Introduction

Hanhart syndrome (HS) is a very rare condition that is congenital therefore symptoms are present at birth. Hanhart syndrome causes limb abnormalities as well as some limbs appearing to be absent. Certain organs such as the tongue can also be underdeveloped with some earlier patients not having a clearly defined tongue. The lower jaw is also very commonly underdeveloped and this can lead to many difficulties regarding feeding and swallowing mechanisms.¹

This condition has a prevalence of 1 in 20,000 with HS prevalence increasing in instances of consanguineous marriage. Craniofacial abnormalities lead to HS having very adverse effects on the quality of life of those affected with breathing and swallowing being impaired.² As a result, growth in these children is abnormal as nutrition is limited however there are measures in place to try and mitigate this. This article will focus on the causes of HS and how this leads to feeding and swallowing difficulties. Treatment strategies will also be explored.

Causes of feeding and swallowing difficulties in hanhart syndrome

The three main causes of feeding and swallowing difficulties in HS instances are orofacial malformations, neuromuscular issues as well as airway obstructions. Microglossia is common in HS cases and this is when the tongue is underdeveloped. Sometimes the tongue may not be present, tongue abnormalities are also referred to as glossopalatine anomalies. Without the tongue being the optimal size and shape it can be difficult to eat and swallow food. Jaw abnormalities as well as a cleft palate are further examples of orofacial malformations.³ Cleft palates arise when there is incorrect fusion of tissue prior to birth which leads to a split being present in the mouth. Due to the palate not being formed correctly, feeding can be difficult as this is required for normal feeding and swallowing functions. As aforementioned the jaw may also be underdeveloped which is a major cause of these issues.¹

Muscles such as the mylohyoid muscle which are used for proper tongue function and therefore leads to correct swallowing may not be coordinated in HS instances which can therefore further contribute to the difficulties present with this condition.⁴ As the tongue may be hard to prevent from falling and the mouth cannot be kept open effectively due to the jaw and neuromuscular issues this can lead to breathing difficulties and lead to the respiratory tract being obstructed. It is much more difficult to coordinate breathing and swallowing in HS instances and due to certain tract abnormalities and a lack of muscle coordination this leads to an increased prevalence of choking amongst HS patients.⁵

Types of feeding and swallowing difficulties

There are three main types of feeding and swallowing difficulties, these are oral phase difficulties, pharyngeal phase difficulties and esophageal phase difficulties. Due to the tongue being underdeveloped in the majority of HS cases as well as other malformations chewing solid foods can be very difficult therefore there have been times when fingers have had to be used in order to assist with feeding and swallowing. As well as this the tongue and palate do not function properly and the tongue does not touch the palate this can add to these issues, moving food to the back of the mouth requires assistance from the tongue therefore macroglossia is the main reason that causes these difficulties.¹ Swallowing issues occur due to tongue deformities as this reflex does not get initiated correctly, as well as this the reflex is weak and HS patients tend to release more saliva than individuals without this condition due to the tongue being incorrectly positioned.⁶ The palate abnormalities are a major contributing factor

These difficulties and teeth being missing can also add to the pharyngeal phase issues associated with HS. Esophageal atresia is observed in some HS patients and this occurs when the oesophagus does not form properly prior to birth hence, this congenital defect is caused by HS. As a result, it is very difficult for food to move down the oesophagus thus affecting the feeding mechanisms and limiting available nutrition for the child. This can also lead to choking and blockages of the oesophagus, if food enters the trachea as a result choking is observed.⁷ Gastroesophageal reflux (GERD) occurs when acid in the stomach such as pepsin travels up the oesophagus and this leads to the lining of the oesophagus being exposed to the acid which harms and irritates the lining due to the low pH. The abnormalities in the oesophagus due to HS leads to this being likely.⁸

Diagnosis and evaluation

Clinical evaluation is integral in diagnosing HS in individuals. Physical examinations are typically given to those suspected of having HS. These examinations assess the extent of the aforementioned abnormalities which are orofacial malformations and neuromuscular issues.² These examinations are used to show symptoms such as lower lip fusion (indicative of cleft palate) as well as teeth abnormalities for example.⁹ Growth patterns are also analysed as growth and nutrition are hindered due to this syndrome. By monitoring these patterns, it can be shown whether the patient is making any progress despite these difficulties.

The feeding difficulties make weight maintenance very difficult therefore this is a useful metric in assessing the extent to which HS is affecting the individual. Specific tests are also used for this purpose. For example, a modified barium swallow study (MBSS) is used in order to visualise swallowing by utilising videofluoroscopy, this is, therefore, a very useful strategy to elucidate whether potential HS cases have swallowing difficulties.¹⁰

Fiberoptic endoscopic evaluation of swallowing (FEES) is another technique which involves assessing swallowing however this is done by identifying whether pharyngeal dysphagia has occurred which is when food is not effectively pushed into the oesophagus. The multidisciplinary team is also essential in evaluating HS cases as paediatricians alongside ear, nose, and throat (ENT) doctors and dieticians can assess the effect of HS on the throat and swallowing. Nutrition can also be assessed, and speech pathologists are also useful as speech difficulty is a common HS symptom.⁹

Management and treatment strategies

There are currently many strategies to manage HS symptoms. As solid foods are difficult to swallow softening food or making food pureed can make swallowing much easier.⁶ Feeding positions are also important as ensuring that patients are upright can make this a more efficient process. Feeding tubes are also beneficial. Feeding using a nasogastric tube is commonly used in terminally ill patients of various illnesses and is also safe in severe HS instances although this is used sparingly.¹¹ Tubes such as gastronomy tubes are another example of feeding tubes to assist in feeding HS individuals. Speech therapy is integral in ensuring that those affected by HS are able to communicate effectively in the long term and there can also be therapy to help the muscular coordination that is impaired as a result of this condition (McPherson). Caregivers who are responsible for occupational therapy need to be trained so that they can administer certain feeding techniques safely, particularly when using feeding tubes for example.¹¹ GERD and other secondary symptoms of HS including breathing difficulties can be treated using medical interventions such as antacids for GERD.¹² Techniques such as continuous positive airway pressure (CPAP) and oxygen therapies are useful in alleviating symptoms caused by airway issues in HS cases.¹³

Long-term considerations

There are many long-term implications of this condition. Nutrition should be monitored as mentioned previously as this is difficult to manage which can cause further issues with growth and development in these children. Calorie intake is a key metric which can be used to demonstrate any potential improvements. Therapy should also be provided for those affected and their families as this condition can cause many psychological difficulties due to feeding and swallowing being adversely affected. Educating families on management and treatment strategies is essential in helping HS patients have a good quality of life. The amount of intervention needed does depend on the extent of HS symptoms as these symptoms and their severity vary greatly from patient to patient.²

Conclusion

Overall, Hanhart syndrome causes many issues regarding feeding and swallowing due to malformations and abnormalities that particularly affect the facial area. Chewing and swallowing are both affected negatively, and this can lead to HS patients having a poor quality of life.

There are many strategies to diagnose patients and some management strategies available although there is no long-term cure for HS. By addressing symptoms early malnutrition and issues with breathing and aspiration can be limited therefore it is essential to administer treatment as early as possible. Multidisciplinary care is needed as this team can help monitor nutrition, feeding and speech to provide those with the condition an opportunity to lead a somewhat normal life despite the difficulties that they face.