Neurodiagnostics Flashcards
Normal CSF pressure
70-180 mm H20
Normal CSF total protein
15-60 mg/100ml
Normal CSF glucose
50-80 mg/100ml
Normal CSF cell count
0-5 WBCs and no RBCs
Site of lumbar puncture
L3-L4 or L4-L5
CI to lumbar puncture
increased ICP, spinal cord mass, uncontrolled bleeding diathesis, spinal column deformities
xanthochromia
yellow, orange or pink CSF from lysis of RBCs (occurs within 2 hours, lasts 2 weeks)
How do you distinguish between viral and bacterial meningitis?
Meningitis WBC < 100 (predominance of lymphocytes) more likely viral, WBC > 100 more (predominance of PMNs) likely bacterial meningitis
CSF has positive India ink stain
cryptococcus
CSF has positive Wright or Geisma stain
toxoplasmosis
One of the most sensitive indicators of CNS pathology
CSF protein
When is the CSF glucose level low?
CNS bacterial infection
Measures how well and how fast the peripheral nerves send the signals. Evalution of entrapment neuropathies (carpal tunnel) and Guillian-Barre’
Nerve conduction velocity
Measures the electrical activity of muscles during rest and contraction. Evaluate herniated disc, amyotrophic lateral sclerosis (ALS) or myasthenia gravis
Electromyelography (EMG)
Why does NCV not work for assessing diabetic neuropathy?
NCV only measures velocity of fastest conducting fibers and diabetic neuropathy affects small nerve fibers
Used to differentiate organic causes of encephalopathy or delirium, to distinguish epileptic seizures from other causes, testing for brain death, and to determine if you should wean anti-epileptic meds
EEG
wave forms labeled according to their amplitude
Delta 0-4 Hz, Theta 4-8 Hz, Alpha 8-12 Hz, Beta greater than 12 Hz
What type of waves indicated increased slow activity in the brain due to focal brain lesion?
theta and delta waves
Indicative of focal brain lesion
polymorphic delta activity (PDA)
Indication of encephalopathy
Generalized theta and delta activity
When looking for neoplasm, infection, vascular dz, inflammatory dz, should you use IV contrast?
yes
What does a new hemorrhage look like on CT?
bright
What does water/CSF look like on CT?
dark
Difference between subdural and intracerebral hematoma
subdural is located between dura and arachnoid mater whereas intracerebral is localized within the brain substance
water/CSF is dark, fat is bright, White matter is brighter than gray matter
T1 MRI
water is bright, blood is bright, White matter is darker than gray matter
T2 MRI
Gold standard for imaging the carotid arteries and evaluating cerebral aneurysms after subarachnoid hemorrhage
cerebral angiography
Patient exhibits: + Babinsky. Right sided hemi-paresis/paralysis. Hypereflexia. Mental Confusion. Amnesia. Slurred Speech. MRI shows displaced left cerebrum. Dx?
left subdural hematoma
