Kapitel 26 (Tobias) - Neurologic examination Flashcards
Which 6 parts can the neurologic examination be divided into?
1) Sensorium and behavior
2) Posture and gait
3) Postural reactions
4) Spinal reflexes, muscle mass and muscle tone
5) Cranial nerves
6) Cutaneous sensation
Define “sensorium”
The cognitive or mental state of a patient
Normal sensation depends on the function of the cerebrum and the reticular activating system - what is the reticulate activating system?
A collection of nuclei located throughout the brainstem - from the thalamus to the medulla
Define “Obtundation”
A state of decreased arousal with response to voice or touch
Define “Stupor”
Arousal to vigorous stimuli, but response is incomplete or inadequate
Define “coma”
Sustained unresponsiveness to stimuli
Name examples of changes in quality of sensorium vs level of sensorium
Quality:
Aggression, hyperactivity, hysteria, propulsive movement, loss of housebreaking
Level:
Depression, Obtundation, Stupor, Coma
Recumbency is associated with 3 neurological localizations. Which?
1) Brainstem
2) Cervical spinal cord
3) Diffuse neuromuscular disease (Lower motor neuron)
Which neurologic localization does headtilt suggest?
Vestibular disease
A head or bodyturn suggests which neurologic localization?
Prosencephalon or forebrain
Name 2 neurologic localizations resulting in a lowered head position
1) Neck
2) Diffuse neuromuscular disease
Describe “Decerebrate rigitidy”
Which neurologic localization does this imply?
- Opisthotonus
- Extensor tonus of all limbs
- Midbrain or rostral cerebellar
Describe the impact on mentation in patients with decerebrate vs. decerebellate rigidity
Decerebrate: Always severe impact on mentation and menace response
Decerebellate: Does not always affect mentation
Describe “Decerebellate rigidity”
Neurologic localization?
1) Opisthotonus
2) Extensortonus of limbs
3) Flexion of hip joint
Describe “Pleurothonus”
neurologic localization?
- Deviation of the head and neck to one side
- Mid to rostral brainstem or cerebral lesions.
Define “Paresis”
- Reduced ability to support weight or a deficiency in the ability to generate a gait
- Also implies the presence of voluntary motor function
Define the suffix “-plegia”
The absence of voluntary motor function.
What caracterizes a “lower motor neuron peresis or plegia”
- Decrease in muscular tone (flaccidity)
- Reduced or absent reflexes
- Pronounced muscular atrophy may be seen
What caracterizes an “upper motor neuron peresis or plegia”
- Increased muscular tone (spasticity)
- Normal to exaggerated reflexes
- Relative preservation of muscle mass
Name the 3 clinical forms of ataxia
1) General proprioceptive ataxia
2) Vestibular ataxia
3) Cerebellar ataxia
Describe General Proprioceptive Ataxia
1) Crossing of the limbs
2) Scuffing or dragging of the digits
3) High stepping
4) Overreaching stride
5) Standing or landing on the dorsal aspect of the paws 6) and sometimes a delay in initiation of the swing phase of the gait
Appears “drunk”
Describe Vestibular Ataxia
1) Headtilt
2) Circling
3) Loss of balance
4) Nystagmus
5) Loss of CN V and CN VII - central (Ipsilateral to lesion)
6) Loss of CN V and sympathetic innervation (Horners´s syndrome) - peripheral (Ipsilateral to lesion)
- CN V = Trigeminus = Motor -> chewing muscles
- CN VII = Facialis = Motor -> Face
How can you differentiate central and peripheral vestibular disease?
Central:
1) +/- loss of proprioception
2) +/- Ipsilateral upper motor neuron paresis
3) +/- Deficits in CN V and CN VII function
Peripheral:
1) Deficits in CN VII and loss of sympathetic innervation to the head (as evidenced by Horner syndrome)
- CN V = Trigeminus = Motor -> chewing muscles
- CN VII = Facialis = Motor -> Face
Describe Cerebellar Ataxia
- Hypermetric gait
- “High stepping, overreaching”
- Intention tremor
- Wide base stance
- May sway or stumble forward and back, as well as from side to side
*Because of the close connection between the cerebellum and the vestibular system, head tilt, loss of balance, and abnormal nystagmus may be present
What is necessary for a normal postural reaction?
1) Intact major sensory (generel proprioceptive) pathways of CNS and PNS
2) Intact motor pathways (UMN and LMN) of CNS and PNS
Pelvic limbs: Paraparesis with general proprioceptive ataxia. Normal to exaggerated muscle tone and spinal reflexes.
Neurologic localization?
Spinal segment T3-L3
In a dog or cat with deficits in proprioception - how do you differentiate a prosencephalic lesion from a lesion caudal to the midbrain?
- Cranial nerve deficits
- Changes in sensorium
The patellar tendon reflex is mediated by which nerve and spinal cord segment?
Femoral nerve - segment L4-L6
A deficit in the withdrawal reflex of the thoracic limb indicates a leison in which spinal segment?
C6-T2
A deficit in the withdrawal reflex of the pelvic limb indicates a leison in which spinal segment?
L6-S1
What can you say about the location of the lesion if a dog or cat has deficits in the cutaneus trunci reflex at a certain point?
The lesion is located 1 or 2 vertebral bodies cranial to the deficit
Describe “the clasped knife reflex”, when we see this and the function of this reflex
in patients with upper motor neuron deficits and
cponsequent extensor tone.
Analogous to closing a pocket knife, the limb shows increased extensor tone preventing forced flexion until
a certain point where it suddenly gives away and flexes.
This reflex is aimed at protecting from overstretch of the muscle. It is mediated through Golgi tendon organs embedded in tendons; when stimulated, there is a reflex inhibition of the muscle.
How can an upper motor neuron deficit result in hypertonia?
Much of the descending upper motor neuron influence provides for inhibition of extensor musculature. With lesions disrupting the upper motor neuron pathways, the lower motor neurons may be released from inhibition, leading to overactivity of the extensors, resulting in hypertonia of the limb.
What is “Neurogenic atrophy”?
Muscle atrophy secondary to disturbance of the lower motor neuron innervations of the muscle
