Correlation of the Havemeyer endoscopic laryngeal grading system with histopathological changes in equine Cricoarytenoideus dorsalismuscles

The establishment of a single validated endoscopic laryngeal grading system for assessing recurrent laryngeal neuropathy (RLN) is desirable to facilitate direct comparisons between the findings of different clinical and research groups worldwide. The objective of this study was to assess the relationship between the Havemeyer endoscopic laryngeal grading system and histopathological changes consistent with RLN in the left cricoarytenoideus dorsalis (CAD) muscle of horses of different breeds with a full range of clinical severities of RLN, i.e., from normal endoscopic laryngeal function to complete laryngeal hemiplegia. Endoscopic grading of laryngeal function of 22 horses was performed using the Havemeyer endoscopic laryngeal grading system. A biopsy sample of the left CAD muscle was obtained from each horse, either at post mortem examination (n = 16), or during routine laryngoplasty surgery (n = 6). A semi-quantitative histopathological scoring system was used to grade the severity of histopathological lesions consistent with RLN in the left CAD muscle of each horse. A significant positive correlation (rs = 0.705, p < 0.001) was found between the Havemeyer grades and sub-grades of laryngeal function and the semi-quantitative assessment of histopathological lesions consistent with RLN in the left CAD muscle. However, a wide spread of muscle histopathological scores was obtained, particularly from horses with Havemeyer sub-grades II.1, III.1 and III.2. In conclusion, the Havemeyer endoscopic laryngeal grading system was found to broadly correlate with histopathological changes consistent with RLN in equine cricoarytenoideus dorsalis muscle.     

Equine paranasal sinus disease: a long-term study of 200 cases (1997-2009): ancillary diagnostic findings and involvement of the various sinus compartments

Reasons for performing study: There is a lack of objective information on the value of ancillary diagnostic techniques used to investigate equine sinus disease, and also on which sinus compartments are commonly affected in this disorder. Objectives: To record the ancillary diagnostic findings used to investigate equine sinus disease and to document which compartments are affected. Materials and methods: The clinical case records of 200 consecutive cases of sinus disease, including subacute (<2 months' duration) primary (n = 52); chronic (>2 months' duration) primary (n = 37); dental (n = 40); traumatic (n = 13); sinus cyst (n = 26); sinus neoplasia (n = 10); dental related oromaxillary fistula (n = 8); mycotic sinusitis (n = 7) and intra‐sinus progressive ethmoid haematoma (n = 7) were retrospectively examined. Results: Nasal endoscopy showed exudate draining from the sino‐nasal ostia in 88% of cases and a sino‐nasal fistula was present in 15% of cases. Sinoscopy was performed in 79% of cases and was of great diagnostic value. More recently, 22% of cases had fenestration of the ventral conchal bulla performed to allow sinoscopy of the rostral sinus compartments. Radiography was performed in 97% of cases and showed intra‐sinus fluid lines to be common (69% prevalence) in subacute primary sinusitis. Radiographic dental apical changes were not specific to dental sinusitis, e.g. 29% of chronic primary sinusitis cases had radiographic dental changes. Scintigraphy was performed in 20% of cases and was helpful in identifying dental apical changes when radiography was inconclusive. Overall, the caudal maxillary (78% involvement) and rostral maxillary (61%) sinuses were most commonly affected, with the ventral conchal sinus (VCS) (54% involvement) and conchofrontal sinuses (48%) less so. The VCS showed the greatest tendency to contain inspissated pus (present in 46% of all affected VCS). Conclusions: Nasal endoscopy, sinoscopy and skull radiography are of great value in diagnosing the presence and causes of equine sinus disease.     

Historical and clinical features of 200 cases of equine sinus disease

The historical and clinical findings in 200 referred cases of equine sinus disease were reviewed retrospectively. Univariable and multivariable analyses were performed to detect significant differences in historical or clinical features between various categories of sinus disease. The causes of sinus disease were classified as subacute primary (less than two months duration) (n=52), chronic primary (more than two months duration) (n=37), dental (n=40), sinus cyst (n=26), traumatic (n=13) or mycotic sinusitis (n=7), sinus neoplasia (n=10), dental-related oromaxillary fistula (n=8) and intrasinus progressive ethmoid haematoma (n=7). The majority of sinus disorders were of chronic duration at the time of referral and most (including 97 per cent of chronic primary sinusitis cases) had not responded to previous antibiotic therapy and/or sinus lavage in some cases. Clinical signs included unilateral nasal discharge in most cases, including purulent or mucopurulent discharge in all horses with primary, dental and mycotic sinusitis. Haemorrhagic nasal discharge was a feature of traumatic sinusitis and intrasinus progressive ethmoid haematomas. Firm facial swellings and nasal airflow obstruction were features of sinus cysts and neoplasms. Ipsilateral lymphadenitis was a more prominent feature of sinus disease with active infections such as primary, dental or mycotic sinusitis.     

