Lecture: Forebrain disease Flashcards
1
Q
Lesion localization (test question)
A
- Intracranial
- C1-C5
- C6-T2
- T3-L3
- L4-S3
- Lower motor Neuron
2
Q
Forebrain disease
Hallmark clinical signs
A
- Seizures (always come from forebrain)
- Altered mentation, behavoiral change, dementia, loss of training
- Pacing, wandering, wide circles towards lesion
- Head turn towards lesion
- Postural reaction deficits opposite side
- proprioceptive pathways cross over
- Blindness opposite side
- visual pathways cross over
- Head pressing, star gazing, fly biting
- Possible hemiparesis opposite side of lesion
- 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
- cerebellar
- proprioceptive/sensory
- 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
- Lysosomal storage dz
- genetic and breed specific, young animal
- untreatable
- Leukodystrophy
- white matter dz (abnormal myelinated tracts)
- rare
- untreatable
- 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
- Hepatic encephalopathy
- liver failure
- looks like a sick animal
- Portosystemic shunt (extra vs intra-hepatic)
- runty puppy
- liver failure
- 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
Brain is completely dependant on _______ for metabolism
glucose
26
Causes of forebrain dz
Neoplasia
Primary tumors
* 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
Dont see many brain tumors in
horses and cows
28
Definitive DX for tumors
* Can't be made without histopath
* often diagnosis is presumptive
29
Tumors
Signalment
CS
TX
* Signalment
* typically older than 5, any breed
* CS
* variable
* behavoir change
* endocrine disruption
* TX
* palliative vs definitive
* sx, radiation, chemo
30
Causes of forebrain dz
Nutritional
* Thiamine deficiency
* cats on all coldwater fish diet
* hypoglycemia
* hypocalcemia
31
Causes of forebrain dz
Inflammatory
* Immune-mediated (require histopath for def dx)
* necrotizing leukoencephalitis (NLE)
* Yorkies
* Necrotizing meningoencephalitis (NME)
* pugs
* Granulomatous meningoencephalitis (GME)
32
Causes of forebrain dz
Infectious
* 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
Equine infectious encephalitidies
* 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
Other equine neurologic diseases
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
Equine infectious neuropathy
DX
TX
* DX
* CSF
* look for significant pleocytosis
* TX
* must cross BBB
* Antibiotics
* potentiated sulfas
* doxy
* clindamycin
* Immune suppression
* pred
* cytosine arabinoside
* procarbazine
* leflunomide
* cyclosporine
36
Causes of forebrain dz
Toxin
* Xylitol
* drugs
* ivermectin
* bromethalin (rodenticide)
* metaldehyde (snail bait)
* caffeine/methylxanthines
* lead
* strychnine
* organophosphates
* pyrethrins
* ethylene glycol
37
Causes of forebrain dz
Trauma
* Neonates
* birthing/extraction
* Small breeds
* fall, mishandling
* Large
* HBC
* blunt trauma, penetrating trauma
* Felines
* penetrating trauma
38
Causes of forebrain dz
Vascular
* Brain infarcts (stroke)
* non hemorrhagic vs hemorrhagic
* causes
* hypertension
* cardiac disease
39
Vascular dz
Causes
* Hypercoagulability
* Hyperviscosity
* Intravascular neoplasia
* Atherosclerosis
40
Vascular dz
CS
TX
* CS
* typically per-acute to acute
* signs may be transient
* TX
* treat underlying cause
* supportive care
