Asymmetric Crying Facies (ACF), also known as congenital unilateral lower lip palsy (CULLP), is a condition present at birth, affecting approximately 1 in 160 newborns. This anomaly is characterized by a distinctive facial expression when a baby cries: one side of the mouth pulls downwards, while the other side remains still. This weakness is specifically localized to the muscles of the lower lip and predominantly occurs on the left side in about 80% of reported cases. It’s crucial to differentiate ACF from unilateral facial palsy; in ACF, the face appears symmetrical at rest, and the muscles controlling the eyes and forehead are unaffected.
It’s important to note that congenital ACF carries about a 10% risk of being associated with other significant congenital anomalies. These associated anomalies are most frequently found within the cardiovascular system, accounting for about 44% of cases. ACF accompanied by heart defects is specifically termed Cayler syndrome. Besides cardiac issues, other anomalies can involve the neck, face, and genito-urinary system.
What are the Causes of Asymmetric Crying Facies? Understanding the Diagnosis
When diagnosing asymmetric crying facies, it’s essential to consider the potential underlying causes of lower lip facial weakness in newborns. There are primarily two categories:
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Birth Trauma: Pressure on a branch of the facial nerve during delivery is a common cause of facial weakness in newborns, classified as birth trauma. This pressure, for instance, can arise from the mother’s pelvic bones during childbirth. In these instances, ACF is considered acquired. This type of injury to the facial nerve can result in temporary weakness or paralysis of facial muscles.
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Congenital Developmental Issues: Congenital ACF, present from birth and not due to birth trauma, originates from developmental anomalies during pregnancy. These anomalies involve either the incomplete development (hypoplasia) or complete absence (agenesis) of certain lip depressor muscles. The key muscles involved are the depressor anguli oris and depressor labii inferioris on one side of the mouth. The depressor anguli oris muscle is responsible for connecting the lower jaw to the corners of the mouth and controlling the downward movement of the lip. These developmental issues are thought to have a genetic basis.
Distinguishing between birth trauma and congenital causes of ACF can be challenging. Accurate diagnosis requires careful evaluation to determine the origin of the facial weakness.
Congenital ACF is believed to have a genetic component, likely resulting from alterations (mutations) in an individual’s genes. Genes, the units of heredity passed from parents to children, are located on chromosomes within cells. Humans typically have 23 pairs of chromosomes in each cell nucleus, with thousands of genes on each chromosome.
Cayler syndrome, the specific presentation of ACF with cardiac defects, has been linked to the deletion of a small segment of chromosome 22, known as ‘22q11.2 deletion syndrome’. It is critical to understand that this genetic deletion is specific to Cayler syndrome and certain other conditions, and not a general characteristic of all congenital ACF cases. The majority of individuals with congenital ACF do not have associated complications.
Symptoms of Asymmetric Crying Facies: Key Indicators for Diagnosis
Identifying asymmetric crying facies relies on recognizing a distinct set of symptoms, particularly noticeable when the infant expresses emotion. Babies with ACF typically exhibit the following characteristics:
- Asymmetrical Mouth Movement During Crying: The most prominent symptom is the uneven movement of the mouth during crying or grimacing. One side of the mouth is pulled downwards, while the other side shows limited or no movement.
- Subtle Lip Thinning: There may be a slight thinning of the lower lip on the affected side, sometimes accompanied by an inward turning of the lip.
- Facial Symmetry at Rest: Crucially, when the baby’s face is relaxed and not expressing emotion, it appears symmetrical. This is a key differentiator from other facial nerve conditions.
- Unaffected Forehead Movement: The ability to wrinkle the forehead remains normal, indicating that the upper facial nerve branches are functioning correctly.
- Normal Eye Closure: Both eyes close normally and symmetrically, further confirming that the facial nerve branches controlling the eyes are not affected.
- Normal Sucking and No Drooling: Infants with ACF typically have normal sucking reflexes and do not experience drooling, indicating that oral motor functions are generally intact.
