A Case in Respiratory DistressG. Patrick Daubert, MDEmergency Medicine ResidentDetroit Receiving Hospital

                    

                               

PresentationOne month old male infant presenting to the emergency department for respiratory distressParents state that the patient has had difficulty breathing for the past 24 hours which has progressively gotten worsePatient was seen by primary medical doctor this morning and received albuterol nebulizers and 1 mg of Decadron intramuscularly prior to being transferred to the emergency department Patient arrived to the emergency department in moderate to severe respiratory distress with stridor

                    

                               

History of Present IllnessInfant was born at 38 weeks gestational age via a spontaneous vaginal delivery without complication.Over the past week he has developed post-prandial respiratory distress. Distress described as stridor, retractions, and cough.Night before presentation, the infant had an attack of heavy coughing with short apneic episode.

                    

                               

Primary Physician Yes – Pediatrician

Medical History None,

Surgical History None

Birth History 38 weeks gestation Mother G4P4004 Apgar scores of 8/9 No complications with the

pregnancy; 8lb2oz HBV Vaccine at birth

Allergies None known

Family History No congenital defects

knownSocial History

3 siblings, No day care, no exposure to smoke in the home, no sick contacts

Normal prenatal care

Past History

                    

                               

Review of SystemsConstitutional: No history of fever, acting apporpriate for age. Eyes: No redness or drainage. Ears, nose, Mouth, Throat: No congestion or drainage. Cardiovascular: Good colour. No history of congenital cardiac disease, no difficulty with nipplingRespiratory: Post-prandial cough, positive stridor, positive retractionsGastrointestinal: One episode of vomiting 4 days PTA, (white in colour), no diarrhea, breast milk feeding,Genitourinary: 6-7 wet diapers/day, stool 2-3/day Musculoskeletal: No swelling, deformity, nor change in movements or posture. Skin: No swelling, rash, no lesions. Neurological: No seizures, normal behavior.

Differential Diagnosis…

                    

                               

Physical ExamVS 38.0 rectally, P 172, RR 72, 5 kg, sat 91% RA General: Patient in respiratory distress with audible wheezing and notable stridor. The infant was moving all four extremities and did not appear to be lethargic. HEENT: PERRL. EOMI. Anicteric sclerae, pink conjunctivae. Oropharynx was clear. There was no tonsillar exudate or enlargement. Moist mucous membranes. Neck, supple, no JVD, positive stridor.

                    

                               

Physical Exam Continued…

RESP: Stridorous. Mild, late wheezing, IC/SC retractions noted. No grunting.CVS: Regular rhythm and rate, no murmurs. Abdomen, soft, nontender to palpation, no hepatosplenomegaly. MS: Pulses were equal upper and lower extremities bilaterally. Capillary refill is two seconds, no peripheral edema. SKIN: warm and dry, no petechiae or bruising; There is no rash on the palms or soles of the feet. NEUROLOGIC: Patient moving all four extremities. Arousable and consolable.

DiscussionInitial management decisions to be made…

                    

                               

Initial Management in the ER

Patient was given humidified oxygen which improved his saturation to 99%Patient was given racemic epinephrine 0.5 mg nebulizer with nearly complete resolution of his stridor CBC, electrolytes, and blood cultures orderedIV was establishedChest and Neck soft tissue x-rays obtained...

                    

                               

Laboratory StudiesCapillary blood gas:

7.38/33.2/69.7/19.5/94%

RSV - NegativeBlood gram stain - negative

                    

                               

Esophogram Ordered…

                    

                               

Diagnosis...

There was a double aortic arch with a ligamentum arteriosum. The arches were approximately equal in size, measuring about 5 mm in diameter each.The left (anterior) arch clearly gave off the left subclavian artery and the left common carotid artery

Double Aortic Arch

                    

                               

Respiratory Tract AbnormalitiesExtrathoracic airway obstruction Supraglottitis Croup

Intrathoracic, extrapulmonary airway obstruction Vascular ring Mediastinal tumors

Parenchymal Pneumonia Pulmonary edema

                    

                               

Determining the Site of Obstruction…

5 important clinical observations Rate and depth of respirations Presence of retractions Inspiratory stridor Expiratory wheezing Grunting

                    

                               

Interpreting the Clinical Signs

Extrathoracic

Intrathoracic/ Extrapulmona

ry

Intrapulmonary

Parenchymal

Dyspnea + + ++ ++++Retractions ++++ ++ ++ +++Stridor ++++ ++ - -Grunting +/- +/- ++ ++++Wheezing +/- +++ ++++ +

                    

                               

Arterial Blood GasesObstructions above the carina ABG reflects overall alveolar

hypoventilation This manifests as PaCO2 and

proportionate PaO2 Since there is no parenchymal disease

causing R L shunting, hypoxia responds well to supplemental O2

                    

                               

Arterial Blood GasesIntrapulmonary airway obstruction ABG reflect ventilation/perfusion imbalance and

venous admixture - caused by non-uniform obstruction throughout the lungs

In mild cases hyperventilated areas predominate resulting in a PaCO2

However, the PaO2 in these areas cannot compensate for the PaO2 in hypoventilated areas resulting in venous admixture and a total PaO2 and PaCO2

Response to O2 depends on the amount of venous admixture and illness severity

                    

                               

Double Aortic ArchDouble aortic arch is the most common vascular abnormality requiring operationIn this condition, the trachea or esophagus are completely encircled by the bilateral aortic arches owing to persistence of both right and left embryologic fourth aortic archesBoth aortic arches may be patent, or one may be atretic and remaining as a fibrotic cord

                    

                               

Double Aortic ArchFirst surgical correction in 1945The incidence of anomalies of this type is not known, as many are asymptomaticThere is no predilection of these anomalies for either sexAbnormal vascular structures causing extrinsic compression of the trachea is uncommon, but is a common cause of serious, persistent respiratory problems in infancy

                    

                               

Double Aortic ArchClinical manifestations may vary considerably depending on the type of lesion and severity of encroachment on trachea, bronchi or esophagusThe most common presentation is the picture of airway obstruction, mainly stridor, wheezing, or excessive secretion

                    

                               

Double Aortic ArchIn the newborn, respiratory symptoms are usually mild and rarely recognizedSymptoms usually become apparent during the first few months of lifePatients often have a history of recurrent respiratory embarrassment, or infection, requiring frequent medical attentionSome have been referred for evaluation of a possible allergic problem such as asthmaSymptoms are frequently exacerbated by crying or exertion

                    

                               

Double Aortic ArchAll cases reported to date have had a left side ductus arteriosusThe luminal size of the two arches in relation to each other varies considerably Occasionally double aortic arch has been reported to be found in combination with other congenital cardiac anomalies In one series of 16 cases of double aortic arch associated with

intracardiac defects, 15 of the 16 were cyanotic and included Tetralogy of Fallot and transposition of the great arteries.

Several cases with coarctation in one of the aortic branches have been reported.

                    

                               

Double Aortic ArchA chest roentgenogram with barium filling the esophagous is the simplest and yet the most informative procedure in the evaluation of patients who are suspected of having a vascular abnormalityMost aortic arch anomalies causing vascular rings have a posterior esophageal indentationCareful review of the standard chest xray may be helpful initially to evaluate tracheal or bronchial abnormalities such as an abnormal shift or constriction

                    

                               

Double Aortic ArchIf airway compromise is significant, surgical intervention should be undertaken without delayOperative mortality in recent series is ~5%The prognosis for survival is generally good in most patients with aortic arch anomaliesSome patients may have such significant damage or distortion of the tracheal bronchial tree owing to chronic compression that severe respiratory symptoms may persist postoperatively