Macroglossia

Updated: Mar 25, 2015
  • Author: Talib Najjar, DMD, MDS, PhD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Overview

Background

Macroglossia, meaning large tongue, has been documented for many centuries, with the earliest known description thought to be from around 1550 BC.

Over the years, many criteria have been used to identify large tongue. The term "true macroglossia" refers to macroglossia caused by histologic abnormalities within the tongue, such as muscular hypertrophy and vascular malformation. In pseudomacroglossia, an individual has a normal-sized tongue that, as a result of oral or skeletal abnormalities, such as a narrow mandible (as found in many head and neck syndromes), seems unusually large.

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History of the Procedure

Large tongue has been treated medically and surgically in the last century. Sclerosing agents, leeches, and physical muscular entrapment of the tongue within the oral cavity have all been tried, with limited success, to avoid surgical intervention.

Surgical procedures to reduce tongue size and, more recently, orthognathic surgical intervention, have become the treatment modalities of choice. The use of sclerosing agents to cause scarring of the tongue and vascular strangulation or embolization of the blood vessels supplying the tongue were tried in the past, with complications and limited success.

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Epidemiology

Frequency

Although the exact incidence of macroglossia in the general population is unknown (because the etiologies are too numerous to quantify), the condition is found in some congenital syndromes, such as Down syndrome (1 per 700 live births) and Beckwith-Wiedemann syndrome (0.07 per 1000 live births). In Beckwith-Wiedemann syndrome, 97.5% of patients have macroglossia. The literature also documents two families with autosomal dominant inheritance of isolated macroglossia.

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Etiology

Macroglossia can result from a wide range of congenital and acquired conditions, although it is most frequently the product of vascular malformations and muscular hypertrophy. Because of the large number of possible etiologies, multiple classification schemes have been used to list the causes.

The two broadest categories under the heading of macroglossia relate to true tongue enlargement and pseudomacroglossia.

Pseudomacroglossia

Causes of pseudomacroglossia, ie, conditions that force the tongue to sit in an abnormal position, include the following:

  • Allergic reactions to medications that cause the tongue to swell
  • Enlarged tonsils and/or adenoids that displace the tongue
  • Low palate and decreased oral cavity volume
  • Severe maxillary deficiency with narrow palatal arch
  • Severe mandibular deficiency (retrognathism)
  • Local oral tumor that displaces the tongue

True macroglossia

Congenital causes

Congenital causes of true macroglossia include the following [1] :

  • Idiopathic tongue muscle hypertrophy
  • Salivary gland tumor
  • Syndromes (eg, Beckwith-Wiedemann, Behmel, Laband)
  • Lingual thyroid
  • Mucopolysaccharidoses
  • Hamartomas

Acquired causes

Metabolic/endocrine conditions that cause true macroglossia include the following:

Inflammatory/infectious causes of true macroglossia include the following:

Systemic/medical conditions that cause true macroglossia include the following:

  • Neurofibromatosis

Traumatic causes of true macroglossia include the following:

  • Hemorrhage and hematoma
  • Direct trauma (tongue biting)
  • Intubation injury

Neoplastic conditions that cause true macroglossia include the following:

  • Lymphangioma [2]
  • Hemangioma
  • Carcinoma
  • Plasmacytoma
  • Lymphoma
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Pathophysiology

The pathophysiology of the enlarged tongue is related to the specific etiologic factors. Defining the pathophysiology of each, however, is beyond the scope of this discussion. Nonetheless, the locoregional complications of macroglossia are generally the same relative to the magnitude of the enlargement and the size of the tongue. Macroglossia may cause obstruction of the oral airway, which is usually worsened when the patient lies supine, allowing an enlarged tongue base to more directly block the oropharynx and hypopharynx. Speech and swallowing are also affected by macroglossia.

The size of the tongue affects the shape and structures of the oral cavity, including the teeth, palate, and alveolar ridges. Macroglossia may lead to open bite deformities, prognathism, malocclusion, anterior or posterior crossbite, buccal tipping of posterior teeth, accentuated curve of Spee in the maxillary arch, reverse curve of Spee in the mandibular arch, and increased transverse width of mandibular or maxillary arches. Furthermore, difficulty with mastication may lead to temporomandibular joint pain. If the tongue protrudes beyond the lips, exposing it to the air, it can become dry, with resultant glossitis and stomatitis.

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Presentation

Macroglossia due to an allergic reaction may require lifesaving measures and emergency intervention to maintain a patent airway. The cause of the allergy must be determined and eliminated or treated.

