Neurology: Brain Disease Flashcards

1
Q

What is the purpose of blood work, MRI/Imaging and CSF for diagnostic invesigation of neurology?

A
  • Blood work- rule out metabolic disease
  • MRI- vitamin D
  • CSF- inflammatory disease
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2
Q

What are the signs of forebrain lesions?

A
  • Disorientation, depression
  • Contralateral blindness
  • Normal gait
  • Circling- head pressing
  • Reduced postural responses in contralateral limbs
  • Seizures- behavioural changes, hemi-neglect
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3
Q

What are the signs of cerebellar lesion?

A
  • 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
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4
Q

What are the signs of brainstem lesions?

A
  • Depression, stupor, coma
  • Cranial nerve defectics
  • Vestiublar signs
  • Paresis
  • Decerebrate rigidity
  • Decreased postural responses in all limbs
  • Respiratory or cardiac abnomalities
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5
Q

What are the main differentials for:
1. focal and lateralised
2. Multifocal
3. Diffuse and symmetrical

A
  1. Neoplasia, vascular
  2. Inflammatory/infectious
  3. Metabolic/ toxic
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6
Q

What affects intracranial pressure?

Why does it show signs quickly?

A

Brain itselt, blood, CSF

Skull limits expansion

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7
Q

What are compensatory mechanisms to reduce intracranial pressure?

A
  • If one one component increases another decreases
  • Tissue/CSF/Blood decreases
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8
Q

What happens with sustained increase in intra-cranial pressure?

A

Brain herniation
* Forebrain herniates underneath the tentorium or cerebellum herniates through the foramen magnum

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9
Q

What are signs of raised ICP?

A
  • 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
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10
Q

What is the most likely cause with quick onset of disease?

A

Vascular- strokes

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11
Q

What is the difference between primary and secondary injury causing head trauma?

A

Primary
* Primary disruption of parenchyma
* Concussion, contusion, laceration

Secondary
* Release of inflammatory mediators
* Continues haemorrhage
* Leads to ICP
* Aim of our intervention

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12
Q

How is head trauma assessed and medically managed?

A

Assessment
* Initial assessment
* Serial neurological assessment
* Imaging
* ± surgical intervention

Medical managment
* Fluid therapy
* ICP managment
* O2
* BP
* Pain
* General care

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13
Q

How is head trauma assessed?

A

Modified glasgow coma scale
* Useful for serial monitoring
* Increased score is a better prognosis

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14
Q

How can decisions for head trauma be made?

A

MRI or CT
* Severity and prognosis of lesions
* Need for decompressive surgery or not

Surgery
* Fractures compression brain parenchyma or contaminated fragments
* Haematomas

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15
Q

What fluid therapy is indicated for head trauma?

A
  • 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

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16
Q

With raised ICP what treatment is indicated?

A

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

17
Q

Why does blood pressure need to be maintained between 100-140?

Head trauma

A

Cerebral blood flow is affected outside this range

18
Q

Head trauma

  1. Why does pain of head trauma need to be managed?
  2. Why does temperature need to be managed?
A
  1. Increases blood pressure and therefore ICP- not morphine (emesis)
  2. Avoid hyperthermia/hypothermia- increases oxygen demands
19
Q

What is the general care for head trauma?

A
  • Keep head elevated- 30 degrees
  • Avoid jugular compression
  • turn q4-6h
  • Catheterise bladder
  • Maintain nutritional support- tube

NO STEROIDS

20
Q

How do intoxications commonly present?

A
  • Acute
  • Often GI, CV, resp signs
  • Muscle tremors and fasiculations often seen

Organophosphates, pyrethrin, lead etc

21
Q

What is likely to cause acute and acute onset brain disease?

  1. Inflammatory
  2. Metabolic
A
  1. MUO, bacterial, viral, fungal
  2. Hypoglycaemia, hepatic, electrolytes
22
Q
  1. What are the 3 main routed of bacterial ME?
  2. What are the acute signs?
  3. What does CSF show?
  4. How is it treated?
A
  1. Haematogenous, direct invasion, CSF
  2. CNS- obtundation, CN defecits
  3. Neutrophilic, phagoscyosed organisms possible
  4. ABs ± surgical drainage

Guarded prognosis

23
Q

Other then bacteria what infectious diseases can cause ME?

A
  • Neospora caninum
  • Toxoplasma
  • FIP
  • FIV
  • Canine distemper virus
  • Cryptococcus
24
Q

How is hepatic encephalopathy diagnosed?

A
  • Bile acid stimulation test
  • Fasting ammonia
  • US
  • CT
25
Q

How is hepatic encephalopathy treated?

A

Lactulose
* traps ammonia as non-diffusable ammonium in intestinal lumen
* Decreases absorption

Antibiotics
* reduce of ammonia-prodcuing bacteria in gut

Diet
* aim to reduce gut derived blood ammonia

Minimise
* Increased ammonia production- constipation, GI bleed
* Reduced clearance- dehydration, hypotension
* Affect neurotransmission

Seizure control

26
Q
  1. Why does hypoglycaemia cause brain disease?
  2. What are the clinical signs?
A
  1. Glucose oxidation primary energy source
  2. Lethargy, ravenous appetite, anxiet, weakness and tremors, reduced vision and seizures

Insulinoma, liver disease, insulin overdose, juvenile hypoglycaemia

27
Q

Why does sodium derangments cause brain disease?

A

Blood levels reflect ratio of sodium to water in extracellular fluid

Hypernatraemia- cell shrinkage
Hyponatraemia- cell swelling

Rapid correction dangeous

28
Q

What can cause chronic onset presentations?

A

Neoplasia
Anomalous
Degenerative

29
Q

What primary and secondary neoplasia can affect the brain?

A

Primary
* Intra-axial- gliomas
* Extra-axial- meningiomas, choroid plexus tumours

Secondary
* Metastases
* Extension- nasal tumours

Tx
* less sedative AEDs
* Pred
* Analgesia

30
Q

What are the 2 anomalous chronic causes of brain disease?

A

Hydrocephalus
* Abnormal dilaiton of ventricular system within cranium
* Domed shaped head, obtundation, seizures, vestiublar signs
* Toy breeds, young age

Hydrancephaly and porencephaly
* Communicating with subarachnoid space and/or lateral ventricles
* Signs within 1st few months