Introduction to Neurology Flashcards
1
Q
Upper Motor Neurons
Origin
A
cerebrum or brainstem
2
Q
Upper motor Neuron
pathway
A
spinal cord to connect the brain to the lower motor neurons
3
Q
UMN
Function
A
synapse with the lower motor neurons that innervate the muscles
4
Q
UMN
When Damaged
A
Increased muscle tone (hypertonus)
Exaggerated spinal reflexes (Hyperreflexia)
5
Q
Lower Motor Neurons
Origin
A
CNS
6
Q
LMN
Pathway
A
exits the CNS to form the cranial nerves and peripheral nerves
7
Q
LMN
Function
A
final pathway to innervation and activation of musclular activity
8
Q
LMN
When Damaged
A
Decreased muscle tone (hypotonus)
Diminished or absent spinal reflexes (areflexia or Hyporeflexia)
9
Q
Ipsilateral
A
lesion on the same side of the body as the neurological deficit
10
Q
Contralateral
A
a Lesion on the opposite side of the body as the neurological deficit
11
Q
Sidedness
A
Function of decussation, or the crossing of nerve fibers over midline from one side of the body to the other
12
Q
Ascending Tracts of Spinal Cord
A
Responsible for proprioception and various forms of sensory input, including pain
Sensory tracts designated by the prefix “spino-” although the dorsal white column is also sensory
13
Q
Ascending tracts of Spinal Cord
Proprioception
A
Dorsal white column → contralateral cerebrum
Spinocerebellar Tracts → Ipsilateral cerebellum
14
Q
Ascending Tracts of Spinal Cord
Spinothalamic tracts
A
involved in pain, temperature, and pressure sensation
Lateral spinothalamic tract → “superficial pain” sensation
Ventral Spinothalamic tract → “Deep pain” sensation
15
Q
Descending Tracts of Spinal Cord
Corticospinal tracts
A
conscious motor control over skeletal muscles
16
Q
Descending Tracts of Spinal Cord
Vestibulospinal
A
Controls muscles for posture and balance
17
Q
Descending Tracts of Spinal Cord
Tectospinal
A
Responisible for responses to startling visual or auditory input
18
Q
Cranial Nerves
Ipsilateral vs. Contralateral
A
All cranial nerves have ispilateral lesions except for cranial nerve 4 that has contralteral lesions
19
Q
Descending Tract of Spinal Cord
Reticulospinal
A
Activates respiratory muscles
20
Q
Descending Tracts of Spinal Cord
Rubrospinal
A
Controls Flexor and Extensor Tone
21
Q
Pressure applied to the cord
What do you lose when
A
First: proprioception, then conscious motor, followed by superficial pain, and then deep pain
Reticulospinal tract (respiratory muscles) not lost with cervical and throacic spinal cord lesions and would only happen after deep pain is lost
Function regained in opposite direction
22
Q
Paralysis
A
is the complete loss of function
Also can be referred to by the suffix -plegia
23
Q
Paresis
A
musclular weakness associated with neurological dysfunction
24
Q
“tetra-”
A
Affecting all four limbs
25
“Hemi-”
Affecting the front and rear limbs on one side of the body
26
“Para-”
Affecting only the rear limbs
27
Goals of the initial Evaluation
Determine if the patient has neurological disease
Localize the lesion
Create a reasonable list of differential diagnoses
Determine level of therapeutic intervention prior to a diagnosis
Select appropriate diagnostics
28
The Neurological History
Determine the course of the disease
Slowly progressive
Waxing/Waning
Sudden onset and stable
Sudden onset and getting worse
29
Neurological History
Possible inciting causes
Traumatic Events
Pre-existing medical conditions, drug history
Vaccine history, environmental exposures, whether other animals in the house are affected
30
Neurological History
If we don't ask we will never uncover any clues
listen for clues, discordant answers, vague timelines, assumptions, hearsay
Pursue immediately or “pin it” for follow-up
31
What is a “time course of disease"?
