Also see Laryngeal Hemiplegia in Horses Laryngeal Hemiplegia in Horses Laryngeal hemiplegia is a progressive neuropathy of the recurrent laryngeal nerve, leading to atrophy and dysfunction of the cricoarytenoideus dorsalis muscle, an important abductor for the... read more .
Laryngitis, an inflammation of the mucosa or cartilages of the larynx, may result from upper respiratory tract infection or by direct irritation from inhalation of dust, smoke, or irritating gas; foreign bodies; or the trauma of intubation, excess vocalization, or injury from roping or restraint devices (in livestock). Laryngitis may accompany infectious tracheobronchitis Kennel Cough Kennel cough results from inflammation of the trachea. It is a mild, self-limiting disease but may progress to bronchopneumonia in puppies or to chronic bronchitis in debilitated adult or aged... read more and distemper Canine Distemper Canine distemper is a highly infectious, systemic, viral disease of dogs that occurs worldwide. Dogs commonly exhibit systemic clinical signs (fever, lethargy, loss of appetite), respiratory... read more in dogs; infectious rhinotracheitis and calicivirus Feline Respiratory Disease Complex Feline respiratory disease complex is typically manifested by clinical signs of the eyes, nose, and mouth ( rhinosinusitis, sneezing, conjunctivitis, lacrimation, salivation, and oral ulcerations... read more infection in cats; infectious rhinotracheitis and calf diphtheria in cattle; strangles Strangles in Horses Strangles is a highly prevalent infectious disease characterized by upper respiratory tract lymph node abscessation secondary to infection with Streptococcus equi equi. The abbreviated terminology... read more , herpesvirus 1 infection Equine Herpesvirus Infection Equine herpesviruses are ubiquitous worldwide, with EHV-1 and EHV-4 having the greatest clinical importance in causing respiratory disease in horses. Fever, nasal discharge, malaise, pharyngitis... read more , viral arteritis Equine Viral Arteritis Equine viral arteritis (EVA) is caused by an RNA togavirus and produces clinical signs of respiratory disease, vasculitis, and abortion. Transmission is via respiratory and venereal routes.... read more , and infectious bronchitis in horses; Fusobacterium necrophorum or Trueperella pyogenes infections in sheep; and influenza in pigs Influenza A Virus in Swine Swine influenza is a highly contagious respiratory disease that results from infection with influenza A virus (IAV). IAV causes respiratory disease characterized by anorexia, depression, fever... read more .
Edema of the mucosa and submucosa is often an integral part of laryngitis and, if severe, the rima glottidis may be obstructed. Edema may also result from allergy, inhalation of irritants, or surgery in the area. Intubation for anesthesia, especially when attempted with inadequate induction or poor technique, is likely to provoke laryngeal edema. Brachycephalic and obese dogs, and dogs with laryngeal paralysis Laryngeal Paralysis in Dogs and Cats Laryngeal paralysis is common in dogs and rare in cats. Signs include: dry cough voice changes noisy breathing that progresses to marked difficulty in breathing with stress and exertion stridor read more develop laryngeal edema and laryngitis through severe panting or respiratory effort during excitement or hyperthermia. In cattle, laryngeal edema has been seen in blackleg Blackleg in Animals Blackleg is an acute, highly fatal disease of cattle and sheep caused by Clostridium chauvoei. In cattle, characteristic lesions of emphysematous swelling of the musculature often develop without... read more , urticaria Urticaria (Hives, Wheals) in Animals Urticaria, in its most common form, is an acute immune response resulting in multifocal dermal edema. Diagnosis is generally achieved via history, physical examination, and response to treatment... read more , serum sickness, and anaphylaxis Anaphylaxis in Cattle Anaphylaxis or Type I hypersensitivity reactions in cattle can result in an atypical interstitial pneumonia. The lung is a major target organ in cattle for Type I hypersensitivity. Clinical... read more . In pigs, it may develop as a part of edema disease Edema Disease in Pigs Edema disease is a syndrome of peracute vasculitis causing facial swelling, enteritis and sometimes focal encephalomalacia in post-weaning pigs. The causative agent is F18+ E coli. The disease... read more . In horses, cattle, and sheep, laryngeal edema may lead to arytenoid chondropathy.
Laryngeal chondropathy is a suppurative condition of the cartilage matrix that principally affects the arytenoid cartilages; it is believed to result from microbial infection, often as a sequela of inhalation of irritants or trauma to the area. In herbivores, trauma can occur when administering medications by bolus or drench or by ingestion of rough foodstuffs; in dogs, trauma can occur from sticks or foreign bodies. Laryngeal chondropathy is characterized by necrosis and ulceration of the laryngeal mucosa, over or just caudal to the vocal cords, and abscessation within the arytenoid cartilage. Initially, there is often acute laryngeal inflammation. Later, there is progressive enlargement of the cartilages that commonly results in a fixed upper airway obstruction with stertorous breathing and reduced exercise tolerance. Laryngeal chondropathy is seen in horses, sheep, and cattle, most often young males. There is a distinct breed predisposition in Texel sheep and Belgian Blue cattle. Laryngeal contact ulcers are common in young feedlot cattle and often result in necrotic laryngitis and chondropathy.
