LAM - Exam 1 Flashcards

Comprehensive practice flashcards covering basic medical interventions, respiratory system diseases, cardiovascular disorders, and hemolymphatic pathology in horses.

What is the primary mitigation strategy for controlling animal contact to prevent disease outbreaks?

Separate animals by age groups, sexes, and classes.

How does active immunization function?

It stimulates the body's own immune system to produce antibodies.

What is defined as a preparation of a weakened or killed pathogen?

Vaccine

What is a toxoid?

An inactivated toxin used to stimulate an immune response.

What is the purpose of an adjuvant in a vaccine?

It is an additive used to enhance the body's immune response.

How is passive immunization characterized?

It provides immediate, temporary protection by administering pre-formed antibodies.

What is antiserum?

Blood serum containing specific antibodies against a pathogen.

What is the function of an antitoxin?

An antibody preparation that specifically neutralizes a toxin.

What environmental management practices are most effective for GI parasite control?

Rigorous pasture management and manure removal to disrupt transmission.

What diagnostic tool is used to identify "high worm burden" adult shedders?

Fecal egg counts (FECs).

What is the targeted parasite control protocol for foals in their first year?

Targeting ascarids using benzimidazoles every $60$ days.

How is S. vulgaris controlled in adult horses?

Treat all horses at least once yearly with a macrocyclic lactone like ivermectin or moxidectin.

What is the basic maintenance fluid requirement for an adult horse in thermo-neutral conditions?

$$50\,ml/kg/day$$

What is the approximate daily maintenance fluid volume for an average $500\,kg$ horse?

Approximately $25\,L$ per day (6-8 gallons).

What is the standard continuous IV flow rate for maintenance fluids in a hospital setting?

$1\,L$ per hour.

What is the maintenance fluid requirement for neonates?

$$100\,ml/kg/day$$

What are the clinical signs of early dehydration in a horse?

Dry mucous membranes, dry feces, and concentrated urine.

How does the body compensate for transitioning from dehydration to hypovolemia?

Via increased heart rate and selective peripheral vasoconstriction.

What physiological state results when tissues are forced into anaerobic respiration during hypovolemic shock?

Metabolic acidosis.

What is the typical osmolarity of isotonic crystalloid solutions used for volume replacement?

$$280-320\,mOsm/L$$

Why are Balanced Electrolyte Solutions (BES) such as LRS or Plasmalyte-148 preferred for general use?

They are alkalinizing.

When is the use of Normal Saline (0.9% NaCl) specifically indicated?

When potassium status is unknown or when hyperkalemia/hyponatremia is present.

What is the massive "shock dose" volume for a $500\,kg$ horse in severe shock?

$40\,L$ (approx. $8\%$ body weight).

Describe the "fluid challenge" approach to resuscitation.

Rapidly administer $1/4$ of the estimated deficit, then reassess perfusion parameters (HR, pulse, CRT, lactate).

What are two clinical signs of volume overload (over-hydration)?

Chemosis or tachypnea.

What are the benefits of using synthetic colloids like Hetastarch?

They stay in the intravascular space longer, exert oncotic pressure, and limit edema.

What is the bolus dose for Hypertonic Saline in rapid volume expansion?

$$2-4\,ml/kg$$

What must Hypertonic Saline always be followed by?

Large volumes of isotonic crystalloids.

What are the primary indications for Fresh Frozen Plasma (FFP)?

Failure of passive transfer (FPT) in foals, hypoproteinemia, coagulopathies, and endotoxemia.

When is whole blood transfusion indicated for acute hemorrhage?

Loss of $1/3$ blood volume or PCV $<20\%$ in $12$ hours.

What is the threshold for whole blood transfusion in chronic severe anemia?

PCV $<12\%$

Who is the ideal donor for blood or plasma?

A cross-matched, or Aa and Qa negative, un-sensitized gelding.

What is the primary complication to monitor for during plasma or blood infusions?

