Diagnostic tests Flashcards
Do increased cell counts of CSF correlate with severity of disease?
No - correlate with amount of exfoliation into CSF
Relative to the lesion, where should CSF analysis be done - cranially or caudally?
Caudal to lesion
What is the max volume of CSF that can be taken?
Can you aspirate when taking CSF analysis?
1ml/5kg (0.2ml/kg)
No!
Give examples of when CSF analysis may be contraindicated
Increased intracranial pressure Coagulopathy Chiari like formation (if cervical collection) AA stability Cervical trauma
How long after CSF collection should you do analysis?
Within 1 hr
How should CSF appear grossly? How many RBCs and WBCs should be present?
Clear (cloudy suggests inflammation)
0 RBCs
<5 microleters
Albuminocytological dissociation is an example of an abnormality that can be found on CSF analysis. What does albuminocytological dissociation mean?
Increased protein without increased WBCs
What is pleocytosis?
Increased WBCs in CSF
F-waves are a method of electrodiagnostics used to assess what?
Nerve routes
Repetitive nerve stimulation is an electrodiagnostic test used to assess what?
NMJs
Electroencephalography (EEG) is an electrodiagnostic test used to assess what?
Forebrain activity (e.g. status epileptics)
Electromyography takes how long for results to become apparent? What can electromyography be used in conjunction with?
10-14 days
Used with muscle biopsies
What test is used for junctionpathies?
Neostigmine response test
What is the neostigmine test? What should you watch out for?
IV administration of neostigmine to assess junctionopathies Cholinergic crisis (prolongs ACh at NMJ - bradycardia, salivation, tremors)
The neostigmine response test can cause cholinergic crisis. What should always be prepared whilst doing this test?
Intubation kit
Atropine
Nerve biopsies are most commonly taken from which nerve?
Peroneal
Can be any superficial, easily identified, mixed nerve
Nerve biopsies are fixed in what solution?
Formalin
Keep nerve straight but not stretched
What is myelography?
Injection of non-ionic, low osmolar positive contrast into subarachnoid space
(Radiopaque - used with CT or MRI - must take CSF first!)
Can be extradural (most common), intramural, intramedullay or extramedullary
Give examples of when myelography may be contraindicated
Coagulopathies
Spinal instability
Cloudy/turbid CSF (as suggests inflammation)
What are some complications of myelography?
Exacerbation of neurological signs Seizures Injection into brainstem Central canologram Spinal cord haematoma Epidurogram Rapid movement of contrast Subdural injection (not a problem but not diagnostic) Death
