LA Exam #2 Review (Junior yr/Sem 1)

Give examples of the types of questions you should ask an owner when taking a history for respiratory diseases

-signalment, use, how long have they owned the animal?

-herd history: are multiple animals affected? any new arrivals?

-medical history: vaccination status, deworming, dental disease, concurrent disease

-diet and housing: type of hay, bedding, ventilation, hay/bedding storage

-travel history: duration, dates, reason, origin/destination, head tied

Why is obtaining nutrition history important for respiratory cases?

because hay type, storage, and dust/mold exposure directly influence equine asthma

Why is obtaining travel history important?

travel (especially long-distance with head tied) predisposed horses to shipping fever -> pleuropneumonia

In general, what clinical signs are noted during physical exam in cases of respiratory disease?

-abnormal posture

-increased respiratory musculature use

-cough (spontaneous or induced)

-stridor (upper airway)

What observations should be made on physical exam in cases of respiratory disease?

-respiratory rate and pattern

-nostril flare

-effort (inspiratory vs expiratory)

-nasal discharge (color, thickness, smell, blood/feed, unilateral/bilateral)

-lymph node palpation

-sinus percussion

-tracheal palpation/auscultation

What is a heave line, and what does it indicate?

a visible hypertrophy of the external abdominal oblique muscle caused by chronic expiratory effort in severe equine asthma (heaves)

What are the different respiratory patterns?

eupnea- normal

hyperpnea- normal exercise

tachypnea- abnormally fast

dyspnea- respiratory distress (inspiratory vs expiratory)

Correctly use the medical terms for increased respiratory rate and increased respiratory effort in a sentence. What should be noted regarding nasal discharge?

-the mare is tachypneic with a respiratory rate of 40 brpm

-she shows marked expiratory dyspnea, evidenced by abdominal push

Differentiate unilateral vs bilateral nasal discharge

-unilateral: often upper airway (sinus, guttural pouch)

-bilateral: often lower airway or systemic respiratory disease

What are the clinical signs of a horse in respiratory distress?

-nostril flare

-increased inspiratory or expiratory effort

-abdominal push

-tachypnea

How do we assess the equine upper airway?

-nostril patency

-palpate lymph nodes

-palpate larynx/trachea

-sinus percussion

-tracheal auscultation

What lymph nodes should be palpated? Why? Where are they located anatomically?

-mandibular LN

-medial and lateral retropharyngeal LN

-parotid LN

-cranial and middle cervical LN

purpose: detect lymphadenopathy, especially strangles

location: ventral jaw, pharyngeal region, cervical chain

What disease is indicated by bilaterally enlarged submandibular lymph nodes? What steps need to be taken if this disease is suspected?

strangles (Strep equi subsp. equi)

steps:

-quarantine

-guttural pouch endoscopy

-culture + PCR

How do we ascult and assess the lungs?

-listen for wheezes, crackles, friction rubs

-absent ventral sounds-> pleural effusion

-absent dorsal sounds -> pneumothorax

What technique can be done to assist in ausculting lung sounds on a horse? Outline the steps performed

-place bag loosely over nostrils

-allow CO2 to accumulate -> increases respiratory effort

-auscult during bag use and after removal

-allow small amounts of fresh air around edges

-keep bag out of nostrils (dont occlude)

What is the purpose of percussing the frontal sinuses?

detect fluid or mass in frontal sinuses

What is the purpose of ausculting and palpating the trachea?

identify:

-mucus

-inflammation

-pain

-abnormal airflow

What is a rebreathing bag, what does it do physiologically, and how is it utilized?

-allow CO2 accumulation -> transient increase in respiratory drive

-used to enhance lung sounds

What precautions do you need to take when using a rebreathing bag?

-dont occlude nostrils

-horse may object

-allow fresh air around edges

Describe the lung sounds heard for each of the following conditions: fluid in lungs, bronchoconstriction, pleuritis, pleural effusion, pneumothorax

fluid in lungs: crackles

bronchoconstriction: wheezes

pleuritis: friction rubs

pleural effusion: absent ventral sounds

pneumothorax: absent dorsal sounds

Define hypercapnia. What is the art gas threshold?

PaCO2 >60 mmHg

Define hypoxemia? What is the art gas threshold?

