Roars (Laryngeal Paralysis) in Dogs

Key Takeaways

Laryngeal Paralysis (LP) describes dysfunction of the nerves controlling the vocal folds in the throat. This paralysis leads to subsequent partial blockage of the windpipe in dogs.

• LP is often an early symptom of  geriatric onset laryngeal paralysis polyneuropathy (GOLPP)

• May also occur as an inherited congenital defect, or arise due to injury or infection

• Symptoms of LP include noisy breathing (“roars”), change in the bark, exercise intolerance, and coughing

• LP is identified by visualizing impaired laryngeal movement under anesthesia

• Definitive treatment involves surgery to permanently hold the larynx (voicebox) open

• Lifelong management is necessary to minimize the likelihood of aspiration pneumonia

• Most cases in dogs occur in association with GOLPP and carry a poor long-term prognosis, but early diagnosis and treatment of mild cases can have a good prognosis

A Closer Look: What is LP 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.

Risk Factors

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.  Signs of heatstroke include: 

• Excessive panting

• Collapse

• Vomiting

• Diarrhea

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.

Possible Causes

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

Main Symptoms

Symptoms of LP include:

• High pitched or whistling noises when breathing in

• Noisy breathing called “roars”

• Difficulty breathing 

• Coughing

• Exercise intolerance

• Difficulty eating without choking

• Change in the quality of the bark

• Blue color to the tongue or gums

• Collapse

Testing and Diagnosis

Investigation of LP involves:

• Physical examination: definitive diagnosis involves direct visualization of the laryngeal folds blocking the airway under sedation

Additional diagnostics to rule in/out other potential causes for LP and establish patient status include:  

• Blood work

• Urinalysis

• X-rays

• Muscle stimulation testing

Steps to Recovery

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.

Prevention

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.

Is LP Common in Dogs?

LP is an uncommon condition in dogs

Typical Treatment

• Palliative care

• Surgical correction

• Medication for myasthenia gravis, if present

• Antibiotics for aspiration pneumonia, if present

• Supportive care in cases of acute respiratory distress