diseases of nervous system of farm animals by ali sadiek
DESCRIPTION
short notes on mode of affection, causes, pathogenesis, signs and outcome of CNS diseases farm animals for Vet.Student level 8-9thTRANSCRIPT
Diseases of Nervous System of farm animalsFor the students of Semester 9, 10 Faculty of Vet. Med.
byProf. /Ali Hassan Sadiek
Faculty of Vet. Med. Assiut Univ.
[email protected]. mail:
لطلبة كلیات الطب البیطري-أمراض الجھاز العصبي لحیوانات المزرعة اعداد
علي حسن صدیق. د والتشخیص االكلینیكي والمعملي الباطنةأستاذ األمراض
جامعة أسیوط -كلیة الطب البیطري E. mail: [email protected]
Nervous system
Consist of :Nervous system 1-Central nervous system:
Brain & spinal cord
2- Peripheral nervous system :- Cranial Nerves.(12 pairs in all animal).- Spinal nervous (42 pairs in equines, 37 pairs in cattle, sheep &goats, 36 pairs in camels)
3- Autonomic nervous system :Regulating visceral organs.
Anatomy and physiology
Any pathological changes in structure leading to Modification or loss of function of this part .The nervous system (centrally & peripherally) is highly interactive and integrative , this to achieve the total coordination of body functions Which are necessary for survival
-Function of nervous system : Maintenance of mental, locomotor equilibrium. Control of different body functions in relation
to its surrounding environment.These functions achieved via:
function :function :SensorySensory--11Taste , smell , vision sensations
Motor function :Motor function :--22Voluntary & Involuntary movements Voluntary & Involuntary movements
::Visceral regulating functionVisceral regulating function--33Regulating the internal organs , glandsRegulating the internal organs , glands
Associating function :Associating function :--44Memory , intelligence Memory , intelligence
Clinical terminology of CNS
: inflammation of brain Encephalitis: inflammation of spinal cord Myelitis
: inflammation of both Encephalomyelitisbrain & spinal cord
: inflammation of meninges Meningitis: inflammation of brain &Encephalomeningitis
Its covering (meninges ) : inflammation of nerves Neuritis
: non inflammatory degenerative NeuropathyChanges of peripheral nerve endings .
Clinical terminology of CNS
: repetitive twitching of muscles Tremors: muscular contraction Spasm
: severe muscular contractions Convulsions: feeling ( sensation ) Aesthesia
: increase sensation Hyper aesthesia: no feeling (no sensation ) An aesthesia
: loss of consciousnessComa
-Important technical term :
: Loss of muscle tone (Incomplete Paresisparalysis)
: complete loss of muscular Paralysismotor function
: paralysis of both hind legs Paraplegia : paralysis of ( fore + hind ) Hemiplegia
limbs at one side.
Manifestations of nervous system -dysfunction :
Abnormal mental state-1a) Excited statemania Frenzy (severe mania )b) Depressed mental stateDepression Coma
abnormal behavior-2
Manifestations of nervous system -dysfunction :
Abnormal posture & gait-3Disturbance in sensation-4
Hyperesthesia. Hypoesthesia. Anesthesia
Involuntary muscular movement-5 Tremors Convulsions
Tetanus
Tetanus
Disturbance in posture and gait
Observed in:Encephalitis, meningitis, neuritis
Signs:Deviation of head, neck, Dropping of lips, eye lashes, cheeks,
earsOpisthotonus & Orthotonus.Dog sitting position.Head pressing
Disturbance in posture and gait
Head pressing & loss of sensation
Dog sitting position
Bovine ketosis
Paralysis:
Occur due to injury of locomotor center, it is either Spastic or flaccid paralysis.
Examples for disease assoc. with paralysis1- Trauma of motor pathway in the brain.2- Final stages of encephalitis/ or meningitis.3- Flaccid paralysis (Metabolic dis., Tick
paralysis, Snake venom, Botulism). 4- Spastic paralysis (e.g. Tetanus, tetany,
hypomagnesaemia)
Hyopmagnesemia (Lactation tetany)
Spastic paralysis
Tick paralysis
Boutulism
Disturbance of ANS
1- Dist. Of cran. Ns. (spasmodic colic, grass sickness, Vagus. Indigestion.
2- Dist. Of body sphinctres: Incont. Urine, feces, anuria
3- Blindiness:Central blindness (Brain injury)
decreased ability to avoid danger, +vepupilary reflex
Preph. Blind.: Avitaminosis A: inability to avoid danger, -ve pupilary reflex
Diagnosis of nervous system diseases
Case history. -1Clinical signs.-2Examination of animal-3
A)- General physical examination B)- Laboratory
- Hematology - Biochemical analysis - Serology
- C.S.F collection & analysisC)- Special methods
- Radiology & other imaging techniques
- Electro encephalography
Diseases of nervous system
Acquired Congenital
Infectious Non infectious
Bacterial (listeriosis )
Viral (rabies )
Parasitic (toxoplasmosis)
Fungal (cryptococcosis )
B.E.S ( scrapie )
Trauma
Ischemia
Cerebral anemia
Cerebral hemorrhage
Space occupying
Lesion & neoplasia
Intoxication as :lead
organo ph. cbd
Hypoplasia
Hydrocephalus
Meningeo –
encephalocele
Spinal dysgenesis
Cerebral anemia
Acute or chronic, depends on degree of O2 deprivation. Begins with excitation lasting to loss of function.
Causes: All anemia, hypoxia, it associate:Hydrocynide & nitrite toxicity.Heart failure (copper def. cows).Anesthesia.Pneumonia.At parturition in neonates.Brain injuries
Cerebral anemia
Signs:Acute hypoxia: loss of all brain function
(quadriplasia, loss of consiouness, muscle tremors, recumbency, convulsion, deaths or recovery.