PaO2

What blood tests give us information relative to respiratory issues?

-arterial blood gas

-CBC + chemistry (immune response, renal/systemic compromise)

What determines when an equine patient needs supplemental oxygen?

When PaO2

What does a CBC/Chem tell us about these respiratory cases?

-severity and chronicity of immune response

-renal/systemic compromise

When are radiographs/ultrasound used in equine respiratory cases?

ultrasound: pleural surface, effusion, abscess, consolidation

radiographs: sinus disease, airway disease, parenchymal disease, deep abscessation

-must be done before TW/BAL

Describe what abnormalities are seen on ultrasound for the following respiratory conditions: pleuritis, superficial abscess, pneumonia (lung consolidation), pleural effusion

pleuritis: fibrin, rough pleural surface

superficial abscess: discrete hypoechoic pocket

consolidation: tissue-like appearance replacing air

pleural effusion: fluid line, lung floating

Define thoracocentesis, and explain when it is performed

pleural effusion- therapeutic/diagnostic

pneumothorax- therapeutic

neoplasia- diagnostic

What supplies are needed to perform a thoracocentesis?

-sterile prep

-cut-down

-24-30 Fr tube

-suture

-Heimlich valve

-bandage

-suction ready

What is a Heimlich valve, and why is it used?

one-way valve preventing air entry into chest during drainage

What should you do if a chest tube is found open?

immediately close it to prevent pneumothorax

What are concerns when placing a drain in the thoracic cavity?

-pneumothorax

-infection

-fibrin obstruction

-need for repeated drainage

What diagnostic tests can be performed on fluid obtained via thoracocentesis?

-cytology

-culture (aerobic + anaerobic)

Define hemothorax. What are clinical signs? What diagnostic tools are used?

-blood in the pleural space

signs: dyspnea, muffled sounds, ventral dullness

tools: ultrasound, thoracocentesis

Define pleural effusion. What are clinical signs? What diagnostic tools are used?

-fluid in the pleural space

signs: tachypnea, dyspnea, absent ventral sounds

tools: ultrasound, thoracocentesis

Define pneumothorax. What are clinical signs? What diagnostic tools are used?

-air in the pleural space

signs: dyspnea, absent dorsal sounds

tools: ultrasound, radiographs, thoracocentesis

Why are guide wires needed to scope guttural pouches?

used to safely enter pouch compartments

What are guttural pouch clinical issues?

-hemorrhage

-dysphagia

-neuropathies

-mycosis

What issues occur in the trachea and bronchi?

-blood

-mucus/inflammation

-feed material (choke)

-masses

-foreign bodies

What are two types of tracheal wash, and what are the pros/cons of each?

transtracheal wash (TTW)

-pros: sterile, no contamination

-cons: more complications

endoscopic-guided aspirate

-pros: visual guidance

-cons: not sterile

What supplies are needed for a transtracheal wash (TTW), and how is the animal prepped for the procedure?

-sterile scrub

-sterile gloves

-10 g needle/trocar

-7 Fr catheter

-30 cc saline

-bandage site

When is a transtracheal wash performed?

for suspected infectious disease

What are complications with performing TTW?

-subcutaneous emphysema

-infection

-hemorrhage

-tracheal damage

What supplies are needed for bronchoalveolar lavage (BAL), and how is the animal prepped for the procedure?

-sedation (opioids)

-5 x 60 cc saline OR 500 ml bag

-dilute lidocaine

-BAL tube + stopcock

-endoscope (2-3m)

-suction pump

When is bronchoalveolar lavage (BAL) performed?

for non-infectious diffuse disease (asthma, EIPH)

What is the relevance of the question: "What cells do the lungs want?"

-BAL evaluates desired cells -> normal alveolar population

-TTW evaluates cells lungs are trying to remove (infection)

What is surfactant and how do you identify?

seen in BAL fluid; indicates sampling of alveoli

When is ultrasound used, and what can be observed?

pleural surface evaluation only

When is endoscopy used, and what can be observed? What sizes of endoscope are used when?

pharynx/larynx (1 m)

trachea (1 m)

main bronchi (2-3 m)

guttural pouches (guide wire)

When are radiographs taken, and what can be observed?

-sinus disease

-airway disease

-parenchymal disease

-deep abscessation

When is CT utilized, and what can be observed?

