Topic:Bronchi
The bronchi are part of the lower respiratory tract in horses, serving as air passages that conduct inhaled air from the trachea into the lungs. These tubular structures branch into smaller bronchioles, leading to the alveoli where gas exchange occurs. The health and function of the bronchi are critical for maintaining respiratory efficiency and overall equine health. Conditions affecting the bronchi, such as bronchitis or bronchoconstriction, can impact a horse's respiratory performance and are often a focus in equine veterinary medicine. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of the bronchi in horses, as well as diagnostic and therapeutic approaches for bronchial conditions.
Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. IV. Changes in the bronchial circulation demonstrated by C.T. scanning and microradiography. The purpose of this study was to use radiographic contrast techniques and special imaging methods to identify and high-light bronchial arterial involvement in lung lesions associated with exercise-induced pulmonary haemorrhage (EIPH) in horses. The lungs from four horses with histories of EIPH were prepared for computerised tomographic scanning and microradiography by perfusing the broncho-oesophageal artery with a mixture of red latex and either barium or iodine contrast materials while the pulmonary supply received only blue latex. Computerised tomographic scan slices of the prepared inflate...
Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. V. Microscopic observations. Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lun...
Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. VIII. Conclusions and implications. This paper reviews a series of clinical, post mortem and imaging studies on exercise-induced pulmonary haemorrhage (EIPH) performed on 26 Thoroughbred racehorses. Post mortem techniques included routine gross, subgross and histological examination; coloured latex perfusions of pulmonary and bronchial circulations; and microradiography and computerised tomography scans of lungs with contrast injected vasculature. The major lesions were multiple, separate and coalescing foci of moderately proliferative small airway disease accompanied by intense neovascularisation of the bronchial circulation. A...
Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. III. Subgross findings in lungs subjected to latex perfusions of the bronchial and pulmonary arteries. Latex was injected under pressure into bronchial and pulmonary arteries of the inflated lungs of Thoroughbreds and transverse sections taken to calculate the area of lesions resulting from exercise-induced pulmonary haemorrhage. Extensive areas of dense brown haemosiderin varying from 0 to 45 per cent of total lung volume were identified, predominantly in the dorsocaudal lungfields. Bronchial arterial proliferation appeared to have replaced the pulmonary supply in affected areas of the lung. Closely associated with the staining and bronchial arterialisation, there was widespread small airway d...
Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. I. Clinical profile of horses. Detailed physical and clinical examinations were performed on 26 Thoroughbred racehorses which were used subsequently in a series of studies to investigate the contribution of the pulmonary and bronchial arterial circulations to the pathophysiology of exercise-induced pulmonary haemorrhage (EIPH). Twenty-five of the horses had been retired from race training in Hong Kong during the 1984-85 season, all but four raced that season; one horse had been retired the previous season. The average number of races for the group that season was 4.1 +/- 2 with an average distance of 1502 +/- 216 metres, me...
The histological features of the immune system of the equine respiratory tract. The distribution of mucosa-associated lymphoid tissue along the equine respiratory tract was surveyed in light microscopical sections. Intra-epithelial lymphocytes and similar cells scattered in the lamina propria were identified in all sites from the nasal vestibule to bronchioles of 2 to 4 mm diameter. Isolated lymphoid patches, occasionally with nodules, were common in bronchioles, but the density of this bronchiole-associated lymphoid tissue (BRALT) varied between individual horses. Bronchus-associated lymphoid tissue (BALT) was infrequently encountered. In the upper respiratory tract, nod...
Cellular content of secretions obtained by lavage from different levels of the equine respiratory tract. Lavage procedures were used to obtain samples of respiratory secretions from the nasal cavity, trachea, bronchi and bronchoalveolar level of apparently normal conscious horses, and the cellular composition of the lavage fluids was assessed. There was a progressive increase in total cell count of the secretions obtained from the upper to the lower respiratory tracts. Nasal lavage fluid was composed chiefly of epithelial cells, whereas tracheal, bronchial and bronchoalveolar fluids contained higher proportions of macrophages, lymphocytes and neutrophils. Eosinophils and mast cells were identifie...
