Pediatric Puzzler: Noisy breathing in a 9-month-old: No noise is good noise

Noisy breathing in a 9-month-old: No noise is good noise

During a routine well-infant visit the mother of a smiling, chubby 9-month-oldexpresses concern about his noisy breathing. She states that her son hashad noisy breathing since birth; in fact, the nurses in the well-baby nurserythought that he was very "mucousy." The mother calls the noisybreathing a "rattling in his chest" but denies that her son hashad a chronic cough or wheezing. The noise seems better now that winterhas passed, but it is always there, and worse at night.

You look back through your office notes and see that this child has beenon oral antibiotics several times during his short life. Your records indicateseveral episodes of otitis media, often accompanied by a green nasal mucousdischarge. On one occasion you note that you heard rhonchi in his chest.

The infant was delivered at term, with no complications during the pregnancyand vaginal delivery. He was breastfed until 3 months of age, but afterswitching to cow milk­based, lactose-free formula, he had problems withspitting up. His mother reports that he gagged on solids until he was about7 months old. He has been growing well, and his only hospitalization wasfor a hernia repair. No difficulty with anesthesia was noted at the timeof the herniorrhaphy. His immunizations are up to date.

Family history reveals that the mother, an uncle, and two of the infant'sgrandparents have asthma, and a 4-year-old sibling has multiple environmentalallergies. The baby lives at home with both parents and two preschool siblings.His mother smokes, but "never in the house."

The infant is sitting up, smiling, and babbling as he rips the papercover on the examination table and tries to put it in his mouth. His vitalsigns appear to be normal: heart rate 110 beats per minute, respiratoryrate 36 breaths per minute, height 76 cm (90th percentile), weight 10.3kg (75th to 90th percentile), and head circumference 46.5 cm (75th percentile).The physical examination seems normal, including the chest examination.You note that the child becomes agitated when you lay him down to examinehis ears, and that his breathing becomes noisy, especially on expiration.The mother quickly comments that this is the noise that bothers her.

The change in the noise of breathing is quite obvious. But why? Nasalpassages narrowed with mucus could do it. Common things happen commonly,and this child has had his fair share of upper respiratory infections andotitis media. He does have two older siblings, and they are likely to bringhome plenty of viral illnesses. Maybe it is just mucus. On the other hand,he had noisy breathing in the newborn nursery. Perhaps he has a congenitalproblem, such as laryngomalacia, tracheomalacia, subglottic stenosis, orvocal cord paralysis. His breathing did seem noisier when he was supinefor the ear examination, and this is typical of laryngomalacia. But then,airway noise that arises from extra- thoracic structures is usually heardon inspiration, and this noise seemed to be expiratory.

At 9 months, the infant puts all sorts of things in his mouth, as demonstratedby the attempts with the table paper. And he has two siblings who may leavefood debris, Lego blocks, and other small toys all over the house. Coulda foreign body aspiration be the cause of the noisy breathing? Again, theproblem seems to have been present since birth, and you have only heardthe noisy breathing today.

Reactive airways disease may cause noisy breathing, and it can be episodic.Perhaps you have missed the symptomatic moments during previous visits.The noise seemed to be present on expiration, which usually indicates anintra-thoracic problem. Despite his well appearance, the mother's concernand the noisy breathing prompt you to order a chest X-ray.

The PA view of the chest appears to be normal, without evidence of localizedor generalized air trapping or peribronchial thickening. But the radiologistcalls your attention to the lateral view (Figure 1). The trachea appearsto be bowed and narrowed. Either the upper trachea is displaced posteriorlyor the lower trachea is displaced anteriorly. What could be pushing on theairway? After discussion of possible causes, you decide to order a bariumesophagram to obtain more information.

A noise with a ring to it

The esophagram shows definite compression of the esophagus (Figure 2).There is a large retroesophageal defect and anterior displacement of thelower trachea. A left aortic arch seemed to be present on the frontal viewof the chest X-ray, and, in combination with these findings, an aberrantright subclavian artery is suspected. But, the radiologist warns, the largesize of the defect and the tracheal displacement are atypical for this lesion.You remember that "rings and slings" may cause wheezing and noisybreathing, and you head to your reference books to refresh your memory.After discussion with your radiologist colleague and reading, you opt fora contrast-enhanced CT scan of the chest to better evaluate the possiblevascular anomalies of the mediastinum.¹ The CT scan indicatesa double aortic arch (Figure 3)!

