Microglossia is an underdevelopment or reduction in the size of the tongue due to congenital anomalies or acquired diseases. It is characterized by the presence of a visible defect (the tongue is reduced in size). In mild cases, microglossia is asymptomatic, in severe cases there is a violation of chewing and swallowing, articulation defects, inarticulate speech. It is diagnosed by visual examination of the oral cavity, using radiological methods, ultrasound. Treatment of microglossia is aimed at eliminating functional disorders using orthodontic, surgical, speech therapy methods.
ICD 10
Q38.3 Other congenital anomalies of the tongue
Meaning
Congenital microglossia (hypoglossia, hypoplasia of the tongue, rudimentary tongue) − an extremely rare malformation. The first mention of pathology dates back to 1718; since then, less than 50 cases of microglossia have been described. The extreme degree of anomaly of the language is its complete absence, or aglossia. Rudimentary language is detected in childhood, acquired microglossia occurs mainly in the adult contingent. There is no data on the prevalence of the latter in the literature.
Causes
In clinical dentistry, there are primary (congenital) and secondary (acquired) forms of hypoglossia. Primary pathology is the result of impaired embryogenesis due to teratogenic effects or inherited genetic mutations.
Isolated congenital microglossia is rarely diagnosed. Usually, language underdevelopment is part of congenital syndromes with multiple developmental disorders: Hanhart syndrome, Robin syndrome, etc. Relative hypoglossia can be observed with a shortened sublingual ligament, a high palatine vault, massive jaws.
Acquired microglossia is a consequence of atrophy of the lingual muscles after diseases and injuries. The causes of this condition may be:
- infectious diseases of the oral cavity: actinomycosis, tuberculosis;
- collagenoses;
- wounds of the oral cavity, accompanied by damage to the hyoid nerve;
- traumatic amputation of the tongue;
- operations: resection or removal of the tongue (glossectomy).
Pathogenesis
The laying of the tongue begins at the end of the 4th week of embryonic development. From the I gill arch, the rudiments of the mucous membrane of the tip and body of the tongue are formed, from the II-III arc – the root of the tongue. The muscles of the organ develop from the mesoderm of the pharyngeal floor. The fusion of the posterior part of the tongue with the anterior parts occurs at the 2nd month of embryogenesis. In the course of further development, the tongue increases in length and width, partially separates from the bottom of the oral cavity due to the appearance of deep grooves in its anterior and lateral parts.
Violation of the normal course of morphogenetic processes caused by unfavorable external and internal factors leads to the appearance of various maxillofacial anomalies, including microglossia. Since the development of the tongue proceeds in parallel with the laying of the jaws, lips, palate, the defects of these organs are often formed simultaneously.
The pathogenesis of acquired microglossia may be caused by damage to the motor fibers of the hyoid nerve (XII pair of cranial nerves), responsible for the innervation of the muscles of the tongue. As a result, muscular atrophy develops, the tongue decreases in size.
Symptoms
With congenital hypoplasia, the tongue is underdeveloped, represents rudimentary strands located in the form of separate folds at the bottom of the oral cavity. The absence of the necessary stimuli from the lingual musculature leads to the formation of lower micrognathia, malocclusion.
If microglossia is not clearly expressed and is isolated, then functional disorders do not occur. With severe and combined anomalies, a violation of sucking, (later – chewing), dysphagia develops, salivation is noted. Speech defects − mechanical dyslalia − can be expressed to varying degrees: from minor violations of the sound side to the complete inability to pronounce lingual sounds.
With Hanhart syndrome, or hypoglossia-hypodactyly, an anomaly of the tongue is combined with malformations of the limbs, microgenia, agenesis of the teeth, cleft palate, etc. Multiple developmental defects are characteristic of Robin syndrome: in addition to microglossia and glossoptosis, hypoplasia of the lower jaw, “cleft palate”, hypo- or polydactyly is noted.
Complications
A small tongue does not fully participate in the act of swallowing, which increases the risk of food and water entering the respiratory tract with the subsequent development of aspiration pneumonia. Therefore, with microglossia and severe dysphagia, probe feeding may be required.
