LAM I Exam I Material Flashcards
These are responsible for directing controlled detachment of laminae as required for growth of the hoof:
MMPs
- matrix metalloproteinases, metal-cofactor enzymes*
- Some factors (many proposed, such as direct action of endotoxin) trigger excessive uncontrolled activation of these enzymes such that widespread disruption of laminar attachment occurs.*
What is the maximum rate of intraosseus fluid administration in the horse?
2 L/hr
This rate sufficient in many cases for foals, barely compatible with maintenance in an average adult horse; More applicability with local treatment administration
Why must you be careful when administering Polymyxin B to a dehydrated horse?
can cause renal compromise/toxicity
What are the major contraindications to oral administration of fluids?
gastric distension, “reflux” and ileus
What is the most common cause of profuse hemorrhage of nasal origin in the horse?
Trauma (nasogastric tube)
T/F: Sinking is a clinical diagnosis based on depressing coronary band while rotational disruption is a radiographic diagnosis
True
T/F: Once a horse develops DIC, it is almost always a terminal event
True
What is the determinant of the chronic stage of laminitis?
mechanical disruption/collapse
Disruption involves rotational displacement and vertical displacement (sinking), of the distal phalanx with relation to the hoof wall. This phase is often associated with vascular insufficiency, localized sepsis, metabolic and growth dysfunction
T/F: In an anorexic horse, it is typical to see total body depletion of Ca2+
True
- Typically large amounts ingested in horses diet, thus large amount excreted each day*
- Regulation: geared to excrete large amounts of Ca2+ losses: net result is that suffer substantial losses as soon as intake decreases*
T/F: Unilateral nasal discharge is associated with upper and lower respiratory disease
False
Unilateral nasal discharge is associated with upper airway disease
What is the approximate gastric fluid capacity in a horse?
~15 L
What is the goal of intervention in the acute phase of laminitis?
limit the severity to optimize the progression into subacute phase rather than into the chronic phase
T/F: Endotoxin is generated during both death of gram negative bacteria, as well as during the rapid multiplication phase
True
T/F: Tachycardia is seen with both the hyperdynamic and hypodynamic stages of endotoxemia
True
What structure is responsible for most of the deleterious effects of endotoxin?
Lipid A
IV Mg sulfate should not be given to horses in hypotensive conditions. Why?
has vasodilator properties
What is a major contraindication for administering bicarbonate to an acidotic horse?
respiratory compromise (hypoventilation)
Will result in worsened acidemia through development of respiratory acidosis in addition to already present metabolic acidosis
What is the goal of intervention in the subacute phase of laminitis?
to limit progression into the chronic phase of the disease (i.e. prevent mechanical disruption)
During this phase the hoof is healing but still very weakened, and can still structurally fail
__________ is the highly variable, antigenic region of LPS
polysaccharide O
Synchronous diaphragmatic flutter [SDF] in horses is usually treated with intravenous fluids supplemented with moderate amounts of:
calcium
__________ is the most important factor in rapid fluid flow rate
radius (or diameter) of the catheter
Determinants of flow rate: diameter (“gauge”), length of system components, pressure differential, and viscosity of fluid administered
In what state of clinical endotoxemia do you expect to see a “toxic line” on the oral mucous membranes?
hypodynamic state
In an endotoxemic horse, you will often clinically recognize an apparently normal CBC except for presence of __________
lymphopenia
In an endotoxemic horse, you will often clinically recognize an apparently normal CBC except for presence of lymphopenia
A 12-year-old gelding presents for bilateral fowl-smelling epistaxis. What is your most likely diagnosis?
ethmoid hematoma
Common in older horses (most often 10-12 years) and often is associated with a fowl-smelling epistaxis
T/F: Fever is associated with the hyperdynamic state of endotoxemia
True
What is the most commonly used buffer base to treat metabolic acidosis in the horse?
Lactate
__________, a dietary supplement, can be given as a treatment for endotoxemia to alter the amount of arachidonic acid in cell membranes, thus decreasing inflammatory responses
Linseed oil
Which limbs in the equine have more Type I muscle fibers?
Forelimbs
These are the major weight bearing muscles. They are adapted to constant oxygen supply and therefore have tons of capillaries and low amounts of stored glycogen. Not very powerful, but fatigue slowly
What flow rate (L/hr) can be acheived with a 14 G catheter?
