CYANOSIS

  CYANOSIS

I. Problem. A 1-week-old female infant is brought to the emergency

department because she has turned blue.

II. Immediate Questions

A. What are the vital signs?

 Respiratory rate and respiratory effort

are important indicators of the severity of illness in an infant.

Increased respiratory rate with retractions, nasal flaring, and

grunting indicates significant respiratory disease. An infant who

has cyanosis with increased respiratory rate but no increased

effort (so-called comfortable tachypnea) is more likely to have

congenital heart disease. Oxygen saturation, obtained by peripheral

pulse oximetry, may help establish a differential diagnosis,

especially if saturations are different in upper versus lower

extremities (differential saturations). Significant tachycardia or

bradycardia is an indicator of severe physiologic derangement

requiring immediate attention.

B. How easily does air move into and out of lungs? Wheezing or

stridor indicates airway obstruction. Poor air movement, prolonged

expiration, or other lung sounds (rales, wheezes, rhonchi)

assist in the differential diagnosis. Poor aeration on only one side

may indicate pneumothorax or pneumonia.

C. Is there a murmur? A murmur is present in some types of cyanotic

congenital heart disease (eg, significant right ventricular outflow

obstruction seen in critical pulmonary stenosis or tetralogy of

Fallot) but may not be present in others (eg, transposition of the

great arteries, atrioventricular canal defect, total anomalous pulmonary

venous connection, and hypoplastic left heart syndrome).

An infant with a hypercyanotic episode (so-called tet spell) may

not have a murmur if the episode is severe, because there is not

enough pulmonary blood flow to create a murmur.

D. Is cyanosis peripheral, central, or differential? Cyanosis that

affects skin and lips but spares oral mucosa, tongue, and conjunctivae

is termed peripheral cyanosis. It occurs in the presence

of normal arterial saturation. Cyanosis that affects mucosa of the

mouth and conjunctivae in addition to skin and lips is termed central

cyanosis and suggests arterial desaturation or abnormal

hemoglobin. Differential cyanosis, blueness of the upper or lower

portion of the body, only, is an indicator of heart disease. Cyanosis

of the lower extremities is seen in infants with critical aortic coarctation

or interrupted aortic arch. The lower portion of the body is

supplied by systemic venous blood coursing right to left across a

patent ductus arteriosus (PDA). This differential cyanosis may

also be seen in a newborn with persistent pulmonary hypertension.

Transposition of the great arteries with PDA may produce

differential cyanosis of the upper extremities (oxygenated blood

courses right to left across ductus arteriosus, supplying the lower

body).

E. When does cyanosis occur? Cyanosis that occurs intermittently

is associated with apnea, cold exposure (acrocyanosis), or

intermittent airway obstruction. Intermittent cyanosis that occurs

with feeding is seen with choanal atresia, esophageal atresia

(especially with coughing, sputtering), or severe gastroesophageal

reflux. Cyanosis as a result of cardiac disease, respiratory

disease, or abnormal hemoglobin usually is present

continuously.

F. How old is patient? Differential diagnosis for a child or an adolescent

with cyanosis can be quite different from that of a newborn.

In-depth prenatal and birth history and past medical

history may supply important information for diagnosis. For

example, patients presenting outside of infancy generally do

not have a cardiac cause for cyanosis without a known history

of cardiac disease or illness predisposing them to cardiac

disease.

G. Pertinent Historical Information

1. Is there a relevant family history?

2. Any recent illnesses or surgeries?

3. What is the possibility of exposures or ingestions?

III. Differential Diagnosis. Cyanosis refers to the bluish skin color

attributable most often to the presence of desaturated hemoglobin (5

g/dL). Primary etiologies include respiratory, cardiac, circulatory, and

nervous system disorders, as well as abnormal hemoglobin.

A. Respiratory Diseases

1. Lung disease

a. Newborn. Lung hypoplasia (diaphragmatic hernia), respiratory

distress syndrome, transient tachypnea of the newborn,

bronchopulmonary dysplasia, pulmonary interstitial emphysema,

congenital adenomatoid malformation, meconium

aspiration.

b. Infectious. Pneumonia, pneumonitis, bronchiolitis.

c. Asthma.

d. Cystic fibrosis.

e. Infiltrative disease. Pulmonary hemosiderosis, sarcoidosis.

