIlateral CVAs
Hereditary spastic paraparesis
MS
CP
Spinal cord lesion
What are some causes of a bilateral foot drop / bilateral high stepping gait?
MND
Charcot Marie Tooth
CIDP
BIlateral strokes (?causing plantarflexor spasticity)
What are the causes of a unilateral foot drop / high stepping gait?
L5
Sciatic
Peroneal nerve neuropathy
Or it can be due to a sensory neuropathy (but this might be bilateral)
Peripheral sensory neuropathy
SCID
Syphillis
What is a positive and negative Rhomberg’s test?
What are the causes of each?
Negative test:
- Patient steady with eyes open & closed. = Normal.
- Patient unsteady with both eyes open and with eyes closed. = Cerebellar disease.
Positive test:
- Steady with eyes open, unsteady with eyes closed. = posterior column lesion, peripheral neuropathy (particularly loss of joint position sense), vestibular dysfunction
What are the UMN signs?
Absence of fasciculations
No early atrophy, can be disuse atrophy later
Increased tone
Spastic paralysis
Hyperreflexia
Positive Babinki & Hoffmans
What are the LMN signs?
Fasciculations
Atrophy
Flaccid paralysis
Hyporeflexia
Plantar downgoing, negative Hoffmans
What are the findings of myopathy?
(do fasciculations occur in myopathies?)
No - absence of fasciculations
Proximal muscle weakness
Otherwise normal tone, power, reflexes**
**Can have reduced reflexes due to muscle bulk
What does a positive proator drift represent?
UMN lesion of the ULs
Differentiate the types of hypertonia / rigidity in an UMNL?
- Clasp knife spasticity (pyramidal - eg corticospinal tract).
- Lead pipe rigidity (extra-pyramidal - eg basal ganglia).
- Cogwheel rigidity (extra-pyramidal - eg. basal ganglia)
What is the difference between dysmetria and dysdiadochokinesia?
Dysmetria (hypo or hypermetria)
- Finger-to-nose test: patients with dysmetria are unable to touch the tip of their nose with their index finger ; patients with tremor perform the test with shaking fingers
- Heel-knee-shin test: inability to slide the heel of one foot down the shin of the opposite leg; the heel will deviate to alternate sides
Dysdiadochokinesia
- Inability to perform rapidly alternating agonistic-antagonistic movements eg in rapid alternating movement test such as pronation / supination
A lesion where would give you a bitemporal hemianopia?
Optic chiasm
A lesion where would give you a homonymois hemianopia?
Optic tract
A lesion where would give you monocular blindness / anopsia?
Ipsilateral optic nerve
What peripheral nerve lesions can cause a foot drop?
- L5 nerve root: weakness of hip abduction (gluteal muscles) and pain and sensory loss in the side of the thigh and lower leg, including the dorsum of the foot and toes I-III, in addition to features in items 4 and 5.
- Sciatic nerve: pain in the back of the thigh and calf, in addition to any of the features in items 4 and 5. Depending on the site and severity of the lesion, weakness of foot dorsiflexion and sometimes weakness of plantar flexors and knee flexors can occur. Sensory changes may be present in the foot (sole, dorsum, and lateral lower leg). The Achilles’ tendon reflex may be reduced or absent.
- Common peroneal nerve: any of the features in items 4 and 5
- Deep peroneal nerve: weakness of foot dorsiflexion (tibialis anterior muscle), toe extension (extensor digitorum longus muscle and extensor hallucis longus muscle), foot eversion (peroneus longus and brevis muscles), and sensory loss in first web space
- Superficial peroneal nerve: weakness of ankle eversion (peroneus longus and brevis muscles) and sensory loss of the anterolateral aspect of the lower leg and the foot dorsum (except the first web space).
