Brain Disease Flashcards
Where can you localise brain lesions to?
- Brain =
-forebrain
-brainstem
-cerebellar
-vestibular (peripheral vs central) - Spinal =
-C1-C5, C6-T2, T3-L3, L4-S3 - Neuromuscular system
What are your guides regarding location?
- Neoplasia and Vascular are focal and lateralized
- Infect / inflamm are asymmetric / multifocal
- Degen / anom / nutritional are symmetrical
- Extra-cranial diseases are symmetrical and diffuse
What is seen with forebrain lesions?
- Change in behaviour - disorientated / depressed
- Circling / head turn - towards lesion
- Contralateral menace, blindness
- Contralateral proprioception deficits
- Seizures
What is seen with brainstem lesions?
- Depressed, stupor
- Tetraparetic / ataxia, head tilt
- Ipsilateral cranial nerve deficit
- Ipsilateral proprioception deficit
What is seen in cerebellar lesions?
- Normal mentation
- Hypermetric ataxia, head tilt
- Ipsilateral menace deficit - not blind
- Normal / delayed / hypermetric proprioception
What are your VITAMIN D differentials for brain disease?
- Vascular = ischaemic / haemorrhagic - ‘strokes’
- Inflammatory = MUO (meningo-encephalo-myelitis of unknown origin)
- Infectious = Protozoal (toxo/neospora), viral (CDV/FIP), bacterial/fungal
- Trauma
- Toxic
- Anomalous = hydrocephalus
- Metabolic = HE, hypoglycaemia, electrolyte imbalances, sodium shifts
- Idiopathic = idiopathic epilepsy / vestibular
- Neoplasia = primary (meningioma, glioma), pituitary, nasal, metastatic
- Degenerative = cognitive dysfunction
With vascular disease, what is its progression?
- Peracute (minutes)
- Instataneous
- <24hrs
What are main causes of bacterial meningoencephalitis?
What is seen in the CSF?
- Direct invasion =
-otogenic intracranial infection
-nasal
-dog bite - Haematogenous
- CSF = severe neutrophilic pleocytosis
What are protozoal meningoencephalitis?
- Neopsora caninum
-dogs only
-CEREBELLUM in adults
-causes necrotizing cerebellitis + cerebellar atrophy - Toxoplasma gondii = cats»>dogs
What are causes of viral meningoencephalitis?
- Canine distemper virus (CDV)
-dogs only = REsp, GI, derm, neurologic - Feline infectious peritonitis (FIP)
-Cats = Dry form = brain +/or eye
What are peracute / acute brain diseases?
- Vascular
- Inflammatory / infection
What are the difference between primary + secondary brain tumours?
- Primary = meningioma (cats + long nosed dogs), glioma (brachy dogs)
-often focal + asymmetrical (lateralized), often forebrain - Secondary = haematogenous (haemangiosarc, lymphoma, round cell…)
-direct extension of nasal / skull …
-pituitary tumours = cushings (dogs), acromegaly (cats)
What is treatment of primary brain tumours?
- Symptomatic = prednisolone (2months)
- Surgery alone = meningioma (cures cats +/- dogs)
- Radiation alone
- Combination
What is hydrocephalus? + other anomalous diseases?
- Ventricles too large
- Toy breed (dome-headed) = chihuahua, yorkie
- Abnormal at birth
- forebrain mainly affected = vocalise, house-training
- Porencephaly = focal defect in brain tissue
*Hydranencephaly = absence of cerebral hemispheres
What are genetic / degenerative diseases that act in early age?
- Lysosomal storage disease = accumulation + storage of substrates within cytoplasm of neurons - cerebellar then whole brain
What are old age degenerative diseases? Tx?
- Canine cognitive dysfunction
-changes in behaviour, memory + learning
-disturbances in sleeping (sleep in day + awake at night), staring, getting stuck in corners, loss of house-training
-accumulation of beta-amyloid w senile plaque formation + neurofibrillary tangles - Tx = selegiline
- Lafora disease = muscle twitch + seizures, eventually blind + ataxic
Traumas are easily to diagnose, how are they managed?
- Reduce intracranial pressure
- Address secondary injury
What are primary / secondary injuries of traumatic brain injuries?
- Primary = damage already been done = no intervention
-contusion
-concussion
-laceration - Secondary =
-release of inflammatory mediators
-continued haemorrhage, oedema = increased ICP
How is cerebral perfusion pressure calculated?
- MAP - ICP = CPP
- 100mmHG - 10mmHG = 90mmHG = blood can enter brain
- 60mmHG - 60mmHG = 0mmHG = blood not entering brain
What is cushings reflex? When does this occur?
- Severe hypertension (>160mmHG) with severe bradycardia (HR<60)
- Happens late in ICP raises
- Happens to try increase cerebral perfusion pressure
What occurs with cerebellar herniation?
- Cerebellum moves back into foramen magnum where brainstem sits
- Brainstem gets squashed =
-opisthotonus
-decerebellate rigidity
-coma
-resp depression
-death
What should be done if ICP?
- Resolve hypotension
- Increase osmolarity of circulating blood to “suck” fluid out of the brain
- Resuscitation then maintenance
- Hypertonic saline if hypovolemic
- Hyperglycemia worsens prognosis so avoid glucose-containing fluids
Whats the difference between mannitol and hypertonic saline?
- Mannitol – osmotic diuretic
-↓ blood viscosity, ↑ cerebral blood flow and oxygen delivery, free radical scavenger, osmotic effect
-Follow with crystalloid therapy to prevent dehydration
-Contraindicated in hypovolemia - Hypertonic saline – plasma volume expander
-Hyperosmotic agent, free radical scavenger
-Contraindicated / care in congestive heart failure
-Excellent for hypovolemic, raised ICP patients
What is one of the last brain reflexes to go with ICP + pressure on the brainstem?
- Oculocephalic reflex
-if both pupils completely dilated = grave prognosis
Why would you not use steroids for ICP?
- Cause hyperglycaemia = worse prognosis
How is hepatic encephalopathy treated?
- Lactulose = traps ammonia
- AB = reduce ammonia producing bacteria
- Diet = restrict protein
- Minimise contributing factors
- Seizure control
What does hypoglycaemia cause? What can cause low enough glucose to seizure?
- Brain consumes 25% of total blood glucose
- Low glucose = seizure, changes in mentation, weakness, flaccid tetraparesis, tremors
- Glucose <3mmol/l
- Low enough to seizure = insulinoma, insulin overdose, juvenile hypoglycaemia
