Respi Flashcards

Question

A 12-year-old Warmblood gelding is diagnosed with equine multinodular pulmonary fibrosis (EMPF) based on lung histopathology. Thoracic radiographs show severe caudodorsal lung changes and enlarged tracheobronchial lymph nodes. Lung biopsy qPCR reveals a high EHV-5 viral load. Based on the findings of this study, which of the following statements is most accurate regarding prognosis and treatment? A) The horse has a good long-term prognosis if it survives to hospital discharge B) Corticosteroid treatment is unlikely to improve short-term survival C) The severity of radiographic changes is a reliable predictor of survival time D) Treatment with corticosteroids may improve the odds of short-term survival E) The high EHV-5 viral load indicates a poor prognosis for short-term survival

Answer 1

Correct answer: D) **Treatment with corticosteroids may improve the odds of short-term survival** **short-term survival (discharge) 57%, long-term survival (6 months) 14%.** Short-term survival associated (higher) with **corticosteroid** treatment Short term survival **NOT** associated with **EHV5 viral load** or severity of **pulmonary lesions** on thoracic **radiographs** – requirement of histopathologic diagnosis for inclusion (more severe disease) ## Footnote Prognostic indicators and long-term survival in 14 horses with EMPF

Answer 2

Answer: C) Macrophage atypia Rationale: **Macrophage atypia** was observed in 67% of EMPF cases, a finding that was significantly more common compared to asthmatic horses (8%). ## Footnote Clinical findings and outcome predictors for multinodular pulmonary fibrosis in horses: 46 cases (2009-2019)

Answer 3

Answer: C) **High respiratory effort and tachypnea** Rationale: Increased respiratory effort and tachypnea were common in EMPF cases, but high respiratory rates were associated with a poorer prognosis, as shown by the survival analysis. ## Footnote Clinical findings and outcome predictors for multinodular pulmonary fibrosis in horses: 46 cases (2009-2019)

Answer 4

B) Prognosis is likely poor despite corticosteroid treatment Rationale: Although corticosteroid treatment is commonly used, it was not shown to improve 3-month survival in EMPF horses. The combination of clinical signs, BALF cytology findings, and EHV-5 positivity suggests a poor prognosis for this mare, consistent with the conclusion of the study. Survival > 3 months if: - lower median respiratory rates 30 vs. 41 - higher BALF lymphocyte:neutrophil ratios 4.7 vs. 0.47 - higher blood lymphocyte counts (1.25 vs. 0.90 ## Footnote Clinical findings and outcome predictors for multinodular pulmonary fibrosis in horses: 46 cases (2009-2019)

Answer 5

**Dental**-related sinusitis shows **higher microbial diversity** and a greater proportion of obligate **anaerobic bacteria.** **Primary sinusitis** typically has **lower diversity**, often dominated by a single species (frequently **Streptococcus** equi). **Antimicrobial resistance genes and fungal** components were found exclusively in **dental**-related sinusitis cases. ## Footnote Equine sinusitis aetiology is linked to sinus microbiomeby amplicon sequencing

Answer 6

The **bacterial and fungal** microbiotas of the **pharynx** were found to be **more similar** in composition to those of the **proximal and distal trachea** compared to any other sampling site in the upper respiratory tract of healthy horses. For **fungal** communities, there was significant **overlap among the pharynx, arytenoid, proximal trachea, and distal trachea**, with no significant differences detected between these locations after correcting for multiple comparisons. **Fungal species richness and diversity were highest in the nostrils** The study found more **spatial heterogeneity in bacterial composition compared to fungal** communities throughout the respiratory tract. ## Footnote 2022 Topography of the respiratory, oral, and guttural pouch bacterial and fungal microbiotas in horses

Answer 7

Based on the study results, the most likely upper airway obstruction to be found would be **nasopharyngeal collapse**, which was observed in **49%** of horses with UAOs. Regarding the timing, the paper reports that UAOs were more frequently observed during the **low-speed phase** of exercise (**55%** of UAOs) compared to the high-speed/high-intensity phase (22% of UAOs). - **NasoPharyngeal Collapse → 49%** - **Palatal instability → 42%** - **Intermittent DDSP → 39%** This emphasizes the importance of performing overground endoscopy at *different exercise intensities* to fully assess upper airway function in barrel racing horses. ## Footnote Upper airway endoscopy in exercising horses: Findings in 164 barrel racing horses with respiratory clinical signs and/or poor performance. 2023

