Phys

Question 1

Describe Myasthenia gravis

Answer 1

autoantibodies directed against alpha-1 subunit partially block the Ach-R in the neuromuscular jxn -> more difficult for Ach to open the channel -> fatigue
Using an acetylcholinesterase inhibitor prolongs the interaction of Ach w/ the receptor reversing clinical signs

Question 2

Describe botulism

Answer 2

binds one of the vesicle docking proteins, preventing release of Ach at the neuromuscular junction

Question 3

Describe tick paralysis

Answer 3

CS from a neurotoxin (produced in salivary glands of female ticks) released into the circulation after the tick attaches and feeds for several days -> interferes with Ach release via Ca-mediated mech!
BW, MRI, CSF all normal; typically presumptive when finding an engorged tick
More commonly associated with exposure to Dermacentor (NA) > Ixodes (AU)
NA: Acute, rapidly progressive, ascending flaccid paresis that can progress to tetraplegia over 12-72 hours. Spinal reflexes and muscle tone decreased. Sensory, autonomic, and sphincter abnormalities do not occur. Resp paralysis may require ventilation
AU: much worse tick paralysis form Ixodes, does cause autonomic signs, urinary dysfunction, pul edema
Tx for both – remove tick (or give topical acaricides if cannot find one) and supportive tx. For Australian tick paralysis – ace and phenoxybenzamine to treat for autonomic signs

Question 4

Describe botulism

Answer 4

blocks release of Ach at the presynaptic terminal of skeletal muscle and cholinergic autonomic synapsis by irreversible cleavage of SNARE proteins. SNARE is essential for dicking synaptic Ach vesicles to the presynaptic membrane , allowing release into the synaptic cleft
From Clostridium botulinum a ubiquitous Gram pos anaerobe in the soil, water, and GI tract of mammals and fish
Animals get it by ingesting the preformed botulinum toxin in spoiled or uncooked meat; rarely can get from liver/GI infection.
Botulism neurotoxin type C most common (BoNT)
Acute onset progressive tetraparesis accompanied by autonomic signs – ileus, tachy/bradycardia, mydriasis, urinary retention, CN deficits (decreased palpebral, diminished PLR, ME) are common
Dx: Demonstrating BoNT in blood, feces, stomach contents, or food source
Tx: Supportive, antibiotics if you think infected with actual organism vs eating toxin. Never use aminoglycosides or amoxicillin as they can potentiate neuromuscular blockade. Antitoxin – most od not contain Ab against BoNT-C which is most common in dog so unsure if helpful. Can only bind circulating toxin, wont help with the toxins already bound to nerve terminal. Anaphylactic reactions can occur from antitoxins.
Px: Recovery usually takes 1-4 weeks and prognosis is excellent if they can be supported for that long

Question 5

Describe Elapid Snake Envenomation causing neuromuscular junction diseases

Answer 5

Eastern and Texas coral snakes (tiger, brown, and red bellied black snakes in AU) are elapid
Venom causes either a post synaptic blockade by tightly binding to AchR or it causes presynaptic inhibition of Ach release
Hemoglobinuria or myoglobinuria will cause urine discoloration - helpful in diagnosis as other NMJ disorders or peripheral n. diseases will NOT cause this
CBC may show spherocytosis
Tx: Supportive, antivenin available but can cause anaphylactic reaction since it is for equines

Question 6

Drugs to avoid in botulism and MG?

Answer 6

1. Macrolides (definite)
2. Fluoroquinolones (probable)
3. Aminoglycosides (definite)
4. Penicillins (probable)
5. B-adrenergic blockers (possible)
6. L type calcium channel blockers (possible)
7. Class Ia antiarrhythmics (definite)
8. Magnesium (definite)
9. Neuromuscular blockers and inhalation anesthetics (definite)

Question 7

Drugs to avoid in botulism/MG

Answer 7

1. Immune checkpoint inhibitors (definite)
2. D-penicillamine (definite)
3. Tyrosine kinase inhibitors (doubtful - probable with tandutinib)
4. Interferons (possible)
5. Statins (probable)

Question 8

Diagnostic test for narcolepsy? Rx?

Answer 8

– test for by measuring hypocretin-1 peptide in the CSF, which should be low (<80 pg/ml rr 250 – 350 pg/ml)
Sens and spec but if doh has familial form from mutation in Hcrtr2 receptor gene ay have normal CSF hypocretin conc
Tx with activating adrenergic systems. Tricyclic antidepressants like imipramine, clomipramine, desipramine, SSRI like venlafaxine or alpha-2 adrenergeic antagonist yohimbine

Question 9

A 2-year-old Devon Rex cat presents with decreased muscle mass and dorsal protrusion of the scapulae. Genetic testing reveals a missense mutation in the COLQ gene. Which of the following treatments should be avoided to prevent exacerbation of clinical signs?

