Botulinum toxin in the treatment of asymmetric crying face syndrome: a case report
Toxina botulínica para tratamento de síndrome do Choro Assimétrico: relato de caso

INTRODUCTION

Asymmetric crying face (ACF) syndrome was first described in 1931 by Parmelee while observing the crying of a newborn¹. It is a congenital alteration secondary to hypoplasia or absence of the depressor muscle at the mouth angle. It can develop in up to 0.6% of births² and present with facial asymmetry when crying and loss of saliva in the oral commissure of the affected side. Other facial movement muscles are unaffected³.

The diagnosis may be clinical or aided by electromyography. The association with other congenital malformations is possible and may be from the gastrointestinal, cardiovascular, skeletal, genitourinary, and even central nervous system. Congenital hypoplasia of the depressor muscle of the mouth angle develops in isolation in most cases⁴, and the investigation of other congenital anomalies is controversial². Its etiology is not yet well defined but is believed to be multifactorial.

The clinical diagnosis is more difficult with the child’s growth, since, with the passage of time, the risorius and other muscles begin to dominate facial expression⁴. The main differential diagnosis of this condition is with obstetric traumas and congenital facial paralysis, in which there are other facial expression alterations such as deficient ocular closure, absence of frontal wrinkles, and deletion of the nasolabial sulcus.

The diagnosis and follow-up of this syndrome are well discussed and established in the literature. Nevertheless, the treatment of facial asymmetry is rarely studied, and there are differences in the initial conduct of these cases. Thus, we present here a case of a child with ACF syndrome successfully treated with botulinum toxin on the unaffected side.

Case Report

A 9-year-old female patient, with complaint of mouth asymmetry since birth, currently suffers from bullying at school. She had stable asymmetry throughout growth, with greater prominence of the deformity when crying and smiling.

According to the mother, gestation was uneventful. Personal history is only bronchial asthma with eventual use of inhaled corticosteroids.

The patient was evaluated by a pediatrician, who ruled out associated congenital malformations. Upon examination, there were no significant changes at rest (Figure 1), but the smile was asymmetric due to the absence of action of the depressor muscle at the left mouth angle (Figure 2). The remaining facial muscles had no clinically detectable changes (Figure 3).

Figure 1 - Resting - without significant asymmetry.

Figure 1 - Resting - without significant asymmetry.

Figure 2 - Mouth asymmetry when smiling - absence of depression action at the mouth angle on the left side.

Figure 2 - Mouth asymmetry when smiling - absence of depression action at the mouth angle on the left side.

Figure 3 - Dynamic physical exam normal resting - good function of the orbicular mouth muscle.

Figure 3 - Dynamic physical exam normal resting - good function of the orbicular mouth muscle.

The therapeutic possibilities were proposed for the patient and mother. After the consent of the patient and her caregiver, 5 IU of botulinum toxin type A (Botox^®; Allergan) was directly applied to the depressor muscle at the right (unaffected) mouth angle. After 14 days, an insufficient result was verified (Figure 4), and another 5 IU (total of 10 IU) was applied.

Figure 4 - Result after the first application - application of 5 IU of botulinum toxin type A (Botox^®; Allergan).

Figure 4 - Result after the first application - application of 5 IU of botulinum toxin type A (Botox^®; Allergan).

The patient returned satisfied with the result, showing symmetry when smiling, as seen in Figures 5 and 6.

Figure 5 - Final result after the second application. Resting - total dose of 10 IU botulinum toxin type A (Botox^®; Allergan).

Figure 5 - Final result after the second application. Resting - total dose of 10 IU botulinum toxin type A (Botox^®; Allergan).

Figure 6 - Final result after the second application. Smile - total dose of 10 IU of botulinum toxin type A (Botox^®; Allergan).

Figure 6 - Final result after the second application. Smile - total dose of 10 IU of botulinum toxin type A (Botox^®; Allergan).

DISCUSSION

ACF syndrome has been extensively studied in pediatric publications with a focus on diagnosis and follow-up necessary for these children and differential diagnoses and associations with other congenital malformations, but there are few discussions on the treatment of the central characteristic of this condition: facial asymmetry secondary to hypoplasia of the depressor muscle at the mouth angle.

The most studied and described treatment in the world literature is the weakening of the sound side through selective neurectomy of a marginal nerve branch of the mandible or myectomy of the depressor muscle at the mouth angle⁵. Udagawa et al.⁶ described a surgical intervention on the affected side, in which a fascia lata graft was performed in 7 children with facial asymmetry when crying, showing good results. Other innumerable invasive forms have also been published such as functional microsurgical transfer, fascia graft, and even transposition of the digastric muscle.

The treatment modalities proposed in other studies have the need for surgical intervention as a disadvantage, thus exposing children to anesthetic risk. Therefore, less invasive alternatives such as the selective blockage of the marginal nerve branch of the mandible and application of botulinum toxin were also studied.

Tulley et al.⁷ demonstrated in 2000 the application of botulinum toxin in 5 adult patients who presented with isolated facial paralysis at the marginal branch of the mandible, with excellent results. Isken et al.⁸ published in 2009 two cases of children, one 4 years of age and the other 16 months, with facial asymmetry when crying successfully treated with botulinum toxin on the unaffected side, discussing in this work the benefits of a simple therapy for children with facial deformity that may eventually present psychosocial difficulties and introversion.

Botulinum toxin is already used safely in several childhood conditions such as spasticity in cerebral palsy, strabismus, dystonia, and hyperhidrosis, so there is sufficient evidence to demonstrate safety in its use in children⁸.

Here, we present the case of a 9-year-old child with facial asymmetry of the mouth when smiling and crying, extremely uncomfortable with her physical condition. A safe, quick, and easy treatment was performed with the use of botulinum toxin, demonstrating a good result and with total patient satisfaction.