Neurological Diseases

PNS

Nervous System

• CNS– Brain, spinal cord

• PNS (Links CNS to body)– Cranial nerves (from brain)

– Peripheral nerves (from spinal cord)

• Autonomic nervous system smooth muscle and cardiac muscle : (PNS and SNS)

• Somatic (voluntary) system – skeletal m.

Cranial nerves

Mnemonics

• “Oh, Oh, Oh, To Touch And Feel Various Girl's Very Angelic Hands”

• Olfactory, Optic, Oculomotor, Troclear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal

• “Some Say Marry Money, But My Brother Says Big Business Makes Money”

NUMBER NAME TYPE KEY FUNCTION

I Olfactory S Smell

II Optic S Vision

III Occulomotor M Eye movement, pupil size, focusing lens

IV Trochlear M Eye movement

V Trigeminal B Sensations – head & teeth; chewing

VI Abducent M Eye movement

VII Facial B Face and scalp movement, salivation, tears, taste

VIII Vestibulococlear S Balance, hearing

IX GLossopharangeal B Tongue movement, swallowing, salivation, taste

X Vagus B Sensory from: GI, respiratory; Motor: larynx, pharynx, parasympathetic,

abdomen and thoracic organs

XI Accessory M Head movement, accessory motor with vagus

XII Hypoglossal M Tongue movement

Neurological Exam

• Attitude, Level of consciousness, Gait– Cerebral cortex, thalamus, hypothalamus

• Cranial Nerves– I (S) Olfactory: SMELL• ether on cotton—will pull away

– II (S) Optic: VISION• follow moving objects; drop cotton ball

Neurological Exam

– III (M), IV (M), VI (M) : look up, down, sideways: strabismus, aniscoria (PNS/SN)• Oculomotor: Eye movement, pupil size, focusing lens• Trochlear: Eye movement• Abducent: Eye movement

– V (B) Trigeminal: sensory to face, motor to mastication (Chewing); • anesthesia to face, weakness in jaw muscles. • Head and teeth e.g dropped jaw

Neurologic Exam

–VII (M) Facial: Face/Scalp, salivation, tears, taste • unilateral droop; drool; no

menace• Paralysis: eyelid, lip, ear

–VIII (S) Vestibulocochlear: • balance (nystagmus, head

tilt, circling); deafness

Neurologic Exam

– IX (B), X (B), XI (M): swallowing (9 and 10); muscle atrophy • Glossopharyngeal: tongue movement, swallowing,

salivation, taste, dysphagia• Vagus: Sensory: GI/resp; Motor: larynx, pharynx,

parasympathetic, abdomen and thoracic organs. Dysphagia. Megaesophagus. • Accessory: head movement, accessory motor with

vagus. Laryngeal paralysis.

–XII (M) Hypoglossal • loss of tongue movement; unilateral atrophy

Female Brain

Male Brain

LOCATION

Neurologic Exam

• Observe– Mentation (alert,

lethargic, coma, etc)• Agitation, anxiety

• Seizures

– Posture (Higher center)• Upright or sternal

• Head tilt (vestibular?VIII)

• Wide based stance (ataxia, weakness)

Neuro Exam

• Gait– Walking and running on flat, nonslippery surface

• Walk slowly back and forth with turns and circles

– Proprioceptive deficits – knuckling? (spinal cord defect)

– Paresis (Deficient)/paralysis (No) – cerebral cortex, brainstem, spinal cord or peripheral spinal nerves or muscles

– Circling/pacing – • Tight circling with head tilt – vestibular (VIII)

• With dementia – ipsilateral cerebral cortex

Posterior Paresis (T-L)

• Reflexes presentin the rear legsT3-L3• Reflexes arediminished orabsent in the rear legsL4-S2•IVDD/Trauma

‘My dog is draggin’

Neuro Exam

– Ataxia/incoordination – cerebellum (coordinates motor activity), vestibular system, or spinal cord

– Dysmetria - cerebellar• Hypermetria – too long movements

• Hypometria – movements too short

Neuro Exam

• Postural reactions– Knuckling– Hopping– Wheelbarrowing– Hemiwalking

• Muscle Tone– Atrophy – occurs slowly from disuse

• Rapidly from nerve damage– LMN – decreased– UMN – extensor muscle tone increased– Test by flexing/extending joints

