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Neurological Examination - Dog & Cat (view source)
Revision as of 15:14, 10 October 2011
, 15:14, 10 October 2011no edit summary
There are essentially 8 regions that the lesion can be assigned to:
There are essentially 8 regions that the lesion can be assigned to:
:'''Forebrain'''
:'''[[Forebrain]]'''
:'''Brainstem'''
:'''[[Brainstem]]'''
:'''Cerebellum'''
:'''[[Cerebellum]]'''
:'''C1 - C5''' spinal cord
:'''C1 - C5''' [[Spinal Cord - Anatomy & Physiology|spinal cord]]
:'''C6 - T2''' spinal cord
:'''C6 - T2''' spinal cord
:'''T3 - L3''' spinal cord
:'''T3 - L3''' spinal cord
A full physical examination including an '''orthopaedic and musculoskeletal examination''' should be performed prior to a neurological examination. Any noxious tests such as a rectal exam should be delayed until afterwards.
A full physical examination including an '''orthopaedic and musculoskeletal examination''' should be performed prior to a neurological examination. Any noxious tests such as a rectal exam should be delayed until afterwards.
There 8 parts of the neurological examination are as follows:
There are 8 parts of the neurological examination are as follows:
==Mentation==
==Mentation==
The animal's '''level of consciousness''' can be assessed: it may be alert, obtunded, stuporous, semicomatose, comatose
The animal's '''level of consciousness''' can be assessed: it may be alert, obtunded, stuporous, semicomatose, comatose.
The animal's '''quality of consciousness''' may be appropriate or inappropriate, showing compulsion or dementia.
The animal's '''quality of consciousness''' may be appropriate or inappropriate, showing compulsion or dementia.
==Posture==
==Posture==
<u>The head</u>: a '''tilt''' suggests vestibular disease
<u>The head</u>:
: a '''tilt''' suggests vestibular disease
: a '''turn''' suggests a forebrain disease
<u>The limbs</u>:
: '''wide-based stance''' suggests proprioceptive loss
:'''narrow-based stance''' suggests weakness
:'''decreased weight-bearing''' may be an evidence of pain
<u>The limbs</u>: '''wide-based stance''' suggests proprioceptive loss
<u>The body</u>:
:'''decerebrate posture''': neck and limbs extended, no mentation
:'''decerebellate posture''': neck and forelimbs extended, hindlimbs flexed, mentation ok
:'''Schiff-Scherrington posture''': forelimbs rigid, hindlimbs flexed, mentation ok, due to a spinal lesion at T3-L3
:'''Neck ventroflexion''': neuromuscular weakness
'''decerebellate posture''': neck and forelimbs extended, hindlimbs flexed, mentation ok
'''Schiff-Scherrington posture''': forelimbs rigid, hindlimbs flexed, mentation ok, due to a spinal lesion at T3-L3
'''Neck ventroflexion''': neuromuscular weakness
==Gait==
==Gait==
The animal should be walked or observed to walk on a non-slippery surface.
The animal should be walked or observed to walk on a non-slippery surface. A normal gait requires the '''integration of proprioceptive and motor systems'''. Therefore the gait exam is assessing for both paresis and ataxia.
A normal gait requires the '''integration of proprioceptive and motor systems'''. Therefore the gait exam is assessing for both paresis and ataxia.
===Paresis===
===Paresis===
There may be a failure to generate the gait or to support the weight of the animal.
There may be a failure to generate the gait or to support the weight of the animal.
'''Lower motor neuron paresis''': the walk is short-strided, there is a tendancy for collapse, bunny hopping and neck flexion.
'''Lower motor neuron paresis''': the walk is short-strided, there is a tendency for collapse, bunny hopping and neck flexion.
'''Upper motor neuron paresis''': the stride is spastic and there is stiffness. There are usually proprioceptive deficits as well, which present as knuckling and a swaying gait.
'''Upper motor neuron paresis''': the stride is spastic and there is stiffness. There are usually proprioceptive deficits as well, which present as knuckling and a swaying gait.
===Ataxia===
===Ataxia===
Ataxia refers to incoordination, and comes in three qualities:
Ataxia refers to incoordination, and comes in three qualities:
:'''Sensory ataxia''': which accompanies UMN paresis and refers to a swaying gait and knuckling.
'''Sensory ataxia''': which accompanies UMN paresis and refers to a swaying gait and knuckling.
:'''Vestibular ataxia''': loss of balance shown as a head tilt, a tendency to fall or roll to one side, abnormal nystagmus
:'''Cerebellar ataxia''': uncontrolled limb movements, abnormal rate and range of movements shown as hypermetria, intention and postural tremors.
'''Vestibular ataxia''': loss of balance shown as a head tilt, a tendency to fall or roll to one side, abnormal nystagmus
'''Cerebellar ataxia''': uncontrolled limb movements, abnormal rate and range of movements shown as hypermetria, intention and postural tremors.
==Postural reactions==
==Postural reactions==
Postural reactions require the integration of proprioceptive and motor systems.
Postural reactions require the integration of proprioceptive and motor systems. Useful reactions to test include: '''paw positioning''', '''hopping''', wheelbarrowing, hemiwalking, tactile or visual place and the extensor postural thrust.