2. Airway abnormalities or obstruction

a. Congenital. Choanal atresia, macroglossia, micrognathia

(Pierre Robin sequence), laryngeal web, tracheal stenosis,

vascular ring, tracheoesophageal fistula.

b. Infectious. Acute epiglottitis, croup, retropharyngeal

abscess, laryngospasm.

c. Traumatic. Vocal cord injury, pneumothorax, pneumomediastinum.

d. Other. Lymphoma, cystic hygroma, goiter, laryngeal

hemangioma or neoplasm, foreign body, obesity.

3. Trauma. Pneumothorax, pneumomediastinum, vocal cord

injury.

B. Pulmonary Vascular Diseases

1. Primary pulmonary hypertension. Cyanosis requires a rightto-

left shunt at the atrial or ductal level unless lung disease is

present.

2. Pulmonary arteriovenous malformation. Idiopathic or associated

with congenital heart, hepatic, or portal disease.

C. Cardiac Diseases

1. Cyanotic congenital heart disease

a. As a mnemonic, remember the 6 T’s: Transposition of the

great arteries (most common neonatal cyanotic congenital

heart defect), hypoplastic left heart syndrome (Trichamber),

Tetralogy of Fallot (most common cyanotic congenital heart

defect in children), Truncus arteriosus, Tricuspid atresia,

Total anomalous pulmonary venous connection.

b. Atrioventricular canal defect, Ebstein malformation of the tricuspid

valve, critical pulmonary stenosis, pulmonary atresia,

Eisenmenger syndrome.

2. Persistent pulmonary hypertension of the newborn.

3. Severe congestive heart failure. As a result of congenital

heart disease or acquired heart disease, sustained tachycardia

or bradycardia, or infection (myocarditis).

D. Circulatory Disorders. Cyanosis is the result of increased

venous desaturation due to increased extraction of oxygen in

peripheral tissues from diminished supply of blood to (hypoperfusion)

or venous blood return from (venous stasis) those tissues.

1. Shock.

2. Sepsis.

3. Hypoglycemia.

4. Cardiomyopathy.

5. Vena cava obstruction. Inferior or superior obstruction as a

result of cardiac or hepatic disease.

6. Hypotension. May be associated with autonomic dysfunction

or vasovagal syncope.

7. Peripheral cyanosis. Acrocyanosis related to cold exposure,

Raynaud disease.

E. Neurologic Problems

1. Apnea. Prematurity, cerebral anomalies, intracranial hemorrhage,

meningitis or encephalitis.

2. Breath-holding spells.

3. Respiratory muscle weakness (neuromuscular). Myotonic

or muscular dystrophy, Guillain-Barré syndrome, Werdnig-

Hoffman disease, myasthenia gravis, infant botulism.

4. Seizures.

F. Hemoglobin Abnormalities

1. Methemoglobinemia. Familial, nitrate exposure, aniline dye

ingestion.

2. Low-oxygen-affinity hemoglobin.

3. Polycythemia or hyperviscosity syndrome.

IV. Database

A. Physical Exam Key Points

1. Extent of cyanosis. Constant or intermittent? Peripheral or

central? Is differential cyanosis present?

2. Airway and breathing. Is patient apneic? Any airway noises

audible? Is patient breathing comfortably or with increased

effort? Is there weakness or asymmetry to chest movement?

100 I:

Is patient able to speak or cry? What is the character of speech

or crying?

3. Lungs. Listen for symmetry of breath sounds and quality of air

movement. Any abnormal lungs sounds (eg, wheezing)?

4. Heart. Assess heart rate and BP. Listen to heart sounds and

examine for murmur, gallop, or rub.

5. Pulses. Simultaneously assess pulses for quality in upper and

lower extremities. Use right arm and either femoral area. Left

arm may be distal to an aortic coarctation and misleading in

the assessment. Evaluate for equality of pulsation and presence

of femoral delay.

6. Abdomen. Assess for liver size, presence of ascites, or spider

veins across the abdomen (indicators of congestive heart failure

or liver disease).

7. Neurologic exam. Assess muscular tone and symmetry of

movement. Is there gross seizure activity? Check pupil size

and symmetry. Assess for sunset sign.

B. Laboratory Data

1. ABGs on room air. Significant hypoxemia suggests cardiac or

pulmonary etiology. Relatively normal PaO2 suggests other

causes (eg, methemoglobinemia, neurologic disorder, polycythemia).

If cardiac cause is suspected, check response to

100% oxygen (hyperoxia test).