Effect of halothane, enflurane and isoflurane on bronchomotor tone in anaesthetized ponies. The effects of halothane, enflurane and isoflurane on bronchial calibre were investigated in five anaesthetized ponies using a computer-aided forced airflow oscillation technique to derive specific lower airways conductance (s.Glaw) and expiratory reserve volume (ERV). All the agents tended to increase s.Glaw (indicating bronchodilatation), but ERV was reduced by halothane and enflurane, and increased by isoflurane. It was concluded that the effects of these agents on bronchomotor tone were similar to those which occur in man. However, the reasons for the differences in their effects on ERV co...
Drug therapy of respiratory disorders. The emphasis of this article is on the clinical application of drugs in therapy for treatment of disorders of the lower respiratory tract. Medications discussed include those used to enhance clearance of secretions and those employed to prevent and/or alleviate bronchoconstriction. Antimicrobial agents and respiratory stimulants are briefly mentioned.
Quantification of immunoglobulins in respiratory tract secretions of the horse. Lavage techniques were used to obtain secretions from the nasal cavity, trachea and bronchi of conscious horses. The techniques, which utilised fibreoptic endoscopy for recovery of tracheal and bronchial secretions, were well tolerated by the horses. The recovery rates of the lavaged fluids were acceptable, but were lowest for bronchial secretions, and there was minimal contamination by blood. The fluids were analysed for IgG and IgM by single radial immunodiffusion, and for IgA and albumin by rocket immunoelectrophoresis. Relative to albumin there was significantly more IgA and IgM, and signi...
[Examination and treatment of respiratory tract diseases in the horse in clinical practice]. In spite of regular vaccinations against equine influenza we are still observing a high rate of patients with respiratory problems in the equine practice. In our practice in Munich Riem, into which a horse clinic has been integrated, 4000 horses have been treated in 1985 alone. 874 of these showed some form of respiratory disease (= 22%). All of the 4000 horses have only been treated curatively, i.e. preventive forms of treatment such as vaccinations, deworming and examinations for insurance companies and prior to selling have not been taken into account. From 1983 until today in our clinic 25...
[Pathomorphology of chronic obstructive lung disease in the horse]. The chronic obstructive pulmonary disease (COPD) in horses is primarily based on a chronic bronchitis/bronchiolitis with constriction of the tubes in the lower respiratory tract. The outward appearance of the lung is characterized by a diffuse or marginal alveolar emphysema. The big bronchial tubes are usually not altered. Small bronchi and bronchioli can often be seen through the pulmonal pleura. On the sectional area they are visible as opaque grey-red nodules with a central lumen detectable under a magnifying glass. The histopathological picture of alterations in the bronchial tree can vary...
Pleuritis and pneumonia attributed to a conifer twig in a bronchus of a horse. A conifer twig was responsible for severe fibrinopyogranulomatous adhesive pleuritis and pneumonia in a horse. At necropsy, the twig was found in a terminal bronchus and extended into the lung parenchyma, through the pleura, and into the accumulated exudate. Inhalation of plant material may be a more common cause of pleuritis than previously recognized. Meticulous examination at necropsy would be necessary to make the diagnosis.
Immunofluorescent evaluation of the lower respiratory tract of healthy horses and of horses with chronic bronchiolitis. Pulmonary parenchymal tissues from 6 healthy horses and from 9 horses with chronic bronchiolitis were evaluated by use of an indirect immunofluorescent technique. In horses of both groups, the diffuse interstitial immunofluorescence was most intense for immunoglobulin (Ig)G, moderate for IgA, and minimal for IgM. Intensity of fluorescence was increased markedly in diseased lungs exposed to anti-IgA and anti-IgG. Around small bronchi and large bronchioles of healthy horses, IgA-containing cells generally were more numerous than were IgG-Fc fragment (Fc)-containing cells; in small bronchioles, h...
Effects of phenobarbital treatment on 3-methylindole toxicosis in ponies. To study the role of cytochrome P-450-dependent mixed function oxidase reactions in equine 3-methylindole (3MI) toxicosis, ponies were given 20 mg of phenobarbital/kg of body weight at 72, 60, 48, 36, and 24 hours before 100 mg of oral 3MI/kg to induce cytochrome P-450 or no treatment (controls). Maximal 3MI plasma concentration was decreased and clearance was faster in phenobarbital-treated ponies. Plasma 3MI was still detectable 12 and 36 hours after dosing in phenobarbital-treated and control ponies, respectively. Phenobarbital treatment induced a distribution phase with transition from a 1...
