Diagnostics/PE/GA

Question 1

what are examples of abnormal spontaneous activity? (for electromyography)

Answer 1

1. fibs and sharps (positives) - differ from indentation of electrode; single fibers - destabilization of sarcolemma membrane
2. complex repetitive changes
   - polyphasic repetitive waveforms (uniform frequency)
   - does change frequency
   most often chronic denervation +/- myopathies
3. Myotonic potentials
   - seen with myotonia congenita and radiculopathies
   - similar to complex repetitive discharges BUT wax and wane frequency (and increased amplitudes) = dive bomber potentials

Question 2

what are examples of ‘normal’ spontaneous activity when conducting electromyography

Answer 2

1. insertional activity
   - irritation from needle advancement
2. miniature end-plate potentials
   - needle close to NMJ = ‘end plate noise’
3. End-plate spikes
   - single normal myofiber depolarize completely leads to action potential
4. motor unit action potentials
   - light anesthesia or compound action potential with range of electrode

Question 3

what are the advantages of propofol and etomidate?

Answer 3

propofol - smooth recovery, decreased CBF/ICP preserving cerebral auto regulation, antioxidant properties, decrease vomiting

etomidate - minimal decrease BP, preserves CPP, decreased CMR, CBF, ICP
BUT
may alter epileptiform activity

Question 4

what is the benefit of cord dorsum potentials?

Answer 4

can reward SC dorsum potentials and somatosensory evoked potential concurrently

Question 5

what is a key feature of sensory nerve conduction velocity testing?

Answer 5

potential often appears polyphasic

Question 6

why is ketamine contraindicated?

Answer 6

• increase rate of catechoalmines - increase cardiac output and increased BP
• increase CBF and cerebral metabolic rate in limbic
• decrease CBF/CMR in cortex
• prolonged recovery

Question 7

what are some advantages of ketamine

Answer 7

• improved ICP in some studies with decreased need for vasopressors
• does not impair cerebral autoregulation

Question 8

MUSCLE BIOPSIES
1- can use formalin?
2- common places to acquire?
3- order of samples obtained?
4- 2 types of techniques?

Answer 8

1- No formalin; freeze sample for enzyme histochem except 1st sample in formalin for e-microscopy (use biopsy clamp)

2- distal 1/3 of lateral head of triceps, vastus lateralis, cranial tibial (proximal 1/3) and temporalis

3- order : 1st one for e-microscopy

4-
percutaneous biopsy - local block, quick and less cost but not as good sample
OR
open muscle biopsy - anesthesia, more cost, but better orientation of fibers

Question 9

Ptosis is related to paresis of what muscle

Answer 9

levator palpebral superiaris

Question 10

Elevation of 3rd eyelid from what deficiency?

Answer 10

loss of pterygoid muscles

Question 11

what is the flow of CSF?

Answer 11

lateral ventricle -> interventricular foramina -> 3rd ventricle -> mesencephalic aqueduct -> 4th ventricle ->

from 4th ventricle could go to:
1) subarachinoid space via lateral apetures
OR
2) central canal of SC

Question 12

NERVE BIOPSY:
1- where to sample for generalized NM disease?
2- where to sample for sensory neuropathy?
3- what cranial nerve are described to be biospied?

Answer 12

1 - common fibular (peroneal): has motor, sensory, and autonomic

2- caudal cutaneous antebrachial in TL or caudal cutaneous sural PL

3- facial and trigeminal; recurrent laryngeal (not usually done); hypoglossal medial to digastricus

Question 13

what are the branch names of the brachial plexus?

Answer 13

• brachiocephalic
• suprascapular
• subscapular
• lateral thoracic
• muscular branch
• axillary
• musculocutaneous
• radial
• long thoracic
• median
• ulnar
• dorsal thoracic
• pectoral

Question 14

what is the site of spinal nerve root injury for brachial plexus usually? why?

Answer 14

intradural - where roots arise from spinal cord;

because it there is lack of well-defined epineurium and is weakest structure

Question 15

Downside of cervical collection of CSF?

Answer 15

CSF slower and volume is less

Question 16

What are normal CSF
- WBC
- TP

Answer 16

CSF normal WBC - 0-5 x 10^6/L
TP:
- cerebellomedullary cistern - <250mg/L
- lumbar cistern <450 mg/L

Question 17

What nerve and spinal cord segments are tested with:
- Patellar
- Biceps
- Triceps
- Withdrawal TL vs PL

Answer 17

• Patellar: femoral (L4-L6)
• Biceps: musculocutaneous (C6-C8)
• Triceps: radial (C7-T2)
• Withdrawal:
  1-TL (dorsal thoracic, axillary, musculocutaneous, median, ulnar, radial C6-T2)
  2 - PL (sciatic L6-S1)

Question 18

Sensitivity and specificity for PCR on diagnosing viral meningoencephalitis?

