Diseases of the Respiratory System

Chapter 58 Diseases of the Respiratory System


Respiratory diseases are a problem for horse owners because of their effect on animal performance. A slight respiratory problem may cause a small impairment in the performance of the animal, but that small degree of impairment may make the difference between finishing a race in the money or going home with empty pockets. For diseases that cause coughing and nasal discharge as noticed by the owner, rest has been promoted as one part of the treatment. As the animal is rested, it is losing training and performance time.



EPIGLOTTIC ENTRAPMENT


Epiglottic entrapment is a relatively common condition that occurs more often in Standardbreds and Thoroughbreds than in other breeds. The exact cause of the condition is unknown. It is possible that a congenital formation defect exists in the tissue of the pharynx. The condition is apparent when the epiglottis is trapped by soft tissue in pharynx. This leads to a less efficient breathing system, with subsequent effects on performance.




CLINICAL SIGNS



• Coughing

• Respiratory noise

• Poor performance


DIAGNOSIS



• Endoscopy


TREATMENT



• Epiglottic entrapment can be treated surgically if the horse’s performance is adversely affected.

• If there is no effect on performance, then benign neglect (ignore it) is the treatment of choice for many cases.


EPISTAXIS


Epistaxis is defined as bleeding from one or both nostrils. Epistaxis is usually secondary to some other condition. Nosebleeds can affect all horses equally, and they are often seen in racehorses. Among the many different causes of epistaxis are:


• Trauma, such as from nasogastric intubation or blunt trauma

• Infections/abscesses

• Exercise-induced pulmonary hemorrhage

• Tumors



DIAGNOSIS



• Clinical signs

• Good physical examination

• Endoscopy to help visualize underlying cause

• Complete blood cell count (CBC) to rule out infectious causes


TREATMENT



• Treat the underlying cause.


LEFT LARYNGEAL HEMIPLEGIA


Left laryngeal hemiplegia affects the left side of the larynx, making it unable to retract properly during increased respiratory effort. The condition is more commonly seen in Thoroughbreds and draft horses. The most common onset (or owner notice) of clinical signs is at 2 to 3 years of age. There is a heritable basis to the condition that is a result of demyelination of left recurrent laryngeal nerve, leading to a loss of nervous control of laryngeal muscles and partial airway obstruction.




CLINICAL SIGNS



• Inspiratory noise during exercise

• Poor performance

• Noise becomes progressively worse


DIAGNOSIS



• Endoscopic examination


TREATMENT



• Surgical correction


SOFT PALATE DISLOCATION


Soft palate dislocation is an intermittent condition seen mostly during peak exercise. The condition is most common in racehorses. Problems can occur when the soft palate gets displaced dorsally. This narrows the airway and leads to partial obstruction. The exact cause of soft palate dislocation is unknown, although it is suspected that there may be a problem with the vagus nerve.




CLINICAL SIGNS



• Gurgling noise

• Poor performance

• Dyspnea during exercise


DIAGNOSIS



• Endoscopy while exercising on treadmill

• A diagnosis is often made by ruling out other diseases, plus clinical signs/history


TREATMENT



• Alter the horse’s tack. Tongue ties and figure-eight nose bands are often used with varying degrees of success. If the tack changes do not alleviate the condition, then surgery is performed.


PRIMARY SINUSITIS


Sinusitis is defined as infection and inflammation of the sinuses. The ones most affected are the maxillary and frontal sinuses. Primary sinusitis is most often seen in younger horses. Other upper respiratory infections are often present when a horse is affected with primary sinusitis.


The infection can be caused by any number of bacteria or fungi. Inhalation of these pathogens is a common method by which they infect the sinuses.




CLINICAL SIGNS



• Chronic, persistent mucopurulent nasal discharge

• Often unilateral

• If the condition is severe enough, the animal may be dyspneic

• Occasionally an animal may become systemically ill


DIAGNOSIS



• For the disease to be treated properly, the condition must be differentiated from secondary sinusitis, such as from an infected tooth root

• Percussion of the sinuses, listening for fluid line

• Radiographs of the skull

• Bacterial and fungal culture and sensitivity obtained from the sinuses


TREATMENT



• Lavage and drainage of sinuses; antibiotics or antifungals should be mixed in the lavage fluid (depending on culture and sensitivity results)

• Systemic antibiotic therapy is usually unrewarding


SECONDARY SINUSITIS


The most common underlying cause of secondary sinusitis is infection of the roots of upper cheek teeth. Secondary sinusitis is most common in mature, rather than young, horses. Anything that can affect and cause infection of the tooth roots, such as fractures, abscesses, tumors, and so forth can lead to a secondary sinusitis.




CLINICAL SIGNS



• Unilateral, mucopurulent nasal discharge

• Malodorous breath

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Aug 31, 2016 | Posted by in GENERAL | Comments Off on Diseases of the Respiratory System

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