A
"One mistake does not have to rule a person's entire life."
~ Joyce Meyer
A
a
Breathing dysfunction and the coordination with swallowing.
Seventy percent of the Rett Syndrome patient population have difficulty coordinating breathing and swallowing, which results in dysphagia (156, 157). Several phenotypes of Rett Syndrome affect swallowing, including malocclusion (open bite) (156, 158), difficulty chewing (158–160), poor tongue mobility (156–158, 161), involuntary movements of the tongue (156, 158), poor bolus formation (160) and poor glossopharyngeal seal. Moreover, the pharyngeal cavity over distends (160), which requires more food/liquid to fill the pharyngeal cavity before the so called pharyngeal phase of swallowing can be initiated. There are also reports suggesting the absence of primary and secondary gastric motility and gastroesophageal reflux (157). Because of the complications associated with dysphagia, it is recommended to offer Rett Syndrome patients diets with thickened liquids and purees (159).
Rett Syndrome pts experience aerophagia (air swallowing) and malocclusion (158, 162, 163). Thus, swallow-breathing coordination in Rett Syndrome is weak and in some cases absent (161). Many Rett Syndrome patients are preferential mouth breathers (156) which probably contributes to the increased prevalence of aerophagia causing air bloat (162). According to the Natural history study, 47% of Rett parents also reported a history of air-swallowing during wakefulness (17). Although aerophagia is seen in other neurological and oropharyngeal diseases, it seems to be most common with Rett Syndrome (162), leading to painful distension of the stomach and even bowel perforation (162). Interestingly, the oral motor patterns of the tongue mirrored the motor patterns of the hands (160). In patients with hypotonia and normal tone, wringing of the hands was accompanied by abnormal motion of the tongue; and those patients with more rigidity/hypertonia whose hands lay motionless were also motionless in their tongue (160). These observations suggest that Rett Syndrome is characterized by complex imbalances that concurrently affect several rhythmogenic networks. Dysphagia is a significant, but understudied clinical presentation of Rett Syndrome, and pneumonia is one of the most frequently reported medical conditions (164) and the most common cause of death in Rett Syndrome according to one study (165). It is unknown whether pneumonia is the result of predisposed lung conditions or due to aspirations. However, according to some clinical reports it appears that aspiration has low occurrence in early stages of Rett Syndrome, but it is likely that the occurrence increases as the disorder progresses (160). In Mecp2-null mutant mice aspirations are frequent (64%) (163). Perhaps these aspirations were measured at more advanced states of disease progression. Alternatively, this difference is due to the fact that rodents are unable to cough, thus are more prone to aspirations (166). Fifty percent of Mecp2 mice exhibited lung inflammation and emphysema-like structural changes in the lung, which could be exaggerated by the aspirations (163).
a
a
a
a
No comments:
Post a Comment