neuro investigations Flashcards
Botulism px and RF’s
Clinical?
Sudden muscle weakness, starts with the eye muscles, bulbar palsy
Rf- black tar heroin use, infected food
Myasthenia gravis clinical findings (not test results)
Clinical:
-bilateral facial weakness, squared off smile,
- extra-ocular weakness (double vision common)
- proximal limb weakness
- fatiguability
Diagnostic tests for mysathenia gravus
AChR antibodies (80-90% patients)
Ct for thymus hyperplasia/thymoma (75%)
How to differentite between MG and LEMs (lambort easton syndrome) investigation wise
EMG STUDIES
(electomyography)
(type of nerve conduction study)
LEMs- low amplitude wave which increase with excersize, vice versa for MG
what does diagnosis of ms require (1)
dissemination of lesions in time and space on MRI (with contrast!)
(looks like grey lesions on MRI this represents demyelination and varying shades of grey show that they have occurred at diff times)
Idiopathic raised intracranial pressure Ixs
include 1st line
1st line: MRI brain with MRV sequence- normal
Cerebro spinal fluid
-Elevated pressure
-Normal consitiuents
Visual fields
Trigeminal neuralgia ix
MRI brain
Giant cell arteritis ix
1st: Ultrasound temporal artery
Diagnostic: biopsy
Test to differentiate strokes
CT first line
MRI
what are the investigations to identify if large vessel occluded in stroke (1st and second line)
CT first line
mr angiogram
Most important investigation for epilepsy
ECG- rules out cardiac dysrythmia (long QT)
Who gets a ct scan for epilpesy
Only if u think there has been intracerebral damage/haemorrhage (if u think its an emergency situation)
eg.skull fracture, deteriorating GCS etc
or
new onset seizure- rule out tumour etc
What is eeg useful for regarding epilepsy
Classify epilepsy
Confirmation of non epileptic attacks
Surgical evaluation
Confirmation of non- convulsive status
(Don’t ever do it if u don’t know the cause)
Partial status epilepticus diagnostic ix
(Non convulsive status)
Eeg recording
what people with a head injury require a CT within ONE HOUR of being seen
head injury + …
- GCS <13 on initial assessment or <15 2 hours later
- suspected open or depressed skull fracture
- focal neurological deficit
- more than one episode of vomiting
-suspicion of NAI
what behaviours are checked in glasgow coma score , their scoring and main total scores to know
- eye opening response:
4. Spontaneous
3. To speech
2. To pain
1. None - best verbal response:
5. Orientated
4. Confused
3. Words
2. Sounds
1. None - Best motor response:
6. Obeys commands
5. Localises to pain
4. Withdraws from pain
3. Abnormal flexion to pain (decorticate posture)
2. Extending to pain
1. None
total score= 15- best response, 8 or less- comatose client, 3- totally unresponsive
CT scan within eight hours after head injury if
- > 30 mins retrograde amnesia
or
-temporary LOC or amnesia
+ the following:
-65 or older
-coagulopathy
-dangerous mechanism of injury
general Ms: imaging of choice and what is seen on imaging
MRI
high signal T2 lesions
periventricular plaques
Dawson fingers: often seen on FLAIR images - hyperintense lesions perpendicular to the corpus callosum
general ms: what is seen in cerebrospinal fluid analysis
CSF
oligoclonal bands (and not in serum)
increased intrathecal synthesis of IgG
how are ISCHAEMIC strokes classified
via the Oxford Stroke Classification
classifies ischaemic strokes into 4 categories:
-total anterior circulation stroke (TACS)
- Partial Anterior Circulation Stroke
- Posterior circulation syndrome
-lacunar syndrome
what arteries are involved in a: total anterior circulation infarct and what criteria are met
- middle & anterior cerebral arteries
- all 3 of criteria met:
1. unilateral hemiparesis and/or hemisensory loss of the face/arm/ leg
2. homonymous hemianopia
3. higher cognitive dysfunction e.g. dysphasia/sensory/visual inattention
what arteries are involved in a: partial anterior circulation infarct and what criteria are met
- involves smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
-2 of the criteria are met:
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia/ sensory/visual inattention
what arteries are involved in a: lacunar infarct and what criteria are met
involves perforating arteries around the internal capsule, thalamus and basal ganglia
presents with 1 of the following:
1. pure motor stroke
2. pure sensory stroke.