Progression of clinical signs in a patient as they move further away from their normal
A sudden (peracute) change is described as “lights on/lights off”
Traumatic, vascular, toxicity, Idiopathic cause
Progressive deterioration in a patient's neurological staus is typically caused by infectious disease, immune-mediated disease, neoplasia, and degenerative conditions, although the speed of decline would be different for each of these
32
Mental Status
under the control of the cerebrum and ascending reticular activating system (located in midbrain)
33
Mental status
Alert
This implies a normal state of consciousness
“normal” varies due to different behavioural responses to situations
34
Mental Status
Inappropriate
all-inclusive term for abnormal mental function that firs somewhere between normla and stupor/coma
35
Mental Status
Inappropriate
Depressed
Quiet and unwilling to perform normally but responds to environmental stimuli
36
Mental status
Inappropriate
Obtunded
Dull and relatively nonresponsive but conscious
37
Mental Status
Inappropriate
Demented
Unrecoverable loss of higher brain functions
38
Mental Status
Inappropriate
Delerious
Temporary disturbance of higher brain functions characterized by inappropriate responses or behaviours
39
Mental Status
Stuporus
unconscious in the resence of normal environmental stimuli, but can be roused with more intense stimuli
40
Mental Status
Comatose
Unconscious regardless of the intensity of the stimulus applied
41
Gait Abnormalities
Observe the patient walking around the exam room on their own or leash walked at different speeds
This helps to identify and define abnormalities noted by the client
42
Gait Abnormalities
Ataxia
Sensory, cerebellar, vestibular
43
Gait abnormalities
Hypermetria (dysmetria)
Cerebellum, or cerebellar pathways
44
Gait abnormalities
Circling
cerebellar, cerebral, vestibular
45
Ataxia
* Loss of muscular coordination:
* Instability when walking
* fall or swaying from side-to-side
* Crossing limbs when walking
* Sensory
* peripheral nerves, spinal cord, brianstem, cerebral
* Visual cues can help with compensation
* Vestibular
* peripheral or central vestibular
* Central vestibular disease may have components of sensory and vestibular ataxia
* Cerebellar ataxia
* can be present without loss of motor function
46
Proprioception
Perception or awareness of the position and movement of the body
Orientation in relation to gravity
Orientation of a joint (to prevent hyperflexion of hyperextension) or body parts in relation to each other
Proprioceptive deficits involve disruption of the sensory pathway from peripheral nerve, through spinal cord, brainstem, midbrain and to central recognition of perception
An animal can be ataxia (cerebellar or peripheral vestibular) and still have proprioception, although the ability to place may be affected
47
Different Types of Circles
“Big Circles”
Characteristic of cerebral disease
Generally circle in the direction of where the mass is located
The patient will overstep with the throacic limb contralateral of the mass
On occasion dogs may circle in the direction opposite to the side of the mass (confuzes localization)
Localization: Cerebrum
48
Different Types of Circles
“Small Circles”
Small circles are associated with disease of the vestibular system or cerebellum
Other findings - head tilt in the direction of the circling, nystagmus, cranial nerve 7 deficits, multiple cranial nerve deficits and limb deficits
Localization: Vestibular or Cerebellum
49
Head tilt
Abnormal posture of the head in which one ear is held ventral (lower) that the opposite ear
The nose continues to point straight ahead
Most often caused by disease of the vestibular or cerebellar systems
The tilt (down) is generally towards the lesion
In pradoxical vestibular syndrome, the head tilt is in hte direction opposite the lesion (sometimes seen with disease of the cerebellum)
50
Head Turn
Abnormal posture in which the plane of the ears remians parallel to the ground
The nose id deviated towards the caudal aspect of the body
Most often associated with CEREBREAL lesions
Head turn is usually toward the side of the lesion
Circling may also be associated with the head turn
In some patients with caudal brainstem lesions a component of head turn and head tilt can be seen
51
Conscious Proprioception
Technique
Place the paw where the footfall would land with the dorsal surface of the paw on the ground
Supprot the pet's weight
52
Conscious Proprioception
Severe pain may produce pseudo-deficits
Brusque or excessive movement → additional pain/pressure and proprioceptors may be fired, making subtle abnormalities difficult to identify
53
Hopping
**Technique:**
slightly lift the leg opposite to the one being examined