Answer 18

Sens - >95%
Speci - >99%

Question 19

what are the 4 reasons you can’t rule out infectious meningoencephalitis with PCR of CSF?

Answer 19

1. individual PCR insensitive?
2. nucleic acids in CSF are at indetectable levels
3. nucleic acids in CNS parenchyma, not in CSF
4. disorder ‘triggered’ by pathogen that is not there

Question 20

what inhalant is most recommended for neuro anesthesia?

Answer 20

sevoflurane

Question 21

Describe formation of tympanic plexus

Answer 21

CN IX (glossopharyngeal) and caroticotympanic nerve

CN IX (PS) and (S) craniocervical ganglion carotid plexus
- preganglionic fibers to Parotid/Zygomatic glands
- postganglionic to Parotid gland sensory to middle ear cavity
- postganglionic S to go to dilator pupillae and nictating membrane

Question 22

Which antibiotics have good BBB penetration?

Answer 22

GOOD:
3rd gen ceph
fluroquinolones
metronidazole
sulfonamides
chloramphenicol
trimethoprim

Question 23

Which antibiotics have poor penetration of BBB?

Answer 23

BAD:
1st and 2nd gen cepha
aminoglycosides
clindamycin
vancomycin

Question 24

what sections skin innervated by:
- fibular and tibial?
- saphenous?

Answer 24

fibular and tibial - dorsal and plantar paw

saphenous - medial pelvic limb

Question 25

how does a patient walk with sciatic nerve paralysis?

Answer 25

plantigrade - tibial n dysfunction - during stance paw misplaced on dorsal surface (fibular n dysfunction) limb supported because femoral nerve intact to extend stifle joint in weight bearing

Question 26

how do you calculate nerve conduction velocity?

Answer 26

m/s = distance between (+) electrodes (mm)/proximal latency - distal latency (ms)

Question 27

for muscle biopsy specimen processing: name three ways to secure sample to enable cut on transverse plane?

Answer 27

- blocks (0.5 cm) on cork squares - tissue embedding media - gum tragacanth - tissue - T&K O.C.T. compound

Question 28

What is the underlying result of FLAIR and STIR

Answer 28

FLAIR: - fluid attenuated invasion recovery fluid suppressed - T2 FLAIR - helps distinguish pure fluid with little protein from solid but high water-content lesions like edema STIR: -short tall inversion recovery - fluid or solid tissues with high water hyperintense against dark fat (can work like T2W)

Question 29

what is an M wave and what is its latency?

Answer 29

for motor nerve conduction velocity testing - orthodromic (impulse travels in normal direction) propagation of action potentials along nerve, ach release @ NMJ junction and myofiber depolarization - latency - marking point which baseline deflects in upward direction

Question 30

Signs seen with myopathic syndrome versus neuropathic syndrome

Answer 30

myopathic: - general weakness - exercise intolerance - stiff gait - body tremors - local/general atrophy - 'percussion dimple contracutre' - muscle pain, megaesophagus neuropathic: - motor - paresis/paralysis of structures, neurogenic atrophy; decreased to absent tone, muscle fasciculations - sensory - hypalgesia, or hyperesthesia; CP deficits, abnormal sensation of face and trunk, limbs without atrophy; self mutilation, decreased to absent reflexes

Question 31

what drug can be used to treat hypotension and to maintain CPP > 70?

Answer 31

phenylephrine IV CRI

Question 32

what is the 'clasp knife relfex' what causes it

Answer 32

very difficult to flex up until certain point then suddenly resistance gone and can completely flex UMN tract lesion

Question 33

what is benefit of spectral fat saturation

Answer 33

ID fatty masses - can help distinguish contrast enhancement from natural hyperintense fat to ID lesions

Question 34

what are functions of CN 1-4?

Answer 34

1 - olfactory: smell 2 - optic: vision 3 - oculomotor: - motor to extraocular muscle - parasympathetic to pupil (constrict) 4 - trochlear: motor to dorsal oblique

Question 35

what are functions of CN5-8?

Answer 35

5 - trigeminal: - motor to muscle of mastication (mandibular) - sensory to face (ophthalmic, maxillary, mandibular branches) 6 - abducens: motor to lateral rectus and retractor bulbi 7 - facial: - motor to muscles of facial expression - parasym to lacrimal glands - sensory to rostral tongue 8 - vestibulocochlear - hearing; balance

Question 36

what is repetitive nerve stimulation ? what is it useful for?

