The document discusses diseases of the nervous system in animals. It describes how veterinary neurologists treat problems of the brain, spinal cord, nerves and muscles. Neurological issues in animals can be caused by medication reactions, inherited disorders, infections or trauma. Common conditions include seizures, brain/spinal tumors, meningitis, congenital disorders, and disk problems. A neurological exam involves taking a patient history and doing palpation, percussion and image analysis. Treatment depends on the underlying cause but may include surgery, medications, antibiotics or chemotherapy. The document also discusses various neurological signs like changes in behavior, physical changes, involuntary movements and abnormal posture/gait.

1. Diseases of Nervous System in
Animals
Dr. Bibek Sutradhar, PhD
Professor
Department of Medicine and Surgery
Chattogram Veterinary and Animal Sciences University
MRI

2. Introduction
Veterinary neurologists treat nervous-system problems.
The nervous system comprises the brain, spinal cord, muscles and the nerves that
connect them. Just as in humans, neurological problems in animals can be caused by
a reaction to medication, hereditary disorders, infection or trauma.
Changes in behavior
• Not recognizing you
• Forgetting training or failing to obey
• Lethargy
• Aggressiveness
• Irritability
Physical changes
• Weakness -Seizures and tremors
• Problems swallowing -Back and neck pain
• Deafness -Running in circles or pacing
• Vision problems -Head-pressing against hard
• Balance problems surfaces

3. Introduction
Common neurologic conditions
• Seizure disorders (epilepsy)
• Brain and spinal tumors
• Meningitis and encephalitis
• Congenital disorders
• Disk herniation and disease
• Traumatic injuries
Neurological exam
The exam itself is gentle and non-invasive.
History
Palpation
Percussion
Image analysis (X-ray, CT scan, MRI etc)
Treatment options
Tumors, herniated disks and traumatic injuries are often treated with surgery, but
many neurological conditions also respond to medications – antibiotics,
immunosuppressive drugs, anti-seizure medication, and chemotherapy.

4. CNS - Spinal cord, Brain stem, Cerebellum, and Cerebrum (Higher centers)
PNS - Neurons of the cranial and spinal nerves (26 pair spinal and 12 pair cranial)
a) Sensory/afferent neurons – Nociception (pain), Proprioception (position),
equilibrium, touch, temperature, taste, hearing, vision, and olfaction
b) Motor/efferent neurons - Upper Motor Neurons (starts from brain)
UMN from cortex – voluntary movements
UMN from brain stem – flexion of limbs/inhibit extensors
Lower Motor Neuron-LMN (starts from spinal cord)
Spinal compression – extensor weakness/paresis/paralysis
Introduction

5. Introduction

6. What is paresis?
• Paresis refers to a condition in which muscle movement has
become weakened or impaired. (“mild paralysis” or “partial
paralysis”)
•Although paresis affects your muscles, it usually occurs due to
nerve damage.
• A vast network of nerves controls the movement of the muscles
in our bodies. If a part of this network is damaged, muscles in the
affected area may not work properly.
• There are several factors that can cause paresis, and there are
many different types of paresis. Paresis is often categorized by
the area of the body that’s impacted.

7. How is paresis different from paralysis?
Paresis is characterized by muscle weakness. A patient with
paresis can still move the affected muscle or muscles. However,
these movements are weaker than normal.
Paresis is different from paralysis. An individual who has
paralysis isn’t able to move a specific muscle or muscle group
at all.
You may also see paresis used as a suffix to distinguish what part
of the body is affected. For example, a person with monoparesis
has muscle weakness affecting one limb.
The corresponding suffix for paralysis is “-plegia.” Using the
same example, a patient with monoplegia has paralysis that
affects one limb.

8. Causes and types of paresis
There are many different factors that can cause nerve damage that results in
paresis.
Examples of causes include:
•Head injury
•Spinal cord injury
•Pressure on the spinal cord or nerves due to things like inflammation,
bone spurs, or a tumor
•Diabetes
Spastic paresis