Use this hold to push the dog toward the limb to be examined
As the paw goes toward midline, the patient will hop the limb laterally to maintain balance
Pivot point are the paired limbs not examined
Paper Slide test
Can do in cats
54
Wheelbarrowing
Performed by lifting the pelvic limbs off the ground and walking the patient forward
THe head can be elevated (eyes covered) to remove visual cues and detect subtle deficits
Cat's don't like this test
55
Hemiwalking
Performed by lifting the limbs (fore and rear) on one side of the body and pushing the dog towards the other limbs
The limbs will correct to keep the patient form losing balance and falling
Cat's dont like this test
56
Extensor Postural Reaction
Performed by holding the patient vertically and bringing them down to land on the pelvic limbs
The patient will natureally step back so that they can then land on their front feet
Cats will definitely participate in this test
57
Tabletop Placing
Performed by holding the patient and bringing their feet to the table top, individually or in pairs
Avoid “deceleration reaching”
Covering the eyes is important to remove the visual cues
One of the better tests for cats
58
If proprioceptive deficit is identified, determine if UMN or LMN lesion
Upper Motor Neuron Lesion
increased muscle tone (hypertonus) and normal to exaggerated reflexes
59
If proprioceptive deficit is identified, determine if UMN or LMN lesion
Lower Motor Neuron Lesion
Flaccid muscle tone and diminished to absent reflexes
60
Spinal Reflex Scale
Absent - 0
Hyporeflexia (diminished) - 1+
Normal response - 2+
Hyperreflexia (exaggerated) - 3+
Hyperreflexia with Clonus - 4+
Lesion is classified as an UMN lesion (2, 3, 4+) or a LMN lesion (0, 1+)
Reflexes will never classify the limb as normal
61
Quadriceps (Patellar) Reflex
Most reliable reflex to interpret in dogs and cats
Evaluates the L4-L6 spinal cord segment and the femoral nerve
If patient is tense, reflex can be difficult to elicit
THe expected response is extension of the stifle
62
Cranial Tibial Reflex
Evaluates the L6-L7 spinal cord segment and the peroneal branch of hte sciatic nerve
THe proximal aspect of the muscle belly is percussed
The expected response is flexion of the hock
63
Gastrocnemius Reflex
Evaluates the L7-S1 spinal cord segment and the tibial brach of the sciatic nerve
Two Techniques: Percuss the insertion of the tendon and look for extension of the hock; flex the hock to tense the tendon prior to percussion of the distal tendon and look for contraction of the gastrocnemius muscle
64
Flexor (withdrawal) responses
Evaluates the sensory component, reflex arc, and motor component
Often dependent on the force applied and the nature of hte patient
THe interpretation of this reflex is questionable at best
A flextion response requires no input from above and should be lost with LMN lesion and present with an UMN lesions
This does not require higher input and is often misinterpreted as the central recognition of pain
65
Biceps Reflex
Evaluates the C6-C8 spinal cord segment and the musculocutaneous nerve
Technique: Index finger is wrapped around the distal insertion of the biceps tendon; elbow pulled slightly caudally to stretch the tendon; The finger is tapped with the pleximeter and the examinier watches for contraction of the biceps muscle
66
Triceps Relfex
Evaluates teh C7-T1 spinal cord segment and the radial nerve
Technique:
Hold the forearm and pull the elbow slightly caudally and rotate the elbow outwardly to stretch the triceps tendon
The tendon is then percussed and the examiner looks for contraction of the triceps
The index finger can also wrap around the triceps tendon to tension it further and the finger tapped with the pleximeter
ALTERNATE method: tap the triceps tendon or muscle belly and look for extension of the elbow, although paradoxically this will sometimes elicit flexion of the elbow
67
Extensor Carpi Radialis Reflex
Evaluates the C7-T1 spinal cord segment and the radial nerve
Technique: Percuss the proximal musle belly of the extensor carpi radialis muscle
Extension of the carpus, limb is supported passively to elicit this reflex
68
Babinski Reflex
Has no real bearing on the exam
Normally absent in the neurologically intact patient
Plantar or Palmer surface of the paw is stroked in a proximal to distal direction
Normal →\> nothing or slight flexion of hte foot
UMN lesion → Extension of hte Foot and splaying of the toes
69
Pain Sensation
Important prognostic information
Superficial pain elicitied by pinching the skin overlying or in between the toes
Deep pain evaluated by applying pressure to bone or joints
Need ot see a central response
Withdrawal of the limb alone does not indicate the presence of deep pain
Loss of deep pain is a grave prognostic finding
