Roars (Laryngeal Paralysis) in Dogs

A healthy larynx creates sound, opens during breathing to allow airflow into the lungs, and closes during swallowing to prevent material from entering the windpipe. When the nerve supply to the larynx becomes dysfunctional, the vocal folds become paralyzed and block the opening of the trachea.

Laryngeal paralysis in dogs is most commonly an early symptom of geriatric onset laryngeal paralysis polyneuropathy (GOLPP). GOLPP is a progressive neurological disorder that leads to noisy breathing, coughing, megaesophagus and poor nerve function in the hindlegs. Associated symptoms include regurgitation, hindlimb weakness, and loss of muscle mass.

LP is a serious, progressive condition primarily affecting older dogs. It is a common condition which usually arises as a progressive neurologic disorder with no known cause and carries a poor long-term prognosis.

Laryngeal paralysis sometimes results in failure of the larynx (voicebox) to protect the airway and leads to aspiration pneumonia. AP describes lung infection that occurs as a result of liquids or solids entering the lungs.

AP is a dangerous condition requiring early recognition and treatment. Some cases respond to treatment but other cases are fatal.

Dogs with LP are predisposed to overheating since they can’t breathe well enough to pant and cool themselves efficiently.

Since LP is most commonly associated with GOLPP, it occurs most often in senior dogs. In rare cases puppies are born with an inherited form of LP which has a grave prognosis.

Sometimes adult dogs acquire LP as a result of an injury or infection. This is rare, but cases of LP caused by injury carry a better prognosis than congenital cases or those associated with aging.

Most cases have no known cause and arise spontaneously in older dogs as an early symptom of geriatric onset laryngeal paralysis and polyneuropathy (GOLPP). This is a spontaneous, progressive nerve disorder with no identifiable trigger.

Less common causes of LP include:

• Myasthenia gravis
• Paraneoplastic - secondary to tumors such as tracheal tumors
• Bite wounds to the neck
• Surgical trauma
• Congenital - a rare, inherited disease with genetic predisposition

Blue gums, difficulty breathing, and collapse are medical emergencies requiring immediate veterinary care.

Investigation of LP involves:

• Physical examination: definitive diagnosis involves direct visualization of the laryngeal folds blocking the airway under sedation
• Blood work
• Urinalysis
• X-rays
• Muscle stimulation testing

Treatment of LP depends on the underlying disease process. Strategies include

• Surgical correction
• Reducing exercise intensity
• Management of complications such as megaesophagus, aspiration pneumonia, and hindlimb weakness as required
• Medication of myasthenia gravis where present

Some cases present in acute respiratory distress and require intensive care including sedation, oxygen supplementation, steroids, and emergency tracheostomy. Euthanasia is common in these cases due to poor prognosis and quality of life.

Dogs with GOLPP continue to develop other symptoms despite surgical treatment of LP. Further progression usually affects the esophagus and hindlimbs resulting in severely impaired mobility and complications like aspiration pneumonia. Prognosis for dogs with GOLPP is poor and most dogs are euthanized within 18 months of diagnosis.

LP due to myasthenia gravis has a fair prognosis if there is a good response to MG treatment, but concurrent megaesophagus worsens the prognosis.

In the rare event that the underlying trigger is identifiable and treatable, such as a bite wound or tumor, LP has a good prognosis.

Complicated cases of LP such as non-removable tumors and inherited forms of LP normally have a poor prognosis.

Most cases of LP and GOLPP have no known cause, so prevention is not possible.

A rare congenital form of LP is inherited. These puppies usually do not survive, but selective breeding can help prevent this condition. A genetic component is suggested for GOLPP, so selective breeding may also help reduce the incidence of this condition.

LP is an uncommon condition in dogs.

• Palliative care
• Surgical correction
• Medication for myasthenia gravis, if present
• Antibiotics for aspiration pneumonia, if present
• Supportive care in cases of acute respiratory distress