Respiratory Noise in detail
Epiglottic entrapment
This condition occurs when the epiglottis becomes trapped under the lining of the pharynx and is usually asymptomatic. In some cases it will cause a respiratory and coughing and can either be intermittent or constant.
Endoscopy is required for diagnosis. Surgery can be performed in some cases to release the epiglottis.
Lymphoid hyperplasia
This is usually an incidental finding an causes no problems. It is an increase in tissue around the pharynx (lymphoid tissue) in young animals, most likely due to mild infection or immune response. Endoscopy is required for diagnosis.
Laryngeal hemiplegia (roaring)
Laryngeal hemiplegia is the paralysis of one of the cartilages that open up the larynx during respiration. It is caused by damage to the nerve that controls this cartilage.
Signs
Horses will ‘roar’ on exercise, affected horses are often known as roarers, and may have a reduced performance.
Diagnosis
To gain a definitive diagnosis an endoscopic examination should be carried out to see the asynchronous movement of the larynx.
Treatment
Two surgical techniques are usually carried out at the same time these are the tie back and the hob day.The tie back operation is to hold the malfunctioning piece of cartilage open and the hob day is to remove the tissue that vibrates producing the noise.
Intermittent dorsal displacement of the soft palate (choking up/gurgling)
In this condition the soft palate displaces causing the airflow to become blocked. Horses will produce a gurgling noise, appear to be choking and pull up during exercise.
Diagnosis
Endoscopy is used for diagnosis, however, as the condition usually only occurs at exercise this is often performed on a treadmill.
Treatment
Surgery is required to prevent this occurring. The technique is often referred to as a tongue tie and only has a 60% success rate.
Subepiglottic cysts
These are small cysts just underneath the epiglottis. They can cause the horse to produce a noise during exercise.
Diagnosis
Endoscopy is required for diagnosis.
Treatment
Surgical removal.
Tracheal collapse
Occurs in miniature horses and is a condition they are born with and causes coughing, respiratory noise at rest and difficulty swallowing.
Endoscopy is required for diagnosis.
Affected horses will usually have a good quality of life and no treatment is performed.
Cleft palate
In this condition the palate has not formed properly and milk can flow from the mouth to the nasal passages and then into the lungs. Milk can be seen coming from the nostrils after drinking and the foal will develop pneumonia due to the milk running into the lungs.
Surgery is usually unsuccessful and therefore, the prognosis is poor.
Masses and cysts
Masses and cysts can develop anywhere in the respiratory tract to cause respiratory noise, coughing, increased respiratory rate and a nasal discharge (sometimes containing blood).
The common types are cysts, granulomas (caused by bacterial or viral infection) and tumours (lymphosarcoma and squamous cell carcinoma). Endoscopy is required for diagnosis.Treatment is surgical removal.
Foreign body
Material such as twigs can get stuck in the respiratory tract causing a variety of signs, often dependant on where the object is positioned, these include respiratory noise, coughing, increased respiratory rate, difficulty swallowing and a nasal discharge (sometimes containing blood).
Treatment is to remove the object.
Trauma
Trauma to the respiratory tract can cause a variety of signs depending on the damage caused and it’s location.
Radiographs and endoscopy are often required to assess the damage. The treatment depends on the severity of the signs and the particular area damaged.