Multiple myeloma in a horse. Multiple myeloma was diagnosed in a 22-year-old Arabian mare with a history of chronic weight loss. Quantitative immunoglobulin analysis revealed monoclonal gammopathy (IgG(T), 9,800 mg/dl). Due to progressive weight loss, the horse was euthanatized. Microscopy of tissues revealed plasma cell infiltrates in bone marrow, spleen, pituitary gland, adrenal cortex, muscle of the tongue, and bronchial, renal, and mesenteric lymph nodes.
Airway responses to aerosolized methacholine and citric acid in ponies with recurrent airway obstruction (heaves). We measured lung function and airway reactivity in response to methacholine and citric acid administered by aerosol in 2 groups of ponies (principal and control). Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction. Control ponies had no history of respiratory disease. Both principal and control ponies were paired (principal and control), and measurements were made when principal ponies were in clinical remission (Period A), following barn exposure when principal ponies had acute airway obstruction (Period B), and 1 and 2 wk after they were returne...
Intravenous histamine administration in ponies with recurrent airway obstruction (heaves). Pulmonary function and airway reactivity to IV histamine were measured in a group of ponies with a history of recurrent airway obstruction (heaves) and their age-, weight-, and gender-matched controls. Ponies were studied during a period of clinical remission (period A), after exposure to a barn environment (period B), and twice during a 2-week recovery phase (periods C and D). At periods A, C, and D, PaO2, dynamic compliance (Cdyn), pulmonary resistance, tidal volume, respiratory frequency, and the log dose of histamine required to reduce Cdyn to 65% of base-line value (log ED65Cdyn) of princ...
Inclusions in equine cytologic specimens. Inclusions and cellular changes were seen in cytologic specimens from 1 healthy horse, 6 horses hospitalized because of respiratory problems, and 1 horse hospitalized because of colic and hepatitis. Two bronchial aspirates contained detached ciliated cytoplasmic tufts and cytoplasmic inclusions characteristic of the specific degenerative process called ciliocytophthoria. These changes and inclusions resembled those seen in bronchial aspirates from human beings with parainfluenza virus infection. Four bronchial aspirates and 2 serous fluid specimens had nuclear inclusions resembling those seen ...
Airway reactivity in ponies with recurrent airway obstruction (heaves). We measured lung function and airway reactivity to histamine administered by aerosol in two groups of ponies. Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction when ponies are housed in a barn and fed hay; control ponies had no history of airway obstruction. Ponies were paired (principal and control) and measurements were made when principal ponies were at pasture and in clinical remission (period A), following barn housing when principal ponies had acute airway obstruction (period B), and after a further 1 and 2 wk at pasture (periods C and D). ...
Alkylation of bronchiolar epithelial cells by 3-methylindole metabolites in the horse. Autoradiographs of horse-lung explants incubated with [3H]3-methylindole (3MI) showed 8 times greater labeling per area to bronchiolar epithelial cells than to the interalveolar septa. Incubations of horse-lung microsomes with [14C]3MI resulted in alkylation of microsomal proteins, which could be reduced by exogenous glutathione. An apparent covalent adduct of glutathione and 3MI was isolated from these incubations. These results suggest that the target cells of 3MI-induced injury in the horse, the bronchiolar epithelial cells, are alkylated by an electrophilic 3MI intermediate.
Equine tracheobronchial lavage: comparison of lavage cytologic and pulmonary histopathologic findings. Differential cell counts were done on bronchial lavage specimens from 166 horses. Postmortem gross and histologic examinations were done to determine the pathologic diagnosis of the lungs from these horses. Ninety-two (55%) were normal, 18 (11%) had interstitial pneumonia, 13 (8%) had bronchopneumonia, 13 (8%) had focal eosinophilia, 11 (7%) had diffuse eosinophilia, 11 (7%) had chronic bronchitis, and 8 (5%) had suppurative bronchitis. Little relationship was found between cellular features of the lavage specimens and the pathologic status of the lungs of individual horses.