Type I hypersensitivity (anaphylaxis).

How long is the sedative effect of Xylazine?

Short-acting ($20$ mins).

Why is Detomidine often used for standing procedures?

It is longer-acting and provides excellent sedation.

What is a disadvantage of using Detomidine during a colic evaluation?

It masks surgical pain.

Why is Butorphanol never used alone in adult horses?

It lacks a sedative effect and frequently causes excitement.

What risk is associated with using Acepromazine in stallions?

Priapism.

Which NSAID is considered the drug of choice for visceral pain (colic)?

Flunixin Meglumine

Which NSAID is primarily used for musculoskeletal and orthopedic pain?

Phenylbutazone

What is the drug of choice for treating equine Streptococci and most anaerobes?

Penicillin

Which antibiotics are first-line choices for Gram-negative aerobes?

Gentamicin and Ceftiofur.

What is the "gold standard" broad-spectrum antibiotic protocol for serious mixed infections?

Penicillin and Gentamicin combination.

When is Metronidazole added to an antibiotic regimen?

For penicillin-resistant anaerobes (B. fragilis) or enteric clostridiosis.

What is the drug of choice for EPM (Equine Protozoal Myeloencephalitis) and CNS infections?

Potentiated Sulfas (TMS).

What is the specific treatment for Ehrlichial agents like Tick fever and Potomac Horse Fever?

Tetracyclines

Which drug combination is reserved specifically for Rhodococcus equi pneumonia in foals?

Macrolide and Rifampin.

What does unilateral nasal discharge signify?

It localizes the disease to the nasal passage or paranasal sinuses on the affected side.

What do food or milk in the nostrils suggest?

Pharyngeal neuropathy or anatomic defects.

What are common signs of increased respiratory effort (lower airway disease)?

Flared nostrils, tachypnea, increased thoracic/abdominal effort, and shallow breathing.

Which equine herpesvirus (EHV) is associated with abortion storms and neurologic disease?

EHV-1

What is the vaccination schedule for EHV-1 in pregnant mares?

Killed vaccine at $3, 5, 7,$ and $9$ months gestation.

What is the etiology of Equine Influenza Virus?

Type A/2 (H3N8) orthomyxovirus.

How long does epithelial regeneration take following an Equine Influenza infection?

At least $21$ days.

What pathogen is a normal resident flora but acts as a major opportunistic secondary invader in the respiratory tract?

Streptococcus equi zooepidemicus

What is the primary pathogen responsible for Strangles?

Streptococcus equi equi

What feature of S. equi equi's cell wall inhibits lysosomal killing?

M-protein (SeM).

What is "bastard strangles"?

Systemic metastasis of Strangles to internal organs.

What are common complications of Strangles?

Airway obstruction, guttural pouch empyema, purpura hemorrhagica, myositis, and bastard strangles.

What is the recommended quarantine period for newcomers to prevent Strangles?

$30$ days.

What clinical sign distinguishes pleuropneumonia from simple bronchopneumonia?

Severe pleurodynia (reluctance to walk, shallow breathing, pain on percussion).

What is the prognosis for adult horses with pleuropneumonia if caught early?

Favorable (approximately $90\%$ survival).

Where does Rhodococcus equi typically survive within the host?

Within alveolar macrophages.

What plasmid is required for Rhodococcus equi to be pathogenic?

Virulence-associated protein A (vapA).

What are the common clinical signs of Rhodococcus equi pneumonia in foals?

Fever, cough, tachypnea, respiratory distress, and crackles/wheezes.

Contrast the epidemiology of IAD vs. RAO.

IAD affects all ages (common in young horses); RAO affects middle-aged and older horses ($>7$ years).

What is a "heave line"?

An expiratory abdominal lift seen in horses with severe asthma (RAO).

What cytological finding is diagnostic for RAO in a BAL sample?

Severe suppurative, non-septic inflammation with neutrophils $>20\%$ and Curschmann's spirals.