Answer 8

Controverses The study found **no significant differences** in thoracic ultrasound findings between pre-anesthesia and **3 hours post-recovery** in healthy horses. This suggests that any significant changes observed on thoracic ultrasound within 3 hours post-anesthesia in clinical cases are more likely to represent true pathology rather than normal post-anesthetic changes. These findings can help clinicians differentiate between normal post-anesthetic findings and potential complications like atelectasis or pneumonia when interpreting thoracic ultrasounds in the **immediate post-anesthetic period.** ## Footnote General anesthesia does not induce ultrasonographic changes in the pleura of healthy adult horses anesthetized for elective magnetic resonance imaging javma 23

Answer 9

Controverses. The study found significant **increases in I-lines, B-lines, and coalescent B-lines** on lung ultrasound following general anesthesia in healthy horses, with **peak changes at 2 hours post-anesthesia**. Factors associated with **more pronounced post-anesthetic lung ultrasound changes included longer total procedure time and abnormal cardiorespiratory values during anesthesia.** ## Footnote Perioperative lung ultrasonography in healthy horses undergoing general anesthesia for elective surgery"

Answer 10

Picornavirus : - **ERAV (Aphthovirus)**, formerly known as **equine rhinovirus 1**, - **ERBV (Erbovirus)**, formerly known as **equine rhinovirus 2**, are capable of affecting both the **lower and upper airways**. In **young performance horses**, ERAV has been associated with the development of **inflammatory airway disease**. Both natural and experimental infections of seronegative horses with ERVs have been considered to be a cause of **fever, anorexia, seromucoid nasal discharge, coughing, lymphadenopathy and occasionally lower limb swelling** **Difficulties in virus isolation** **very short shedding time** following the development of clinical signs **Serology,** using acute and convalescent serum samples, has remained a diagnostic pillar when ERAV is suspected but detection via **qPCR** has yielded negative results ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 11

Determining EIV clade affiliation is important for **epidemiological** monitoring, understanding outbreaks, and updating **vaccine strains** to improve protection against clinical disease. H3N8 Florida sublineage, clade 1 in North America, Africa, Japan; **clade 2 in Europe**, China, India ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 12

A multigene approach is crucial to **reduce the risk of false negatives**, as recent outbreaks have identified a **new H752 genotype** that may be missed by single-gene allelic discrimination assays. SNP at position 2254 of DNA polymerase gene correlates with EHM **D752** genotype (G2254) associated with **neurological** outbreaks **N752** genotype (A2254) associated with **non-neurological** outbreaks **14-24% of EHM** isolates do **not have neuropathogenic** marker **New H752 genotype (C2254)** recently identified ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 13

Quantitative PCR helps **differentiate between lytic and non-replicating EHV-4**, with **high viral loads indicating active infection** and presence of clinical signs. ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 14

A **positive qPCR result for EAV generally suggests clinical infection** in horses. ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 15

Testing is not recommended due to the **high detection rate in healthy horses**, which makes interpretation of positive results difficult in the context of respiratory disease. ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 16

A key challenge in diagnosing ERAV infections is the **very short shedding time** following the development of clinical signs, making PCR detection difficult and necessitating the use of **serology for diagnosis.** ## Footnote Challenges in navigating molecular diagnostics for common equine respiratory viruses 2021

Answer 17

6 fungal genera (Alternaria, Bipolaris, Microascus, Spegazzinia, Paraconiothyrium, Claviceps) 1 bacterial genera (Staphylococcus) were significantly different The fungal genus **Bipolaris** had increased abundance in nasopharyngeal cicatrix syndrome (NCS) affected horses and on NCS affected farms. Therefore, Bipolaris warrants further investigation. **Pythium insidiosum was absent** in the nasopharyngeal wash of all horses, irrespective of health status. ## Footnote Nasopharyngeal bacterial and fungal microbiota in normal horses and horses with nasopharyngeal cicatrix syndrome jvim 2021

Answer 18

**Transpharyngeal diode laser fenestration** appears to be an effective and well-tolerated treatment for chronic guttural pouch infection in horses. The procedure resulted in **complete resolution of clinical signs in 12 out of 13** horses, with the one exception having concurrent equine asthma syndrome. **All owners expressed satisfaction with the outcome**. This technique offers several advantages over traditional surgical approaches: It can be performed on **standing**, **sedated** horses, avoiding risks of general anesthesia. It **avoids potential iatrogenic nerve damage** associated with transcutaneous approaches. There is **no need for postoperative wound management**. The procedure was uncomplicated to perform and had minimal complications. While this study did not directly compare the technique to other surgical approaches, the **high success rate (92.3%) and owner satisfaction suggest it may be preferable to more invasive methods.** ## Footnote Clinical outcome of horses with guttural pouch infection following transpharyngeal fenestration javma 2022