Chronic hypoxia: General weakness, loss of equilb., blindness, tremors, convulsions.
Diagnosis: DD from hypglycemia,Treatments:O2 therapy, respiratory stimulants,
removal of causes.
Increased intracranial pressure, Brain edema
Associate other disease, it may be recoverable.
Causes:1- Vasogenic (Brain Hrge, meningitis,
trauma)2- Cellular toxicity (Salt poisoning in pigs).3- Brain edema: Closure of drainage of
cranial cavity fluids, it may congenital,)
Increased intracranial pressure, Brain edema
Signs: Central blindness observed within 12
hours of increased ICP, Fits of Opisothonus, Nystagmus, muscle tremors alternative with weakness and flaccidity.
Treatment: Hypotensive drugs (Thiamine, hypertonic
solutions, diuretics, cortisone “1 mg/kg bw)
Hydrocephalus
Encephalitis
Ruminants Equines
Cattle Sheep & Goats
Bacteria
Listeriosis, Hemophilus
Ricketsia, Clostridium
MHCV.,RabiesViruses:
.BSE
Toxoplasma: Parasitic
Staphylococus
Viscna.
Scrapie
Equine infectiousanemia
Signs of encephalitis
According to the causes and severity: Early stage: Excitation, violence, kicking, blowing,
yawing, convulsions, exophthalmoses, empty mastication, Salivation, Muscl. Tremors,
Later stage: Recumbency, fever, depression, tachycardia, change in animal behavour. Blindinss,incoordination , ataxia
Scrapie sheep
Encephalitis
Atrophy of cerebral cortex (CCN)
Rabies
Rabies
Rabies
Dianosis
It is difficult because of signs inter-related with other brain disease.
It could be confirmed on PM.Treatment:According to the cause, but generally you can use:1- Fluid therapy containg electrolytes.2- Narcotic in excitement stage and stimulant on
the depression stage.3-Antibiotics, Anti-inflammatory, antipyretics.4- Vitamin B cpx.
Brain Abscesses
Commonly in fattening calves and lambs. Its signs related to brain occupying lesions
Causes: usually hematogenous1-A. mallei of glanders lesion in lungs2-St. equi of strangles.3-Actinomyces & T.B.4-Fusobac.necrophrum from oropharynx.5-St. aureus in tick pyemia of lamb.6- Cryptococcosis (fungi )
Abscess of spinal cord
Cenurosis
Ruminants eat grass infested with dog feces containing the intermediate host T. multiceps, E.granulosus, reaching blood via intestine, invading brain & Sp. Cord forming cysts causing pressure onto neuronal and sensory centers..
Signs:
During the acute stage of latrvalmigration: blindness, ataxia, muscle tremors, dizziness. When adult cyst formed ( 2-5 cm):
Nystagmus, salvation, crazy running, convulsions, walking on circles.Cysts on spinal cord: Gradual
paralysis and inability to move or stand.
Cysticercus cerebralisThin walled cyst in brain
Diagnosis and treatment
Diagnosis:History of excess dogs on pastures and
farms.Signs of circling and incoordination.X-rayPost slaughtering examin. Treatment:Rafoxinide and other Antiparasitic with
little success.
Bovine Spongioform Encephalomylities (BSE)
Affect adult cattle & Transmit to human, resemble scrapie of sheep.
Causes: It may be the same of scrapie after feeding
cattle on food containing meat and bone extract of sheep infected with scrapie.
The lesion (spongiofrom vacuoles) was found in brain of infected cattle, man and sheep.
Isolated heat stable protein called prions.
BSE
Occurrence: It affect highly lactating cows and all
exposed cows as well. The disease is fatal with 100 %
mortality.Other cases observed in dogs, cats,
Tigers those imported from Britain
Scrapie Incoordination spastic
contracted Muscle
Nystagmus
Signs of BSE
Gradual increasing Change in animal behavior, posture, position, movement
Aggressive behavior, hyperesthesia, ataxiaRefuse to enter the milk allays, with violent
voices. Loss of orientation, aims, contracted ears,
muscle tremorsKicking, head pushing, attack of attendants
&other animals. Violent Licking, dragging of hind limbs. Falling & unable to stand.
Dragging of hind legs (BSE)
Postmortem exam.
Intracytop. vaculation of the neurons and grey matter & neutrophils of brain stem.
:DiagnosisDisease should be differentiated from all nervous system disease e.g.:Milk tetany, ketosis, rabies, lead poisoning
Histopathology
Secretions of prions
Secretions of prions in human
Treatment
No treatment, Condemenation of affected farms is the solution.
Prophylaxis: Avoid importing animals from endemic
countries. Avoid adding feed additives of animal origin
from infected countries. Notification of Authorities Avoid eating of animal products from affected
animals. Histopathological exam. Of the brain of any
suscpected animals.
Heartwater disease. Affects ruminants, caused by Ricktessia
(Cowardia ruminatum), transmitted by Ampyloma ticks.
Signs: Peracute form: Fever, diarrhea, convulsion
and death. Acute form: o Fever, nervous signs, o Pricking of eye leads.o Protruded tongue.o Biting of Jaw. o Walking in circles, convulsionso Extension of limbs in recumbent animals
Postmortem Exam,
Hydrothorax, hydropercardium, hydropleuraAscitisEnteritis, hepatomegaly,
splenomegaly, enlargement of L. nodes.Edema and brain Hrge.
( Heartwater)
Estrus ovis