Encephalopathies, Pt. 2 Flashcards

1
Q

What are 3 anomalous/developmental brain disorders?

A
  1. chiari-like malformation
  2. congenital hydrocephalus
  3. intracranial arachnoid (quadrigeminal) cyst
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2
Q

What is chiari-like malformation? What secondary condition does it commonly cause?

A

congenital malformation of the skull resulting in overcrowding of caudal fossa and compression of the cervicomedullary junction

cervical syringomyelia - fluid-filled cyst (syrinx) forms within the spinal cord

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3
Q

What signalment is most commonly affected by chiari-like malformation?

A

small breeds, most commonly young adult Cavalier King Charles Spaniel

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4
Q

What are the 4 most common manifestations of chiari-like malformation?

A
  1. multifocal CNS dysfunction
  2. cervical myelopathy
  3. cerebellovestibular dysfunction
  4. forebrain dysfunctions, including seizure activity
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5
Q

What are some unique manifestations of chiari-like malformation?

A

due to syringomyelia

  • persistent scratching at head, neck, or shoulder region
  • scoliosis
  • crying out when defecating
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6
Q

What is thought to cause the development of syringomyelia?

A

accumulation of ECF with reduction in fluid pressure that results when a fluid flows through a constricted section (Venturi effect)

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7
Q

How is chiari-like malformation diagnosed? What 4 things are seen?

A

MRI

  1. attenuation/obliteration of dorsal subarachnoid space @ cervicomedullary junction
  2. rostral displacement of caudal cerebellum by occiput
  3. “kinked” appearance of caudal medulla
  4. syringomyelia, cerebellar herniation
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8
Q

What are some medical therapy options for patients with chiari-like malformation?

A
  • Gabapentin/Pregabalin
  • Tramadol
  • Omeprazole
  • Acetazolamide - decrease ICP
  • Furosemide
  • NSAIDs
  • Prednisone
  • acupuncture
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9
Q

What is Pregabalin? How does it compare to Gabapentin?

A

next generation of Gabapentin

more potent effect at the alpha-2-delta subunit of voltage-gated calcium channels

(2-4 mg/kg PO BID)

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10
Q

How is chiari-like malformation surgically managed?

A

foramen magnum decompression - removal of bone from the caudal occiput and C1 dorsal lamina with resection of meninges

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11
Q

What is prognosis of foramen magnum decompression for the treatment of chiari-like malformation like?

A

80% success rate, BUT 25-50% relapse due to excessive scar tissue impinging FMD site

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12
Q

Other than FMD, what is another possible option for surgical chiari-like malformation?

A

cranioplasty with the goal of decreasing the rate of post-op scar tissue

  • standard FMD + titanium screws around the periphery of the occipital defect and the placement of a titanium mesh and polymethylmethacrylate plate
  • fewer re-operations!
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13
Q

What is congenital hydrocephalus?

A

excessive CSF accumulation thought to be caused by obstructions and inadequate absorption or abnormal compliance of the brain due to a brain/cranial cavity mismatch

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14
Q

What signalment is most commonly seen with congenital hydrocephalus? How do these patients present?

A

young dogs and cats

forebrain dysfunction

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15
Q

What dog breeds are most commonly affected by congenital hydrocephalus?

A
  • Chihuahua
  • Yorkshire Terrier
  • Maltese
  • Boston Terrier
  • English Bulldog
  • Toy/Mini Poodle
  • Lhasa Apso
  • Poneranian
  • Pekingese
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16
Q

How is congenital hydrocephalus diagnosed? How are other diseases ruled out?

A

typical clinical signs and imaging

CSF analysis

17
Q

What are the 2 treatment options for congenital hydrocephalus?

A
  1. prednisone with diuretics - not commonly used, works best for mild cases
  2. surgical shunting - last ditch effort, better option with favorable prognosis
18
Q

How is surgical shunting performed for patients with congenital hydrocephalus?

A

ventriculoperitoneal shunt (VPS) - move CSF from the ventricles into another body cavity, such as the abdominal cavity

  • intracranial shunt placed
  • tunneled to the abdomen
19
Q

What complications are associated with ventriculoperitoneal shunt placement for congenital hydrocephalus treatment?

A
  • shunt occlusion or dislodgement
  • shunt-related infection
20
Q

What are intracranial arachnoid cysts? How are they diagnosed? What medical treatment is performed?

A

noncancerous fluid-filled sac that grows on the brain or spinal cord

MRI or CT

prednisone with diuretics

21
Q

What is the most commonly suggested surgical treatment for intracranial arachnoid cysts?

A

fenestration or shunting - cytsoperitoneal shunt with caudolateral craniotomy

  • suspected link with caudal occipital malformation syndrome
22
Q

What is hypoglycemic encephalopathy? What are 3 causes?

A

coma/stupor due to blood glucose levels at 45 mg/dL or less

  1. pancreatic insulinoma
  2. insulin overdose
  3. miniature/toy breed puppies or kittens with increased glucose requirements
23
Q

What is mitochondrial encephalopathy? What signalment is most commonly affected?

A

heritable deficiencies in mitochondrial enzymes resulting in diffuse, symmetric encephalo(myelo)pathy due to a buildup of lactate and pyruvate in the brain

young dogs

24
Q

What is seen on MRI in patients with mitochondrial encephalopathy?

A

bilaterally symmetric lesions

25
Q

What is organic acidurias? What signalment is most commonly affected?

A

measurable organic acid accumulation due to enzyme deficiencies in respiratory chain enzymes

young dogs

26
Q

What are 2 signs of organic acidurias? How is it diagnosed?

A
  1. multifocal/diffuse CNS dysfunction
  2. bilaterally symmetrical MRI lesions

increased levels of organic acids