9. Examples of different types of paresis
Monoparesis. muscle weakness that affects one limb, such as a leg or an arm.
Paraparesis. Paraparesis is muscle weakness that affects both legs.
Hemiparesis. Hemiparesis is muscle weakness that affects one side of your body, such
as the left arm and left leg.
Quadriparesis. Quadriparesis is muscle weakness that affects all four limbs.
Bell’s palsy. Bell’s palsy is a condition that leads to temporary weakness in your facial
muscles, which can cause facial drooping and pain.
Vocal cord paresis. Vocal cord paresis affects the movement of your vocal cords.
Gastroparesis. Gastroparesis is a condition where the emptying of the stomach is
impaired due to muscle weakness. It’s associated with symptoms like nausea, vomiting,
bloating, and feeling full quickly.
Todd’s paresis. Todd’s paresis is a type of paresis that occurs following a seizure. It’s
often associated with paresis in one limb (monoparesis) or on one side of the body
(hemiparesis).
Neurosyphilis. Neurosyphilis occurs when a syphilis infection attacks the nervous
system. It can cause paresis as well as headaches, changes in behavior, and dementia.
Spastic paresis. Spastic paresis is a condition that causes muscle overactivity and
spasticity. It’s due to nerve damage that often results from conditions like stroke; can
lead to pain as well as difficulty with activities like walking or getting dressed.

10. Treatment options
Treatment for paresis depends on the cause. Possible treatment options
include:
Physical therapy. Physical therapy uses techniques such as exercise and massage to
aid in promoting mobility, improving flexibility and range of motion, and
stimulating the nerves and muscles.
Occupational therapy. Occupational therapy can teach the strategies for carrying
out the day-to-day activities more easily while patient experiencing paresis
(Human).
Assistive devices. Assistive devices are items that can help with the mobility and
daily activities. Examples include:
• walkers
• wheelchairs
• grab bars
• specialized handles and grips
• voice-activated technology
Medications. In some cases, medications may help treat a condition that’s causing
paresis. Examples include:
antimicrobial medications for infections
corticosteroids to reduce inflammation that’s putting pressure on a nerve

11. Autonomic Nervous System (ANS)
• Sympathetic
• Parasympathetic

12. • Functions:
Sensory motor system: Maintenance of normal posture
and gait
ANS: Activity of internal organs; Homoeostasis
Sense organs
Psychic system: Mental and behavioural state
• Dysfunction:
• Increased response to sensory stimuli
• Failure to respond to sensory stimuli
• Transmission of impulses enhanced or depressed
• Complete failure of transmission

13. Reflex
Sensory neuron (PNS) – Internuncial neuron (CNS) - Lower Motor Neuron
(PNS)
Higher center not involved. No Perception
Monosynaptic reflexes – Patellar reflex
LOCATION OF LESION????.....

14. Paralysis -> Paresis Vs Plegia
• Paresis: Partial loss/weakness/Impaired voluntary
movement
• Plegia or Paralysis: Inability/complete loss of
voluntary movement

15. NERVOUS DYSFUNCTION
CAUSES: congenital or familial, infectious or
inflammatory, toxic, metabolic, nutritional, traumatic,
vascular, degenerative, neoplastic, or idiopathic
• Exaggerated activity:
Excitation (irritation) signs
Release of inhibitory
control
Neuropathic pain
• Depressed activity:
Paresis or paralysis due to tissue
damage
Nervous shock

16. Neurologic Evaluation/Description
1)The anatomic location(s) of disease
2)The problem may be defined as
- diffuse, multifocal, or focal
- symmetric or asymmetric
- painful or nonpainful
- progressive, regressive or static
- mild, moderate, or severe
3) Clinicopathology (serum/blood/urine/feces/CSF)
4) Plain and Contrast radiography, CT, and MRI

17. EXCITATION (IRRITATION) SIGNS
• Increased activity of reactor organ
• Increase in nerve impulses received
Excitation of neurons
Facilitation of passage of stimuli
• Motor system: Tetany, convulsions etc.
• Sensory system: Hyperaesthesia, Paresthesia

18. Clinical Manifestations of Diseases of the
Nervous System
ALTERED MENTATION - Excitation states
a) Mania - acts in a bizarre way and appears to be unaware of
its surroundings. Maniacal actions include licking, chewing of
foreign material and sometimes themselves, abnormal voice,
constant bellowing, apparent blindness, walking into strange
surroundings, drunken gait, and aggressiveness in normally
docile animals.
Eg: Rabies, Aujeszky’s disease, nervous ketosis, pregnancy
toxemia, acute lead poisoning, severe hepatic insufficiency etc

19. b)Frenzy - violent activity, movements are uncontrolled and
dangerous
eg: Hypomagnesemic tetany, Aujeszky’s disease,
Acute colic, ammonia poisoning
c)Aggressive Behavior: willingness to attack other
animals, humans, and inert objects
Eg: early rabies, postparturient hysteria in sows