An association between macroglossia and a syndrome or congenital disorder can be determined by assessing family history and through genetic counseling. Severe congenital cases may require surgical intervention in infancy.

Should the cause of macroglossia go undetermined on initial presentation, further investigation is indicated to narrow the list of differential diagnoses. Direct questions regarding the etiologic class (eg, inflammatory, neoplastic) will lead to the exact diagnosis and ultimate treatment. Physical examination and diagnostic testing can significantly aid in the diagnosis.

Physical examination of the tongue alone should reveal signs of the cause or at least help to rule out the etiologic classes that are not involved. For example, hemangiomas can often be observed on the surface of the tongue in a variety of positions, bearing a characteristic blue coloration. Infectious processes often present with characteristic findings, such as painful swelling or white plaques (which are pathognomonic for candidiasis). Unusual discolorations or other obvious findings may lead the clinician to consider local involvement of the tongue, as in hemangioma.

Physical examinations of the head and neck, the oral cavity, and the maxilla and mandible are helpful in differentiating true macroglossia from pseudomacroglossia. Severe retrognathia and unusually small maxillary or mandibular size may indicate the latter.

In addition to the oral cavity and airway, assess other features in the patient that may indicate congenital or systemic syndromes. Certain vitamin deficiencies may manifest with angular stomatitis, nonpitting edema of the lower extremities may indicate hypothyroidism, [3] and unusual body morphologies may indicate the early signs of diseases such as acromegaly.

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Indications

Surgical intervention in macroglossia is reserved for severe cases that cause functional and airway impairment. A partial glossectomy may be required as a first step in surgical care. In some cases, an elective tracheostomy is performed prior to surgical correction.

The goal of nearly all surgical intervention in macroglossia is to return the patient to an anatomically and physiologically normal condition that includes articulation, mastication, deglutition, protection of the airway, and gustation.

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Relevant Anatomy

The lingual anatomy is relatively simple, although its complex three-dimensional location makes it more interesting.

Muscles

Four intrinsic and four extrinsic muscles control the motion of the tongue.

Extrinsic muscles

Extrinsic muscles, which are supplied mainly by the hypoglossal nerve, include the following:

  • Genioglossus: Allows protrusion of the tongue apex from the mouth and permits depression of the tongue center, enabling the tongue to take a concave form
  • Hyoglossus: Depresses the tongue
  • Styloglossus: Elevates and retracts the tongue
  • Palatoglossus: Elevates and retracts the tongue; is supplied by the vagus nerve

Intrinsic muscles

Intrinsic muscles are supplied by the hypoglossal nerve and include the following :

  • Superior longitudinal muscle: Shortens the tongue; turns the apex and sides upward
  • Inferior longitudinal muscle: Shortens the tongue; turns the apex and sides downward to create a convex dorsum
  • Transverse muscle: Narrows and elongates the tongue
  • Vertical muscle: Flattens and widens the tongue

Arteries

The main artery of the tongue is the lingual branch of the external carotid. Contributing arteries include the tonsillar branch of the facial artery and the ascending palatine branch of the ascending pharyngeal artery. An extensive submucosal plexus is responsible for the vigorous bleeding with even superficial wounds.

Nerves

Sensory nerves of the tongue are from the following :

  • Lingual branch of the third division of the trigeminal nerve: Provides general sensation for the anterior two thirds of the tongue
  • Chorda tympani of facial nerve: Provides taste sensation for the anterior two thirds of the tongue
  • Lingual branch of glossopharyngeal nerve: Provides general sensation and taste for the posterior one third of the tongue
  • Superior laryngeal branch of the vagus nerve: Provides sensation for the root of the tongue at the lingual base of the epiglottis

Other

A relatively avascular median fibrous septum creates a partition along the length of nearly the entire tongue. It anchors to the hyoid bone and clinically can serve as a site for placement of an anchor stitch when significant traction is needed during a surgical procedure.

Multiple minor salivary glands are present in the tongue and consist of all three types: mucous, serous, and mixed.

The foramen caecum can be viewed in the midline of the tongue; the site of fusion of the anterior two thirds and posterior one third of the tongue, it marks the origin of the thyroid gland in the embryo. Persistent thyroid tissue may be present in this location as the lingual thyroid, or it may descend into the neck, leaving a thyroglossal duct cyst.

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Contraindications

As with all intervention, whether medical or surgical, the benefits of the operation must outweigh the risks. Relative contraindications are those associated with most surgeries and include coagulopathies and other comorbidities that make general anesthesia more dangerous. [4] In the pediatric population, many cases of macroglossia are associated with syndromes that may have lesions that increase the risk of general anesthesia.

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