A review of equine paranasal sinusitis: Medical and surgical treatments

Treatment of the different types of equine sinusitis, in particular those of chronic (>2 months' duration) sinusitis can be difficult, with many such cases not responding to more conservative measures such as rest, antibiotic therapy or sinus lavage. Such refractory cases require further clinical examinations and imaging as outlined in a companion article to achieve confirmation of the cause of the sinusitis. Many sinusitis cases will then require some form of surgical treatment that may include sinusotomy, dental extraction or intrasinus growth removal, that are increasingly being performed by less invasive techniques under standing sedation.     

A review of equine paranasal sinusitis. Aetiopathogenesis,clinical signs and ancillary diagnostic techniques

The equine paranasal sinuses are air filled cavities of uncertain function that are susceptible to inflammation, usually associated with bacterial infection. A common feature of most types of sinusitis is the accumulation of exudate within the affected sinus and subsequent ipsilateral nasal discharge. Equine sinusitis can have a variety of causes, including primary sinusitis following upper respiratory tract infections, and secondary sinusitis caused by dental infections, intrasinus benign and malignant growths and head trauma.     

Equine paranasal sinus disease: a long-term study of 200 cases (1997-2009): treatments and long-term results of treatments

Reasons for performing study: There is limited objective information available on the treatment and the long‐term response to treatment of the different types of equine sinus disease. Objectives: To document the treatments and long‐term response to these treatments in 200 cases of equine sinus disease (1997–2009). Methods: The treatments of horses affected with subacute primary sinusitis (n = 52); chronic primary sinusitis (n = 37); dental sinusitis (n = 40); sinus cyst (n = 26); traumatic (n = 13); dental‐related oromaxillary fistula (n = 8); sinus neoplasia (n = 10); mycotic sinus disease (n = 7); and intrasinus progressive ethmoid haematoma (n = 7) and the long‐term response to these treatments were retrospectively reviewed. Results: Treatments evolved throughout the study and latterly were as conservative as possible, including sinoscopic lavage and standing sinusotomy, with a maxillary sinusotomy approach preferred for the mainly mature horses treated in this study. Removal of intrasinus inspissated pus, including transendoscopically (by sinusotomy and via existing sinonasal fistulae), was the main treatment for chronic primary sinusitis and sinonasal fistulation was seldom performed latterly. Attempted oral extraction of infected cheek teeth, even if unsuccessful, facilitated subsequent dental repulsion, resulting in few post operative problems. Sinus cyst removal carried an excellent prognosis. Except for cases of sinus neoplasia (only 22% cured), an excellent long‐term response to treatment (91% fully cured, 7% partially cured) was obtained for all other types of sinus disease following a median of one treatment. Conclusions: More conservative treatments, including removal of intrasinus inspissated pus by sinoscopy, pre‐existing sinonasal fistula or sinusotomy, are effective for chronic primary sinus disease. Standing sinusotomy, mainly using a small maxillary site, was suitable for most cases of sinus disease in mature horses.     

Oral endoscopy as an aid to diagnosis of equine cheek tooth infections in the absence of gross oral pathological changes: 17 cases

Reasons for performing study: Removal of cheek teeth in all but the aged horse or pony is a serious undertaking with potentially deleterious sequellae. Rigid endoscopy permits detailed examination of the oral cavity and erupted dental tissues and has the potential to assist in the correct identification of the diseased tooth. Objectives: To document oral endoscopic findings associated with infected equine cheek teeth in cases without gross oral pathological changes and thereby determine the usefulness of rigid oral endoscopy as an aid to diagnosis of such infections. Methods: Records of all cases of equine cheek tooth removal attempted under standing sedation over a 38 month period were examined. Cases were excluded from the study if apical infection was associated with gross dental fracture, malalignment, diastema/periodontal pocketing or supernumerary teeth. Endoscopic and radiographic findings were analysed and correlated to diseased tooth location. Results: Seventeen cases of apical dental infection fitting the inclusion criteria (nonresponsive to antibiotics and with no gross oral abnormality of the affected arcade) were identified in which oral endoscopy was used as an aid to diagnosis. In 15 (88%) of the 17 cases, oral endoscopy revealed abnormalities specific to the infected tooth. Focal gingival recession (10/17 cases) was the most common visible abnormality associated with infected teeth. Conclusions: In the majority of cases of apical infection of equine cheek teeth there is visible intraoral evidence implicating the affected tooth. Potential relevance: Oral endoscopy facilitates detailed examination of the mouth and should be considered along with radiography as an important aid to diagnosis in cases of equine dental infection.     