Knuckling

Neuro exam – Spinal Reflexes• Thoracic limb withdrawal – pinch toe• Patellar – strike patellar ligament – extension of stifle• Pelvic limb withdrawal – pinch toe • Sciatic – Strike between greater trochanter and

ischium – flexion of stifle and hock• Cranial tibial – strike cranial tibial m just below

proximal end of tibia – flex hock• Perineal – pinch perineum/anus – anal sphincter

contraction, tuck tail• Panniculus – stimulate skin over dorsum just lateral

to vertebral column – twitch of cutaneous trunci m.

Patellar Reflex

Reflex examination

• http://www.youtube.com/watch?v=NFqFABsIa7Q&feature=related

Pelvic Limb Withdrawal – Or Not

Panniculus Test

Palpebral reflex

• http://video.google.com/videosearch?q=neurological+exam+in+dogs&hl=en&emb=0&aq=f#

Neuro Exam – Summary UMN vs LMN

UMN LMN

• Muscle tone N or I D

• Spinal reflexes N or I D

• Motor fxn Spastic Flaccid

• Muscle atrophy Mild Severe

• disuse neuro

• Bladder Tense Flaccid

Neuro Exam – Cranial Nerves

• Blind II• No menace II/VII• Anisocoria II, III• Atrophy of temporal V

Muscles• Dropped jaw V• Nares, lip pinch, cornea V

– Inside ear• Lip/ear droop VII• No blink VII• Head tilt VIII

Neuro exam – Cranial Nerves

• Nystagmus VIII

• Deafness VIII

• Difficulty swallowing IX, X

• Loss of gag reflex IX, X

• Laryngeal paralysis IX, X

• Weakness, assymmetry XII– Of tongue

Cranial nerve

• http://www.youtube.com/watch?v=S8f9-GPW9IE&feature=related

The Nervous System

And its associated diseases

Diseases of Brain: Trauma

Dog skull and brain2º Trauma: edema, hemorrhage

1º Trauma—Direct trauma to (↑ intracranial pressure) brain tissue

Brain Trauma

• Signs:– Seizures

– Blood in eyes, ears, nose, oral cavity

– Loss of consciousness or decrease in response to external stimuli

– Shock, coma, altered respiratory patterns

• Dx– Hx of trauma (HBC, falling)

– Chem. panel to rule out other metabolic diseases

Brain Trauma

• Treatment—aimed at reducing 2° effects (edema)– Osmotic agents: Mannitol (20-50%) IV slow bolus

– Diuretics: Furosemide IV q4h

– Anti-seizure Rx if needed: Diazepam, Phenobarbital

• Client info– Some brain injury is irreversible

– Dog in coma >48 h usually does not survive

– Worsening neuro signs → bad prognosis

Idiopathic Vestibular Disease

• Signs– Loss of balance

– Head tilt

– Nystagmus

– Disorientation

– Ataxia

– Vomiting/anorexia

Signalment: Dogs (middle aged) and cats, acuteSignalment: Dogs (middle aged) and cats, acute

IVD: NYSTAGMUS

Click for video

Idiopathic Vestibular disease

http://www.youtube.com/watch?v=ZccUdSH91zc&feature=PlayList&p=E13C63C661759E7C&playnext_from=PL&playnext=3&index=30

http://www.youtube.com/watch?v=Y25T7dZ77T4&feature=related

http://www.youtube.com/watch?v=HjwGY2vJk0E&feature=related

IVD: Ataxia

Click for video

Idiopathic Vestibular Disease

• Dx– Clinical signs

– Blood work to r/o other diseases of nervous system

– Ear exam to r/o inner ear infection

• Rx– Treatment is not recommended; does not alter course of

disease (antibiotics, steroids often given to cover possible causes not found by PE and lab work)

– Clinical signs resolve in 3-6 wks

PEOPLE“The man who smiles in the face of

trouble…

Has found someone to blame it on.”

References

• Alleice Summers, Common Diseases of Companion Animals

• http://neuro.vetmed.ufl.edu/neuro/courses/vem5171/Neuropharmacology.pdf