20. Clinical Manifestations of Diseases of
the Nervous System
DEPRESSIVE STATES
a) Coma
b) Syncope
c) Narcolepsy (Catalepsy)
d) lassitude
e) Somnolence
COMPULSIVE WALKING OR HEAD PRESSING
Eg: PEM, Increased ICP
AIMLESS WANDERING
**protein energy malnutrition (PEM)

21. Clinical Manifestations of Diseases of the
Nervous System
INVOLUNTARY MOVEMENTS
A) Tremor: continuous, repetitive twitching of skeletal muscles
If local skin only  fasciculations
eg: early stages of hypocalcemia in the cow
B) Tics: spasmodic twitching movements made at much longer
intervals than in tremor.
C) Tetany: Sustained contraction of muscles without tremor.
eg: C. tetani infection
D) Myoclonus: brief, intermittent tetanic contraction of the skeletal
muscles that results in the entire body being rigid for several seconds,
followed by relaxation.
eg: canine distemper

22. E) Convulsions: Convulsions, seizures, fits, or ictus are violent muscular
contractions affecting part or all of the body and occurring for relatively
short periods. result of abnormal electrical discharges in forebrain neurons
Stage I - Prodromal phase or aura (lasts for minutes to hours, restless)
Stage II – Ictal phase (Proper convulsions)
Stage III – Post Ictal phase (Fatigue, rest, loss of conciousness)
E) Involuntary Spastic Paresis:
eg: Stringhalt in Horses – hind leg flexion
Clonic Convulsions (Paddling in Meningitis) Vs
Tonic Convulsions (Strychnine/Tetanus)

23. Clinical Manifestations of Diseases of the
Nervous System
ABNORMAL POSTURE AND GAIT
A) Posture Abnormality: Vestibular disease
B) Gait Abnormality: Weakness (Paresis) andAtaxia(Swaying)
- Hypermetria (increased range of movement/Overreaching)
- Dysmetria (goose stepping –pantothenate def.)
- Cerebellar ataxia (BVD) and Sway back (Cu def.)

24. •Stimulant drugs and mild degrees of those influences that in
severe form causing depression of excitability (hypoxia,
inflammation, poisons, edema, increased ICP)
•Fluctuation in Intensity of signs due to discharge and re-
accumulation of energy
•Sign and extension of symptoms varies with the focus of lesion

25. RELEASE OF INHIBITORY CONTROL
•Release of inhibitory effects of higher centres over lower
nervous centers
• Decerebrate rigidity due to transection of brain stem
• Cerebellar ataxia: combined limb movements exaggerated

26. PARESIS OR PARALYSIS DUE TO TISSUE DAMAGE
•Destruction of nervous tissue Infection
depressed metabolic activity
•Failure of oxygen and nutrient supply General
absence
Failure of local circulation
• Motor system: Muscular paralysis
• Sensory system: Anaesthesia, hypoaesthesia

27. Suprascapular Neuropathy in Horses (Sweeney)

28. Schiff-Sherrington Phenomenon
•Due to acute, severe lesions of the spinal cord between T2 and
L3, the pelvic limb paralysis is accompanied by an extensor
rigidity of the thoracic limbs

29. NERVOUS SHOCK
An acute lesion of the nervous system, which
causes damage to nerve cells in the immediate vicinity
of the lesions, but there may be, a temporary cessation
of function in parts that are not directly affected.
eg: Stunning

30. Horner syndrome
• Sunken appearance to the eye (enophthalmia)
• Small pupil (miosis)
• Droopy upper eyelid (ptosis)
• Absence of sweating of the face (anhidrosis)
• Prominent third eyelid.
• Loss of Sympathetic innervations to eyes and face

31. CONCLUSIONS
•Determining type of lesions is difficult: Limited range of
mode of reaction
• Destruction of tissue or reduced nutrient supply
•Proper Anamnesis and Special examination is essential for
proper assessment
• Sign-time relationship:
Rapidly developing lesions: maximum disturbances
Slow developing lesions: Compensation

32. References:
•A Text book of diseases of the cattle, sheep, goats, pigs
& horses 10th edition by Otto M Radostits, Clive C Gay,
K W Hinchcliff, P D Constable.
•Duke’s Physiology of Domestic animals 12 th edition
edited by William O Reece