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Flashcards in Lecture: Forebrain disease Deck (40)
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1
Q

Lesion localization (test question)

A
  1. Intracranial
  2. C1-C5
  3. C6-T2
  4. T3-L3
  5. L4-S3
  6. Lower motor Neuron
2
Q

Forebrain disease

Hallmark clinical signs

A
  1. Seizures (always come from forebrain​)
  2. Altered mentation, behavoiral change, dementia, loss of training
  3. Pacing, wandering, wide circles towards lesion
  4. Head turn towards lesion
  5. Postural reaction deficits opposite side
    • proprioceptive pathways cross over
  6. Blindness opposite side
    • visual pathways cross over
  7. Head pressing, star gazing, fly biting
  8. Possible hemiparesis opposite side of lesion
  9. Proprioceptive deficits
3
Q

Motor tracts in veterinary species

A
  • midbrain
  • brainstem
4
Q

Other clinical signs forebrain dz

A
  • Hemi-inattention/hemi-neglect
    • thalamus damage inhibiting perception of pain
  • Brain pain
    • stretching of meninges
    • OR brain perceives pain that is not there
    • May look like neck pain, IS NOT NECK PAIN
5
Q

Ataxia

A
  • three types
    1. cerebellar
    2. proprioceptive/sensory
    3. vestibular
  • NOT ASSOCIATED WITH FOREBRAIN DZ
    • dogs with forebrain dz usually have NORMAL GAIT
6
Q

Clinical signs NOT associate with forebrain dz

A
  • Head tilt-vestibular
  • Nystagmus-vestibular
  • Stupor, coma-midbrain/brainstem involvement
  • Ataxia
  • Abnormal spinal reflexes
  • Significant cranial nerve deficits
  • Intention tremors
7
Q

Cranial nerves associated with forebrain

A

CN I, II

8
Q

Location of lesion if there is a visual deficit

A

Opposite from the eye with the visual deficit

9
Q

DX workup for forebrain dz (7)

A
  • GOOD HISTORY
  • Neuro exam
  • Minimum database (CBC, chem, UA)
  • Abdominal and thoracic imaging
  • MRI
    • requires general anesthesia
    • expensive
  • CSF analysis
  • Infectious dz testing if indicated
    • short list of dz that cross BBB
10
Q

Causes of forebrain dz

Degenerative

A
  1. Lysosomal storage dz
    • genetic and breed specific, young animal
    • untreatable
  2. Leukodystrophy
    • white matter dz (abnormal myelinated tracts)
    • rare
    • untreatable
  3. Cognitive dysfunction
    • model for human alzheimers, accumulation of beta amyloid
    • dx of exclusion (MRI shrunken brain)
    • seleginline, antianxiety meds
11
Q

Cognitive dysfunction

CS

A
  • progressive cognitive impairment
  • inactivity, abnormal sleep/wake cycle
  • wandering/pacing
  • dementia, urinary/fecal incontinence
  • anxiety
  • decreased interaction
  • hearing loss, vocalization
  • cats may develop aggression
12
Q

Cognitive dysfunction

Diagnosis

A
  • HX, CS, exclusion of other causes
  • +/- brain abnormalities on MRI
    • atrophy
    • ventricular enlargement
    • microhemorrhages and infarcts
    • small interthalamic adhesion
13
Q

Cognitive dysfunction

Treatment

A
  • No known cure
  • MAOI therapy - selegeline
  • SAM-e
  • Holistic
  • anti-anxiety meds
14
Q

Causes of forebrain dz

Anomalous

A
  • Congenital Hydrocephalus
    • toy and brachycephalic breeds: chihuahua
    • excessive CSF in ventricular system: white matter damage
    • many animals can be asymptomatic
    • If progressive, can cause dysfuntion from compression/stretching of brain parenchyma
  • Primary epilepsy
    • typically pure-breed dogs 1-5 years old
    • documented in cats
15
Q

Congenital Hydrocephalus

General exam findings

A
  • dome-shaped head
  • open fontanelle or calvarial defect: skull sutures don’t close
  • sun-set sign (ventrolateral strabismus) from orbital malformation
16
Q

Congenital Hydrocephalus

Neurologic exam findings

A
  • typically apparent by 6 months old
  • behavoir change, obtundation, dementia, circling
  • innapropriate aggression
  • blindness, seizures
17
Q

Color of fluid on an MRI

A

WHITE

18
Q

Congenital Hydrocephalus

TX

A
  • Reduction of CSF production
    • prednisone
    • PPI (omeprazole) about 40% reduction
    • Furosemide: loop diuretic - better in crisis than maintenance
  • surgical
    • ventriculoperitoneal shunt - last 7-10 years
19
Q

Primary epilepsy

Treatment

Emergency treatment

A
  • Treatment
    • phenobarbital
    • Potassium Bromide (KBr)
    • Levetiracetam (Keppra)
    • Zonisamide
  • Emergency
    • Phenobarbital
    • Diazepam
    • Levetiracetam
20
Q

