NEURO Flashcards
WHat are the different CSF investigations?
- pressure - normal 10-18cmH20 on side or 20-30 if sitting up
- bichemistry
- microscopy
- Culture
- PCR
what are normal CSF findings?
5-20cmH20 pressure normal/clear appearance 0.18-0.45 protein glucose 2.5-3.5 normal gram stain WCC <3
Bacterial Meningitis on CSF?
>30cmH20 (raised pressure) turbid/cloudy appearance >1 protein <2.2 glucose 60-80% +ve gram stain WCC >500
Viral meningitis on CSF?
Normal or mildy increased pressure clear appeance <1 protein normal glucose normal gram stain <1000 WCC - monocytes
Fungal/TB meningitis on CSF?
fibrin web appearance 0.1-0.5 protein 1.6-2.5 glucose 100-500 WCC - monocytes
Indications of a lumbar puncture?
diagnosing meningitis/encephalitis diganosis of MS/GBS/Sarcoid diagnosis of SAH Measure pressure - intracranial HTN therapeutic removal of CSF
contraindications of Lumbar puncture?
suspicion of mass lesion in brain/spinal cord
raised ICP
local infection near site of LP
Congenital spinal problems - spina bifida
low platelets (<40), on anticoags or coagulopathy
SAH CSF/LP results …..
…..
blood-stained initially, then xanthochromia (yellowish) of LP >12hrs later,
elevated opening pressure, elevated WBC to RBC 1:1000, elevated RBC,
normal glucose,
elevated protein
GBS CSF/LP results ,…….
...... clear or xanthochromia appearance, normal/elevated opening pressure, WCC normal, Glucose normal, elevated protein
Multiple sclerosis results …..
.... clear appearance, normal opening pressure, WBC 0-20cells/uL (mainly lymphocytes), glucose normal, protein mildly elevated
When are nerve conduction studies used?
carpel tunnel syndrome
GBS
peripheral sensory/motor problems
what are contraindications of nerve conduction tests?
anticoagulation
what are complications of nerve conduction tests?
risk of infection
bleeding
pain
damage to underlying structures of nerves
CT indications:
tumours intracerebral haemorrhages intracerebral infarction sub/epidural haematomas, sub-arachnoid bleed, lateral shift in structures ventricular dilatatin, atrophy bone
risks/contraindications of CT scans?
pregnancy, young and women - risk of radiation
contrast - allergy/renal impairment
what is an MRI?
a strong magnetic field that forces protons in the body to align with that field
when radiofrequency turned off - energy released as protons realign is detected by sensors
pros of MRI?
pros = analyse brain soft tissue more detail spinal cord nerve roots skill base resolution no radiation angiogram (MRA) - without contrast
cons of MRI?
takes 30-80mins noisy claustrophobic expensive access to MRI scanner
risk and contraindications of MRI?
pacemaker/metal work/foreign bodies
non-compliant patients (younger patients/diabilities)
IV contrast is used
Investigations for suspected bacterial meningitis?
LP - CSF stain and cultures, bacterial antigen and PCR
Blood culture
Imaging - CT to r/o intracranial pathology
Bloods - FBC, CRP, Coag, Blood PCR, Glucose
Blood gas
Investigations for suspected viral meningitis?
LP - CSF
Viral PCR
Investigations for suspected whipple’s disease?
jejunal biopsy - usually has deposition of macrophages containing PAS granules
Investigations for suspected Lyme disease?
usually a clinical diagnosis if evidence of erythema migrans if present
ELISA assay - first line
Immunoblot is confirmatory Ix
Investigations for suspected Encephalitis?
LF - CSF analysis
PCR HSV
CT - medial temporal and inferior frontal changes
EEG - lateral periodic changes
Investigations for suspected Creutzfeldt-Jakob/Prion disease?
CSF - typically normal
EEG - biphasic, high amplitude sharp waves seen in biphase CJD
MRI - hyperintense signals in the basal ganglia and thalamus
Investigations for suspected Migraine headaches?
usually a clinical diagnosis
Investigations for suspected Cluster Headache?
usually a clinical diagnosis
if presents with Horner’s syndrome or pulsatile tinnitus = needs a angiogram to r/o carotid dissection
Investigations for suspected tension headache?
usually a clinical diagnosis
Investigations for suspected Cerebral venous sinus thrombosis
CTH
CT cerebral venography or MRV
Investigations for suspected Temporal Arteritis?
bloods - ESR
Gold standard - USS and temporal biopsy
Investigations for suspected Sub Arachnoid Haemorrhage?
CTH - exclude haemorrhage
If CTH NAD - do an LP - xanthachromia and opening pressure
if confirmed SAH - CT intracranial angio
Investigations for suspected Epidural Haemorrhage?
CTH
findings:
usually can see a convex/oval appearance of bleed
mass shift of midline
Investigations for suspected Subdural Haemorrhage?
CTH
Findings:
crescent shaped feathered fluid
often mass effect of midline shift
Investigations for suspected Essential tremor?
usually a clinical diagnosis
Investigations for suspected Parkinson’s disease?
also usually clinically diagnoses
if difficult to differentiate from Essential tremor
SPECT - loss of pigmentation in substantia nigra
Investigations for suspected Huntington’s Disease?
genetic testing - trinucleotide repeat HTT gene
Investigations for suspected Epilepsy?
EEG - atypical pattern
MRI brain - ?structural abnormalities
Investigations for suspected Febrile seizures?
usually a clinical diagnosis
Investigations for suspected Status Epilepticus?
usually a clinical diagnosis
Investigations for suspected foot/wrist drop?
usually a clinical diagnosis
Investigations for suspected Brain tumour?
MRI - midline shift
Investigations for suspected Amyotrophic lateral sclerosis?
usually a clinical diagnosis
nerve conduction studies - usually normal
electromyography - reduced action potentials with higher amplitudes
MRI - usually done to r/o cervical cord compression and myelopathy
Investigations for suspected cerebral palsy?
usually a clinical diagnosis - MDT involvement
Investigations for syncope?
ECG or a 24HR tape
LSBP
Investigations for Bell’s Palsy
usually a clinical diagnosis - unilateral facial droop where forehead IS affected
Investigations for Diabetic/peripheral neuropathy?
Bloods = HbA1c, hepatitis serologies, autoimmune markers and VitB12
Nerve conduction studies -
Investigations for Guillain barre Syndrome?
LP = elevated protein, normal Glucose /WCC
nerve conduction studies = decreased motor conduction
Chronic IDP has similar investigations
Investigations for Stroke?
non-contrast CT = check for hemorrhagic stroke
MRI
Investigations in TIA?
usually MRI preferred over CT = allows detection of ischaemic area
urgent carotid doppler
Investigations for Raised ICP?
CTH = rule out any space occupying lesions or bleeds
LP = invasive LP monitoring - Drain >20mmHg at regular intervals
Investiagtions for Alzheimers DIsease?
bloods - rule out any reversible causes
Structural imaging = MRI/CT
Investigations for Suspected multiple sclerosis?
MRI brain = multiple areas of focal demyelinations
LP - CSF will have oligoclonal bands
Investigations in Suspected Cavernous Sinus Thrombosis?
CTH
CT Venography and MRV
Investigations for suspected myasthenia Gravis?
ACh antibodies
Musk antibodies
LRP4 Antibodies
CT/MRI of thymus gland
Investigations in suspected sarcoid?
Largely clinical
CXR (can do CT scans)
ACE levels - not hugely sensitive or specific
Spirometry = restrictive picture
Tissue biopsy = caseating granulomas
