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20 Cards in this Set
- Front
- Back
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What are some stresses that predispose to development of resp. dz?
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poor immune status: foals: FPT, CID, etc.; adults: debilitating condition, PPID
mixing of foals w/ adults high parasite loads overcrowding poor ventilation heavy exercise transport contact w/ new horses |
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What are some general & specific signs of resp. dz?
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general: depression, anorexia, fever, wt. loss, ↓ exercise performance, fatigue
specific: nasal d/c, cough, tachypnea, dyspnea, “heave line”, cyanosis |
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What is the dx workup for horse w/ suspected infectious resp. dz of upper airways?
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CBC, ABG +/- Chem
endoscopy: anatomical &/or surgically correctable upper airway problems (primarily non-infectious); source of nasal d/c: guttural pouch infection, lungs, (sinuses); guarded culture, retropharyngeal abscessation U/S: ln’s, retropharyngeal area, guttural pouches rads: sinuses, guttural pouches, larynx/pharynx, retropharyngeal area |
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What is the dx workup for horse w/ suspected infectious resp. dz of lower airways?
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CBC, ABG, +/- Chem
TTW: cytology, gram stain, bacterial C/S (potential complications: catheter breaks off in trachea, SQ infection/abscess, SQ emphysema, pneumomediastinum) thoracic U/S: pleural surfaces (roughening), pleural fluid, collapsed or fibrotic lung, surface abscesses thoracic rads thoracocentesis: confirmation of presence of fluid, analysis of fluid (cytology, pH, glucose), anaerobic & anaerobic bacterial C/S, fluid drainage |
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What is the dx workup for horse w/ suspected non-infectious resp. dz?
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ABG +/- fecal
upper airway: endoscopy, rads of sinuses, guttural pouches lower airway -thoracic U/S, thoracic rads -BAL: cytology -pulmonary function testing: conventional vs. forced oscillatory mechanics; commonly measured variables: transpleural or intrapleural pressure, resistance to flow, lung compliance |
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equine URIs
a. pathogenesis b. etiology & facts about agents |
a.primarily viral
-highly infectious w/ short incubation period -multiplication in & desquamation of ciliated epi of upper airway --> ↑ susceptibility to 2º bacterial infections b. equine influenza (myxovirus) -antigenic drift & shift: vaccines not as effective -certain strains can also cause myalgia, myositis, myocarditis, pericarditis, etc. equine rhinopneumonitis -herpesvirus: EHV-1 & EHV-4 -4 manifestations: resp. dz, late term abortions, neuro dz, neonatal weakness/death -poor stimulation of immunity equine viral arteritis: rare -togavirus arteritis --> additional possible signs: limb &/or ventral edema, petechia, photophobia, keratitis, conjunctivitis, lacrimation, palpebral edema |
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equine URIs
a. clinical signs b. dx c. tx d. prevention |
a. pharyngitis, laryngitis, tracheitis, depression, anorexia, high fever, dry hacking cough, serous nasal d/c, normal to harsh BV lung sounds
b. clinical signs, compatible hx virus ID: may be done if severe clinical signs or a pop’n is at risk (large # or broodmares) -isolation: nasopharyngeal swab -serology: acute & convalescent titers c. rest -isolation -supportive care: minimize stress, dust free ventilation, palatable food, +/- NSAIDs, +/- ABs d. vaccination schedules -equine influenza: IM q 3-6 m or IN q 6-12 m -equine herpesvirus: IM q 4-6 m, broodmares: EHV-1 at months 3, 5, 7, 9 of gestation -equine viral arteritis: vaccine only available in certain states |
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bacterial pneumonia
a. pathogenesis b. clinical signs c. tx |
a. occurs 2º to impaired immune defenses &/or stress: viruses, noxious gases, endotoxemia, severe neutropenia, malnutrition, hypoproteinemia, crowding, poor ventilation, transport, cold temps
b. productive cough, mucopurulent nasal d/c, fever, exercise intolerance, tachypnea, wheezes, crackles, dull areas on auscultation c. rest, ABs if prolonged: bloodwork, TTW, thoracic U/S or rads |
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pleuritis/pleuropneumonia
a. predisposing factor b. clinical signs c. dx d. tx e. complications f. px |
a. stress of transportion
