Clin Med- Neurodiagnostics

kelseyfmeyer's version from 2015-11-30 13:51

Neuroimaging--> radiography

Question Answer
radiography is described in terms of..opacity
what state should the pt be in when you are performing neurodiagnostics?All require very sedate or anesthetized patients
what should you know about positioning of the pt when performing neurodiagnostics?proper positioning obv.... SYMMETRY is helpful
what does a myelography look at? the spine
what can computed tomography look at?spine and skull (brain)
magnetic resonance imaging can look at?brain and spinal cord
what's an Orthogonal view and which imaging technique has this?when a 3d object is looked at in 2d- which means this is a RADIOGRAPH (described in terms of opacity). there is NO cross-sectional imaging
when might you you do radiographs on the head?(not as useful as other methods, however) can be used to evaluate for skull fractures, disease of the middle ear
if you are going to do radiographs of the spine, what must you keep in mind? what must you do to have a good image?they must be perfectly straight if you wanna take a spine rad!! be sure to collimate to the area of interest
*what can you DEFINITIVELY DIAGNOSE with a spine radiograph? (4)Vertebral malformations, Diskospondylitis, Trauma (fracture, luxation, subluxation), Degenerative disk disease
*what can you PRESUMPTIVLY DIAGNOSE with a spine radiograph? (3)Intervertebral disk extrusion, Wobbler syndrome, Certain tumors
whats a Hemivertebra, how can you dx?when only half of the vertebral body formed (kinda causes a wedge shape) and can be dx with rads
how can you dx spina bifida with radiographs?look for the missing spinous processes on your image
atlanto-axial subluxation can be dx with a radiograph but looking at how theyre dislocated from each other. what is a reason that an animal might be prone to this problem which you can pick up on rads?a missing dens, which would uusally help keep the atlas and axis together
how can Diskospondylitis be dx from a radiograph?you can see an open space and a moth-eaten appearance of the bone
If you have Suspected Spinal Trauma and wish to do radiographs, what are 2 special precautions you should take when doing them?(1) If possible, hold off on sedation until radiographs are obtained--> their tense muscles might actually be holding something important together. (2) use of a horizontal beam (beside instead of above them, so you don't have to flip them to take a different view)--> Sometimes just one view will have to do!
three ways to dx INTERVERTEBRAL DISK DZ with a radiograph?(1) Shape and size of intervertebral disk space (2) Shape, size, and opacity of intervertebral foramen ("horse head" or "snoopy head") (3) Size of articular facet joint space
what is a Myelography, why would you do one (what can you assess)?you inject iodinated contrast intrathecally (in subarachnoid space) so you can evaluate the subarachnoid space and extrapolate information about the spinal cord (you can't see the spinal cord though)
what are the three abnormal patterns you can see on a myelography?extradural, intradural (extramedullary), intramedullary (spinal cord swelling or edema) (see slide 17 for pic of each in diagram form)
myelography--> in what situations might you see an EXTRADURAL pattern?***IVDD--> intervertebral disk dz**! Also can see with extradural masses such as a hematoma, lymphoma, or primary bone tumor
myelography--> you would see an Intradural, Extramedullary Pattern in what situations?Meningioma**(golf tee sign), or a nerve sheath tumor
what unique sign will you see if there is a meningioma and you perform a myelography?"GOLF TEE SIGN"= looks like a gold ball sitting on a golf tee sideways (*this is an intradural/extramedullary pattern)
when would you see an intramedullary pattern on a myelograph?spinal cord sweling/edema

Neuroimaging--> Computed Tomography (CT) and Magnetic Resonance Imaging (MRI)

Question Answer
CT is described in terms of?density, attenuation (saying opacity is ok though)
CT is useful what ___ or ___ lesionsmineralized or bony
if it involves ____, CT will be helpfulbones
can you do cross sectional imaging with CT?yes!
how might you make a CT image even more accurate?Can be used with IV contrast, can be combined with myelogram
can you image in multiple planes with CT?yes, with a little difficulty. if you Reposition patient for dorsal plane (head), you can reconstruct for sagittal plane. You can Reconstruct for sagittal and dorsal planes (spine)
6 dzs of the vertebral column where CT is useful to use?Hansen type I intervertebral disk disease (Acute onset often in young chondrodystrophic breeds), Lumbosacral stenosis, Diskospondylitis, Wobbler syndrome, trauma, and Destructive tumors
2 dzs of the head where CT is useful to use?trauma, focal tumors of the forebrain
what is wobblers dz?Cervical stenotic myelopathy, a compressive cervical spinal cord syndrome caused by vertebral canal stenosis, articular process osteophyte proliferation, and vertebral body tipping
MRI is described in terms of?intensity
what kind of tissue is MRI best for looking at?Excellent soft tissue resolution
can you see different planes in MRI?yes! Image in 3 planes without repositioning
MRI is good for looking at...use for the brain and spinal cord
how can you make MRI even more specific/accurate?can use contrast
how can you change up the MRI machine to target specific things?you can use different sequences for different affects. (she said you don't have to remember, however in the notes it says for the BRAIN you can use: T1 (pre- and post-contrast), T2, FLAIR, T2*, diffusion-weighted imaging..... and for the SPINE you can use: T1 (pre- and post-contrast), T2, STIR, HASTE, T2*)
what are 6 dzs of the BRAIN you can look at with an MRI machine?tumors, stroke, Congenital malformations, Inflammatory disease, Abscess, Senile changes/cognitive dysfunction (all soft tissue stuff!)
8 dzs of the SPINAL CORD/ NERVE ROOTS you can look at with an MRI machine?Intervertebral disk disease (BOTH types), Fibrocartilaginous embolism, Diskospondylitis, Myelitis, Vertebral and neural tumors, Lumbosacral stenosis, Wobbler syndrome, Atlantoaxial subluxation
how should the pt be when you are taking MRIs?anesthetized
does an MRI have better resolution on a smaller or larger patient?better res on a larger pt
better resolution depends on what (of the machine?)higher field strength
will fluid appear darker or lighter on an MRI?brighter/whiter

