ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
Fifteen of a group of 200, 7 month old feedlot calves are lame. The calves arrived
at the feedlot approximately one month ago, and one week later, 40 of the
animals developed pneumonia. These calves were treated with oxytetracycline,
and the pneumonia appeared to resolve. On physical examination, the affect
calves have swellings in the carpi, tarsi, and stifles with distension of associated
tendon sheaths, and stiff gait. Two calves are euthanized. Postmortem eamination
shows fibrinous pleuritis and papillary muscle necrosis. Which of the following
organisms is the most likely cuase of these signs?
a) arcanobacterium (actinomyces) pyogenes
b) histophilus somni
c ) mannheimia hemolytica
✅
d) pasteurella multocida
e) salmonella thyphimurium - correct answer B) histophilus somni
Histophilus somni is a well known cause of systemic disease in feedlot cattle,
including respiratory disease, speticemia, and polyarthritis. In this case, the calves
initially developed pneumonia, and now soe of them show signs of lameness, joint
swelling, and stiff gait, which are consistent with septic arthritis, and polyarthritis
that can occur after a histophilus somni infection
- additionally the post mortem finding of fibrinous pleuritis and papillary muscle
necrosis also strongly suggest histophilus soni as the causative agent.
-Known to cause arthritis, pleuritis, myocarditis, and septicemia in calves
What is hyperkalemic periodic paralysis in a horse - correct answer ✅
-a genetic
disorder that affects muscles causing episodes of muscle weakness or paralysis.
-It is autosomal dominant
,ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
What is the cause of hyperkalemic periodic paralysis - correct answer ✅ THe
disorder is caused by a mutation in the sodium channel gene, leading to increased
potassium levels in the blood. This affects the electrical activity of muscle cells,
causing the muscles to contract abnormally
✅
What are symptoms of hyperkalemic periodic paralysis in horses - correct answer
-muscle twitching or trembling
-weakness or partial paralysis especially in hindquarters
-episodes of muscle stiffness
-respiratory issues in severe cases
-horse remains alert
what are triggers of hyperkalemic periodic paralysis - correct answer
potassium intake from feed such as alfalfa, molasses or certain grains
✅-high
-stress, exercise or fasting
how would you manage hyperkalemic periodic paralysis - correct answer
dietary modification like feeding low potassium diets and aoiding alfala and
✅
-
monitor potassium intake
-medicate with acetazolamide and hydrochlorothiazide
-consistent exercise and minimize stress
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
,ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
Which of the following is the most likely diagnosis?
A) Equine degenerative myeloneuropathy
B) Equine motor neuron disease
C) Exertional rhabdomyolysis
✅
D) Hyperkalemic periodic paralysis
E) Tetanus - correct answer D) hyperkalemic periodic paralysis
HYPP leads to episodes of periodic muscle weakness or paralysis.
-Prolapse of the nictitating membrane is characteristic of HYPP due to muscle
weakness in the face
-Weakness and collapse suggest muscle paralysis or severe weakness, dog sitting
posture strongly supports this
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
incorrect - correct answer ✅
This is a case of HYPP, why would Equine Degenerative Myeloneuropathy be
EDM is a neurodegenerative disease that causes
, ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
progresse ataxia ( incoordination) and weakness in young horses, particularly
those deficient in vitamin E.
Although it causes weakness, EDM is more associated with ataxia ( uncoordinated
movement) rather than acute muscle fasciculations or prolapse of the nictitating
membrane. It is a chronic, progressive condition, unlike the episodic nature of
HYPP
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
correct answer ✅
This is a case of HYPP, why would Equine Motor Neuron Disease be incorrect -
vitamin E deficiency
EMND is a neurodegeneratie disorder and is associated with
-EMND causes muscle atrophy and weakness, primarily affecting posture and gait
over time. However it does not typically cause acute episodes of weakness with
fasciculation and prolapse of the third eyelid like HYPP does. EMND is also more
chronic in its progression, not episodic.