-sinus disease

-dental disease

-guttural pouch disease

-layngeal/pharyngeal masses

What are the primary respiratory viruses?

-Influenza (H3N8)

-EHV-1

-EHV-4

-minor: rhinovirus, adenovirus, EVA

What is a latent infection?

EHV-1 and EHV-4 remain dormant in host and can reactivate

What are viral respiratory preventative measures?

-quarantine new horses

-vaccinate (influenza + EHV-1/4 q6m)

What diagnostic tests are commonly performed for equine respiratory viruses, and how are samples obtained?

-nasal swab PCR

-endoscopy (pharyngeal hyperplasia)

What is common viral respiratory therapy?

-rest

-treat secondary infections

-antivirals

-quarantine 2-3 weeks

Why is quarantine important with new horses?

to prevent introduction of highly contagious viruses and strangles

What is strangles? How does it develop? What are the clinical signs? What are the main diagnostics?

-gram positive Strep equi

-spreads via fomites -> lymph node abscessation

-signs: fever, pharyngitis, lymphadenopathy, mucopurulent discharge, stridor

-diagnostics: guttural pouch endoscopy + PCR/culture

How is strangles treated? How is it prevented?

Treatment:

-quarantine

-drain abscesses

-no antibiotics unless complications

-NSAIDs

-manage carriers

Prevention:

-isolate/test new arrivals

-modified live intranasal vaccine

-do not give IM

-check SeM titer; do not vaccinate if >1:3200

Why are antibiotics contraindicated with strangles?

slows abscess maturation, increases metastasis

Define empyema

pus accumulation in guttural pouch

What is "bastard" strangles?

metastatic abscessation in distant lymph nodes/organs

What is purpura hemorrhagica?

type III hypersensitivity -> necrotizing vasculitis

What are contraindications for strangles vaccination?

SeM titer >1:3200

What is pleuropneumonia? How does it develop? What are the clinical signs? What are the main diagnostics?

-a severe bacterial bronchopneumonia that extends into the pleural space

develops from:

-recent stress or viral infection

-long distance travel with head tied

-trauma

-choke/aspiration

-improper NG tube placement

signs:

-fever, anorexia, lethargy

-tachypnea/dyspnea

-chest pain

-auscultation

-muffled heart sounds

-ventral edema

-foul breath odor

diagnostics:

-CBC/chem

-ultrasound

-tracheal wash

-thoracocentesis

How is pleuropneumonia treated?

-chest drainage

-broad-spectrum antibiotics

-NSAIDs

-IV fluids

-laminitis prophylaxis

Why is it important to know if a horse has been tied with its head during transport?

because tying the head prevents normal mucociliary clearance, allowing bacteria to accumulate -> shipping fever -> pleuropneumonia

Define pleurodynia

chest pain associated with inflammation of the pleura

What are complications with pleuropneumonia?

-thrombophlebitis

-sepsis-associated laminitis

-abscesses/adhesions

-need for thoracotomy/rib resection

What is the connection between pleuropneumonia and laminitis?

systemic inflammation/sepsis -> laminitis risk

What is Rhodococcus equi? What population does it affect? What are the clinical signs? What are the main diagnostics?

-a coccobacillus that replicates inside macrophages

population affected:

-foals 1-6 months, rare >8 months

signs:

-acute: fever, cough, lethargy, tachypnea/dyspnea

-chronic: weight loss, poor growth

-subclinical: US abscessation

diagnostics:

-CBC/fibrinogen

-thoracic ultrasound/radiographs

-tracheal wash: intracellular coccobacilli

-culture + PCR

How can Rhodococcus equi infection be prevented?

-reduce dust exposure

-hyperimmune plasma at 1 week + 25 days

-early detection via US/temp/hematology

How is Rodococcus equi infection treated?

macrolide + rifampin

What are complications/contraindications with macrolides?

-macrolide-induced anhidrosis

-fatal colitis in adult horses

What is Parascaris equorum and how does it affect the respiratory system?

-roundworm/ascarid

-respiratory effects due to larval migration -> coughing, mucoid discharge, wheezes/crackles

-TW: eosinophils

What is equine lungworm? What is the host species? What are the clincial signs?