Answer 19

**Salpingopharyngostomy and topical oxygen therapy (TOT)** are both potential treatments for guttural pouch mycosis, each with its own advantages. **Salpingopharyngostomy**: Creates a **fistula between the pharynx and guttural pouch**, introducing varying **gas** levels that may inhibit fungal growth. Can be performed as a **single** procedure, requiring **no further treatments or hospitalization.** Allows for simultaneous treatment of **bilateral cases** with a **single opening** in the dorsal pharyngeal recess. Does **not significantly alter temperature or humidity** within the guttural pouch. **Topical oxygen therapy (TOT)**: Involves placing an indwelling **catheter** in the affected guttural pouch and administering oxygen at **15 L/min, four times daily for 1-2 weeks**. Showed promising results with fungal plaque **regression after a minimum of two treatments.** Reported resolution or significant **improvement in 10/12 neurological disorders**, compared to 9/18 cases with transarterial coil embolization. May be used as an **adjunct treatment or primary treatment in non-bleeding cases.** In terms of efficacy, TOT shows promising results for neurological sequelae resolution, while salpingopharyngostomy aims to create an environment less hospitable to fungal growth. Practically, **salpingopharyngostomy offers the advantage of being a single procedure without need for prolonged hospitalization, whereas TOT requires multiple treatments over 1-2 weeks.** The choice between these treatments may depend on factors such as the **severity of neurological signs, the presence of bilateral disease, and the ability to hospitalize** the horse for an extended period. In some cases, a **combination approach** might be considered, with **TOT performed initially, followed by salpingopharyngostomy** if needed. ## Footnote Treatment of guttural pouch mycosis with salpingopharyngostomy 2023

Answer 20

1. Perform **endoscopy** of both **guttural pouches** to look for fungal-like plaques. In this case, endoscopy revealed fungal-like plaques in the medial compartment of both guttural pouches. 2. Obtain **samples** from the plaques for fungal culture to confirm the diagnosis. The paper reports that **Aspergillus** was cultured from the samples. 3. Consider debridement of the mycotic plaques, though this may be challenging if the plaques are strongly adherent. 4. Perform **laser salpingopharyngeal fistulation** under standing sedation. 5. Initiate treatment with oral potassium iodide. The colt in this case received **potassium iodide at a dose of 20 mg/kg bwt per os s.i.d.** 6. Monitor for potential complications such as **bacteremia**, which occurred in this case and was treated with appropriate antibiotics based on culture and sensitivity. 7. Conduct serial endoscopic evaluations to monitor resolution of the fungal plaques. In this case, **complete resolution was observed 4 months post-operatively.** 8. Follow up on neurological signs, as the paper reports **minimal neurologic deficits remained 6 months post-operatively**. ## Footnote Successful combination treatment of bilateral guttural pouch mycosis with salpingopharyngeal fistulation and potassium iodide 2023

Answer 21

Laryngeal tie-forward surgery generally **improves racing performance** in harness racehorses diagnosed with iDDSP: 1. **Performance index increased in 67%** of experienced racehorses postoperatively. 2. **66% of horses established or improved their racing speed** mark after surgery. 3. As a group, performance index increased by 0.5 points and racing speed improved by 0.83 seconds postoperatively. Factors influencing the success of the procedure include: 1. **Individual** variation: Some horses (**25%) did not show a decline in performance index** before diagnosis, suggesting iDDSP affects horses differently. 2. Presence of **complex upper respiratory tract** disorders: 43% of horses had additional disorders, which may impact outcomes. 3. **Age**: The study found a non-linear relationship between age and performance index. 4. **Breed:** While both **Standardbreds and Norwegian-Swedish Coldblooded Trotters showed improvement**, there were some differences in outcomes between breeds. The **degree of basihyoid-cricoid distance shortening during surgery did not significantly affect postoperative performance**. Additionally, there was a **21% recurrence rate of iDDSP within 2 years** post-surgery, indicating that long-term follow-up is important. No method to predict which horses will respond most favorably to the procedure. ## Footnote Outcome analysis of 95 harness racehorses with confirmed dorsal displacement of the soft palate treated with laryngeal tie-forward surgery EVJ 2021

Answer 22

The sternomandibularis muscle shows **increased activity with increasing exercise speed**, particularly at gallop. Muscle activation **coincides with inspiration at gallop**. There is predominant **recruitment of type I** (slow-twitch, fatigue-resistant) muscle fibers during both feeding and exercise. The **muscle is activated at rest** when horses are **grazing**. These characteristics suggest the **spinal accessory nerve** could potentially address limitations of current **laryngeal reinnervation** techniques, such as reducing cricoarytenoideus dorsalis muscle fatigue and potentially shortening rehabilitation time. ## Footnote Laryngeal reinnervation using the spinal accessory nerve: Electromyographic study of the sternomandibularis muscle 2022