1. Albuterol
2. Pyridostigmine bromide
3. Edrophonium chloride
4. Corticosteroids

Answer 9

Pyridostigmine bromide

In COLQ-associated congenital myasthenic syndromes, acetylcholinesterase inhibitors like pyridostigmine bromide should be avoided as they can exacerbate muscle weakness.

Question 10

A 6-week-old Old Danish Pointing dog presents with muscle weakness after exercise. Genetic testing reveals a mutation in the CHAT gene. Which of the following is most likely to be observed on electrophysiological testing?

1. Decremental response on repetitive nerve stimulation after a high-frequency conditioning train
2. Positive sharp waves and complex repetitive discharges on electromyography
3. Increased postsynaptic acetylcholine receptor concentration
4. Normal nerve conduction studies without a decremental response

Answer 10

1. Decremental response on repetitive nerve stimulation after a high-frequency conditioning train

In CHAT-associated congenital myasthenic syndrome, a decremental response on repetitive nerve stimulation is observed, especially after a high-frequency conditioning train.

Question 11

A 3-year-old Cavalier King Charles Spaniel presents with episodes of falling, often triggered by exercise or excitement. During these episodes, the dog shows signs of muscle hypertonicity and an inability to maintain balance. Genetic testing reveals an autosomal recessive mutation. What is the most likely diagnosis for this dog?

1. Canine epileptoid cramping syndrome
2. Episodic falling syndrome
3. Paroxysmal dyskinesia
4. Dancing Dobermann disease

Answer 11

Episodic falling syndrome

Episodic falling syndrome is an autosomal recessive disorder in Cavalier King Charles Spaniels characterized by exercise or excitement-induced episodes of muscle hypertonicity and falling.

Question 12

A 5-year-old Border Terrier presents with episodic episodes of muscle cramping and stiffness, often triggered by waking, excitement, or stress. The owner reports that a gluten-free diet has ameliorated some symptoms. What is the most appropriate classification of this disorder?

1. Paroxysmal kinesigenic dyskinesia
2. Paroxysmal exertion-induced dyskinesia
3. Paroxysmal nonkinesigenic dyskinesia
4. Dystonia

Answer 12

Paroxysmal nonkinesigenic dyskinesia

Paroxysmal nonkinesigenic dyskinesia is characterized by episodes that are not triggered by movement or exercise and can be improved with a gluten-free diet in some cases, such as canine epileptoid cramping syndrome in Border Terriers.

Question 13

A 4-year-old Labrador Retriever is diagnosed with a hyperkinetic movement disorder characterized by episodes of generalized muscle stiffness without pain. The episodes occur randomly and improve with age. Which of the following is the most likely underlying genetic mutation?

1. SERAC1
2. PIGN
3. CLCN-1
4. KCNJ10

Answer 13

SERAC1 mutation is associated with canine multiple system degeneration, which can present as hyperkinetic movement disorders in Labradors with generalized muscle stiffness that improves with age.

Question 14

A Jack Russell Terrier presents with continuous muscle activity leading to stiffness and delayed relaxation. Electromyographic studies show high-frequency discharges of motor unit potentials that persist during sleep and anesthesia. Which of the following best describes this condition?

1. Myokymia
2. Neuromyotonia
3. Fasciculations
4. Myoclonus

Answer 14

Neuromyotonia is characterized by high-frequency discharges of motor unit potentials that persist during sleep and anesthesia, leading to continuous muscle activity, stiffness, and delayed relaxation.

Question 15

A 4-year-old Miniature Schnauzer presents with a stiff and stilted gait after periods of rest, which improves with activity. Genetic testing reveals a mutation in the CLCN1 gene. What is the most likely diagnosis for this dog?

1. Hyperkalemic Periodic Paralysis
2. Paramyotonia Congenita
3. Myotonia Congenita
4. Myotonic Dystrophy

Answer 15

3. Myotonia Congenita

Myotonia congenita is caused by mutations in the CLCN1 gene and is characterized by muscle stiffness that improves with continued activity.

Question 16

A 6-month-old Labrador Retriever exhibits sudden, brief, shock-like muscle contractions in response to auditory stimuli. The dog’s owner reports normal behavior between episodes. Which condition should be considered, and what is the best initial diagnostic step?

