Bovine Neurology Flashcards
What are the clinical signs of Vestibular lesions?
Circling and head tilt
What are the clinical signs of Frontal lobe lesions?
Propulsive movement
What are the clinical signs of Brainstem lesions?
Disturbed sensorium
blind
seizures
What are the clinical signs of Cortex lesions?
Consciousness
Occipital lobe
Responsible for visual reception and interpretation
Basal Ganglia
Processing link
Initiates and directs voluntary movement
What are the clinical signs of Cerebellar lesions?
Spastic ataxia
Dysmetria
Tremors
Brainstem
Neurological function for survival: breathing, digestion, heart rate, blood pressure, awake and alert
Most cranial nerves arise from here
Upper Motor neuron
Initiation of voluntary motor activity
Maintenance of muscle tone and posture
Control of muscular activity associated with visceral functions
Lower motor neuron
Efferent neuron of PNS
Connects CNS with muscle
Function of CNS manifested through LMN
Spinal reflexes
Signs of Upper motor neuron disease
Spasticity and hypertonia
Loss of inhibition of myotactic reflexes
Spinal reflexes intact and/or exaggerated
Loss of voluntary motor function
Signs of Lower Upper motor neuron disease
Hypotonia Hyporeflexia Muscle weakness Loss of spinal reflexes Muscle atrophy Loss of motor innervation
What diseases cause Hydrocephalus?
Bluetongue
Akbane
Vitamin A deficiency
Interferes with the absorption of CSF at the arachnoid villi
Increased CSF pressure causing blindness
Papillidema at the optic chiasm
What is an autosomal recessive trait of Herefords and Shorthorns?
Cerebellar abiotrophy
What causes Cerebellar abiotrophy?
BVD between 100-200 days gestation
BVD brain lesions
Retinal atrophy
optic neuritis
cataracts
micro-ophthalmia with retinal dysplasia
Tetanus
Clostridium tetani that remains viable for years producing and releasing neurotoxins and tetanolysin
Clinical signs of Tetanus
Tetanospasm Tissue necrotizing effect Stiff gait mild bloat Difficulty rising "Pump-handle" tail Loss of ruminations Erect ears pulled back to poll "sardonic grin" Prolapsed third eyelid - spasm of retractor oculi muscle Spasm of masseter - "Lock jaw" Loss of swallowing
Pathogenesis of Tetanus
binds to nerve cells taken up by endocystosis
Moves retrograde up the axon
internalized into interneurons that regulate motor neuron activity
Inhibits action of inhibitory neurons
Prevents the release of glycine and GABA
Neurotoxin binds irreversibly
How do animals recover from Tetanus?
Recovery only with growth of new nerve terminals (days to weeks)
How is tetanus acquired?
wound infection castration tail docking Puncture wounds retained placenta
What is Tetanus known as?
Spastic paralysis
What is the cause of death with Tetanus?
Death by respiratory paralysis
Treatment for Tetanus
Eliminate infection - wound debridement - Gram + antibiotics Neutralization of Tetanus - Tetanus antitoxin Relief of muscle spasms - Tranquilization: Acepromazine - Muscle relaxation: Diazepam Good nursing care
How do you prevent Tetanus?
Routine vaccination with tetanus toxoid
Booster pregnant ewes/does in late gestation
Tetanus antitoxin when docking/castrating
When do you vaccinate Tetanus?
at least twice at 2-4 week intervals
Start around 6 weeks of age
Booster 8-10 weeks
Where does Botulism come from?
decaying vegetation, carrion
How does Botulism work?
Exotoxin blocks Ach release and causes flaccid paralysis
What are the clinical signs of Botulism?
Inability to eat
limberneck
How do you prevent Botulism?
no vaccine available
How do you treat Botulism?
Antitoxin
Tick paralysis
Ascending LMN disease caused by neurotoxin in tick saliva
How do you treat Tick paralysis?
Remove the tick
What are the stages of Rabies?
Prodromal
Furious
Paralytic
How do you prevent Rabies?
Vaccination of valuable animals
How is the the furious stage of Rabies caused?
Infection of limbic system
How is the the paralytic stage of Rabies caused?
Infection of neocortex
How is Listeriosis spread?
feces of may mammals, birds, and fish
What are the sources of Listeria exposure?