Lab tests and cytology/ other tests

Question Answer
what are some other lab tests you can do in addition to neuroimageing?Complete blood count, chem panel, endocrine testing, Infectious disease titers, Miscellaneous testing
what might Peripheral neutrophilia on the CBC indicate?Steroid responsive meningitis-arteritis
what two things on a chem panel might indicate/cause a neuro problem?Muscle enzyme elevation, Electrolyte abnormalities
which two endocrine disorders are you most likely to see neuro problems with?Cushing’s syndrome, Hypothyroidism
what are some infectious tick-bourne dzs which can cause neuro problems in dogs that you can test for?RMSF, E. canis
what are some viruses which can cause infectious dzs of the neuro system in dogs that you can test for?Canine distemper virus
what are some parasites (protozoa) which can cause infectious dzs of the neuro system in dogs that you can test for?neospora, toxoplasma, Hepatozoon
what is a fungi which can cause infectious dzs of the neuro system in dogs that you can test for?Blastomyces
what is a bacteria which can cause infectious dzs of the neuro system in dogs that you can test for?Bartonella
what are some viruses which can cause infectious dzs of the neuro system in cats that you can test for?Coronavirus/FIP, FeLV, FIV
what are some fungi which can cause infectious dzs of the neuro system in cats that you can test for?Blastomyces, Cryptococcus, and others
what is a parasite (protozoa) which can cause infectious dz of the neuro system in cats that you can test for?toxoplasmosis
if you suspect Myasthenia gravis, what test can you do?Anti-acetylcholine receptor Ab titer
if you suspect Masticatory muscle myositis, what test can you do?Anti-type II M muscle Ab titer
Miscellaneous Testing---> Therapeutic drug monitoring--> what are two anticonvulsants you can monitor?Phenobarbital and bromide
what are two bing things you check for with Cerebrospinal Fluid (CSF) Analysis?Increased number of WBCs in fluid of CSF (this is pleocytosis), or an Increased amount of protein
what is pleocytosis and how do you check this? Increased number of WBCs in fluid of CSF, check with a Cerebrospinal Fluid (CSF) Analysis
why would you never want to do a CSF tap if there is inc intracranial pressure (such as there is a tumor)? what should you do?because you can cause brain herniation (brain rapidly moves toward lower pressure gradient)- and this can happen with a lumbar OR cisternal tap. DO IMAGING FIRST and only do CSF tap if absolutely necessary
what is Pithing? when is it a risk?this is when you directly stab the brainstem, and can happen with a cisternal CSF tap
how often does CSF tap provide a definitive diagnosis? what can a CSF tap do for you?Rarely yields definitive diagnosis, but does add to our pile of information
what are 5 types of electrodiagnostics?Electromyography, Nerve conduction velocity, Repetitive nerve stimulation, Brainstem auditory evoked response, and Electroencephalography
what does Electromyography test for? What can it tell you?Detects abnormal muscle cell membranes-- such as denervation, an axonal disease, or primary mm disease
what does a Nerve conduction velocity test tell you?tells you about abnormalities in myelination- this can pertain to motor OR sensory nerves
a Repetitive nerve stimulation test might help you determine...?might be Helpful for some disorders of the neuromuscular junction, like myesthenia gravis or botulism
how does myesthenia gravis present with a Repetitive nerve stimulation test?looks like Decremental response (aka reduced response each time)
how does botulism present with a Repetitive nerve stimulation test?you will see Pseudofacilitation- ie, appears to get better
Brainstem Auditory Evoked Response can diagnose what two things?deafness (is it congenital aka Sensorineural, or is it acquired aka conduction?) and brain(stem) death
Electroencephalography--> what is this test doing? what can it be used for?it does A Recording of spontaneous brain activity, which can confirm seizure focus. (not used much clinically but Could be useful to determine nonconvulsive seizures)
histopathology--> what often leads to definitive dx?necropsy :(
what can a brain biopsy tell you about?cerebral dz, tumor removal