Vascular ring anomalies, first described more than 250 years ago, arealterations of normal aortic arch development. The incidence in the generalpopulation is about 3%.²Although many variations have been reported,only a few cause extrinsic tracheal compression. The most common anomaliesare:

• a right aortic arch with left ligamentum arteriosus (or patent ductus arteriosus)
• double aortic arch
• anomalous innominate or left carotidartery
• pulmonary artery sling.³

An aberrant right subclavian arteryis usually asymptomatic, and if itdoes cause symptoms, they are usually related to swallowing rather thanbreathing.

Radiologic evaluation for a suspected vascular ring begins with a plainfilm study. If the trachea appears normal in both the frontal and lateralviews, a vascular ring is unlikely. In most instances, a right-sided aorticarch will be visible on the frontal film, but if the frontal film is normal,as in this case, the lateral view may show some degree of tracheal displacement.An esophagram is extremely helpful as a next step and potentially the mostinformative part of the work-up.³ If further evaluation is needed,either a contrast-enhanced CT scan or a magneticresonance imaging studyshould be performed to elucidate the vascular anatomy. Angiography is rarelynecessary these days.

When a double aortic arch is present, the aorta splits into two channels.Usually one vessel passes in front of and to the left of the trachea, whilethe other passes to the right of the trachea and esophagus. The two fuseposteriorly at the origin of the descending aorta,⁴ so that thetrachea and esophagus are caught together in a ring. No wonder this infanthad noisy breathing and trouble swallowing.

Double trouble

Of all the ring anomalies, a double aortic arch is usually the most symptomatic.Symptoms may be present at birth, as noted here. Compression of the tracheaprobably causes weakness of the cartilaginous rings that keep the tracheaopen. Even after the surgical treatment recommended for individuals withsymptomatic vascular rings, children may be left with tracheomalacia, andthe noisy breathing may persist.^2,3,5 Children with more severeor long segments of tracheomalacia may have an ineffective cough becauseof poor airway tone, and occasionally they need humidification of inspiredair and chest physiotherapy to help them clear secretions. However, manychildren have normal pulmonary function after surgery.²

Noisy breathing is a common symptom in young children. Most often thenoises are related to upper respiratory infections. As always, it is importantto listen to concerns of parents; one must also listen to the noise to determinewhether it is inspiratory, expiratory, or both. In this infant, clues indicatingthe need for further evaluation included a change in noise with positionand a subtle history of difficulty swallowing solids. Once the diagnosisof a vascular ring is made, especially with improved diagnostic and surgicaltechniques, few of these children will have to "suffer the slings [andrings] and arrows of outrageous fortune."

REFERENCES

1. Katz M, Konen E, Rozeman J, et al: Spiral CT and 3-D imagereconstructionof vascular rings associated tracheobronchial anomalies. J Comput AssistTomogr 1995;19:564

2. Marmon LM, Bye MR, Haas JM, et al: Vascular rings and slings: Long-termfollow-up of pulmonary function. J Pediatr Surg 1984;19:683

3. Lierl M: Congenital abnormalities, in Hilman BC (ed): Pediatric RespiratoryDisease. Philadelphia, PA, WB Saunders Co, 1993, pp 477­487

4. Gross RE, Neuhauser EBD: Compression of the trachea by vascular anomalies:Surgical therapy in 40 cases. Pediatrics 1951;7:69

5. Backer CL, Ilbawi MN, Idriss FS, et al: Vascular anomalies causingtracheobronchialcompression. J Thorac Cardiovasc Surg 1989;97:725

Susan Millard, MD, Jerald Kuhn MD, Karen McDowell, MD,Nadine Mazyrka, RN, Drucy Borowitz, MD, and Walter W. Tunnessen, Jr., MD

DR. MILLARD is with the Department of Pediatrics, MichiganState University, Grand Rapids Campus.
DR. KUHN is with the Department of Pediatric Radiology, Children's Hospital,Buffalo, NY.
DR. McDOWELL is affiliated with the Cleveland Clinic, Cleveland, OH.
MS. MAZYRKA and DR. BOROWITZ are with the Division of Pediatric Pulmonology,Children's Hospital of Buffalo.
DR. TUNNESSEN, who serves as Section Editor for Pediatric Puzzler, is SeniorVice President, American Board of Pediatrics, Chapel Hill, NC, and a memberof the Contemporary Pediatrics Editorial Board.




Noisy breathing in a 9-month-old: No noise is good noise. Contemporary Pediatrics 1999;0:041.