b. depression, anorexia, fever, pain, reluctance to move, rapid shallow breathing, endotoxemia, ↓ breath sounds ventrally (muffled), fluid line on percussion c. thoracic U/S: pleural roughening, pleural fluid, surface abscesses, etc. -thoracocentesis, TTW (before starting ABs), bloodwork, thoracic rads post-drainage d. long term tx w/ appropriate AB based on C/S -drain chest as needed -supportive care: NSAIDs, other anti-endotoxic drugs, foot support (laminitis prevention), rest e. hypoproteinemia/ventral edema, laminitis, jugular vein thrombosis (endotoxin or long term IV catheter placement), colitis (endotoxin or ABs), pulmonary abscesses, bronchopleural fistula f. guarded |
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pulmonary abscesses
a. clinical signs b. dx c. tx d. complications e. special cases: etiologic agents |
a. prolonged pneumonia, intermittent or recurrent fever, wt. loss, poor body condition, +/- halitosis, +/- hemoptysis
b. thoracic U/S: can only see abscesses if they are on pleural surface -thoracic rads, TTW, bloodwork (↑ fibrinogen, leukocytosis), +/- transthoracic aspiration/drainage c. long term tx w/ appropriate AB based on C/S +/- rifampin, isoniazid for penetration +/- drainage (if feasible) -thoracotomy: performed when pleural effusion or surface abscess is too think or too walled off into separate compartments to drain adequately via chest tube, or when there are chunks of fibrin, necrotic lung, etc. that need to be removed; wait until a good capsule exists, so lung won’t collapse when chest opened -supportive care: NSAIDs, other anti-endotoxic drugs, foot support, rest d. laminitis, jugular vein thrombosis (endotoxin or long term IV catheter placement), colitis (endotoxin or ABs), rupture of large abscess into airway or pleural space, erosion of pulmonary vessels & bleeding/rupture e. strangles (Strep equi var equi), Rhodococcus equi, strep equi var zooepidemicus |
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equine strangles
a. etiologic agent b. pathogenesis c. clinical signs |
a. Strep equi var equi
b. mainly affects young horses -infection via purulent d/c, fomites -short incubation: 2-6 d. -pure form: upper respiratory dz, mainly pharyngitis w/ abscessed retropharyngeal ln’s -high morbidity, low mortality -may persist in guttural pouches (carriers) c. fever, depression, ↓ appetite, mucopurulent nasal d/c, moist cough, pharyngitis, abscessed ln’s |
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equine strangles
a. dx b. tx c. complications d. prevention & control |
a. culture (pharyngeal swab, ln aspirate, TTW)
-need to culture b/c clinical signs may be very similar to Strep equi var zooepidemicus b. rest, isolation (control spread), nursing care, drain abscesses, +/- ABs (penicillin; may not be sensitive to TMS) c. complications: swollen ln’s --> dyspnea, anorexia, guttural pouch infection, myocarditis/myositis, “bastard strangles”: multiple disseminated abscesses, purpura hemorrhagica d. difficult b/c highly infectious, difficult to clear from environment, vaccines not very effective (IN more effective) -prevent spread of purulent material -vaccinate at risk horses |
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Rhodococcus equi
a. pathogenesis b. clinical signs |
a. not pathogenic in adults
-soil borne organism: may become endemic on farms -infection occurs at very early age (1-2 wks) -infected by inhalation: more common in dry, dusty environment -insidious onset -clinical signs not obvious until foal is severely affected: 2-3 m -on endemic farms, watch foals closely for lethargy, ↓ nursing, or fever -forms abscesses, primarily in lungs: requires tx w/ ABs that can penetrate & be effective in a purulent environment -abscesses can also seed to other sites: ln’s, mesentery, joints, physes (incl. spinal cord) b. if caught early: fever, tachypnea, mild malaise -if caught later: unthrifty stunted foal, fever, dyspnea, depression, cough, cyanotic or muddy mm, exercise intolerance, +/- diarrhea -sometimes only in joint, physis, etc. |
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Rhodococcus equi
a. dx b. tx c. prevention & control |
a. CBC: leukocytosis, neutrophilia, ↑ fibrinogen
-thoracic rads: multiple pulmonary abscesses -thoracic U/S: pleural roughening, surface abscesses -culture &/or PCR: TTW &/or abscess aspiration b. appropriate AB for a prolonged period of time: erythromycin & rifampin, azithromycin, or clarithromycin: reassess prior to discontinuing -supportive care: hydration, nutrition, oxygenation, fever control, etc. c. good hygiene -hyperimmunized serum: if don’t expect mare will pass Ab in colostrum, give serum to foal w/in 1st week of life (may need to repeat; questionable efficacy) -don’t bring previously unexposed mares to foal on endemic farms unless they will be there long enough to develop colostral Abs -caution taking unexposed mare/foal to endemic farm when rebreeding mare |
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What are some parasitic infections of the lung?
