Focal Brain Disorders Flashcards
what makes up the intracranial tissue volume?
brain parenchyma
blood
CSF
what is the most effective compensatory mechanism for volume increase?
CSF shifts: shunt caudally, decrease production, increase absorption
is the blood brain barrier disrupted in cytotoxic edema?
not initially
what is normal intracranial pressure?
less than 20 mmHg
what are the types of brain herniation in dogs due to intracranial disease?
cingulate gyrus herniation
caudal transtentorial herniation
foramen magnum herniation
what is transtentorial herniation?
caudal displacement of hemispheres ventral to tentorium cerebelli
why is a foramen magnum herniation bad?
compresses medulla
what are some clinical signs of foramen magnum herniation?
stupor to coma
tetraplegia
non-responsive and dilated pupils
absent physiological nystagmus
respiratory abnormalities
what are some focal space occupying lesions?
dermoid, epidermoid cyst
hematoma, hemorrhage
encephalitis focal, abscessation
neoplasia
granuloma
what are two differentials for circling cats?
meningioma
stroke
what are some extra-axial bleeding types?
epidural hematoma
subdural hematoma
what type of fractures are most common in head trauma?
linear fractures
what is there high risk of with basilar skull fractures?
nerve damage or entrapment
CSF otorrhea or rhinoorhea
what are some primary brain tumors?
meningioma
astrocytoma
oligodendroglioma
plexus papilloma
pituitary adenoma
what are extra-axial tumors mainly?
meningiomas
what are common intra-axial tumors?
glial tumors
plexus papilloma
what are some differentials for intraventricular tumors?
plexus papilloma or carcinoma
ependymoma
meningioma
what are some etiologies of fungal granulomas?
Aspergillus fumigatus
Cryptococcus neoformans
Blastomycosis
Histoplasmosis
Colored fungii
what is a stroke?
neurological deficits because of cerebrovascular disease
what is ischemia?
reduction in blood flow to a level incompatible with normal function
what are some possible causes of stroke in dogs?
often not understood
hypertension, chronic kidney disease, Cushing’s disease, diabetes mellitus
what regulates cerebral blood flow?
cerebral metabolic rate
local cerebrovascular autoregulation
where does vasogenic edema usually happen?
white matter
does vasogenic or cytotoxic edema respond to hyperosmolar IV fluids?
vasogenic edema
what is normal mean arterial pressure in the brain and below what is concerning?
80-100 mmHg
below 70 mmHg is concerning
why is transtentorial herniation a problem?
compresses midbrain and rostral cerebellum
what can compressing the medulla lead to?
respiratory compromise
death
what are possible signs of an acute foramen magnum herniation?
stupor to coma
tetraplegia
non-responsive and dilated pupils
absent physiological nystagmus
respiratory abnormalities
what is the cushing’s reflex?
primary brain ischemia
increase in MAP to improve blood flow and oxygen delivery to brain
reflex bradycardia
is a hemorrhagic stroke from intra-axial or extra-axial bleeding?
intra-axial bleeding
what are comminuted fractures like?
fragments aligned
depressed bone pieces
which antibiotics have good blood brain barrier penetration?
metronidazole
enrofloxacin
3rd or 4th generation cephalosporins
what is most impacted by cytotoxic edema?
gray matter
what are the possible signs of acute brain herniation with transtentorial downwards?
dullness, stupor, coma
tetraparesis and ataxia
abnormal PLR, anisocoria
abnormal physiological nystagmus
what are the possible signs of acute brain herniation with foramen magnum?
stupor to coma
tetraplegia
non-responsive and dilated pupils
absent physiological nystagmus
respiratory abnormalities
what is of concern with intraventricular tumors?
metastatic spread along CSF flow
especially with plexus papilloma or carcinoma
where are granulomas often with focal GME in the focal form?
brain stem
what is the blood supply to the brain?
rostral cerebral artery
middle cerebral artery
caudal cerebral artery and perforating arteries
rostral cerebellar artery
caudal cerebellar artery