Answer 36

RNS - repeat supramax (+) of motor or mixed nerve while recording M waves from muscles innervated test- helps diagnose junctionopathies (MG, botulism)

Question 37

(RNS) difference between decremental, facilitation, pseudofacilitation?

Answer 37

decremental - AUC and amplitude decrease facilitation - AUC and amplitude increase pseuodacilitation - AUC same and amplitude increase

Question 38

what is purpose of single fiber electromyography?

Answer 38

to investigate physiologic status of end plate in NM junction transmission disorders (sensitive to diagnosing MG) evaluates jitter - latency from stimulus to response varies with consecutive stimulation of single muscle fiber

Question 39

nerve biopsy: tips of securring?

Answer 39

- dissect fat and fascia away - can pin to balsa wood or tongue depressor - suture to CTA - suspend with weight

Question 40

what stain is used for light microscopy? on nerves for biopsy?

Answer 40

toluidine blue

Question 41

what are the 2 forms of assessing nerve root function? how are each explicitly used?

Answer 41

F- wave: - long latency action potential (antidromic AP) - lower amplitude, latency inversely related to M wave - represents motor event - assess ventral nerve root and proximal part of motor/mixed nerves H-reflex: - electrically stretch reflex (tap tendon) - afferent arm group 1a sensory fiber; efferent and motor neuron ventral gray column - use low stimulus - diagnose polyneuropathies, proximal nerve injury

Question 42

what are minimum database tests for neuromuscular disease?

Answer 42

- CK - >10,000 U/L (muscular dystrophy, myopathies) - electrolytes (especially to r/o hyper/hypokalemia - lactate and pyruvate (measure rest and 10 min post exercise) - urine myoglobin (to differentiate from Hg -> NH4SO4 test) - thyroid screening - acetylcholine receptor antibody - others: 1) masticatory myositis serum ab against 2m. 2) infectious agents/tick diseases

Question 43

Name the neurological grades 0 -> 5

Answer 43

0: tetraplegia or paraplegia w no deep pain 1: tetraplegia or paraplegia w no superficial pain 2: tetraplegia or paraplegia w nociception 3: nonambulatory tetraparesis/paraparesis 4: ambulatory tetraparesis with GP ataxia 5: spinal hyperesthesia only or no dysfunction

Question 44

explain the cusing's reflex

Answer 44

intracranial pressure increased leading to CPP decrease CPP decrease leads to decreased CBF which increased catecholamine increase the catecholamine increase leads to increase in MAP and stimulation of carotid bodies stimulation of carotid bodies leads to decrease in HR increase in ICP leads to decrease in HR but increase in systemic MAP

Question 45

what are 2 syndromes of protozoal meningoencephalomyelitis? what serology tests are needed to diagnose? treatment? prognosis?

Answer 45

meningoencphalitis - multifocal neuro signs; cerebellar myositis - polyradiculoneuritis (<6 mo age) T. gondii: IgM >1:64 means active infection T. gondii IgG >1:64 support active Neospora IgG >1:64 suspect clindamycin/TMS; pyrimethamine Guarded in young dogs and cats

Question 46

What are the benefits of dexmedetomidine for neuro anesthesia?

Answer 46

- blunt sharp increase in HR to protect ICP - cooperative sedation - decrease ischemic cortical volume by 40% and helps with hemodynamics - short extubation times - less bleeding - lower nausea and vomiting

Question 47

what are options to help prevent spike in HR/BP with intubation

Answer 47

IV lidocaine or fentanyl to decrease sympathetic input

Question 48

what are the benefits of opioids with neuro anesthesia?

Answer 48

doesnt alter cerebral vascular response to changes in PaO2 and PaCO2 and MAP

Question 49

which near/skin areas innervated by: median and ulnar ulnar alone radial ulna and musculocutaneous

Answer 49

median and ulnar: palmar surface of paw ulnar alone: lateral digit 5 radial: dorsal paws; craniolateral antebrachium ulna and musculocutaneous: caudal and medial antebrachium and brachium

Question 50

which matters make up leptomeninges? pachymeninges?

Answer 50

L - pia and arachnoid P - dura and arachnoid

Question 51

where is subarachnoid space? contains?

Answer 51

subarachinoid space - between pia and arachnoid - CSF

Question 52

what is subdural space? contains?

Answer 52

subdural - between dura and arachnoid - blood vessels