70
Crossed Extensor Reflex
Can be elicited in a patient wiht an UMN lesion
Normal in very young animals
While performing the withdrawal reflex, as one limb is flexed, the other limb extends
71
Cutaneous Trunci Reflex
Evaluates sensory pathway to skin overlying the dorsum
Extends form C8-L4 spinal cord segments
Skin Pinch → cutaneous trunci muscle contract
ABSENT reflex: Lesion is somewhere within 2 vertebrae cranial or caudal of where the reflex disappears
This will not be lost with all spinal cord injuries
72
Cranial Nerve 1
Olfactory
73
Cranial nerve 2
Optic
74
Cranial Nerve 3
Oculomotor
75
Cranial nerve 4
Trochlear
76
Cranial Nerve 5
Trigeminal
77
Cranial Nerve 6
Abducens
78
Cranial Nerve 7
Facial
79
Cranial Nerve 8
vestibulocochlear (s)
80
Cranial Nerve 9
Glossopharyngeal (m,s)
81
Cranial Nerve 10
Vagus
82
Cranial Nerve 11
Accessory
83
Cranial Nerve 12
Hypoglossal
84
Evaluation of the cranial nerves
Lesion localization within the brain and for sidedness
Each response has both a sensory and motor component
Combine results to isplate which nerve are affected
Cerebrum facilitiates action of cranial nerves
85
Pupillary light Reflex
Sensory Pathway: CN2 (optic)
Motor Pathway: Parasympathetic nerve as a component of the oculomotor nerve (CN3)
Perform in dark room with a very bright light
PLR can be absent due to disease of the cornea, iris, lens, anterior or posterior chamber, retina, optic nerve, midbrain, and oculomotor nerve pathway
Evaluate direct and consensual responses to localize the lesion
86
Mydriasis
Dilated pupils
Pathologic mydriasis
Parasympathetic denervation CN3, dysautonomia, intraocular disease, Herniation = fixed and dilated or midrange
Iris Atrophy
Fear (especially in cats)
87
Miosis
Constricted pupils
Causes: Uveitis, corneal pain, organophosphate or carbamate poisoining, sympathetic denervation, FeLV infections, Severe cerebrocortical disease = miotic and nonresponsive
88
Anisocoria
Defined by pupils of different sizes
Important to identify which of the two is abnormal for localization purposes
89
Papilledema
Swelling of the optic nerve head seen during retinal examination
Relevance: suggestive of high intracranial pressure
Causes: brain tumor, inflammatory disease, Trauma
90
Horner's Syndrome
Characteristics: Miosis, ptosis (droopy upper eyelid); enophthalmos (sunken globe); Elevate 3rd eyelid (or prolapsed)
Damage to sympathetic innervation to the eye
Post-ganglionic and pre-ganglionic lesions
“Ganglionic” refers to cranial cervical ganglion
91
Horner's Syndrome Differentiation
Pre-ganglionic: 1st or 2nd neuron
“Denervation hypersensitivity”
The iris is sitll innervated (lacks higher input)
Tonic level of norepinephrine prevents denervation hypersensitivity
Dilute phenylephrine on the eye → nothing happens
92
Horner's Syndrome Differentiation
Post-ganglionic
Damage of last neuron form the CCG of the eye
No final nerve to prevent denervation hypersensitivity
Dilute Phenylephrine → pupil dilates
93
Nystagmus
Involuntary rapid movement of hte eyes
94
Nystagmus
Physiologic
normal response to rotation of hte head
eye repetitively moves slowly away from direction of rotation and rapidly in direction of rotation
95
Nystagmus
Pathologic
Present at rest or if placed in an abnormal position
Slow phase is typically toward the lesion and fast phase is away from the lesion
Can be horizontal, rotary, or vertical
96
Physiologic Nystagmus
Sensory Component
Vestibular component of CN 8
97
Physiologic Nystagmus
Motor Component
Cranial nerves 3, 4, and 6
98
Menace Response
Senory pathway: CN2
Motor Pathway: CN 7
When threatened or presented with something that suddenly appears close to the eyes/face, the patient will bling
If create a breeze with the hand → sensory pathway of hte cornea (CN5) can be elicited
Generally easy to evaluate
Patients with cerebral disease may have an intact CN2 and CN7 and still not have a menace response
99
Palpebral Reflex
Sensory Component: CN5
Motor Component: CN7
Technique: gently touch the medial and lateral canthus of the eye and look for a blink
100
Facial Sensory Reflex
Sensory: CN5
Motor: CN7
Technique: stroke whiskers, side of face, pinch skin
Retraction of side of face or lip
101
Corneal Relfex and Retractor Bulbi Reflex
Sensory: CN5
Motor: CN7, CN6
Technique:
Evaluate at the same time
Blow on the cornea or gently touch it with sterile cotton swab
Corneal reflex → blink
Retractor bulbi reflex → Retraction of the globe
102
Gag Reflex
Evaluates both motor and sensory components of the glossopharyngeal nerve and vagus nerve (CN 9 and 10)
Technique: touch lateral aspects of pharynx, patient should vigorously move the tongue, pharynx, and head in an attempt to remove the finger
This is not performed on rabid or aggressive animlas EVER