Collection and evaluation of tracheobronchial washes in the horse. A flexible endoscope was used to obtain 223 tracheal washes from 191 horses in three clinical categories. Total cell counts, cytological and bacteriological examinations are reported and the features of the main cell types encountered described. The presence and degree of inflammatory airway disease was determined by a semiquantitative assessment of the neutrophil response and was an important consideration in the interpretation of the bacteriological results. Potential pathogens were isolated from approximately 30 per cent of samples. Cytological changes suggestive of lungworm infestation, vi...
Effects of tryptamine antagonists on the anaphylactic contractions of the bovine pulmonary smooth muscles. Calves were sensitized with horse plasma (H.P.), 0.2 ml/kg, i.v., and H.P. (0.2 ml/kg) in Freund's complete adjuvant, s.c. The latter injection was repeated 1 week later and the animals were killed 10 days after the second injection. Spirally cut strips of pulmonary artery and vein and the trachealis muscle from the sensitized calves contracted to 5-hydroxytryptamine (5-HT) and specific antigen (horse plasma). Antigen-induced contractions of the pulmonary smooth muscles were significantly blocked (P less than 0.05) by the 5-HT antagonists, methysergide and ketanserin. The trachea, however, app...
3-methylindole as a model of equine obstructive lung disease. 3-methylindole was administered orally and intravenously to horses and ponies in order to determine the ability of this chemical to provide a model of equine pulmonary disease. Both routes produced a severe and sometimes fatal pulmonary disease, characterised by bronchiolitis. Clinical signs developed 48 to 72 h after dosing and were most severe between Days 4 and 10 post dosing. Intravenous administration of 3-methylindole produced lung injury more rapidly and at a lower dose rate than the oral route. It is suggested that the respiratory condition induced by this chemical could become a metho...
The pathology of experimental Corynebacterium equi infection in foals following intrabronchial challenge. Six foals were inoculated intrabronchially with a suspension of Corynebacterium equi. Six weeks before this challenge, three foals were vaccinated with a C. equi bacterin. Three foals were unvaccinated controls. All foals developed a severe bronchopneumonia in the inoculated lung, indicating that vaccination was not protective. Three foals (two vaccinated, one control) were killed eight to nine days after infection. One control died on day 9 with lesions of disseminated intravascular coagulation. The remaining two foals (one vaccinated, one control) were killed on day 17. C. equi was cultured ...
Chronic obstructive pulmonary disease in the horse. 2: Therapy. The therapy of equine chronic obstructive pulmonary disease (COPD) essentially entails minimising the horse's exposure to the aetiological antigens which are predominantly thermophilic actinomycetes and moulds occurring in hay and straw. This can be achieved, for example, by keeping affected horses permanently out of doors, or when stabled, using shredded paper, wood shavings or peat moss as bedding and feeding a complete cubed diet. There should be no supplementary hay feeding apart from dust-free vacuum-packed hay. Applying such measures generally allows horses to become asymptomatic in seve...
Chronic obstructive pulmonary disease in the horse. 1: Nature of the disease. The aetiology, pathophysiological changes, pathology and clinical signs of the disease as presently understood are discussed. The condition appears to be a hypersensitivity of the respiratory system in some horses to poor quality hay and straw. Micropolyspora faeni is the chief agent identified in the northern part of the United Kingdom. In other locations, the chief agent is probably different. The principal changes are spasm of the airways and bronchiolitis of the small airways. Onset may be acute or insidious. The chief clinical signs are well known but the disease process is reversible if ...
The pathogenicity in mice of respiratory, abortion and paresis isolates of equine herpesvirus-1. Eleven isolates of equine herpesvirus-1 (subtype 1) all infected the brain following intracerebral inoculation of 2 d.o. mice. Most isolates were from cases of paresis, abortion or respiratory disease in the U.K., but established strains were also included. They divided into two subgroups. The 5 less pathogenic isolates were characterized by being restricted predominantly to the olfactory lobes. The 6 pathogenic isolates included the three known to cause equine paresis and were detected in neurones throughout the brain as well as giving rise to viraemia and infecting bronchial and renal epithe...