Neurology Flashcards
Give two examples of things that differ in neuro exam between central and peripheral vestibular disease
- central: cranial nerves other than CN VII affected (ipsilateral to lesion) (peripheral can have affected CN 7 and horners syndrome)
- central: loss of proprioception and motor function
- central: mentation changes
What are the three parameters measured in modified glasgow coma score?
Motor activity, brainstem reflexes, level of consciousness
what are the levels/points in motor activity in the modified Glasgow coma scale?
- normal gait, normal spinal reflexes
- hemipares, tetrapares
- recumbent, intermittent extensor rigidity
- recumbent, constant extensor rigidity
- recumbent, constant extensor rigidity with opistotonus
- recumbent, hypotonia of muscles, depressed or absent spinal reflexes
what are the levels/points in brain stem reflexes in the modified Glasgow coma scale?
- normal PLR and oculocephalic reflexes
- slow PLR and normal to reduced oculocephalic reflexes
- bilateral unresponsive miosis with normal to reduced oculocephalic reflexes
- pinpoint pupils with reduced to absent oculocephalic reflexes
- unilateral, unresponsive mydriasis with reduced to absent oculocephalic reflexes
- bilateral, unresponsive mydriasis with reduced to absent oculocephalic reflexes
what are the levels/points in level of consciousness in the modified Glasgow coma scale?
- occasional periods of alertness and responsive to environment
- depression or delirium, capable of responding but response may be inappropriate
- semicomatose, responsive to visual stimuli
- semicomatose, responsive to auditory stimuli
- semicomatoes, responsive to repeated noxious stimuli
- comatose, unresponsive to repeated stimuli
What is the probability of survival in px with MGCS of 8 within the first 48h after initial TBI?
50%
Describe the gait in LMN and in UMN
LMN: Short and choppy gait.
UMN long, strided, spastic stiff gait. Often with general proprioceptive ataxia
Where can the neuro localisation be with a head turn?
Cerebral/thalamic lesion or forebrain lesion, rostral brainstem
Describe decerebrate and decerellebrate posture? How do these differ from Schiff Sherrington?
Decerebrate: extensor rigidity all four limbs and optisotonus, comatosed
Decerebellate: extensor rigidity front legs, hinds legs can be flexed at hips, opistotonus
Schiff Sherrington: extensor rigidity front legs with normal proprioception and voluntary movement. hind legs none ambulatory but normal spinal reflexes
Where is the lesion in the spine in a px with Schiff sherrigton
T3-L3
What does pleurosthotonus look like and where is the lesion localised?
Deviation of head and neck to one side. Brainstem or cerebral lesion.
What are the three types of ataxia
General proprioceptive, vestibular, cerebellar
What pathways can have been disturbed in general proprioceptive ataxia?
Peripheral nerve, dorsal root, spinal cord, brainstem.
Number and name the cranial nerves
- N. Olfactorius (I)
- N. Opticus (II)
- N. Oculomotorius (III)
- N. Trocklearis (IV)
- N. Trigeminus (V
o 3 delar: oftalmicus, maxillaris och mandibularis - N. Abducens (VI)
- N. Facisalis (VII)
- N. Vestibulocochlearis (VIII)
- N. Glossofaryngeus (IX)
- N. Vagus (X)
- N. Accesorius (XI)
- N. Hypoglossus (XII)
At what age does the menace response normally become present?
10-12 week of age
Where is the lesion in relation to the cutaneous trunci muscle reflex?
Reflex preserved for one to two vertebral bodies caudal to the level of the lesion (aka lesion is two vertebral bodies cranially)
Describe your clinical neuro findings in a spinal shock px
LMN (reduced or absent spinal reflexes and muscle tone) in pelvic limbs in a px with otherwise UMN localization (T3-L3 injury). Loss of flexion/withdrawal reflex seems most common, but loss of tendon reflexes also possible. Improvement noted in most px, ranging from h to weeks (12-24 m most common)
How do you different spinal shock and myelomalacia?
Myelomalacia: often complete loss of reflexes and deep pain perception both hind limbs. Grave to poor prognosis
Spinal shock: reflex deficits often partial (ie absent flexion and withdrawal but tendon reflexes intact). Might lack deep pain perception but will have improvements of reflexes and tone to be more consistent with an UMN lesion
What cells produce myelin in the CNS and the PNS?
Oligodendrocytes in cns, schwann cells in the pns
What type of synaptic transmission does cardiac and smooth muscle cells have?
Electrical (ion flow directly between gap junctions if adjacent cells)
(the other option is chemical with gaba, glycine, glutamate, acetylcholine, occurs in cns, pns)
Where is the neuro localisation in paradoxical vestibular syndrome?
Cerebellum (has head tilt contralateral to lesion due to the lack of inhibitory effect from cerebellum causing excessive tone in ipsilateral extensor muscles)
Metronidazole intoxication and thiamine deficiency can cause neurological dysfunction, localised to where?