1. Canine distemper virus myoclonus; MRI
2. Epileptic myoclonus; Electroencephalography (EEG)
3. Hyperekplexia (startle disease); Genetic testing
4. Hemifacial spasm; Electromyography (EMG)

Answer 16

Hyperekplexia (startle disease) is characterized by exaggerated startle responses to stimuli, and genetic testing can confirm mutations in genes like GlyT2.

Question 17

A 7-year-old Miniature Wirehaired Dachshund is diagnosed with late-onset myoclonic seizures triggered by visual stimuli. Which of the following is the most likely diagnosis?

1. Neuronal Ceroid Lipofuscinosis
2. Lafora Disease
3. Familial Reflex Myoclonus
4. Canine Distemper Virus Myoclonus

Answer 17

Lafora disease is a late-onset condition causing myoclonic seizures triggered by visual stimuli, commonly seen in breeds like Miniature Wirehaired Dachshunds.

Question 18

A 2-year-old Irish Wolfhound presents with generalized stiffness and episodes of extensor rigidity triggered by handling. Genetic testing reveals a microdeletion in the GlyT2 gene. What is the most appropriate diagnosis?

1. Hyperekplexia (startle disease)
2. Hemifacial Spasm
3. Progressive Myoclonic Epilepsy
4. Reflex Myoclonus

Answer 18

Hyperekplexia (startle disease) is characterized by generalized stiffness and extensor rigidity triggered by stimuli, with a known genetic mutation in the GlyT2 gene in Irish Wolfhounds.

Question 19

A 3-year-old Australian Cattle Dog exhibits muscle stiffness after rest, which improves with continued activity. Genetic testing identifies a mutation in the CLCN1 gene. Which of the following conditions does this most likely indicate?

1. Myotonia Congenita
2. Potassium-Aggravated Myotonia
3. Paramyotonia Congenita
4. Myotonic Dystrophy

Answer 19

Myotonia congenita is characterized by muscle stiffness that improves with activity and is caused by mutations in the CLCN1 gene.

Question 20

A 5-year-old Beagle presents with myoclonic seizures and generalized tonic-clonic seizures, with a slowly progressive course. Which of the following genetic mutations is most likely responsible for these clinical signs?

1. CLCN1
2. SCN4A
3. EPM2B (NHLRC1)
4. GlyT2

Answer 20

The EPM2B (NHLRC1) gene mutation is associated with Lafora disease, which causes progressive myoclonic epilepsy in breeds like Beagles.

Question 21

A 2-year-old Labrador Retriever presents with repetitive myoclonic jerks affecting multiple limbs. These movements are continuous and not associated with epileptic seizures. What is the most likely underlying cause?

1. Epileptic Myoclonus
2. Canine Distemper Virus Myoclonus
3. Hemifacial Spasm
4. Progressive Myoclonic Epilepsy

Answer 21

Canine distemper virus myoclonus is characterized by continuous myoclonic jerks that are not associated with epileptic seizures.

Question 22

A 4-year-old Standard Poodle is diagnosed with progressive myoclonic epilepsy characterized by myoclonic and generalized tonic-clonic seizures. Which breed-specific condition should be considered?

1. Lafora Disease
2. Neuronal Ceroid Lipofuscinosis
3. Familial Reflex Myoclonus
4. Hyperkalemic Periodic Paralysis
   Your Answer: 1
   Correct Answer: 1

Explanation: Lafora disease is a condition seen in Standard Poodles that causes progressive myoclonic epilepsy with both myoclonic and generalized tonic-clonic seizures.

Answer 22

Lafora disease is a condition seen in Standard Poodles that causes progressive myoclonic epilepsy with both myoclonic and generalized tonic-clonic seizures.

Question 23

During a neurological exam, a cat exhibits orofacial automatisms, including licking and chewing, along with facial twitching. Which stage of the six-stage seizure progression system does this correspond to?

1. Stage 1
2. Stage 2
3. Stage 3
4. Stage 4

Answer 23

Stage 3 in the six-stage seizure progression system includes orofacial automatisms such as salivation, licking, and facial twitching.

Question 24

A 4-year-old cat is brought to the clinic after experiencing episodes of staring, motor arrest, and head turning. The owner reports that these episodes sometimes progress to generalized clonic convulsions. Which experimental model best explains the progression of these seizures?

1. Kainic Acid Model
2. Tetanus Toxin Model
3. Electrical Stimulation of the Hippocampus
4. Tungstic Acid Model

Answer 24

The Kainic Acid Model is known to produce limbic seizures that can progress to generalized convulsions, resembling the described clinical progression.