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Parascaris equorum: foals only
Dictyocaulus arnfeldi: donkeys, horses Pneumocystis carinii |
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recurrent airway obstruction
a. etiology b. pathogenesis |
most common non-infectious airway dz of horse
a. unknown: possible factors: allergy, diet, previous infection, genetic predisposition b. bronchiolar inflammation --> exudation & mucus plugs in small bronchioles, bronchoconstriction --> narrowing of airways --> wheezes heard on auscultation |
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What are the possible clinical manifestations of recurrent airway obstruction?
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mild exercise intolerance: no obvious signs, just not performing up to expected ability
-normal CBC, thoracic auscultation, U/S, & rads +/- mildly ↑ tracheal exudate post-exercise -BAL: mild ↑ in eos or mast cells, perhaps very mild ↑ in mature neutrophils moderate dz: chronic intermittent cough, nasal d/c, afebrile, +/- dyspnea -MOST common presentation -normal CBC +/- stress leukogram -thoracic auscultation: may reveal ↑ BV sounds or expiratory wheezes -thoracic rads: normal or mild bronchial pattern -mucopurulent tracheal exudate present pre- & post-exercise -BAL: ↑ mature neutrophils +/- ↑ eos, mast cells “respiratory cripple”: severe dyspnea, wt. loss, +/- 2º pulmonary infections -CBC: neutrophilia (stress, steroids, 2º inflammation) or neutropenia (2º infection) -thoracic auscultation: loud moist sounding lungs, may have both inspiratory & expiratory wheezes, inspiratory crackles -thoracic rads: marked bronchial pattern, may have areas of alveolar pattern (d/t 2º pneumonia -expanded lung field -mucopurulent nasal d/c, moist cough -TTW if suspect 2º infection |
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How is recurrent airway obstruction diagnosed?
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preliminary: based on clinical signs & workup
-cough, nasal d/c, ↑ resp. effort, ↓ exercise performance -recurrent nature: often brought on by certain weather patterns, time of year, etc. -no fever definitive -BAL: evidence of airway inflammation w/o infection (↑ neutrophils (> 5%), ↑ mast cells (> 2%), ↑ eosinophils (> 1%)) -pulmonary function testing: conventional, forced oscillatory mechanics (FOM): horses w/ small airway inflammation have ↑ Fres, low PC100RRS, frequency dependence of RRS |
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How is recurrent airway obstruction treated?
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environmental change
-↓ exposure to allergens: straw, hay, molds, dust, etc. -house outdoors, unless SPA-RAO +/- diet change +/- drugs anti-inflammatory therapy: corticosteroids -effects: ↓ inflammation, may help prevent down regulation of β-2 receptors -systemic: dexamethasone, prednisolone, (triamcinolone) -inhaled: beclomethasone, fluticasone bronchodilators: ↓ work of breathing, but may worsen V/Q mismatches -anti-cholinergics: most potent bronchodilators *many undesirable side effects: ileus, tachycardia, etc. *systemic or inhaled: atropine, glycopyrolate, ipratropium bromide, (oxytropium bromide), (tiotropium bromide) -β-adrenergics: most commonly used bronchodilators *many are not absorbed well orally or absorption is erratic *systemic or inhaled: clenbuterol, albuterol, pirbuterol -xanthine derivatives *relatively inexpensive *low margin of safety: therapeutic blood concentration near toxic range *systemic: aminophylline, theophylline, etaminphylline camsylate mucolytics & expectorants: nebulization, iodides, bromhexine HCl, glyercol guaiacolate other drugs: antihistamines, anthelminthics, sodium chromolyn, DMSO, MSM, furosemide |
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exercise induced pulmonary hemorrhage
a. incidence b. etiology c. dx d. tx |
a. incidence related to speed of racing (flat racing > harness racing > polo ponies)
b. unknown: normal physiologic event, mild form of RAO, 2º to upper airway stenosis or combination of these c. endoscopy: w/in 90 min of exercise -hemosiderin in TTW fluid -thoracic rads: ↑ opacity in caudodorsal lung fields -necropsy: caudodorsal lung fields: small airway dz, collateral circulation, ↑ bronchial aa., ↑ fibrous CT d. furosemide, other drugs for RAO (steroids, β2 bronchodilators, sodium chromolyn) |