Central vestibular disease
Hypothyroidism, aminoglycosides, chlorhexidine can cause neurological dysfunction, localised to where?
peripheral vestibular disease
what pain fiber give a dull, aching pain and what give sharp pain?
Dull C fibers. Sharp A δ (a-delta)
What is the Monroe-kellie doctrine?
the sum of volumes of brain, CSF and intracranial blood is constant. An increase in one component must accompany a decrease in or both of the other components in order to maintain a stale and constant pressure.
What is the percentage of brain tissue, CSF and blood of the intracranial volume?
Brain tissue 80%, CSF 10%, blood 10%
Draw an intracranial pressure volume curve. What is on the x axel and the y axel?
X intracranial volume. Y intracranial pressure
_____/
In primary brain trauma, what are the three gradients of trauma and shortly describe their difference
Concussion, contusion, laceration
Concussion. No underlying histopathology changes
Contusion: parenchymal haemorrhage and oedema
Laceration: physical disruption of the brain barrier
What % of animals with severe head injury has extra-axial head injury?
80%
What % of animals with mild head injury has extra-axial hematoma?
10%
Give 5 examples of local changes that exacerbate neuronal cell death in the secondary phase of TBI/ most common factors leading to secondary brain injury
Glutamate accumulation (exitotoxicity)
Influx of Na and Ca intracellularly
Free radical production (ROS)
Inflammatory mediator release
Depletion ATP stores
NO accumulation
Cerebral lactic acidosis
ischemia
Loss of autoregulation
(systemic insults: hyperglycemia, hypoglycemia, acidbase disturbance, electrolyte disturbance, hyperthermia, hypoxemia, hypotension, hypercapnia, hypocapnia, systemic inflammation)
What are the two types of brain odema
Vasogenic and cytotoxic
What is normal ICP
5-12 mmHg
What are the 4 protective haemostatic effects in increased intracranial pressure?
- Volume buffering (expansion of dura mater and displacement of csf and blood)
- Autoregulation if cerebral blood flow
- Cushings reflex
- Herniation of the brain parenchyma
What is the formula for cerebral perfusion pressure
CPP= MAP - ICP
What is normal cerebral perfusion pressure?
60-70 mmHg, ideal in TBI 50-90
Between which systemic systolic blood pressure can brain maintain normal CPP
50—150 mmHg
Name three herniation types (localisations)
Cerebellar, cirgulate, central, transcalvial, downward, upward
What does Biots respiration look like?
Apnea, alternating with periods of quick, shallow breathing
What does Cheyne-stokes respiration look like
Quick respiration in crescendo-decrescendo pattern followed by apnoea
Interpretation of pupil size and PLR in head trauma. (Table 128.1 saccm)
If pupil size is midposition and PLR is normal, what is the prognosis?
If pupil size is midposition and there is no PLR, the prognosis is? And where is the localisation?
If pupil size is bilateral mydriasis and PLR is poor to none, what is the prognosis?
Good
Poor to grave (lesion is in pons, medulla)
Poor to grave
What are the indications for CT in TBI?
if moderate to severe neurological abnormalities on presentation,
lateralizing signs,
failure to improve significantly within the first few days,
acute deterioration in neuro status
give some neuroprotective strategies in TBI
- hypoxemia, keep paO2 >80 mmHg
- hypoventilation, keep arterial co2 30-35 mmHg, venous 40-45 mmHg
- hypotension, keep MAP > 80 (if doppler >100)
- elevate head 15-30 degrees
- glycemic control > 10 mmol, avoid hypoglycemia
- decrease cerebral metabolic demand with analgesia, neuromuscular blockers
temperature control
name 3 advantages to hypertonic saline over mannitol in TBI
less likely to cause hypovolemia and decreased cerebral perfusion. Less likely to cause increased permeability of the blood brain barrier.
what is the initial effect of mannitol in TBI
rheological (increase in cerebral blood flow and cerebral oxygen delivery)
what percentage of dogs have seizures after TBI?
6.6%
Should you treat TBI dogs with prophylactic antiseizure medication?
No evidence that it help, but if have seizure treat aggressively and for at least 7 days
What are some poor prognostic indicators in TBI
Pupillary dilation, loss of PLR, deterioration of consciousness.
Small animal coma scale: retrospectively to correlate with 48-hour outcome in dogs with head trauma.
Hyperglycaemia at admission and persistent hyperglycaemia associated with worsened mortality and outcome in people, some evidence in vet med
Probability of survival is 50% in patients with an MGCS of 8 within the first 48h after initial head trauma and TBI
Draw a cerebral perfusion pressure curve. What is on the x and y axel
X cerebral perfusion pressure
Y cerebral blood flow
___________________/
/
Explain the cerebral perfusion pressure curve?