-host: donkeys (asymptomatic carriers; 30% infected)

-horses co-housed develop chronic cough, weight loss

What is guttural pouch mycosis? What are the clinical signs? How is it treated?

-fungal plaque invading internal/external carotid or maxillary arteries

signs:

-mild -> catastrophic hemorrhage

-dysphagia

-neuropathies

treatment:

-surgical occlusion of affected artery

-systemic + topical antifungals

What is equine asthma? How does it develop? What are the clinical signs? What are the main diagnostics?

-chronic inflammatory airway disease (mild-moderate IAD or severe RAO)

development:

-environmental allergens: mold, dust, ammonia, endotoxins

signs:

-severe RAO: chronic cough, abnormal lung sounds, increased respiratory effort, exercise intolerance, BAL: neutrophils >25%

-mild IAD: cough during exercise, normal effort, poor performance, BAL: neutrophils/eosinophils/mast cells

diagnostics:

-BAL cytology

-environment history

-clinical signs

How is equine asthma managed?

-environmental control: turnout, ventilation, change bedding/hay

-steam hay

-pelleted feed/haylage

-steroids (systemic or inhaled)

-bronchodilators

What is the difference between round bales and square bales with regard to equine asthma?

round bales = more dust/mold -> worse asthma

What is EIPH? How is it diagnosed? How is it treated?

-stress failure of pulmonary capillaries during intense exercise

diagnosis:

-endoscopy 30 min - 2 hours post-exercise

-BAL/TW: RBCs (up to 14 d), hemosiderophages (up to 4 wks)

treatment:

-furosemide 1 mg/kg 4 hrs pre-exercise

Which equine respiratory conditions are reportable diseases?

-strangles is not federally reportable but is state-reportable in many states

-EVA is reportable

Which equine respiratory conditions are highly contagious?

-strangles (Strep equi)

-influenza

-EHV-1/4

What role does predation pressure play in shaping a horse's behavior?

-speed and rapid escape responses

-fight or flight predominance

-high vigilance

-short recumbency periods

Define behavioral needs. How are they different from a preference?

behavioral needs = species-specific, highly motivated behaviors performed even without functional outcome

preference = something an animal likes but can live without

List the three primary behavioral needs of horses, and give examples of each

1. eating (grazing) - trickle feeding for long periods

2. locomotion - traveling long distances

3. social contact - herd living, dominance hierarchy

What welfare concerns arise when a horse's behavioral needs are restricted?

-stress response

-anxiety, frustration

-development of abnormal behaviors

How does being a "trickle feeder" affect how horses should be managed in domestic settings?

horses need:

-frequent access to forage

-long periods of grazing/chewing

restricting forage -> GI issues, stress, stereotypies

What functions does locomotion serve for wild and domestic horses?

wild:

-travel for food, water, safety

domestic:

-exercise, mental stimulation, social interaction

Why is social contact so essential to equine welfare?

horses are herd animals; social contact supports:

-safety

-emotional stability

-reduced stress

How does dominance hierarchy contribute to social stability in horse herds?

-reduces conflict

-establishes predictable interactions

-organizes access to resources

Compare the social structure of feral horses with that of domestic horses

feral:

-1 stallion + 4-7 mares + offspring

-stable hierarchy

domestic:

-artificial grouping

-frequent changes -> instability, increased aggression

Define "pair bond" and explain its importance

a pair bond = strong affiliative relationship between two horses

importance:

-social stability

-reduced stress

Explain the fight-or-flight mechanism and how it benefits horses as prey animals

primary defense = flight

if escape impossible = fight (aggression)

What anatomical adaptations support a horse's ability to flee from predators?

stay apparatus -> stand long periods

long limbs, strong muscles

Why do horses typically rest standing rather than lying down?

standing = safer; allows for rapid escape

Under what circumstances will horses lie down, and what does this indicate?

-when other horses are standing/vigilant

-when they feel safe

Describe interspecies aggression in horses and when it might occur

-horse cannot flee

-threat is close

Describe typical stallion behavior during courtship and breeding

-increased reactivity

-marking (elimination)

-posturing, vocalization

-sniffing, flehmen

-biting, chin on rump

-mounting

What is the flehmen response, and what purpose does it serve?

upper lip curl -> draws scent to vomeronasal organ

used to detect pheromones