Answer 23

Based on the study results, **high-load IMT significantly increases inspiratory muscle strength (IMSi)** in race-fit Thoroughbreds beyond the improvements seen with conventional race training alone. The high-load group showed a mean increase in IMSi from 26 cmH2O to 34 cmH2O after 10 weeks of IMT, while the low-load control group showed no significant change. ## Footnote Training the equine respiratory muscles: Inspiratory muscle strength EVJ 2022

Answer 24

A **bitless bridle** does **not reduce the severity of dynamic laryngeal collapse (DLC)** compared to a conventional snaffle bit bridle in affected horses. There was **no significant difference in inspiratory tracheal pressures during the poll flexion** phase between the bitless bridle (-43.7 ± 15.6 cmH2O) and the snaffle bit bridle (-42.1 ± 10.8 cmH2O) (P=0.2). All horses developed **DLC in both bridles when exercised in poll flexion.** The **change in mean inspiratory tracheal pressure between free and flexion** phases was actually **greater with the bitless bridle** (-15.2 ± 12.3 cmH2O) compared to the snaffle bit bridle (-9.8 ± 7.9 cmH2O) (P<0.001). **Head and neck angles induced by rein tension** , rather than the presence of a bit, appear to be the key factor in provoking **DLC** in susceptible horses. Mean inspiratory pressure during the **free phase** was significantly (P < .001) **more negative with the snaffle bit bridle** (−32.3 ± 6.3 cmH2O) vs the bitless bridle (−28.5 ± 6.9 cmH2O). ## Footnote A bitless bridle does not limit or prevent dynamic laryngeal collapse

Answer 25

- Rhinitis, sinusitis - **Progressive ethmoidal hematoma** (PEH) - **Guttural pouch** : mycosis, empyema, tympany - Lymphoid pharyngeal hyperplasia - **Dorsal displacement of the soft palate (DDSP)** - **Recurrent laryngeal neuropathy (RLN)** - Epiglottic entrapment - Arytenoid chondritis - Rostral displacement of the palatopharyngeal arch (rare) - Nasopharyngeal cicatrix (rare) - Neoplasia

Answer 26

**Infectious :** cough +/- increase in respiratory effort, fever, lethargy, nasal discharge - Bacterial broncho-pneumonia, pleuro-pneumonia - Parasitic pneumonitis - EMPF / EHV-5 **Inflammatory :** exercise impairment - IAD - RAO - Parasitic - MEED Other : - EIPH - Neoplasia (primary or metastatic)

Answer 27

DDSP results in a **loud, vibratory expiratory noise** with exercise. It is a common cause of **poor performance** in race horses and has a prevalence of **10% to 20%.** A definitive diagnosis is made, during **high-speed treadmill** examination, if the caudal border of the soft palate is seen **dorsal to the epiglottis for more than 8 seconds.** Surgical advancement of the larynx (**laryngeal tie-forward procedure**) demonstrated a success rate of **80%** in racehorses.

Answer 28

**RLN** is a major cause of **poor performance** in racehorses and affects 1.6% to **8% of Thoroughbreds**. The prevalence in **draft horses** is nearly **42%**, and the risk of RLN increases with **increasing height in Belgians and Percherons**. Consensus on a four-level resting grading system : - **Grade I** : all arytenoid cartilage mvt are **synchronous** and **symmetrical**, and full arytenoid abduction can be achieved and maintained. - **Grade II** : **asynchronous** but full arytenoid abduction achieved and maintained - **Grade III** : **asynchronous** or **asymmetrical**, and full arytenoid abduction **not achieved** and maintained - **Grade IV** : immobility Grading system at exercise : - **Grade A** : full abduction during ispiration - **Grade B** : abduction > resting position - **Grade C** : abduction < resting position - **Grade D** : collapse to the controlateral side Surgery : **tie-back** (prosthetic laryngoplasty) → **48-68%** success rate for racehorses

Answer 29

- Metastatic neoplasia - Fungal granulomas (Aspergillus spp, Histoplasma capsulatum (rare)) - Nodular interstitial pneumonia

Answer 30

Enteritis, colitis, and typhlocolitis are proposed to predispose horses to the development of **systemic fungal dissemination**. Gastrointestinal inflammation results in the disruption of the epithelial barrier, allowing for translocation of fungal organisms and subsequent systemic dissemination. For this reason, horses that demonstrate evidence of pulmonary disease and have appropriate risk factors such as gastrointestinal disease, particularly if **immunocompromised** (marked neutropenia is present, corticosteroid adm°, PPID), **fungal pneumonia should be considered.**