X cerebral perfusion pressure
Y cerebral blood flow
___________________/
/
Stable during autoregulation when CPP if 50-150 mmHg. Cerebral vascular tone responds to CPP. When autoregulation impaired (<50 and >150) the cerebral vascular tone passively follows systemic arterial blood pressure
What is the formula for cerebral metabolic rate of oxygen (CMRO2)?
Cerebral blood flow x (arterial blood oxygenation in % - venous blood oxygenation in %) x Ca (constant representing the amount of oxygen-carrying molecules per unit of blood)
How can brain death be diagnosed
Deep coma, absence of spontaneous respiration/apnea, loss of brainstem reflexes (fixed, dilated pupils)
EEG: prolonged inactivity or burst suppression in the absence of anaesthetic drugs. Dont depend on single reading, do several, wait 72 h after trauma, combine with BAER
BAER: early waveforms but no late
Reticular activating system (RAS), is important for which neurological function?
Level of consciousness/mentation
What parts of the CNS are involved in the oculocephalic reflex?
Brainstem pathway from the cranial cervical cord and medulla oblongata to CN III, IV, VI (oculomotor, trochlear, abducens)
What is spontaneous positional nystagmus in a head trauma patient indication of?
Vestibular dysfunction, common in increasing ICP
What is the most important factor for controlling cerebral volume and flow in intracranial hypertension?
PaCo2. Ideally 35-45 if mild to moderate, 30-35 if severe
Somebody suggest prophylactic hyperventilation in a px with ICH (intracranial hypertension), what do you say?
No. Not recommended by brain trauma foundation as can cause neuronal ischemia and exacerbation of ICH
When is corticosteroids recommended in intracranial hypertension?
Benefits unproven, only recommended if vasogenic oedema associated with primary inflammatory disease, tumour-associated oedema and acute ischemia
Why is it important to control pain, temperature and seizures in a px with intracranial hypertension?
Those things increase cerebral metabolic rate. Increased cerebral metabolic rate increases cerebral blood flow. Increased cerebral blood flow increases ICP
Give three immunomodulatory effects of hypertonic saline infusion
Decreased neutrophil activation and adherence, stimulate lymphocyte proliferation, inhibit proinflammatory cytokines (TNFa) by macrophages. Increase IL10, may reestablish Na/glutamate pump activity following TBI and reduce excitoxicity
What receptor does glutamate bind to?
AMPA, NMDA
What receptor does GABA bind to?
GABAa (or GABAb)
Give 5 negative effect of hypertonic saline
Hypernatremia
Hyperosmolality
Hyperchloremic metabolic acidosis
Irritant if given im or sc
Bradycardia
Brochospams
If conc >10% can cause increased brain blood barrier permeability
Contraindications: if severe electrolyte disturbances, uncontrolled haemorrhage, lung oedema, hypertonic dehydration, hypertonic fluid overload
Give 5 negative effects of mannitol
Increased permeability blood brain barrier if ICP
Acute renal failure/nephrotoxicity if serum osmolality exceed 320 mOSM/L
Rebound intracranial hypertension
Fluid and electrolyte imbalance (Na, Cl, P). Intravascular volume depletion. Reduced serum Na reabsorption + hypo na due to osmotic effects
May influence measurement urine SG
May increase osmolar gap and increased osmolality
seizures
Cant give if overhydrated or anuria as requires large amounts
Give 6 precautions to take when administrating mannitol
Maintain euvolemia. Correct hypovolemia first but don’t overhydrate. U cath to monitor outs
Use a fluid filter or dissolve visible crystals first
Administer slow bolus over 20 min
If possible, monitor and maintain serum osmolality at or below 320 mOsm/L, particularly if concern for renal failure
Avoid prophylactic administration and multiple repeat dosages (typically <3 doses/day)
Monitor serum electrolytes and maintain normal range
Monitor urine output. If urine production is not evident within 15 min of admin, give furosemide to induce diuresis
Do not use when ongoing intracranial haemorrhage is suspected
Give three findings indicative of brain herniation in dogs presenting with neurological signs in admission (clinical exam and blood pressure measurement)
High SBP, greater difference between SBP and HR, combination of higher SBO and HR, low MGCS
Does Cushing’s response have a high or low specificity and sensitivity for brain herniation
Sensitivity 24%, specificity 100%. Her et al jvecc 2022
What is on the x and y axel of a ICP pressure waveform curve
X time.
Y intracranial pressure (mmHg)
What does a P2 increase in a ICP pressure waveform mean
Raised ICP and reduced intracranial compliance, is a proxy for intracranial compliance
What physiological systems affect the ICP pressure waveform W1 and W2 fluctations
W1 fluctuations due to systemic arterial cycle
W2 fluctuations in response to respiratory cycle