3. ataxic hemiparesis (ataxis + mild hemiparesis affecting same side) (clumsy hand dysarthia)
4. sensorimotor stroke
posterior circulation infarcts- what arteries and symptoms (5)
vertebral arteries (forms basillar and its branches)
-Cranial nerve palsy and a contralateral motor/sensory deficit
-Bilateral motor/sensory deficit
-Conjugate eye movement disorder (e.g. horizontal gaze palsy)
-Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
-Isolated homonymous hemianopia
guillian barre syndrome investigation
gold standard: lumbar puncture (raised protein with normal wcc)
nerve conduction studies may also be performed
what scale measures disability/dependance in activities of daily living in stroke patients
Barthel scale
what test is used to differentiate between organic and non organic hip extension? and how?
hoovers sign
if the clinician cannot feel the patients limb pushing downwards as the patient tries to lift leg= non-organic
what reflex test investigates corticospinal tract lesions
hoffmans sign
gold standard ix for venous sinus thrombosis
MR venogram
investigation for suspected subarachnoid haemorrhage
non-contrast CT head is the first-line
(hyperdense star)
if CT head <6 hours of symptom onset and is normal do not lumbar puncture
consider an alternative diagnosis
if CT head> 6 hours after symptom onset and is normal
do a lumber puncture (LP) 12 hours following onset of symptoms to allow the development of xanthochromia*
if the CT shows evidence of a SAH
referral to neurosurgery to be made as soon as SAH is confirm
Ix for confirmed subarachnoid haemorrhage
(so after non contrast CT)
CT intracranial angiogram (to identify underlying cause e.g. aneurysm or AVM)
+/- digital subtraction angiogram (catheter angiogram)
dementia Ix
CT standard- may not always be necessary eg. old and classic presentation
MRI- if young. fast progression. any other atypical features
frontotemporal dementia ix
SPECT
Dementia Lewy Body Ix
DAT
Utilises spect (single photon emission computerised camera) and injects dopamine active transporter
what presentation= probable MSA
(as a definitive diagnosis can only be made by autopsy confirming case)
sporadic progressive adult >30 years (usually between midlife) onset disease characterised by:
-urinary incontinence (w/ erectile dysfunction in males)
or
-orthostatic hypotension (at least 30 s & 15 d)
and one of the following predominant motor features:
poorly levodopa-responsive parkinonism
or
cerebellar syndrome ( ataxia, cerebellar dysarthia, cerbellar occulomotor dysguntion ge. nystagmus)
what is the definitive diagnosis of MSA (Multiple System Atrophy)
autopsy confirming- alpha-synuclein containing Glial cytoplasmic inclusions
what imaging can support a diagnosis of MSA
brain MRI showing volume loss on cerebllum, pons, cerebellar peduncles
encephalitis Ixs and results (5)
CSF: lymphocytosis, elevated protein
PCR for HSV
CT: medial temporal and inferior frontal changes (e.g. petechial haemorrhages) - normal in one-third of patients
MRI is better
CJD (cruetzfeld-jakob disease) ix
EEG: biphasic, high amplitude sharp waves (only in sporadic CJD)
MRI: hyperintense signals in the basal ganglia and thalamus
guillian barre ix
1st line: check vital capacity and monitor resp
diagnose: lumbar puncture: raised protein with normal white blood cell count
nerve conduction studies: dec motor nerve conduction velocity (due to demyelination)
what is the ASPECTS score and its clinical use
10 point score system for MCA (middle cerebral artery) strokes. 1 point is lost for each region of brain affected
(higher the score the better)
(PC-ASPECTS- same scoring system adjusted for posterior circulation infarcts)
score 8-10= small core
0-5= large core
first line investigation for suspected stroke
urgent NON CONTRAST CT head
(rule out intracranial haemorrhage- has to be non contrast as contrast agent shows up as hyperdense therefore cannot differentiate between agent and bleeding)
TIA IX
MRI brain + carotid doppler (unless not candidate for carotid enderectomy)
what test can help differentiate seizures from pseudoseizures
prolactin- raised in true seizures
narcolepsy ix
multiple sleep latentcy eeg