Assessment of dynamic upper respiratory tract function in the equine athlete

Dynamic upper respiratory tract (URT) obstructions occur commonly in the equine athlete. During the past 25 years, veterinary diagnostic capabilities have improved greatly with the ability to perform endoscopy during exercise and thus to visualise upper airway function during various types of exercise. After correctly reproducing and diagnosing an URT obstruction, the veterinary surgeon must consider the functional significance of the endoscopic findings for that individual athlete. This is the third paper in this series and focuses on the diagnosis of URT obstructions, their relationship to the exercise test and their functional significance.     

Lower respiratory tract disease in Thoroughbred racehorses: analysis of endoscopic data from a UK training yard

REASON FOR PERFORMING STUDY: There has been much research directed at potential causative agents and the epidemiology of lower respiratory tract disease (LRTD), but few reports of the clinical progression and outcome. OBJECTIVES: To define clinical features of LRTD in racehorses, including association with age and average duration of disease, through the analysis of endoscopic data. METHODS: A retrospective analysis of records from a single training yard of endoscopic examinations undertaken over a 2-year period was performed. Horses were subjected to regular endoscopic examination for a variety of reasons, and all horses placed on antibiotic therapy for lower respiratory tract disease were rescoped following treatment. Data analysed included a 0-8 tracheal mucus score based on visible endoscopic mucus and gross tracheal lavage turbidity, as well as age and treatment duration and type. RESULTS: A total of 522 endoscopic examinations undertaken on 123 horses and tracking 169 episodes of lower respiratory tract disease were recorded. Mean duration of disease episode was 15.5 days (median = 11 days, range = 4-61 days). Horses age 2 years were significantly more likely than those age > or=3 years to have at least one episode of respiratory disease (P<0.001). There was a direct association between initial tracheal mucus score and rescope score after treatment. CONCLUSIONS: Lower respiratory tract disease was more common in 2-year-olds than in older horses. Affected horses had endoscopic evidence of increased tracheal mucus accumulation for an average of 15.5 days per episode, a considerably shorter period than that suggested by previous studies. POTENTIAL RELEVANCE: Endoscopic examinations permit longitudinal tracking of lower respiratory tract disease in Thoroughbred racehorses. A prolonged duration of disease, sometimes extending for months, can be expected in a small proportion of cases, some of which appear to be refractory to treatment. There is a clear need for evidence-based analysis of treatment regimes to assist clinicians in decision making when managing disease in both individual and group situations.     

Treatment of equine oro-nasal and oro-maxillary fistulae

Equine oro-nasal or oro-sinus fistulae are usually problematic disorders to treat. As these lesions are mainly a sequel to standard dental repulsions, it is obvious that safer exodontia techniques such as oral extraction should now be used. The initial treatment of such fistulae is to ensure that there is a healthy granulating alveolus, without any dental or alveolar sequestrae and that all epithelium lining the fistula is removed. Provided there is a tooth on either side of the fistula, the initial and usually successful treatment is the use of an acrylic alveolar plug attached to adequately prepared adjacent teeth. Reinforcing such prostheses with wire tied between adjacent teeth will stabilise such prostheses. For fistulae that extend far onto the hard palate or those at the Triadan 06 or 11 alveolar sites that cannot be treated by acrylic prostheses, a variety of surgical treatments including; mucoperiosteal sliding flap, transposition of facial muscles, maxillary bone flap or an ear cartilage graft are all potential therapies, but there  are no large, objective long-term reports on their success available.     

Successful treatment of equine sarcoids with cisplatin electrochemotherapy: a retrospective study of 48 cases

Reasons for performing study: Sarcoids are the commonest form of equine skin tumour. Several therapeutic measures have been described but none is considered to be universally effective. Electrochemotherapy (ECT) is a new anticancer therapy that utilises electrical field pulses to induce increased cell membrane permeability to antitumour hydrophilic drugs, such as cisplatin. The increased intracellular concentration of the drugs has a significant therapeutic benefit. The procedure has not been previously reported in a large number of horses. Objective: To validate ECT as a novel alternative treatment for equine sarcoids. Methods: A retrospective study evaluating the efficacy of cisplatin ECT in the treatment of equine sarcoids was performed. Electrochemotherapy treatments were applied under general anaesthesia at 2 week intervals with or without prior excision or debulking. Electric pulses were directly applied to the lesions following intra‐tumoural injections of an aqueous solution of cisplatin. Results: One‐hundred‐and‐ninety‐four sarcoids on 34 horses, 2 ponies, 11 donkeys and one mule were treated with ECT. The 4 year nonrecurrence rate was 97.9% for animals (47/48) and 99.5% (193/194) for tumours. When ECT was used as a single treatment, a significant influence of tumour size (ρ= 0.55) on the number of treatments required for cure was shown. When prior surgery was performed, there was a significant influence (P<0.001) of the excision quality (complete or incomplete) and the healing mode (closed or open wound) on the number of treatments. The most common adverse effect was a slight oedematous reaction for lesions located on thin skin regions. Conclusion and clinical relevance: Results demonstrate that ECT, with or without concurrent tumour debulking, is an effective alternative for treatment of equine sarcoids.     

