INTRODUCTION: The primary muscular element that maintains the tone of the upper esophageal sphincter (UES) is the cricopharyngeal muscle (CPM). CPM dysfunction is a known cause of dysphagia. Incidence of dysphagia is significant in preterm infants and is double that of the general population. Disorders of CPM are rare in neonates and can present with choking, salivation, and reflux while feeding. Hypertrophy of the CPM has been associated with dysphagia in adults, but there were no reported cases in neonates on our literature review. We report a rare case of CPM hypertrophy causing dysphagia in a preterm infant in the neonatal period.
CASE: History: This is a case of dysphagia in a premature neonate born to a 28 year old G4P202 mother via vaginal delivery, induced at 33 weeks gestation due to severe maternal preeclampsia. Prenatal care was established in the first trimester and maternal medical history was significant for the presence of cytomegalovirus and parvovirus IgG antibodies (without IgM antibodies) during this pregnancy. The infant required minimal resuscitation at birth and did not require supplemental oxygen throughout her NICU stay. Physical exam: Her exam was within normal limits for her age. Enteral feeds were established on day of life (DOL) 0 and advanced to full enteral feeds on DOL 4. Although oral feeds were initiated on DOL 3, due to immature suck/swallow and bradycardia/desaturation events during feeds, they could not be advanced. Speech therapy was consulted on DOL 14, however, this did not improve her coordination skills. Labs and Imaging: A modified barium swallow study was performed at 40 weeks corrected gestational age and identified persistent narrowing of the upper esophagus above the aortic arch ( Image 1). Upper gastrointestinal series was performed to further delineate this anomaly, and showed persistent posterior filling defect within the upper esophagus at the level of the thoracic inlet/sixth cervical vertebrae, possibly secondary to prominent CPM/spasm (Image 1). A nasopharyngolaryngoscopy was performed on DOL 55 to better visualize the upper airway and noted mild laryngomalacia and sequelae of gastroesophageal reflux. A flexible esophagoscopy was performed on DOL 67 to directly visualize the upper esophagus and examine the CPM. This revealed a soft midline posterior bulge near the CPM, the esophagoscope passed easily into the distal esophagus and the UES opened easily with insufflation of the area. No esophageal masses, mucosal lesions or strictures were noted. Due to persistent intolerance of oral feeds, a gastrostomy tube was placed and she was discharged home at 44 weeks corrected gestational age. Final diagnosis: Cricopharyngeal hypertrophy.
DISCUSSION: This case depicts a premature female with dysphagia and persistent narrowing of the UES concerning for possible achalasia. Manometric studies were not pursued due to the patient's age and size. However, during esophagoscopy the UES opened easily, which did not support the diagnosis of cricopharyngeal achalasia. Instead CPM hypertrophy, an unusual etiology of dysphagia in neonates, was seen. In premature neonates, dysphagia is typically attributed to immature coordination of sucking, swallowing and breathing. This can lead to delay in diagnosis of other etiologies of dysphagia, such as CPM dysfunction. Zaino and colleagues defined two varieties of CPM hypertrophy, an idiopathic type and a type secondary to persistent hypertonicity, that caused compensatory hypertrophy, inflammation, and fibrosis. Another classification of CPM hypertrophy is by histopathological variety - hyperplasia or connective tissue replacement of atrophic muscle. In our literature review, CPM hypertrophy was seen in adults most commonly secondary to prolonged gastroesophageal reflux. CPM dysfunction should be included in the differential diagnosis of neonates with dysphagia, even in premature infants. Further studies need to be done to establish the incidence of dysphagia secondary to CPM hypertrophy in neonates.