Answer 31

- **Parascaris equorum** in foals and weanlings - Dictyocaulus arnfieldi

Answer 32

The most common viral cause of pneumonia isolated from **foals and yearling's** is **EHV-1** > EHV-5 > equine adenovirus. **Equine adenovirus** is frequently detected in **healthy foals and mares** but **rarely causes** clinical disease including **upper respiratory infections, pneumonia or diarrhoea**. **Fatal** adenoviral pneumonia has been reported in **Arabian foals** with **severe combined immunodeficiency syndrome**. In severely immune deficient or suppressed animals, adenoviral infection may present as a **bronchitis**. ## Footnote 2022 Pathological approach to respiratory infections: Should underlying immunodeficiencies be widely considered?

Answer 33

**Bacterial** pneumonia: 67.2% of pneumonia cases in young horses were attributed to bacterial agents. **Rhodococcus** most likely foal 0-1year: Bacterial * Rhodococcus equi * Streptococcus equi ssp. zooepidemicus * Actinobacillus equuli * Klebsiella pneumoniae * E. coli * Staphylococcus sp. * Bordatella bronchiseptica yearling :1-5year Bacterial * Streptococcus equi ssp. zooepidemicus * Streptococcus equisimilis * Streptococcus sp. * Pasteurella sp. * Actinobacillus sp. * Bordatella bronchiseptica * E. coli * Mycoplasma felis 87.7% of bacterial pneumonias occurred in horses under 6 months old. ## Footnote 2022 Pathological approach to respiratory infections: Should underlying immunodeficiencies be widely considered?

Answer 34

The aetiology of acute interstitial pneumonia has not been clearly determined. A wide range of **bacteria** (eg Rhodococcus equi, Klebsiella pneumoniae, Escherichia coli and Streptococcus equi subspecies zooepidemicus) and **viruses** such as EHV and EIV and Equine adenoviruses have been detected in foals with **acute interstitial pneumonia** but no common denominator has consistently been identified. A few reports also identified **Pneumocystis** carinii infection as a cause of acute interstitial pneumonia, but these foals were mostly **immunocompromised**. Additionally, **various toxic** substances have been associated with acute interstitial pneumonia in **adult** horses and other species. ## Footnote 2020 Acute interstitial pneumonia in foals: A severe, multifactorial syndrome with lung tissue recovery in surviving foals

Answer 35

Answer: E) Pericardial effusion ## Footnote Feasibility of a point-of-care ultrasound protocol for cardiorespiratory evaluation of horses in different clinical settings jvim 23

Answer 36

At pasture, alveolar macrophages from horses with severe equine asthma showed significantly higher expression of IL-10 compared to control horses (4.35 ± 2.32 fold change, P<0.006). This elevated IL-10 expression persisted in SEA horses both at pasture and after natural challenge, while control horses only developed this phenotype after challenge. ## Footnote 2020 Alveolar macrophage phenotypes in severe equine asthma

Answer 37

**EIT** generates images of the lungs based on impedance change. EIT can detect: - changes in airflow during histamine challenge (**bronchoconstriction**), - subsequent albuterol adm° (**bronchodilation**), - **ventilation distribution** in cardiogenic pulmonary disease. EIT can discriminate **flow variables after exercise** between healthy and MEA/SEA horses, but differences between MEA and SEA were not observed. ## Footnote Evaluation of histamine-provoked changes in airflow using electrical impedance tomography in horses evj 21 Can bronchoconstriction and bronchodilatation in horses be detected using electrical impedance tomography? jvim 2021 Electrical impedance tomography to measure lung ventilation distribution in healthy horses and horses with left-sided cardiac volume overload jvim 21 Exercise-induced airflow changes in horses with asthma measured by electrical impedance tomography jvim 2021

Answer 38

The study concluded that **nebulized dexamethasone** treatment affected the **upper respiratory tract microbiota** but **not the mycobiota**, which was overwhelmed by the effect of a sustained **dusty environment**. Equine herpesvirus effects: **Increased EHV-2 DNA** levels in **nasal swabs** (28-fold increase) **Decreased EHV-5 DNA** levels The authors emphasized the importance of environmental modification as part of the treatment strategy for asthma in horses. ## Footnote 2020 Effects of nebulized dexamethasone on the respiratory microbiota and mycobiota and relative equine herpesvirus-1, 2, 4, 5 in an equine model of asthma

