Neurology: Brain Disease Flashcards
(30 cards)
What is the purpose of blood work, MRI/Imaging and CSF for diagnostic invesigation of neurology?
- Blood work- rule out metabolic disease
- MRI- vitamin D
- CSF- inflammatory disease
What are the signs of forebrain lesions?
- Disorientation, depression
- Contralateral blindness
- Normal gait
- Circling- head pressing
- Reduced postural responses in contralateral limbs
- Seizures- behavioural changes, hemi-neglect
What are the signs of cerebellar lesion?
- Normal mentation
- Ipsilateral abnormal menace with normal vision
- Vestibular signs (head tilt)
- Ataxia, broad-based stance, hypermetria
- Intention tremors
- Delayed initiation and then often hypermetric postural responses
What are the signs of brainstem lesions?
- Depression, stupor, coma
- Cranial nerve defectics
- Vestiublar signs
- Paresis
- Decerebrate rigidity
- Decreased postural responses in all limbs
- Respiratory or cardiac abnomalities
What are the main differentials for:
1. focal and lateralised
2. Multifocal
3. Diffuse and symmetrical
- Neoplasia, vascular
- Inflammatory/infectious
- Metabolic/ toxic
What affects intracranial pressure?
Why does it show signs quickly?
Brain itselt, blood, CSF
Skull limits expansion
What are compensatory mechanisms to reduce intracranial pressure?
- If one one component increases another decreases
- Tissue/CSF/Blood decreases
What happens with sustained increase in intra-cranial pressure?
Brain herniation
* Forebrain herniates underneath the tentorium or cerebellum herniates through the foramen magnum
What are signs of raised ICP?
- Mental status- ARAS
depression, stupor, coma - Cushing’s reflex
bradycardia and hypertension- only with ischaemia - Pupil size and PLR
- Vestiublar eye movement- pysiological nystagmus
- Abnormal postures- decerebrate, decerebellate
What is the most likely cause with quick onset of disease?
Vascular- strokes
What is the difference between primary and secondary injury causing head trauma?
Primary
* Primary disruption of parenchyma
* Concussion, contusion, laceration
Secondary
* Release of inflammatory mediators
* Continues haemorrhage
* Leads to ICP
* Aim of our intervention
How is head trauma assessed and medically managed?
Assessment
* Initial assessment
* Serial neurological assessment
* Imaging
* ± surgical intervention
Medical managment
* Fluid therapy
* ICP managment
* O2
* BP
* Pain
* General care
How is head trauma assessed?
Modified glasgow coma scale
* Useful for serial monitoring
* Increased score is a better prognosis
How can decisions for head trauma be made?
MRI or CT
* Severity and prognosis of lesions
* Need for decompressive surgery or not
Surgery
* Fractures compression brain parenchyma or contaminated fragments
* Haematomas
What fluid therapy is indicated for head trauma?
- Restore intravascular volume to ensure adequate CPP
- Hypotension significantly increases mortality
- Resuscitation then maintenance
- 7.5% saline- reverses shock, decreases ICP, increases CBF and oxygen delivery
Avoid glucose containing fluids- hyperglycaemia associated with poorer outcome
With raised ICP what treatment is indicated?
Mannitol
* Reduces blood viscosity
* Increased CBF and oxygen delivery, free radical scavenger
* Follow with crystalloid therapy
* Contraindicated in hypovolaemia
Hypertonic saline
* hyperosmotic, free radical scavenger
* Contraindicated- hyponatraemia, cardiac or resp diease
Why does blood pressure need to be maintained between 100-140?
Head trauma
Cerebral blood flow is affected outside this range
Head trauma
- Why does pain of head trauma need to be managed?
- Why does temperature need to be managed?
- Increases blood pressure and therefore ICP- not morphine (emesis)
- Avoid hyperthermia/hypothermia- increases oxygen demands
What is the general care for head trauma?
- Keep head elevated- 30 degrees
- Avoid jugular compression
- turn q4-6h
- Catheterise bladder
- Maintain nutritional support- tube
NO STEROIDS
How do intoxications commonly present?
- Acute
- Often GI, CV, resp signs
- Muscle tremors and fasiculations often seen
Organophosphates, pyrethrin, lead etc
What is likely to cause acute and acute onset brain disease?
- Inflammatory
- Metabolic
- MUO, bacterial, viral, fungal
- Hypoglycaemia, hepatic, electrolytes
- What are the 3 main routed of bacterial ME?
- What are the acute signs?
- What does CSF show?
- How is it treated?
- Haematogenous, direct invasion, CSF
- CNS- obtundation, CN defecits
- Neutrophilic, phagoscyosed organisms possible
- ABs ± surgical drainage
Guarded prognosis
Other then bacteria what infectious diseases can cause ME?
- Neospora caninum
- Toxoplasma
- FIP
- FIV
- Canine distemper virus
- Cryptococcus
How is hepatic encephalopathy diagnosed?
- Bile acid stimulation test
- Fasting ammonia
- US
- CT