Fecal contamination Chronic intramammary infection Poultry litter used as bedding Bacteria found in decaying organic matter (pH>5) venereal transmission possible
Clinical signs of Listeria
Dysphagia Circling Multiple unilaterally cranial nerve deficits Fever Silage eye: uveitis, conjunctivitis, keratitis Anorexia Recumbent Opisthotonos padding
Causes of Listeria
Requires wound for entry
Rough browse/hay
Erupting teeth
Environmental and nutritional stress
Pathogenesis of Listeria
Rootlet trigeminal leads to intra-axonal migration to the brainstem
Cell to cell movement evades phagocytosis
Treatment for Listeria
Nasogastric intubation with gruel
Procaine Penicillin or Tetracycline
Supportive care: NSAIDs, fludis, vitamins
Listeria Lesions
Turbid CSF
Softened medulla oblongata
Autolyzed fetus
Diagnosis for Listeria
Stress Leukogram
Dehydration
CSF: increased protein high in mononuclear cells
Multifocal to coalescing areas of necrosis
Severe infiltration of macrophages/neutrophils
Axonal swelling & degeredation
Lesions most severe in pons & medulla
What is the cause of Thromboembolic meningoencaphalitis?
Histophilus somni
Clinical signs of Thromboembolic meningoencaphalitis?
pneumonia arthritis UTI abortion myocarditis neurologic disease: Ataxia, weakness Lateral recumbency profound depresison opisthotonus convulsions "sleeper syndrome" Vision loss in contralateral eye Depression mania head pressing circling with head tilt toward the side of the lesion
Treatment for Thromboembolic meningoencaphalitis
Antibiotic: gram -
Euthanasia
Lesions of Histophilus somni
Focal myocarditis
Abscess of the heart
What causes Brain and Pituitary abscesses?
Trueperella pyogenes
What are the clinical signs of Brain and Pituitary abscesses?
Vision loss in contralateral eye depression mania head pressing circling with head tilt toward other side of the lesion
Clinical signs of Pituitary abscess
Blindness Pupillary dysfunction nystagmus dysphagia facial paralysis circling head tilt
What is the cause of Pituitary abscess?
Dehorning complication
Head butting
Polioencephalomalacia
Swelling and softening of gray matter
Dysfunction of Na-K ATP pump
What is the pathogenesis of Poliencephalomalacia?
Thiaminases cause sulfur and sulfates metabolized to toxic sulfide ions
Grain diets promote H2S gas that is absorbed or inhaled post-eructation
S interferes with oxidative processes of mitochondria, leading to depletion of ATP
Clinical signs of Polio
Central blindness ataxia proprioceptive deficits head pressing hyperexcitability Recumbency opisthotonus seizures coma death Dorsal medial strabismus convulsions
Which animals are commonly affected by Polio?
growing animals
Diagnostic tests for Polio
Test food/water for H2S
greater than 1000ppm in water
greater than 4000ppm in diet
greater than 1000ppm in rumen gas
Treatment for Polio
Thiamine IV or IM until improvement
Increase forage add glucogenic precursors
Dexamethasone
Clinical signs of Nervous ketosis
Wandering
head pressing
compulsive licking
Bilateral blindness with intact pupillary function
Lesions associated with nervous ketosis
Diffuse cerebrocortical neuronal necrosis
Cerebellar Purkinje cell necrosis
What is the main isolate for Otitis media/externa?
Mycoplasma bovis
Cause of Meningitis
Septicemia in calves
Chronic sinusitis
Sources of Lead toxicosis
grease oil old paint lead-headed nails batteries linoleum smelter discharges
Clinical signs of Lead Toxicity
Sudden death central blindness tremors chewing fits seizures bellowing occasional aggressive behavior
Lesions of Lead Toxicity
Basophilic stippling
normocytic
normochromic anemia
Treatment for Lead Toxicity
Remove from source
Intermittent CaEDTA to chelate from bone
Thiamine early in disease
Clinical signs of Spinal cord disease in C1-5
UMN to front and hindlimbs
Clinical signs of Spinal cord disease in C6-T2
LMN to front limbs and UMN to hindlimbs
Clinical signs of Spinal cord disease in T3-L3
UMN to hind limbs
Clinical signs of Spinal cord disease in Sacral intumescence
LMN to hindlimbs
Anus
bladder
Clinical signs of Spinal cord disease in Coccygeal nerves
LMN to tail and spinal area
Common name of Enzootic Ataxia
“Swayback”
Lesions of Enzootic Ataxia
Bilateral symmetric myelin degradation in dorsolateral spinal cord tracts +/- cavitations in cerebral white matter
Myelin degeneration secondary to oxidative degeneration
Clinical signs of Enzootic Ataxia
Rear limb ataxia
muscle atrophy and paresis
Tetraparesis
Progressive paresis in older animals
Treatment of Enzootic Ataxia
Supplement Cu to prevent
Diagnostics for Enzootic Ataxia
Measure body tissue Cu
Plasma copper status and assess dietary Cu
Liver biopsy
What is the recessive defect in pure/mixed breed Charolais calves 6-36 months?