Answer 39

This study does not support the hypothesis that bacterial overgrowth is a common feature of chronic moderate asthma in horses. Instead, it suggests that there may be a fundamental **shift in the microbial populations**, characterized by **lower overall bacterial load** and differences in the **presence of certain bacterial species**. 1. the** overall bacterial load was lower in asthmatic horses** 2. some **bacterial differences**: Corynebacterium spp. were significantly more common in control horses. Actinobacillus spp. were isolated only from horses with asthma and not from any control horses. 3. **Streptococcus** spp. were the **most common bacteria isolated in culture and detected by qPCR in both groups**, but there was **no significant difference in their prevalence between asthmatic and control horses**. 4. **no association between microbial populations and clinical signs, tracheal mucus, or bronchoalveolar lavage fluid (BALF) inflammation.** The study suggests that the l**ower bacterial load in asthmatic horses could indicate dysbiosis **of the lower airways, either as a consequence of chronic inflammation or previous treatments, or as a perpetuating factor of inflammation. ## Footnote 2020 Tracheal microbial populations in horses with moderate asthma

Answer 40

Evidence of airway smooth muscle remodeling in horses with mild to moderate equine asthma (MEA), but with some key **differences compared to severe equine asthma**: 1. MEA showed approximately 1.5 times** greater expression of the (+)insert SMMHC isoform** compared to controls. Overexpression suggests changes in the **contractile** apparatus that could contribute to airway **hyperresponsiveness**. 2. **No significant difference** was found in the **proliferation rate of airway smooth muscle cells** between MEA horses and controls (P=0.4). This differs from **severe equine asthma, where increased proliferation is typically observed.** 3. **No significant difference in myocyte density** was found between **MEA** horses and controls (P=0.3). This suggests that smooth muscle hyperplasia and hypertrophy may not be characteristic of this stage of the disease. 4. A **positive correlation was found between pulmonary neutrophilia and PCNA expression** in horses with neutrophilic inflammation (r=0.80, P=0.01). ## Footnote 2021 Airway smooth muscle remodelling in mild and moderate equine asthma

Answer 41

Global peak expiratory flow (**PEF_Global**) and peak inspiratory flow (**PIF_Global**) were significantly **higher** in horses with **SEA and MEA** compared to controls after exercise. **PEF_Global** **increased significantly after exercise in both SEA and MEA **horses, but not in controls. **PIF_Global** **increased** significantly **after exercise** only in **SEA** horses. Regional differences were observed, with more pronounced **changes in ventral airflow after exercise in asthmatic horses.** **No significant differences were found between groups before exercise or between MEA and SEA horses.** Cl: **EIT could be a useful, non-invasive tool for assessing lung function in horses with asthma, especially for detecting subtle changes that may not be apparent at rest.** ## Footnote Exercise-induced airflow changes in horses with asthma measured by electrical impedance tomography

Answer 42

The intestinal microbiota of horses with asthma does not adapt in the same way to **changes in diet and environment** compared to the microbiota of healthy horses. ## Footnote Fecal microbiota in horses with asthma jvim 20

Answer 43

**Correct Answer:** **C) No significant association was found between microbial populations and clinical signs, tracheal mucus, or BALF inflammation.** --- This question emphasizes the finding that despite the presence of certain potential pathogens in asthmatic horses, there was no direct link between bacterial populations and clinical signs or inflammation. This study **does not support** that bacterial overgrowth is a common feature of chronic moderate asthma in horses. ## Footnote Tracheal microbial populations in horses with moderate asthma jvim 2020

Answer 44

Nebulized dexamethasone treatment affected the upper respiratory tract **microbiota** (**decreased microbial diversity**), but not the **mycobiota**, which was overwhelmed by the effect of a sustained dusty environment. ## Footnote Effects of nebulized dexamethasone on the respiratory microbiota and mycobiota and relative equine herpesvirus-1, 2, 4, 5 in an equine model of asthma jvim 2020

Answer 45

**Dust exposure** was significantly higher with dry hay feeding, compared to steamed hay, haylage and pellets, and equivalent between haylage and pellets. Despite similar reduction in dust exposure, horses fed **haylage** displayed **greater resolution of airway inflammation** (lower BAL neutrophils) than those fed pellets and steamed hay. Only haylage increased the ratio of **anti-inflammatory** to pro-inflammatory lipids while reducing BAL neutrophil proportions within 6 weeks (increased plasma **omega-3** ?) ## Footnote Effects of forages, dust exposure and proresolving lipids on airway inflammation in horses AJVR 2021 Dust exposure and pulmonary in ammation in Standardbred racehorses fed dry hay or haylage: A pilot study Vet J 21 Effects of low-dust forages on dust exposure, airway cytology, and plasma omega-3 concentrations in TB racehorses: A randomized clinical trial JVIM 2023