Variability of resting endoscopic grading for assessment of recurrent laryngeal neuropathy in horses

Reasons for performing study: The extent to which variability affects endoscopic grading of arytenoid cartilage movement is uncertain. Objective: To determine the observer and within horse variability of grading arytenoid cartilage movement in horses during resting endoscopic examination, using a 7‐grade system. Methods: Endoscopic recordings of the upper respiratory tract made at rest in 270 draught horses were reviewed independently by 2 veterinarians to assess interobserver variability when scoring horses' laryngeal function with a 7‐grade system. Grading was repeated by both examiners in 80 randomly selected recordings in order to assess intraobserver variability. In 120 horses, endoscopy was repeated after 24–48 h, with videos graded by both veterinarians to assess intrahorse variability. Results: The mean weighted κ statistic for concordance within examiners was 0.867, with a mean intraobserver agreement of 76.3%. The weighted κ statistic for concordance between the 2 examiners was 0.765, with an interobserver agreement of 63.1%. Of the horses receiving 2 endoscopic examinations, the same grade was assigned to 57.1% of horses at the second examination, when effects resulting from interobserver variability were removed. The mean weighted κ statistic for concordance between the grade assigned at first vs. second examinations was 0.588, indicating only moderate agreement. Conclusions and potential relevance: Intra‐ and interobserver reliability of resting endoscopic grading of arytenoid cartilage movement using a 7‐grade system was high when examinations were conducted by experienced veterinarians. However, there was moderate daily intrahorse variability, suggesting that results of resting endoscopic examinations performed on a single day should be interpreted with caution.     

Peripheral nerve sheath tumour of the equine maxillary sinus

This case report describes an 8‐year‐old Belgian Warmblood mare that was initially diagnosed and treated for a dental sinusitis. Despite removal of the diseased teeth and appropriate treatment, the sinusitis did not resolve. Over time, growth of a peripheral nerve sheath tumour of the left maxillary sinus became apparent, with recurrence after surgical removal. The clinical, radiographic, computed tomography, magnetic resonance imaging and pathological (gross and histological) findings of the first reported peripheral nerve sheath tumour of the equine paranasal region are described and illustrated.     

Post-exercise endoscopic and cytologic diagnosis of equine asthma syndrome in asymptomatic Brazilian pacers

The objectives were: 1. to investigate the occurrence of equine asthma syndrome (EAS) in a group of Campolina and Mangalarga Marchador horses through post-exercise respiratory endoscopy and cytology; 2. compare the efficiency of different diagnostic criteria; and 3. compare the incidence of EAS by breed, age group and sex. A standardised exercise test was conducted in the field, followed by respiratory endoscopy and bronchoalveolar lavage and fluid collection 30 min post-exercise. Clinical evaluation pre- and post-exercise, respiratory endoscopy post-exercise and bronchoalveolar lavage, also post-exercise, were conducted in 30 horses (15 Campolina and 15 Mangalarga Marchador) aged 3–18 years, without a history of respiratory illness and without clinical evidence of active respiratory disease. All horses were in active training and were considered fit to participate in equestrian competition characteristic of these breeds. Post-collection, the horses were subdivided into healthy or EAS-positive, depending on several diagnostic criteria. Statistical comparisons between breeds, age brackets (up to 7 years of age and above 7 years of age) and sex were conducted using appropriate statistical tests. According to bronchoalveolar lavage fluid (BALF) cytology, 56.7% of the horses showed at least one inclusion criteria that contributed to classification as EAS-positive. Of those, only one was classified as moderate EAS, while the others were classified as mild. Total cell count in the BALF above 530 cells/µL was the single most common diagnostic criteria (100%), followed by increased tracheal mucus (53%) at endoscopy, eosinophilia (47%) and neutrophilia (35%) in BALF. Significant differences were found between macrophage and lymphocyte numbers according to breed, but no other differences between breeds, age brackets, sex or status (healthy vs. EAS-positive). A high occurrence of EAS was found in competition-ready Mangalarga and Campolina pacer horses in this study.