Macroglossia in Dogs

The canine tongue plays an important part in day to day activities such as aiding in the processes of grooming, eating, and drinking. Additionally, the functions of chewing and swallowing are greatly impacted by the tongue. Having an excessively large tongue can affect a dog’s ability to thrive.

Macroglossia may be due to congenital hypertrophy (an enlargement of cells and subsequent increase of tissue or organ size) or hypertonia (muscle tension and loss of ability to stretch), or develop as a symptom of other underlying diseases such as hypothyroidism, amyloidosis, and neoplasia. If your veterinarian is able to determine a disease such as hypothyroidism as the causation of this condition, the treatment of the underlying cause may correct the issue. In cases of unknown etiology the prognosis is guarded.

Macroglossia is a very rare condition in dogs. This is often characterized by an abnormally large tongue that may have reduced range of motion and cause breathing difficulties.

The most common symptom of macroglossia is a tongue that is constantly out of the pet’s mouth. Symptoms may vary but the following have been noted:

• Dyspnea (labored breathing)
• Expiratory cheek puff
• Increased salivation
• Pharyngeal dysphagia (restricted range of movement of the tongue and difficulty moving food to the pharynx for swallowing to take place)
• Oral dysphagia (difficulty orally controlling food and increased risk of aspiration)

Pseudo macroglossia – In these cases the tongue is a normal size, however, due to oral or skeletal factors (such as narrow midline) seems abnormally large. Many breeds of dogs may appear to have macroglossia due to constant tongue protrusion, however have no negative symptoms. Other causes may be acute such as allergic reactions to medication or ingesta (nourishment).

True macroglossia – There can be a range of causes of true macroglossia in pets, including congenital causes such as idiopathic tongue muscle hypertrophy and acquired causes due to endocrine diseases such as hypothyroidism.

During the diagnostic examination, your veterinarian will want to discuss how much of an impact the large tongue is having on your pet. If your dog is able to perform functions like eating and drinking without a problem, this is a consideration that will be noted. Your veterinarian will perform a full, clinical examination of your pet and ask questions to determine a history of your canine’s symptoms; this may help to inform the veterinary caregiver whether your pet’s macroglossia is of a congenital or acquired nature. 

If your dog will tolerate an oral examination the veterinarian will inspect the tongue and throat. In some cases, dog’s may require sedation for adequate visualization. Some dogs with macroglossia will not have issues that cause discomfort while others with this condition may suffer effects such as a dry or sore tongue.

Other diagnostic tools that may be necessary are:

• Pharyngeal and thoracic radiography
• Fluoroscopy
• Lingual ultrasonography
• Tissue samples may be taken to rule out neoplasia or other tissue diseases
• Blood work will be performed to verify markers that may point to an underlying illness, such as one of an endocrine nature

If your veterinarian is able to determine an illness causing the condition, the first line of action will be treating the underlying illness. Surgery may be an option for some pets. As there is research that shows up to 60% of the tongue can be successfully resected in dogs, this may be the best option for your pet.  This will be performed under general anesthetic. Although there are risks involved with general anesthetic,  your companion will be monitored throughout the surgery, with close cardiovascular and respiratory monitoring. If your pet is geriatric, your veterinarian may perform blood chemistry tests prior to anesthesia to rule out kidney or liver dysfunction that would contraindicate surgery. Your pet may require fluid therapy throughout the surgery to help regulate body temperature and hydration.

If your pet requires surgical correction, rapid healing is expected due to the vascular nature of the tissue. It is normal after an anesthetic for your pet to have reduced appetite, especially in this case due to oral pain. Your veterinarian will be able to recommend the best diet for your pet to support healing and will prescribe medication as needed in order to minimize the discomfort. As the anesthetic agent can cause hypothermia, it is important to provide a warm, dry area for your pet to recover in. Monitor him over the first several days after he returns home from the hospital and contact a member of the veterinary team if you have concerns about the rate of recovery.