A deficit in these reactions may show a deficit in conscious proprioception, but a failure to return the paw to a normal position may also be caused by a LMN denervation of the digit extensors or a UMN paresis.
A deficit in these reactions may show a deficit in conscious proprioception, but a failure to return the paw to a normal position may also be cause by an LMN denervation of the digit extensors or a UMN paresis.
==Spinal reflexes==
==Spinal reflexes==
Ideally these spinal reflexes will be diminished to absent in LMN disorders and increased in UMN disease.
Ideally these spinal reflexes will be diminished to absent in LMN disorders and increased in UMN disease.
It is important to evaluate the tone and spinal reflexes '''together with the gait abnormality'''. Dogs can exhibit profound neuromuscular paresis with myasthenia gravis and still have normal tone and reflexes. Similarly some dogs with T3 - L3 lesions often have normal muscle tone and reflexes.
It is important to evaluate the tone and spinal reflexes '''together with the gait abnormality'''. Dogs can exhibit profound neuromuscular paresis with [[Myasthenia Gravis|myasthenia gravis]] and still have normal tone and reflexes. Similarly some dogs with T3 - L3 lesions often have normal muscle tone and reflexes.
The animal should be placed in lateral recumbency and be as relaxed as possible.
The animal should be placed in lateral recumbency and be as relaxed as possible.
The '''cutaneous trunci reflex''' involves pinching the skin on either side of the trunk and assessing contraction of the cutaneous trunci muscle.
The '''cutaneous trunci reflex''' involves pinching the skin on either side of the trunk and assessing contraction of the cutaneous trunci muscle.
A ''decreased or absent reflex'' may show: a lesion within the reflex arc, physical limitation of movement due to joint fibrosis or muscle contracture, excitement and fear
A ''decreased or absent reflex'' may show: a lesion within the reflex arc, physical limitation of movement due to joint fibrosis or muscle contracture, excitement and fear.
An ''exaggerated reflex'' may indicate a lesion to UMN pathways cranial to the spinal cord segments tested, or may simply be due to excitement and fear.
An ''exaggerated reflex'' may indicate a lesion to UMN pathways cranial to the spinal cord segments tested, or may simply be due to excitement and fear.
==Cranial Nerves==
==Cranial Nerves==
The cranial nerve exam should be done when the patient is the most relaxed.
The [[Cranial Nerves - Anatomy & Physiology|cranial nerve]] exam should be done when the patient is the most relaxed. It can be done [[Cranial Nerves - Anatomy & Physiology|"by the numbers"]] or by region. Either part or all of cranial nerves II through to VIII are evaluated in the region of the eyes.
'''Vision''' can be evaluated by assessing response to dropping cotton wool in front of the animal or watching it follow something in the distance. It assesses cranial nerve II and the forebrain. Occasionally it is necessary to set up a maze of objects in the animal’s environment to see if they can avoid the objects when walking around them.
'''Vision''' can be evaluated by assessing response to dropping cotton wool in front of the animal or watching it follow something in the distance. It assesses cranial nerve II and the forebrain. Occasionally it is necessary to set up a maze of objects in the animal’s environment to see if they can avoid the objects when walking around them.
==Palpation==
==Palpation==
This should first be light and assess and '''swelling or atrophy''' of muscles.
This should first be light and assess any '''swelling or atrophy''' of muscles.
Deep palpation may reveal '''pain''' in an area.
Deep palpation may reveal '''pain''' in an area.
==Further investigation==
==Further investigation==
The neurological examination should enable an anatomical diagnosis to be established.
The neurological examination should enable an anatomical diagnosis to be established. It may be important to consider if one lesion can explain all deficits, or if the disease is more '''diffuse or multifocal'''.
It may be important to consider if one lesion can explain all deficits, or if the disease is more '''diffuse or multifocal'''.
The next step is to investigate the area involved, common tests and diagnostic include:
The next step is to investigate the area involved, common tests and diagnostic include:
:'''Clinical pathology''': haematology, biochemistry, serology, microbiology, CSF analysis
'''Clinical pathology''': haematology, biochemistry, serology, microbiology, CSF analysis
:'''Diagnostic imaging''': radiography, ultrasound, CT, MRI
:'''Electrophysiology''': nerve conduction studies, brainstem auditory evoked potentials, electro-encephalography
'''Diagnostic imaging''': radiography, ultrasound, CT, MRI
:'''Tissue biopsy''': nerve, muscle, brain
'''Electrophysiology''': nerve conduction studies, brainstem auditory evoked potentials, electro-encephalography
'''Tissue biopsy''': nerve, muscle, brain
{{Learning
{{Learning
DeLahunta, A. (2001) '''Braund's Clinical Neurology in Small animals: Localization, diagnosis and treatment''' ''IVIS''
DeLahunta, A. (2001) '''Braund's Clinical Neurology in Small animals: Localization, diagnosis and treatment''' ''IVIS''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]
{{review}}
[[Category:Neurological Diseases - Cat|A]][[Category:Neurological Diseases - Dog|A]]
[[Category:Expert Review - Small Animal]]