- Symmetrical Nasolabial Folds: The nasolabial folds, the creases running from the nose to the corners of the mouth, are symmetrical in depth on both sides of the face.
- Normal Nostril Dilation: Both nostrils dilate equally when the baby breathes, indicating that nasal functions are unaffected.
These symptoms are primarily observed during crying or similar facial expressions. The symmetrical appearance of the face at rest is a vital diagnostic clue for ACF.
Diagnosing Asymmetric Crying Facies (ACF): Diagnostic Procedures
When a newborn presents with signs of asymmetric crying facies, the primary diagnostic step is to determine whether the facial weakness is a result of birth trauma or is congenital in nature. This differentiation is critical for guiding further diagnostic and management strategies.
A thorough physical examination is crucial in the diagnostic process. The examination will assess for:
- Jaw Asymmetry: Checking for any asymmetry in the jaws.
- Non-parallel Gums: Evaluating the alignment of the gums, looking for non-parallelism.
These findings can suggest nerve compression as the cause of facial weakness, pointing towards birth trauma. In such cases, if birth trauma is strongly suspected and no other concerning signs are present, further investigation for associated anomalies may not be immediately necessary.
However, in cases where congenital ACF is suspected, further investigations are recommended to rule out any associated malformations. While a careful physical examination can exclude many potential anomalies, additional tests may be considered.
One such test is the FISH test (Fluorescence In Situ Hybridization). This genetic test maps the genetic material within a person’s cells. It is used to visualize specific genes or portions of genes and can detect chromosomal abnormalities. In the context of Acf Diagnosis, a FISH test is used to check for chromosomal abnormalities such as the 22q11.2 deletion, which is associated with Cayler syndrome (ACF with heart defects). This test helps to identify cases of ACF that might be part of a broader syndrome involving other health issues.
Treatment Options for Asymmetric Crying Facies: Management and Prognosis
The treatment approach for asymmetric crying facies is largely dependent on the underlying cause – whether it is acquired due to birth trauma or is congenital. Understanding the cause is crucial for determining the appropriate management strategy and prognosis.
For ACF acquired during birth trauma, the prognosis is generally excellent. The facial asymmetry observed when the baby cries or smiles typically shows noticeable improvement within the first month. In the vast majority of these cases, the asymmetry resolves completely over time without specific interventions. Parents can be reassured that the condition is likely temporary and will improve naturally as the baby grows.
In cases of congenital ACF, the facial asymmetry tends to become less noticeable as children age. The natural development and growth of facial muscles often compensate for the initial asymmetry. However, if the asymmetry persists and remains a cosmetic concern for older children, surgical options can be considered to improve facial symmetry.
Surgical treatment options for persistent congenital ACF include:
- Neurotomy: This procedure involves selectively cutting the marginal mandibular branch of the facial nerve on the unaffected side. By partially paralyzing the stronger side of the lip, better symmetry can be achieved, especially when smiling.
- Myotomy or Partial Myectomy: This involves surgically altering the lip depressor muscles on the unaffected side. By weakening these muscles, the movement of the stronger side is reduced, leading to improved symmetry of the lower lip.
- Lower Lip Reanimation: In more complex cases, reanimation of the lower lip on the paralyzed side can be performed. This may involve transferring the anterior belly of the digastric muscle, a small muscle located under the chin. This procedure, potentially requiring one or two operations, aims to restore movement to the paralyzed side and achieve better symmetry.
For mild cases of muscle asymmetry, or when surgery is not preferred, botulinum toxin (Botox) therapy can be a viable option. Tiny injections of botulinum toxin can be used to create muscle balance across the mouth, improving the symmetry of the smile.
It is also critical to manage any associated complications. If ACF is diagnosed as Cayler syndrome or is associated with other defects such as heart or kidney problems, the child should be monitored and treated by a multidisciplinary team of specialists. This comprehensive approach ensures that all aspects of the child’s health are addressed.
Sources
http://smj.sma.org.sg/4808/4808cr1.pdf
http://www.ncbi.nlm.nih.gov/pubmed/17572570
