neurological investigations W1 Flashcards
types of lesions?
vascular
infective
inflammatory
autoimmune
inherited
associated malignancy/paraneoplastic
neurodegenerative
types of neurological investigations?
routine and special blood tests
molecular genetic tests
imaging
CSF examination
neurophysiology
biopsy
types of neurological scans - imaging?
CT
MRI
angiography/venography
doppler ultrasound
nuclear medicine
what is the first line imaging type for neurology?
CT!
what can CT scans detect?
cerebral tumours
intracerebral haemorrhage
mature infarcts
subdural/extradural haematoma
free blood in subarachnoid space
lateral shift of midline structures
displacement/enlargement of the ventricles
cerebral atrophy
intracranial calcification
skull and scalp lesions
what are the limitations of CT
lesions under 1cm diameter may be missed
lesions with attenuation similar to brain or bone are poorly imaged
poor grey-white matter differentiation
can miss lesions within posterior fossa
spinal cord not imaged directly
radiation
what lesions are poorly imaged due to similar attenuation to the brain
MS plaques
isodense subdural haematoma
advantages to MRI?
distinguishes between white and grey matter
allows imaging of spinal cord, nerve roots, large nerves
greater resolution than CT
no radiation
MRA images blood vessels without contrast
MS plaques
posterior fossa
pituitary
foramen magnum
focal atrophy
limitations of MRI?
time
cost
patients need to cooperate
claustrophobia
general anaesthetic may be necessary
cardiac pacemakers, vagal nerve stimulators, metal in eye
over-interpretation of changes
when is CSF examination useful
diagnosis of neurological infection (meningitis, encephalitis)
study of blood products following suspected SAH
aid to diagnosis in inflammatory disorders
measurement of CSF pressure
therapeutic removal of CSF
intrathecal injection of contrast media and drugs
SAH?
subarachnoid haemorrhage
route of administration for drugs via injection into spinal canal/subarachnoid space?
intrathecal
typical CSF observations/measurements?
crystal clear and colourless
pressure 60-150mm lying down
cell count <5/mm3 (mononuclear only)
protein 0.2-0.4g/L
glucose 2/3 to 1/2 of blood glucose
culture = sterile
IgG <15% of total CSF protein
oligoclonal bands absent
IgG?
immunoglobulin G
most common antibody
complications of lumbar puncture?
low pressure (low volume) headaches
intracranial subdural haematoma
local infection and meningitis
trauma - local pain, nerve root damage
bleeding
spinal epidural haematoma
arachnoiditis
what conditions can be diagnosed by NCS/EMG
radiculopathies
anterior horn cell disease (MND)
neuropathies
NMJ pathology
myopathies
NCS? EMG?
nerve conduction studies
electromyography
NMJ?
neuromuscular junction
myopathy meaning?
any disease that affects the muscles that control voluntary movement in the body
what occurs during electromyography
needle electrode inserted into voluntary muscle
amplified recording from muscle viewed on oscilloscope and heard through speaker
3 main features seen/recorded in electromyography?
normal motor unit recruitment
denervation and reinnervation changes
myopathic, myotonic, myasthenic and other changes
myotonic meaning?
impaired relaxation of a muscle
what are the 5 measures of value in nerve conduction studies?
motor conduction velocity (MCV)
sensory conduction velocity
distal motor latency (DML)
sensory (nerve) action potentials (SAPs or SNAPs)
compound muscle action potentials
types of neuropathy?
demyelination
conduction block (impulse blocked along nerve pathway)
axonopathy (damage to nerve axon)
vasculitic
