Introduction:
Congenital hemifacial hyperplasia, also known as facial hemihypertrophy, is a rare condition characterized by the asymmetry of the face. The affected side of the face may be larger than the non-affected side, and the condition may also include overgrowth of the bones and tissues of the eye, ear, and jaw. The exact cause of congenital hemifacial hyperplasia is unknown, but it is believed to be a result of an overgrowth of cells in the developing fetus.
What Is Congenital Hemifacial Hyperplasia?
Congenital hemifacial hyperplasia is a rare condition. The prevalence and incidence of congenital hemifacial hyperplasia are not well-established. However, it is estimated to occur in every 1 in 500,000 live births. It affects both males and females equally. It is important to note that congenital hemifacial hyperplasia is rare, and the reported prevalence and incidence may be underestimated. Some cases may not be diagnosed or reported. It is also worth mentioning that congenital hemifacial hyperplasia can be associated with other medical conditions, such as hemihypertrophy, a rare condition that affects the bones and tissues of one side of the body. The prevalence of hemihypertrophy is estimated to be 1 in 1,000,000 live births.
What Is the Cause of Congenital Hemifacial Hyperplasia?
The exact cause of congenital hemifacial hyperplasia is not fully understood, but several theories have been proposed to explain the condition. These are as follows-
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Genetic Causes - One theory suggests that a genetic mutation or a chromosomal abnormality may cause congenital hemifacial hyperplasia. Studies have identified several genes that may be associated with the condition, including the PIK3CA gene and the NSD1 gene. However, these genes have not been confirmed to cause congenital hemifacial hyperplasia. Genetic testing can be done to confirm the presence of a genetic mutation in some cases.
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Developmental Causes - Another theory suggests that congenital hemifacial hyperplasia may be caused by an abnormal response of the cells in the developing fetus to specific growth factors. This abnormal response may cause the cells to divide and grow more rapidly, leading to the overgrowth of the bones and tissues of the face.
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Teratogenic Causes - Another possible cause of congenital hemifacial hyperplasia is teratogenic exposure during pregnancy. This occurs when a developing fetus is exposed to certain toxins, drugs, or infections that can cause malformations or abnormal growth.
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Idiopathic Causes - In some cases, the cause of congenital hemifacial hyperplasia may not be identified. These cases are classified as idiopathic, meaning the cause is unknown.
What Are the Symptoms of Congenital Hemifacial Hyperplasia?
The symptoms of congenital hemifacial hyperplasia can vary depending on the severity of the condition and the specific structures affected. Common symptoms of the condition include the following-
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Facial Asymmetry - The affected side of the face may be larger than the non-affected side, and there may be a noticeable difference in the eye, ear, jaw, and cheek on the affected side.
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Overgrowth of Facial Structures - There may be an overgrowth of the bones and tissues of the eye, ear, and jaw on the affected side. This can cause the eye to appear larger, the ear to appear more prominent, and the jaw to appear larger or more pronounced.
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Difficulty in Opening the Mouth - Due to overgrowth of the jaw, some individuals may have difficulty opening their mouths wide. This can make it difficult to eat or speak.
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Difficulty in Swallowing - Overgrowth of the jaw and cheek can also cause difficulty in swallowing.
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Developmental Delays - In some cases, congenital hemifacial hyperplasia can cause developmental delays, such as speech difficulty or gross motor skills.
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Cranial Nerve Palsy - As the facial bones and tissues overgrow, it could pressure the cranial nerves. This could cause weakness or paralysis of the muscles of the face, which can lead to difficulty with facial expressions, closing the eye, or smiling on the affected side.
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Dental Issues - The overgrowth of the jaw may cause malocclusion (misalignment of the teeth), which can lead to difficulty in biting and chewing. Also, the overgrowth of the jaw and cheek may cause crowding of the teeth, which can lead to dental problems.
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Hearing Loss - As the ear on the affected side is larger, this may cause conductive hearing loss (a type of hearing loss caused by problems in the middle ear) due to the overgrowth of the bones in the middle ear.
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Eye problems - As the eye on the affected side is larger, this could cause visual problems such as double vision, or it could also cause problems with the eyelid such as drooping eyelid or ectropion (outward turning of the eyelid), which can lead to dry eyes, irritation, or infection.
