Download MulscleLab

Case #9 - History
A thoroughbred colt died unexpectedly. Two days before
was healthy and running around. The owner rode it
almost every day, except for last two days, when he was
very busy with his broiler farm.
Your clinic is 400 km away from a diagnostic lab and you
decided to do necropsy and submit tissues to lab (if
needed) to determine diagnosis.
Owner is anxious about risk for his other two horses.
Case #9 - Necropsy
You were hoping to find some kind of intestinal accident
and to build your reputation in front of your client as a
good diagnostician.
However, your findings were rather disappointing. You
found a few pale areas in the heart and some skeletal
muscles, but you were not sure about their significance.
What are you going to do next? Owner wants to know if
there is a risk for the other horses.
Case #9 - Reasoning
Many diseases may cause unexpected and sudden death in
animals. Which one is it? Is it muscle disease of something
else?
You decided to re-examine the carcass, but did not find
anything else. What to do?
You decided to start at the beginning and obtain a bit more
information from the owner.
Case #9 - Action
• Sample collection from all vital organs (including pale
areas of cardiac and skeletal muscle) in a formalin jar
• Sample collection from major blood filtrating organs for
microbiology.
• Collection of gastric content
• Collection of a feed material
Case #9 - Results
• Acute myodegeneration and necrosis in the heart and
skeletal muscles – most significant finding
• Bacteriology: mixed bacteria - probably contamination
Case #9 - Results
• Feed material - normal monensin concentration
Case #9 - Results
• Stomach content - high monensin concetration
Comments: Monensin toxicity was considered to be the
cause of death. The source of monensin was not
determined, because submitted feed did not contain
monensin.
Case #9 - Results
Case #9 - Results
The owner phoned you about the risk.
Case #9 - Results
Monensin LD50
(mg/kg)
Horse
2-3
Dog
5-6
Sheep
10-12
Cattle
20-34
Poultry
90-200
E. Simko WCVM
Case #10 - History
An adult horse presented due to:
• Apparent stiffness
• Difficulty in mastication
Case # 10
Slides
Case # 10
Clinical exam:
• Salivation
• Prolapsed eyelid
• Stiff
Case # 10
Next day
Clinical exam:
• Salivation
• Prolapsed eyelid
• Stiff
• Lockjaw
• “Sawhorse”
Case # 10 Necropsy
A focal necrotizing myositis
Case # 10 Necropsy
Bacteriology:
Aerobic culture: mixed bacteria
Case # 10 Necropsy
Bacteriology:
Aerobic culture: mixed bacteria
Anaerobic culture: Clostridum tetani
Case #11 - History
A healthy young adult mixed breed dog presented for
spaying.
After 5-10 min. under GA with halothane:
• Rigid muscle tones
• High temperature
• Increased HR and RR
• Died
Case #11 - Necropsy
Apparent excessive muscle rigidity of the face and legs
Diffuse pulmonary congestion
Cause of death not determined, histology is pending
Case #11 - Necropsy
Slides
Case #11 - Histology
• Acute myodegeneration hypercontraction and
sarcoplasmal tearing
(Malignant hyperthermia)
• Inherited disease initiated by stress or
halothane anesthesia
• Lesions: pale, moist, and swollen muscles of
shoulder, back and thigh
• Known as pale, soft, exudative pork (PSE)
E. Simko WCVM
Case #12 - History
A thoroughbred 8 yr
sudden onset of severe lameness of left hind limb
severe swelling and crepetance over the left gluteal
Duration of illness: 12 hours.
How did the process get started.
Case # 12 - History
How did the process get started?
Case # 12 - Necropsy
• Hemorrhagic myositis, acute, severe,
• Dermal and subcutaneous emphysema and
edema, acute, severe
Case # 12 - Results
• Bacteriology: C. novyi
Case # 13 - History
• A cat with acute onset of hind end ataxia and pain