What is the primary pharmacologic management for Equine Asthma Syndrome?

Systemic or inhaled corticosteroids and bronchodilators.

What is the diagnostic finding for EIPH in a tracheal wash or BAL?

Hemosiderophages (macrophages containing digested hemoglobin).

How is a progressive ethmoidal hematoma restricted to the nasal passage treated?

Standing transendoscopic laser ablation or $4\%$ formalin injection.

What is a common cause of secondary sinusitis involving malodorous discharge?

Dental disease (apical tooth root abscesses).

What are the clinical signs of Dynamic Dorsal Displacement of the Soft Palate (DDSP)?

Acute obstruction with a "choking down" gurgling noise and immediate exercise intolerance.

What muscle is paretic/paralyzed in idiopathic left laryngeal hemiplegia?

Left cricoarytenoideus dorsalis.

What causes the characteristic "roaring" noise in laryngeal hemiplegia?

Inability to abduct the left arytenoid cartilage during inspiration.

What is epiglottic entrapment?

The epiglottis becomes enveloped in the aryepiglottic fold.

What anatomical feature defines the floor of the guttural pouch and provides surgical access?

Viborg's Triangle

What are chondroids?

Inspissated, stone-like pus resulting from chronic guttural pouch empyema.

What fungus is typically responsible for guttural pouch mycosis?

Aspergillus spp.

What are the two major immediate life-threatening concerns with guttural pouch mycosis?

Fatal epistaxis and pharyngeal neuropathy (dysphagia/aspiration).

What are the components of Horner's syndrome in the horse?

Ptosis, miosis, enophthalmos, and sweating.

What is the normal resting heart rate range for an adult horse?

$$28-44\,BPM$$

Which rhythm is considered a normal finding in a resting horse due to high vagal tone?

Second-degree AV block (Mobitz Type 1).

What are unique clinical signs of right-sided heart failure?

Jugular distention, abnormal jugular pulses, and dependent ventral edema.

What is the most common toxic cause of myocarditis in horses?

Ionophore antibiotics (e.g., monensin).

What laboratory marker is highly specific for myocardial injury?

Cardiac troponin I (cTnI).

Which valves are most commonly affected by degenerative valve disease (endocardiosis)?

Mitral and aortic valves.

What is the most common congenital heart disease in the horse?

Ventricular Septal Defect (VSD).

Describe the ECG features of Atrial Fibrillation.

"Irregularly irregular" rhythm with no P waves.

What is the drug of choice for medical conversion of "Lone" Atrial Fibrillation?

Quinidine

What ECG changes are observed with severe hyperkalemia ($>6\,mEq/dL$)?

Broad flat P waves, wide QRS complexes, and tall T waves.

What causes verminous arteritis in horses?

Strongylus vulgaris L4 larvae migrating into the cranial mesenteric arteries.

What is the "Coggins test" used for?

Equine Infectious Anemia (EIA).

Why is the horse's splenic reserve significant during acute hemorrhage?

It releases RBCs, which initially masks the drop in PCV.

What are the hallmarks of Red Maple Leaf Toxicosis?

Heinz body formation, methemoglobinemia (muddy brown membranes), and pigment nephropathy.

What is the etiology of Neonatal Isoerythrolysis (NI)?

Alloimmune hemolytic disease where a foal ingests maternal antibodies against its own RBC antigens.

How is Purpura Hemorrhagica described pathophysiologically?

An immune-mediated leukocytoclastic vasculitis resulting in "leaky capillaries" and edema.

Which tick-borne disease is characterized by morulae within neutrophils?

Equine Granulocytic Anaplasmosis (Anaplasma phagocytophilum).

What is the common name for Corynebacterium pseudotuberculosis infection in horses?

Pigeon Fever

Which phlebotomy site is found 1-2 cm ventral to the facial crest?

Transverse Facial Vein ("Facial Sinus").