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
rated A 2026
Fifteen of a group of 200, 7 month old feedlot calves are lame. The calves arrived
at the feedlot approximately one month ago, and one week later, 40 of the
animals developed pneumonia. These calves were treated with oxytetracycline,
and the pneumonia appeared to resolve. On physical examination, the affect
calves have swellings in the carpi, tarsi, and stifles with distension of associated
tendon sheaths, and stiff gait. Two calves are euthanized. Postmortem eamination
shows fibrinous pleuritis and papillary muscle necrosis. Which of the following
organisms is the most likely cuase of these signs?
a) arcanobacterium (actinomyces) pyogenes
b) histophilus somni
c ) mannheimia hemolytica
✅
d) pasteurella multocida
e) salmonella thyphimurium - correct answer B) histophilus somni
Histophilus somni is a well known cause of systemic disease in feedlot cattle,
including respiratory disease, speticemia, and polyarthritis. In this case, the calves
initially developed pneumonia, and now soe of them show signs of lameness, joint
swelling, and stiff gait, which are consistent with septic arthritis, and polyarthritis
that can occur after a histophilus somni infection
- additionally the post mortem finding of fibrinous pleuritis and papillary muscle
necrosis also strongly suggest histophilus soni as the causative agent.
-Known to cause arthritis, pleuritis, myocarditis, and septicemia in calves
What is hyperkalemic periodic paralysis in a horse - correct answer ✅
-a genetic
disorder that affects muscles causing episodes of muscle weakness or paralysis.
-It is autosomal dominant
,ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
What is the cause of hyperkalemic periodic paralysis - correct answer ✅ THe
disorder is caused by a mutation in the sodium channel gene, leading to increased
potassium levels in the blood. This affects the electrical activity of muscle cells,
causing the muscles to contract abnormally
✅
What are symptoms of hyperkalemic periodic paralysis in horses - correct answer
-muscle twitching or trembling
-weakness or partial paralysis especially in hindquarters
-episodes of muscle stiffness
-respiratory issues in severe cases
-horse remains alert
what are triggers of hyperkalemic periodic paralysis - correct answer
potassium intake from feed such as alfalfa, molasses or certain grains
✅-high
-stress, exercise or fasting
how would you manage hyperkalemic periodic paralysis - correct answer
dietary modification like feeding low potassium diets and aoiding alfala and
✅
-
monitor potassium intake
-medicate with acetazolamide and hydrochlorothiazide
-consistent exercise and minimize stress
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
,ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
Which of the following is the most likely diagnosis?
A) Equine degenerative myeloneuropathy
B) Equine motor neuron disease
C) Exertional rhabdomyolysis
✅
D) Hyperkalemic periodic paralysis
E) Tetanus - correct answer D) hyperkalemic periodic paralysis
HYPP leads to episodes of periodic muscle weakness or paralysis.
-Prolapse of the nictitating membrane is characteristic of HYPP due to muscle
weakness in the face
-Weakness and collapse suggest muscle paralysis or severe weakness, dog sitting
posture strongly supports this
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
incorrect - correct answer ✅
This is a case of HYPP, why would Equine Degenerative Myeloneuropathy be
EDM is a neurodegenerative disease that causes
, ICVA NAVLE Exam 1 Study Guide Q&A
rated A 2026
progresse ataxia ( incoordination) and weakness in young horses, particularly
those deficient in vitamin E.
Although it causes weakness, EDM is more associated with ataxia ( uncoordinated
movement) rather than acute muscle fasciculations or prolapse of the nictitating
membrane. It is a chronic, progressive condition, unlike the episodic nature of
HYPP
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
correct answer ✅
This is a case of HYPP, why would Equine Motor Neuron Disease be incorrect -
vitamin E deficiency
EMND is a neurodegeneratie disorder and is associated with
-EMND causes muscle atrophy and weakness, primarily affecting posture and gait
over time. However it does not typically cause acute episodes of weakness with
fasciculation and prolapse of the third eyelid like HYPP does. EMND is also more
chronic in its progression, not episodic.
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical
examination shows bilateral prolapse of the nictitating membrane and muscle
fasciculations of the neck, shoulders, and flank. During examination, the mare's
hindlimbs give way, and she leans back in a dog-sitting posture. Rectal
temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and
respiratory rate is 30 breaths/min.