Clinical Findings of Laryngeal Disorders in Animals
A cough is the principal sign of laryngitis when edema is slight and the deeper tissues of the larynx are not involved. It is harsh, dry, and short at first, but becomes soft and moist later and may be very painful. It can be induced by pressure on the larynx, exposure to cold or dusty air, swallowing coarse food or cold water, or attempts to administer medicines. Vocal changes may be evident, especially in small animals. Stridor may result from swelling and reduced motion of the arytenoid cartilages in laryngeal chondropathy. Halitosis and difficult, noisy breathing may be evident, and the animal may stand with its head lowered and mouth open. Swallowing is difficult and painful. Systemic signs are usually attributable to the primary disease, as in infectious bovine rhinotracheitis, in which temperatures of 105°F (40.5°C) may occur. Secondary systemic signs due to inappetance and dehydration rapidly become apparent. Death due to asphyxiation may occur, especially if the animal is exerted.
Edema of the larynx may develop within hours. It is characterized by increased inspiratory effort and stridor arising from the larynx. Respiratory rate may slow as the effort of breathing becomes exaggerated. Visible mucous membranes are cyanotic, the pulse rate is increased, and body temperature rises. Horses may sweat profusely. Dogs with obstructions of the conducting airways may show extreme disturbance of thermoregulation in hot weather; marked hyperthermia is not uncommon. Untreated animals with marked obstruction eventually collapse and often have signs of pulmonary edema.
Diagnosis of Laryngeal Disorders in Animals
Based on clinical signs and laryngoscopy
A tentative diagnosis of a laryngeal disorder is based on the clinical signs, auscultation of the laryngeal region, and exacerbation of stridor by palpation of the larynx. Definitive diagnosis requires laryngoscopy. In conscious horses and cattle, this can be achieved with a flexible endoscope passed per nasum and usually requires sedation; in dogs and cats, anesthesia or analgesia usually is required. The history and signs usually permit rapid identification of the primary disease and the associated laryngeal involvement. Bilateral laryngeal paralysis Laryngeal Paralysis in Dogs and Cats Laryngeal paralysis is common in dogs and rare in cats. Signs include: dry cough voice changes noisy breathing that progresses to marked difficulty in breathing with stress and exertion stridor read more , laryngeal abscess, pharyngeal trauma Pharyngeal Trauma in Animals Photograph of a temporary rumenostomy, to be used for extraoral supplemental nutrition in a cow. Lateral radiographic view of a stylohyoid fracture in a horse. Pharyngeal trauma in ruminants... read more and cellulitis, and retropharyngeal abscesses or masses can cause similar signs.
Treatment of Laryngeal Disorders in Animals
Steroids or NSAIDs typically
Identification and treatment of the primary disease is essential. In laryngeal obstruction, a tracheotomy tube should be placed immediately; if a tracheotomy is not possible, airway patency may be established by passage of a pliable tube through the glottis. Corticosteroids should be administered to reduce the obstructive effect of the inflammatory swellings. Concurrent administration of systemic antibiotics is also necessary. In cases in which corticosteroids cannot be used, NSAIDs can be given. Administration of diuretic drugs, eg, furosemide, may be indicated to resolve laryngeal edema and, if present, pulmonary edema.
Palliative procedures to speed recovery and give comfort include inhalation of humidified air; confinement in a warm, clean environment; feeding of soft or liquid foods; and avoidance of dust. The cough may be suppressed with antitussive preparations, and bacterial infections controlled with antibiotics or sulfonamides. Control of pain with judicious use of an analgesic, especially in cats, allows the animal to eat, and thus speeds recovery.
Subtotal arytenoidectomy is an effective remedy for laryngeal chondropathy of horses, although a return to full athletic capacity in competitive horses is uncertain.
Tracheolaryngostomies and permanent tracheostomies have been used successfully to salvage cattle and sheep with laryngeal chondropathy but carry significant anesthetic risk. A medical alternative for ruminants is prolonged antibiotic therapy, 14–21 days of parenteral lincomycin (5–10 mg/kg), plus initial, short-acting corticosteroids for 3–5 days.
Laryngeal disorders need rapid treatment, including the recognition and treatment of the underlying problem.
Anti-inflammatory medications and analgesics are important aspects of treatment.
For More Information
Also see pet health content on laryngeal disorders in dogs Laryngitis in Dogs The larynx is the part of the throat often called the “voice box” in humans. Laryngitis is an inflammation of the larynx. It may result from upper respiratory tract infection or by direct irritation... read more and cats Laryngeal Disorders in Cats The larynx is the part of the throat often called the “voice box” in humans. Laryngitis is an inflammation of the larynx. It may result from upper respiratory tract infection or by direct irritation... read more .