Progressive ataxia
Clinical signs of progressive ataxia
Stiff neck dragging rear toes stumbling proprioceptive deficits worsens with exercise Difficulty in maintaining posture during urination and pulsatile micturition
What neurological disease is seen in Brown Swiss calves?
Progressive degenerative myeloencephalopathy
“Weaver Syndrome”
Clinical signs of Progressive degenerative myeloencephalopathy
Paraparesis ataxia dysmetria of pelvic limbs insidious progression muscle wasting over hindquarters
Lesions of Progressive degenerative myeloencephalopathy
Lesions in white matter of spinal cord
Axonal swelling
degeneration
vacuolation
What are the muscarinic effects of Organophosphate toxicity?
Dyspnea Hypersalivation Diarrhea Bradycardia Pupillary constriction
What are the Nictotinic effects of Organophosphate toxicity?
Muscle tremors
Tetany
Recumbency
Opisthotonos
What is the treatment for Organophosphate toxicity?
Atropine in cattle and sheep to reduce muscarinic signs
Oral activated charcoal
Oximes to break bond of OP and AChase within first 24 hours
Clinical signs of Cervical fractures
Pain on palpation
Refuse to lower hear and resist passive flexion
Refuse to lower head to eat
What causes Vertebral osteomyelitis/ spinal abscess?
Pulmonary/umbilical infections
tail docking
What are the clinical signs of vertebral osteomyelitis/spinal abscess?
Malaise fever stiffness lack of proprioception paresis recumbency
What are the causes of Epidural Abscesses?
Trueperella pyogenes
Corynebacterium sp
Treatment for Epidural Abscesses
Surgical curettage
lavage
drainage
Long-term antibiotics
How do you prevent Epidural abscesses?
Adequate colostrum
What causes Spinal cord fractures?
Trauma
Osteodystrophy
Nutritional deficiencies in 3-6 mos ruminants
Clinical signs of Degenerative Myeloencephalopathy
Pelvic limb paresis
Ataxia
recumbency
Lesions of Degenerative Myeloencephalopathy
Lesions in spinal cord white matter
marked axonal degeneration
loss of axons and myelin and status spongiosus
Clinical signs of Hepatic encephalopathy
Hanging head
Pica
Ataxia
Hypoderma bovis
Deposits eggs on legs
Hatch and burrow into skin
1st instar larvae migrate SQ to spinal cord
“Warbles”
Hypoderma bovis
Spinal hypodermosis
Neurologic signs associated with death of larvae near spinal cord when treated with OPs and avermectins
Clinical signs of Spinal hypodermosis
severe inflammatory reaction and/or toxins released by dying larvae
Rear limb paresis and ataxia
recumbency
Treatment for Spinal hypodermosis
Anti-inflammatory agents
Dexamethsone
Deworm with avermectins before larvae reach spinal cord
How do you treat Obturator Nerve damage?
Aqua cow
What must you be careful of causing with the treatment of Obturator Nerve damage?
mastitis
Clinical signs of Rabies
Rear limb paresis Ptyalism Paraphimosis Tenesmus Flaccid distended urinary bladder Large volume of feces in the rectum Elevated rectal temp Elevated pulse dehydration Marked disorientation
Clinical pathology findings of Rabies
Polycythemia Neutrophilia Lymphopenia Hyperglobulinemia Increased aspartate aminotransferase Increased creatinine kinase Elevated serum creatinine Diffuse mononuclear encephalomyelitis Focal areas of necrosis perivascular cuffing Negri bodies
What do you see on CSF with rabies?
Protein
Mononuclear cells
Diagnostic tests for Rabies
Fluorescent Antibody test