Question 25

A cat with suspected FTLE shows head turning, salivation, and facial twitching when stimulated. Which anatomical structure is likely involved based on these clinical signs?

1. Amygdala
2. Insula
3. Occipital Cortex
4. Parietal Lobe

Answer 25

The amygdala is involved in these clinical signs, as stimulation of this structure can produce head turning, salivation, and facial twitching.

Question 26

A 3-year-old cat presents with focal seizures that occasionally generalize. The seizures often begin with an “attention response” where the cat appears alert and stops moving. This initial sign is most commonly associated with stimulation of which brain region?

1. Amygdala
2. Hippocampus
3. Insula
4. Lateral Temporal Cortex

Answer 26

The “attention response” is commonly associated with stimulation of the hippocampus.

Question 27

A 2-year-old cat is being monitored for seizures. During an episode, the cat exhibits behaviors such as sniffing and looking around, followed by facial twitching. According to the staging system, which stage does this behavior likely represent?

1. Stage 1
2. Stage 2
3. Stage 3
4. Stage 4

Answer 27

Stage 3 includes autonomic manifestations such as salivation and licking, along with orofacial automatisms like facial twitching.

Question 28

In experimental research, which method is used to produce chronic focal seizures by blocking the release of inhibitory neurotransmitters like GABA?

1. Kainic Acid Injection
2. Tetanus Toxin Injection
3. Electrical Stimulation of the Amygdala
4. Tungstic Acid Injection

Answer 28

Tetanus toxin injection is used to produce chronic focal seizures by blocking the release of inhibitory neurotransmitters such as GABA.

Question 29

A 7-year-old cat presents with episodes of head nodding and generalized convulsions. Which experimental model might have provided early insights into these seizure patterns?

1. Kindling Model
2. Kainic Acid Model
3. Tetanus Toxin Model
4. Tungstic Acid Model

Answer 29

The Kindling Model provided early insights into seizure patterns that include head nodding and generalized convulsions by progressively increasing the brain’s response to electrical stimulation.

Question 30

A dog with idiopathic epilepsy is experiencing status epilepticus. What is the primary neurotransmitter involved in inhibiting seizure activity?

1. Glutamate
2. Acetylcholine
3. GABA
4. Dopamine

Answer 30

GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter in the brain, and its activity helps to terminate seizures.

Question 31

A 5-year-old German Shepherd presents with status epilepticus. Which diagnostic tool is crucial for confirming the presence of nonconvulsive status epilepticus (NCSE)?

1. MRI
2. CT scan
3. Electroencephalography (EEG)
4. Blood gas analysis

Answer 31

Electroencephalography (EEG) is essential for diagnosing nonconvulsive status epilepticus (NCSE), as it can detect ictal discharges without overt clinical seizure activity.

Question 32

In dogs with status epilepticus, the failure of which cellular mechanism contributes to the development of cytotoxic edema?

Na+/K+ ATPase pump
Voltage-gated sodium channels
Voltage-gated calcium channels
GABA-A receptors

Answer 32

Failure of the Na+/K+ ATPase pump during prolonged seizure activity leads to an influx of sodium and water into the cells, contributing to cytotoxic edema.

Question 33

Which of the following systemic complications is most likely to occur during the second phase (uncompensated phase) of status epilepticus?

1. Hypertension
2. Hyperthermia
3. Hypoglycemia
4. Hyperglycemia

Answer 33

Hypoglycemia.

During the uncompensated phase of status epilepticus, systemic hypoglycemia can occur due to the high metabolic demand of prolonged seizure activity, leading to depletion of glucose reserves.

Question 34

A dog with refractory status epilepticus is found to have elevated serum P-glycoprotein (Pgp) levels. What is the role of Pgp in drug resistance?

1. Enhances drug absorption in the gastrointestinal tract
2. Reduces drug excretion by the kidneys
3. Increases drug uptake into the central nervous system
4. Functions as an efflux pump at the blood-brain barrier

Answer 34

P-glycoprotein (Pgp) functions as an efflux pump at the blood-brain barrier, reducing the uptake of certain drugs, including anticonvulsants, into the central nervous system and contributing to drug resistance.

Question 35

Which of the following findings is associated with the diagnosis of status epilepticus based on electroencephalographic (EEG) monitoring?

1. Generalized tonic-clonic movements without autonomic manifestations
2. Ictal discharges without clinical seizure activity
3. Hypointense lesions on T1-weighted MRI
4. Hyperintense lesions on T2-

Answer 35

EEG monitoring can reveal ictal discharges without clinical seizure activity, which is crucial for diagnosing nonconvulsive status epilepticus (NCSE).