Answer 46

- **MEA** - **EGUS** - Dynamic upper airway obstruction (DUAO) - Myopathies ## Footnote Medical causes of poor performance and their associations with fitness in Standardbred racehorses jvim 2024

Answer 47

The concentrations of several **allergen-specific IgE** were higher in asthmatic horses (**fungi** (Aspergillus fumigatus), **insects** (Culicoides spp.), and **latex** (Hevea brasiliensis)). The protein microarray performed better on **BALF** than serum for detection of asthma. Serological IgE concentrations do **not closely correlate** with BALF concentrations and **should be interpreted with caution.** ## Footnote Protein microarray allergen profiling in bronchoalveolar lavage fluid and serum of horses with asthma jvim 23

Answer 48

BALF **mast cell count** was higher in left lung compared to right lung and compared to pooled samples. Between the two techniques, 17 of the horses had changes in BAL cytology from control to airway inflammation or vice versa. **Pooled BAL sample was the least reliable for detecting airway inflammation**, and was **not representative of the overall lung condition**. ## Footnote Bilateral bronchoalveolar lavage cytology profiles in a warmblood horse population during a 1-year period jvim 2024

Answer 49

**Correct Answer:** **B) BALF NGAL concentrations increased with the severity of EA, with higher levels in severe asthma (SEA) compared to mild–moderate asthma (MEA).** --- This question emphasizes the finding that BAL NGAL concentrations were significantly **higher in horses with asthma compared to controls**, and that NGAL concentrations in BAL fluid reflected the **severity of the disease**, making it a potential biomarker for equine asthma. No differences were found in serum NGAL concentration between any of the groups. ## Footnote Neutrophil gelatinase-associated lipocalin as a potential biomarker for equine asthma evj 24

Answer 50

**Correct Answer:** **D) NAC treatment reduced mucus accumulation and inflammatory cell counts, particularly neutrophils, in horses subjected to head confinement.** --- This question highlights the key finding that NAC treatment was effective in reducing both **mucus accumulation** and **inflammatory cell counts** and neutrophil % in horses with head confinement. But higher macrophages. ## Footnote The efficacy of N-acetylcysteine in decreasing airway inflammation and mucus accumulation in horses with 18 hours of head confinement jvim 2024

Answer 51

**Correct Answer:** **C) A tracheobronchoscopy score of 0 does not exclude EIPH, and follow-up BALFRBC testing is recommended to rule out EIPH.** **Explanation:** The study found that while tracheobronchoscopy scores can indicate the presence of EIPH, **false negatives are common**, particularly with a score of 0. In these cases, the BALF RBC count may still be elevated, and therefore follow-up testing with BALF RBC is **necessary to definitively rule out EIPH.** The study also showed that the **sensitivity** of tracheobronchoscopy for diagnosing EIPH was **low** (59%), while BALF RBC** ≥992/μL** had much **higher sensitivity** (93%), indicating that BALF RBC is a **more reliable diagnostic test for EIPH**. ## Footnote Relationship between tracheobronchoscopic score and bronchoalveolar lavage red blood cell numbers in the diagnosis of exercise-induced pulmonary hemorrhage in horses jvim 20

Answer 52

**Correct Answer:** **C) Increased time in training** --- **Explanation:** The study found that increased time in training was significantly associated with an increased risk of both tracheal blood and significant haemosiderophages in tracheal wash fluid, both of which are indicators of EIPH. This suggests that **prolonged training is a key risk factor** for the development of EIPH in racehorses. Current inflammation was associated with previous haemorrhage, but not current or future haemorrhage, suggesting that **haemorrhage leads to inflammation** but not that inflammation leads to haemorrhage. ## Footnote Training related risk factors for exercise induced pulmonary haemorrhage in British National Hunt racehorses evj 22

Answer 53

**Correct Answer:** **A) Severe equine asthma (sEA) is significantly associated with the presence of hemosiderophages in BALF.** --- **Explanation:** Hemosiderophages were found in the BALF cytology in a subset of horses that perform light or no work and presented for respiratory signs. These cells were found more frequently in horses with **sEA**. ## Footnote Bronchoalveolar lavage hemosiderosis in lightly active or sedentary horses jvim 2023