13.1 L/hr
T/F: All cases of endotoxemia will result in shock presentation
False
Has to do with the AMOUNT of endotoxin that gets in the blood stream. There will always be some because mucosa of the GIT is never 100% intact in any animal (wear and tear)
Describe the clinical signs associated with early endotoxemia:
tachypnea, pale mucous membranes
Within 90 minutes: depression, restlessness, inappetance, increasing temperature
Using the following, what is the correct progressive order of respiratory structures from rostral to distal?
- Pharynx
- Nares
- Larynx
- Trachea
- Ethmoid
- Guttural Pouch
- Nasopharynx
- Nasal passage
- Nares
- Nasal passage
- Ethmoid
- Nasopharynx
- Guttural Pouch
- Larynx
- Trachea
Horses don’t have a pharynx
Calculate maintenance fluid amount for a 400 kg horse
~24 L
- Maintenance = 50-60 mL/kg/day*
- 400kg x 60mL = 24,000mL ÷ 1000 = 24 L*
On a routine prepurchase exam, a potential buyer requests you to scope the horse. You note fungal plaque-like lesions near the internal carotid artery. What is the treatment of choice?
Transarterial coil placement
A horse with 2 days duration of laminitis is found to have absence of indentation at the coronary band, and this image on radiographs. Stage the laminitis.
Chronic
Margination of __________ accounts for the leukopenia found in most horses with endotoxemia
neutrophils
TNF and IL-1 act on neutrophils and endothelial cells. Margination of neutrophils accounts for the leukopenia found in most horses with endotoxemia.
Once activation of neutrophils and endothelial cells occurs the process becomes self-sustaining and malignant
What cell is the ‘major player’ in endotoxemia?
macrophages
Interaction with macrophages is the initiating event from which most all other steps flow
In horses, development of DIC is most typically associated with __________
endotoxemia
In horses, development of DIC is most typically associated with endotoxemia; activation of coagulation cascade by various inflammatory factors, mediators, kinins, and vascular endothelial disruption
T/F: Bronchoalveolar lavage (BAL) is typically indicated if a culture is necessary for evaluation
False
Bronchoalveolar lavage (BAL) is NOT indicated if a culture is necessary for evaluation. BAL is a non-sterile procedure.
T/F: Cough is associated with upper and lower respiratory disease
True
A 3-year-old Thoroughbred presents to you with unilateral epistaxis; no prior history of trauma. Last race was 7 days ago. What is your most likely diagnosis?
guttural pouch mycosis [GPM]
What solution is most typically used to treat metabolic alkalosis in the horse?
an acidifying solution – most typically NaCl
Metabolic alkalosis is characterized by increased HCO3 and increased pH; fairly rare to see in horses
What is the pattern in which muscle fibers are recruited?
Type I → Type IIA → Type IIAX → Type IIX
Type IIX only recruited near maximal intensity (sprinting, jumping) and during extremely prolonged submaximal exercise
What is considered the most thrombogenic catheter material?
polypropylene
What are the three most common causes of reduced performance in horses?
musculoskeletal, respiratory and cardiovascular dysfunction
How do you diagnose DIC in the hypercoagulable (prothrombotic) stage in a horse?
D-dimers
- Increase in D-dimer indicates excessive amounts of fibrin formation within the vascular; increases in many situations but is a reliable indicator of DIC, deep vein thrombosis, pulmonary embolism and catheter associated venous thrombosis*
- Elisa test for D-dimer (one of many tests) seems to have highest sensitivity*
T/F: Cold extremities correlate with the hypodynamic state of the horse
True!
What is ozena?
an atrophic rhinitis marked by a thick mucopurulent discharge, mucosal crusting, and a strong odor
What is the preferred medical treatment for ethmoid hematoma in a horse?
intralesional formalin
- Intralesional formalin causes protein hydrolysis which desiccates and coagulates the tissue.*
- The preferred surgical treatment would be surgical ablation*
What is the most common acid-base disturbance in the equine patient?
metabolic acidosis
T/F: In an adult horse, you would not want to give aminoglycosides before binding the endotoxin because it will release more endotoxin when it kills off the bacteria
False
This is only a concern in foals
A horse presents with cold extremities, tachycardia, congested membranes that are dark near the teeth and lighter above, CRT of > 5 seconds and HR of 128. What is your diagnosis?
Shock, likely due to endotoxemia
MM description is that of a “toxin line”. HR is with in the shock range of 120-140.
As endotoxemia progresses, HR peaks at time of __________
maximal GIT depression
As endotoxemia progresses, HR peaks at time of maximal GIT depression (2 hrs post-endotoxin)
What are the main complications associated with catheter use in a horse?
thrombosis, cracking, breaking, air embolism, extravasation