2. Hyperoxia test. Administer 100% oxygen to patient for 10–15

minutes, then obtain ABGs and compare to values previously

obtained on room air.

a. In patients with cardiac disease, PaO2 will change little with 100%

oxygen. PaO2 will remain < 125 mm Hg in cardiac disease.

b. Patients with pulmonary disease will respond to 100%

oxygen with an increase in PaO2 to > 150 mm Hg.

c. In those with severe pulmonary disease or persistent pulmonary

hypertension, PaO2 may not increase significantly.

3. CBC with differential. May demonstrate polycythemia (hematocrit

> 65%), anemia, or evidence of infection.

4. Glucose.

5. Cultures. Obtain if infection is suspected.

6. Methemoglobin level. When exposed to air, a drop of arterial

blood has a chocolate-brown color. Patient with methemoglobin

level > 40% deserves treatment, as does patient with

neurologic changes or chest pain.

C. Radiographic and Other Studies

1. Chest x-ray. Examine for abnormal cardiac size (decreased in

hypovolemic shock; increased in cardiac shock), presence or

absence of pulmonary vasculature (increased or decreased

blood flow to lungs), signs of interstitial lung disease, evidence

of mediastinal mass, pneumothorax, foreign body ingestion, or

bony abnormalities.

2. ECG. Abnormalities suggest presence of cardiac disease or

abnormal cardiac rhythm.

3. Echocardiogram. Use to confirm cardiac disease when suspected

or determine presence of cardiac disease in cases less

certain.

4. Imaging studies of head. Consider CT scan, MRI scan, or

ultrasonography of the head if neurologic disease is suspected.

V. Plan

A. Initial Management

1. Assess and maintain airway, breathing, and circulation (ABCs).

Tracheal intubation and mechanical ventilation may be necessary,

as might inotropic support. Investigate airway if foreign

body aspiration is suspected.

2. Perform appropriate testing rapidly. Select studies that will give

the most diagnostic information in the shortest amount of time.

In some situations, an echocardiogram may be obtained more

quickly than the hyperoxia test.

B. Prostaglandin Therapy. Cyanotic heart disease in a newborn

is likely to be dependent on the ductus arteriosus for pulmonary

or systemic blood flow. In a severely ill infant, prostaglandin E1

infusion (0.01–0.05 mcg/kg/min initially) should be started until

diagnosis can be confirmed by echocardiogram. Lower infusion

rates may avoid prostaglandin-induced apnea.

C. Treatment of Underlying Cause of Cyanosis. After diagnosis is

determined, treat emergently as necessary or obtain specialist

consultation.

D. Specific Therapies

1. Methemoglobinemia. Infuse 1–2 mg/kg of methylene blue as

a 1% solution in normal saline over 5 minutes.

2. Tet spell. In an infant with known or suspected tetralogy of

Fallot, hypercyanotic episodes (tet spells) should be managed

by increasing preload and systemic vascular resistance to

overcome right ventricular outflow obstruction and increase

pulmonary blood flow. Treatment typically consists of IV

fluid bolus, knee-to-chest positioning, and oxygen (may or

may not be useful). In addition, sodium bicarbonate (0.5–

1.0 mEq/kg IV) should be administered for metabolic acidosis

and morphine sulfate (0.05–0.1 mg/kg IV or SQ) for sedation.

Phenylephrine (5–10 mcg/kg) can be administered IV to

increase systemic vascular resistance and increase pulmonary

blood flow.

VI. Problem Case Diagnosis. Results of the hyperoxia test in the 1-weekold

infant suggested a diagnosis of cyanotic congenital heart disease,

which became symptomatic after PDA closed. Prostaglandin E was

infused to reopen the ductus. An echocardiogram confirmed transposition

of the great arteries.

VII. Teaching Pearl: Question. Why is cyanosis not apparent in a newborn

at the same arterial oxygen saturation that causes cyanosis in

a 1-year-old child?

VIII. Teaching Pearl: Answer. Fetal hemoglobin has a higher affinity for

oxygen than does hemoglobin A.

REFERENCES

Grifka RG. Cyanotic congenital heart disease with increased pulmonary blood flow.

Pediatr Clin North Am 1999;46:405–425.

Tingelstrad J. Consultations with the specialist: Nonrespiratory cyanosis.Pediatr Rev

1999;20:350–352.

Waldman JD, Wernly JA. Cyanotic congenital heart disease with decreased pulmonary

blood flow in children. Pediatr Clin North Am 1999;46:385–404.

Zorx JJ, Kanic Z. A cyanotic infant: True blue or otherwise? Pediatr Ann 2001;30:

597–601.