Answer 54

**Correct Answer:** **B) EIPH severity (grade ≥3) was associated with poorer performance, as indicated by a lower speed index and finishing place.** --- **Explanation:** The study found that **EIPH grade ≥3** was associated with **poorer performance**, as evidenced by lower **speed index** and **finishing place**. This indicates that severe EIPH has a negative impact on racehorse performance. In contrast, **prerace furosemide administration** was associated with **decreased likelihood**, but **not severity**, of EIPH at most tracks. ## Footnote Prevalence and severity of exercise-induced pulmonary hemorrhage in 2-year-old Thoroughbred racehorses and its relationship to performance jvim 2024

Answer 55

- **Fever** - **Pruritus** - **Anemia** - Hypercalcemia (Ca > 14 mg/dL) - Hypertrophic osteopathy : most commonly associated with primary and metastatic pulmonary tumors

Answer 56

A brief inspiration, followed by a period of **apnoea** with **complete collapse of the URT** including closure of the external nares, nasopharynx and rima glottidis and then a short, forced expiration. ## Footnote Complete upper airway collapse and apnoea during tethered swimming in horses evj 20

Answer 57

The study showed a lower grade of **vocal fold collapse** (6/9 horses), **palatal instability** (7/10 horses) and **intermittent dorsal displacement of the soft palate** (5/7 horses) post-IMT. ## Footnote Inspiratory muscle training for the treatment of dynamic upper airway collapse in racehorses: A preliminary investigation Vet J 2021

Answer 58

**Correct Answer:** **C) Horses with preoperative grade III.2/III.3 laryngeal function were more likely to race postoperatively compared to grade IV horses.** --- **Explanation:** **Laryngeal function grade** may affect **likelihood of racing after LPVC**, but not earnings per start. **Grade III. 2/III.3** horses were more likely to race postoperatively than **grade IV** horses, and grade IV horses took a longer time to first race after LPVC. ## Footnote The impact of grade of laryngeal function immediately prior to laryngoplasty and ipsilateral ventriculocordectomy on postoperative performance: 623 Thoroughbred racehorses (1998- 2013) evj 2022

Answer 59

Correct answer: C) Risk factors for respiratory signs included strenuous work, drinking from stagnant water sources, and being housed on a cobbled floor ## Footnote 2020 Pathology, infectious agents and horse- and managementlevel risk factors associated with signs of respiratory disease in Ethiopian working horses

Answer 60

Correct answer: D) **M. equirhinis** was the most commonly detected species and was significantly associated with respiratory signs ## Footnote 2022 Detection of Mycoplasma spp. in horses with respiratory disorders

Answer 61

Correct answer: D) **Hyponatremia was associated with higher rectal temperature, increased fibrinogen concentration, and presence of SIRS** Hyponatremia at admission is associated with the presence of **inflammation**, **SIRS**, and **with longer duration of hospitalization**. Presence or absence of pleural effusion did not influence severity of hyponatremia. ## Footnote Hyponatremia in horses with septic pneumopathy jvim 22

Answer 62

**Monitoring response to antimicrobial using SAA**. SAA decreased significantly over the course of clinical disease and **correlated with clinical improvement of pneumonia**, whereas fibrinogen, neutrophil, and WBC counts did not. ## Footnote Utility of serum amyloid A in monitoring clinical response2023 jvim 23

Answer 63

The correct answer is C) **Soaking hay reduced PM exposure by more than 50%.** The study utilized a custom-built wearable particulate matter (PM) monitor called the Black Beauty (BB) to assess the effect of soaking hay on PM exposure in horses. Results showed that feeding soaked hay significantly reduced both PM2.5 and PM10 exposures. For PM2.5, short-term (20-min) exposure was reduced from 160 μg/m3 (dry hay) to 53 μg/m3 (soaked hay), and extended (8-h) exposure was reduced from 76 μg/m3 to 31 μg/m3. For PM10, short-term exposure was reduced from 2829 μg/m3 (dry hay) to 970 μg/m3 (soaked hay), and extended exposure was reduced from 1581 μg/m3 to 488 μg/m3. ## Footnote 2024 A wearable real-time particulate monitor demonstrates that soaking hay reduces dust exposure

Answer 64

The correct answer is C) **BALFRBC numbers are more sensitive than TBE scores in detecting EIPH. ** The correlation between TBE score and BALFRBC number was significant but **weak** (P<.001; rs=0.42). The sensitivity of TBE for diagnosing EIPH was poor (0.59; 95% confidence intervals [CI], 0.49-0.68), compared to BALFRBC number ≥992/μL (0.93; 95% CI, 0.88-0.96). There were 75 instances where the TBE score equaled 0 although the BALFRBC number was ≥992/μL, indicating **false negatives with TBE**. If the goal is to identify whether a horse is positive for EIPH, then **BALFRBC number is the single test of choice because it has a much higher sensitivity** (0.93 versus 0.59).