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In some cases, congenital hemifacial hyperplasia may be associated with other medical conditions, such as hemihypertrophy, characterized by asymmetrical overgrowth of the bones and tissues of one side of the body.
How to Diagnose Congenital Hemifacial Hyperplasia?
Congenital hemifacial hyperplasia is typically diagnosed during infancy or early childhood, but in some cases, it may not be diagnosed until later in life. The diagnosis process typically includes the following steps:
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Physical Examination - A healthcare professional will conduct a thorough physical examination, which includes measuring the size of the affected facial structures and comparing them to the non-affected side. The professional will also assess the patient's facial movements, speech, and swallowing.
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Imaging Tests - Imaging tests such as CT (computed tomography) scans or MRI (magnetic resonance imagining) may be used to confirm the diagnosis and assess the condition's extent. These tests can provide detailed images of the bones and tissues of the face and help identify any abnormalities or overgrowth.
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Genetic Testing - In some cases, genetic testing may be done to confirm the presence of a genetic mutation associated with congenital hemifacial hyperplasia. This test can help confirm the diagnosis and provide information about the potential inheritance of the condition.
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Differential diagnosis - It is essential to rule out other conditions with similar symptoms, such as Proteus syndrome, neurofibromatosis, and Klippel-Trenaunay-Weber syndrome.
What Is the Treatment of Congenital Hemifacial Hyperplasia?
The treatment of congenital hemifacial hyperplasia depends on the severity of the condition and the specific symptoms. Treatment options may include the following-
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Surgery - Surgery is often used to correct the asymmetry of the face and to address functional difficulties such as difficulty opening the mouth or swallowing. The type of surgery depends on the structures affected; it may involve repositioning or reshaping the bones and tissues of the eye, ear, jaw, and cheek. Additionally, a surgery called ‘distraction osteogenesis’ is used to lengthen the jaw; it is a procedure in which the jaw is gradually lengthened by using an external device. Surgery may be done in multiple stages, depending on the degree of overgrowth and the patient's age.
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Physical Therapy - Physical therapy can help to improve muscle strength, coordination, and function in individuals with congenital hemifacial hyperplasia. This can be particularly beneficial for those who have difficulty with facial expressions or gross motor skills.
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Speech Therapy - Speech therapy can help individuals with congenital hemifacial hyperplasia improve their speech and communication skills. This can be particularly beneficial for those with speech or swallowing difficulties.
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Occupational Therapy - Occupational therapy can help individuals with congenital hemifacial hyperplasia to improve their daily living skills, such as eating and dressing.
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Orthodontic treatment - Orthodontic treatment can help to improve the alignment of the teeth and to correct malocclusion caused by the overgrowth of the jaw.
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Follow-up Care - After treatment, it is essential to have regular follow-up care with a healthcare professional experienced in the management of congenital hemifacial hyperplasia, to monitor the progress and to address any new issues that may arise.
What Is the Prognosis of Congenital Hemifacial Hyperplasia?
The prognosis for individuals with congenital hemifacial hyperplasia can vary depending on the severity and specific symptoms. Individuals with mild congenital hemifacial hyperplasia may have few functional difficulties and an excellent cosmetic outcome with appropriate treatment. Individuals with more severe cases of congenital hemifacial hyperplasia may have more significant functional difficulties, such as speech or swallowing. They may require multiple surgeries over the years to achieve an excellent cosmetic outcome. In some cases, congenital hemifacial hyperplasia may be associated with other medical conditions, such as hemihypertrophy, which may affect the overall prognosis.
Conclusion:
It is important to note that each case of congenital hemifacial hyperplasia is unique, and the prognosis can vary significantly from one person to another. With early diagnosis and appropriate treatment, individuals with congenital hemifacial hyperplasia can achieve an excellent cosmetic and functional outcome. It is crucial to consult with a healthcare professional experienced in managing congenital hemifacial hyperplasia to determine the specific prognosis for your case. Sometimes, a team of healthcare professionals may diagnose and manage congenital hemifacial hyperplasia, including a pediatrician, a geneticist, a plastic surgeon, and a speech therapist. This team approach can help to ensure that all aspects of the condition are considered and that the best treatment plan is developed for the individual patient.