Causes of forebrain dz

Metabolic

A
  1. Hepatic encephalopathy
    • liver failure
      • looks like a sick animal
    • Portosystemic shunt (extra vs intra-hepatic)
      • runty puppy
  2. Hypoglycemia
21
Q

Hepatic encephalopathy

CS

A
  • Obtundation
  • Pacing
  • Head pressing
  • Visual deficits
  • Head pressing
  • Seizures
  • CS may be associated with feedings
22
Q

Hepatic encephalopathy

DX

TX

A
  • DX
    • Blood work
    • pre and post prandial biles acids
  • TX
    • surgical shunt attenuation
    • low protein diet
    • lactulose
    • antibiotics
23
Q

Hypoglycemia

Causes

A
  • glycogen depletion in very young, small puppies/kittens
  • excell insulin (insulinoma)
  • insulin OD
  • Addison’s
  • Liver failure
  • Toxins (xylitol)
24
Q

Hypoglycemia

CS

A
  • Tremors
  • vocalization
  • altered mental status
  • seizures
  • visual dysfunction
25
Q

Brain is completely dependant on _______ for metabolism

A

glucose

26
Q

Causes of forebrain dz

Neoplasia

Primary tumors

A
  • Primary tumors
    • meningioma: most common lesion in dogs and cats
    • Glioma
      • often aggressive/not surgical
    • Choroid plexus tumors
    • Lymphosarcoma: can do whatever they want
    • Histiocytic sarcoma
27
Q

Dont see many brain tumors in

A

horses and cows

28
Q

Definitive DX for tumors

A
  • Can’t be made without histopath
  • often diagnosis is presumptive
29
Q

Tumors

Signalment

CS

TX

A
  • Signalment
    • typically older than 5, any breed
  • CS
    • variable
    • behavoir change
    • endocrine disruption
  • TX
    • palliative vs definitive
    • sx, radiation, chemo
30
Q

Causes of forebrain dz

Nutritional

A
  • Thiamine deficiency
    • cats on all coldwater fish diet
  • hypoglycemia
  • hypocalcemia
31
Q

Causes of forebrain dz

Inflammatory

A
  • Immune-mediated (require histopath for def dx)
    • necrotizing leukoencephalitis (NLE)
      • Yorkies
    • Necrotizing meningoencephalitis (NME)
      • pugs
    • Granulomatous meningoencephalitis (GME)
32
Q

Causes of forebrain dz

Infectious

A
  • Bacterial
    • staph
    • strep
    • e. coli
    • klebsiella
  • Protozoal
    • toxoplasma
    • neospora
    • EPM
  • Viral
    • rabies
    • distemper
    • coronavirus (FIP)
  • Fungal
    • Cryptococcus
  • Rickettsia
    • ehrlichia canis
    • rickettsia rickettsii
  • Parasitic
    • dirofilaria
    • baylisacaris
    • cuterebra
    • taenia
33
Q

Equine infectious encephalitidies

A
  • Mosquito-borne alphavirus
    • EEE (Eastern Equine Encephalitis)
    • WEE (Western Equine Encephalitis)
    • VEE (Venezuelan Equine Encephalitis)
  • Horses don’t become contagious
  • People also susceptible to dz from mosquitos
34
Q

Other equine neurologic diseases

A
  1. Equine protozoal myeloencephalitis
    • apicomplexan protozoa (sarcocystis neurona)
      • forebrain or spinal cord localization
  2. West Nile virus encephalomyelitis (WNE)
    • Flavivirus
  3. Equine Herpes virus myeloencephalopathy
  4. Rabies
35
Q

Equine infectious neuropathy

DX

TX

A
  • DX
    • CSF
    • look for significant pleocytosis
  • TX
    • must cross BBB
      • Antibiotics
        • potentiated sulfas
        • doxy
        • clindamycin
      • Immune suppression
        • pred
        • cytosine arabinoside
        • procarbazine
        • leflunomide
        • cyclosporine
36
Q

Causes of forebrain dz

Toxin

A
  • Xylitol
  • drugs
  • ivermectin
  • bromethalin (rodenticide)
  • metaldehyde (snail bait)
  • caffeine/methylxanthines
  • lead
  • strychnine
  • organophosphates
  • pyrethrins
  • ethylene glycol
37
Q

Causes of forebrain dz

Trauma

A
  • Neonates
    • birthing/extraction
  • Small breeds
    • fall, mishandling
  • Large
    • HBC
    • blunt trauma, penetrating trauma
  • Felines
    • penetrating trauma
38
Q

Causes of forebrain dz

Vascular

A
  • Brain infarcts (stroke)
    • non hemorrhagic vs hemorrhagic
    • causes
      • hypertension
      • cardiac disease
39
Q

Vascular dz

Causes

A
  • Hypercoagulability
  • Hyperviscosity
  • Intravascular neoplasia
  • Atherosclerosis
40
Q

Vascular dz

CS

TX

A
  • CS
    • typically per-acute to acute
    • signs may be transient
  • TX
    • treat underlying cause
    • supportive care