An-Infant with "Dying Spells"
Shyam S Kothari, Ambuj Roy, Sanjiv Sharma, Anil Bhan
Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi
A 45-day-old infant presented with the unusual and intriguing symptom of episodic crying and loss of consciousness. The infant was discovered to have a vascular compression of the trachea by the innominate artery, almost serendipitously. He was cured of his symptoms by anterior suspension of the innominate artery. (
Indian Heart J 2003; 55: 7880)Key Words:
Vascular ring, Apnea, AortopexyV
ascular rings and slings in infants usually present as stridor, feeding difficulties, and recurrent aspiration. Vascular compression of the trachea by the innominate artery is rare. It may present with one of these symptoms or, more dramatically, as reflex apnea. We report such a case to highlight a rare but curable cause for recurrent apneic spells.Case Report
A 45-day-old infant was brought with a history of recurrent episodes of unconsciousness and apnea triggered usually (but not exclusively) by crying. He was born at full term, after an unremarkable pregnancy in a primigravida, and had an Apgar score of 8/10 at birth. There was no history of fever, jitteriness, feeding difficulties, seizures, cyanosis, or stridor, and the baby was otherwise healthy. The infant had had several episodes of unconsciousness and apnea since he was 15 days old and was feared dead during these spells, but would recover spontaneously within 12 minutes.
On examination, his weight was 4.5 kg, and heart rate 120 per minute, regular. His mental and motor milestones were normal. There were no dysmorphic features. He had situs inversus, and a pansystolic murmur. The chest X-ray showed mild cardiac enlargement, situs inversus, and normal lung fields. Detailed echocardiographic assessment revealed situs inversus, corrected transposition of the great vessels (i.e. atrioventricular and ventriculoarterial discordance), a small ventricular septal defect, and mild pulmonic stenosis. The electrocardiogram (ECG) demonstrated situs inversus but was otherwise unremarkable. The electroencephalogram (EEG) and CT scan of the head were normal.
A seizure disorder, complete heart block, or cyanotic spells were suspected in view of the history and cardiac disorder. Breath-holding spells were also considered. Routine blood chemistry was within normal limits. In the hospital, the infant was observed to have episodes of crying and distress followed by apnea and progressive bradycardia, and even asystole. Two of the episodes required brief assisted ventilation and cardiac massage. Cardiac catheterization confirmed the cardiac lesions but could not explain the symptoms. An aortic angiogram revealed an L-posed aorta with a slightly medial origin of the innominate artery (Fig. 1). In the course of illness, a repeat chest X-ray demonstrated hyperinflated lung fields. In view of this finding, a chest CT scan was done which revealed a right aortic arch with anterolateral tracheal compression by the left-sided innominate artery 1 cm above the carina (Fig. 2). Cinefluoroscopy confirmed compression of the trachea at the level of the innominate artery. The infant underwent aortopexy and left innominatepexy for the relief of tracheal compression. The left innominate artery and the aortic arch were plicated to the second costal cartilage. Subsequently, he has had no recurrence of symptoms and was doing well at six months follow-up.
Discussion
The absence of stridor in our patient delayed the correct interpretation of reflex apnea due to tracheal compression by the innominate artery. Innominate artery compression is a rare cause of airway obstruction in infants. The anomalous innominate artery compression syndrome was first described by Gross and Neuhauser
1 in 1948 as consisting of cough, stridor, and occasionally apnea. Other authors24 have subsequently reported abnormal origin and course of the innominate artery as a cause of airway compression, with relief of symptoms following decompressive surgery. However, some authors5 have disputed the role of the innominate artery in causing symptoms in these children, and believe that intrinsic abnormality of the trachea rather than compression by the innominate artery is responsible for the symptoms. Strife et al.6 reported that the innominate artery crosses anterior to the trachea, and produces mild to moderate anterior indentation of trachea in 30% of normal children without causing symptoms. Mustard et al.7 found that only 39 out of 285 children with innominate artery compression had symptoms marked enough to warrant surgery. Thus, the innominate artery probably crosses the trachea in almost all infants, but few children actually have tracheal compression, and even fewer have symptoms requiring intervention. Why only some children have symptoms of compression is not known. A tight or crowded mediastinum and esophageal dilatation due to any cause are some of the reasons postulated. The syndrome has been associated with the presence of congenital heart disease as well as esophageal atresia. The usual symptoms reported due to innominate artery compression are stridor, respiratory distress, recurrent lower respiratory tract infections, and reflex apnea. Apnea is thought to be due to reflex respiratory arrest initiated by compression of the trachea. This may occur as a result of a large bolus of food passing through the esophagus or from accumulation of secretions in the tracheobronchial tree. The symptoms are maximal during infancy with gradual improvement by 2 years of age. The improvement is probably due to strengthening of the airways by increased cartilaginous support and cephalad displacement of the aorta.
The diagnostic modalities are a lateral X-ray that may show an anterior indentation of the tracheal air column. In suspected cases MRI imaging confirms the diagnosis, and is the imaging modality of choice, though a CT scan also provides adequate information, as in our case. Recently, cine MRI has been reported to be useful for dynamic imaging of tracheal compression by the innominate artery.
8 Barium swallow is not helpful because the compression is located anteriorly. The diagnosis can be further confirmed by bronchoscopy, which shows anterior tracheal compression 12 cm proximal to the carina. The area of compression is pulsatile and, when levered anteriorly by the tip of the endoscope, leads to diminution of the corresponding radial pulse.Surgical correction of compression is usually by suspension of the innominate artery to the undersurface of the sternum by a row of braided Dacron sutures (innominatepexy), though some surgeons prefer its reimplantation lower down the aortic arch. Surgical outcomes have been excellent in judiciously selected cases of innominate artery compression.
2Correspondence:
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