Also, the presence of a rudimentary language can cause obstructive apnea syndrome. With a high risk of respiratory arrest, a tracheostomy is resorted to. Inarticulate, slurred speech becomes a barrier to communication and learning. Children with preserved intelligence have secondary violations of phonemic processes and written speech (FFN, dysgraphy).
Diagnostics
Microglossia associated with genetic syndromes is usually diagnosed already in infancy. The anomalies of the tongue are made to think of problems with sucking and swallowing in a child. To diagnose microglossia, an intraoral examination is sufficient. For the purpose of a comprehensive assessment of pathology and drawing up an algorithm of therapeutic tactics , the following are prescribed:
- Consultations of specialists. Patients with microglossia need to visit an orthodontist and a maxillofacial surgeon to develop an interdisciplinary approach to correcting the anomaly. A speech therapist’s consultation is also required to examine the organs of articulation and diagnose oral speech.
- Teleroentgenography. An X-ray of the head in a lateral projection is necessary to assess the anatomy of the facial skull and dental structures. Cephalometric analysis allows you to plan in detail the subsequent orthodontic treatment.
- Ultrasound of the tongue. The echographic examination is aimed at assessing the tissue structure, the true size of the organ, and the features of blood supply. The study has value in planning reconstructive operations.
Treatment
Dental treatment
With a slight decrease in the tongue, which does not affect chewing, swallowing and diction, no treatment is carried out. In other cases, measures are taken to compensate for the impaired functions:
Frenulotomy/frenuloplasty. If the cause of relative microglossia is a massive or shortened sublingual ligament (ankyloglossia), the frenulum is cut or plasticized. The operation allows the tongue to move forward, increase the mobility of the organ, normalize articulation.
Orthodontic treatment. When microglossia is combined with hypoplasia of the mandible, multi-stage treatment is indicated, including hardware orthodontic correction, distraction osteogenesis of the jaw bone and other types of surgical interventions.
Reconstructive operations. It is produced with isolated primary and secondary microglossia in order to replenish the volume of tongue tissues. A free skin flap is transplanted, cut out of the large pectoral muscle, tissues of the patient’s back, hip, and forearm. In world practice, there is a message about the successful transplantation of the donor language.
Speech therapy impact
Depending on the existing disorders, speech therapy work with microglossia can be aimed at eliminating dysphagia and correcting dyslalia. Within the framework of classes for dysphagia, a method of nutrition (independent, probe), optimal consistency of food is selected. Postural techniques, exercises to strengthen oral muscles, breathing simulators, vibration massage, kinesiotaping are used.
Correction of organic dyslalia begins in the preoperative period and continues after the completion of the medical stage. The main directions of speech therapy:
- activation of articulatory motor skills: articulatory gymnastics with an emphasis on the development of the strength of tongue movements, the development of a directed air jet, probe and manual speech therapy massage;
- development of phonemic operations: phonemic hearing, sound analysis and synthesis;
- the production of lingual and other disturbed sounds, their automation, differentiation and introduction to speech.
It should be understood that diction disorders caused by microglossia cannot always be completely eliminated. In these cases, compensatory articulation is achieved, as close as possible to the acoustic norm.
Prognosis and prevention
Microglossia does not directly affect life expectancy, but significantly worsens its quality due to difficulties encountered during food intake, speech communication. If the language anomaly is part of a genetic syndrome, the prognosis is determined by a whole complex of existing developmental disorders.
Prevention of primary microglossia includes responsible pregnancy planning, exclusion of the influence of adverse factors during gestation. Measures to prevent secondary microglossia are regular dental examinations for the purpose of early detection of infectious and tumor diseases of the oral cavity.
Literature
- Isolated microglossia: A case report/ Sanjib Singh Nepram, Pradeep Jain, Rajshree Devi Huidrom// Journal of Medical Society. – 29(3) – December 2015. link
- Microglossia in a Newborn: A Case Report and Review of the Literature/ S.Voigt, A. Park, A. Scott// JAMA Otolaryngology—Head&Neck Surgery. – 2012. link
- Extreme microglossia/ M.A.Thorp, P.J.de Waal, C.A.J.Prescott// International Journal of Pediatric Otorhinolaryngology. – Volume 67, Issue 5, – 2003. link