Pulmonary causes of central cyanosis
| Problem | Mechanism | Presentation and investigations |
|---|---|---|
| Parenchymal disease: Pneumonia Respiratory Distress Syndrome (RDS)/Surfactant deficiency Transient tachypnoea of the newborn Meconium aspiration Congenital abnormality leading to pulmonary hypoplasia: diaphragmatic hernia, congenital cystic adenomatoid malformation (CCAM) | Pulmonary disease leads to impaired alveolar gas exchange resulting in decreased arterial oxygen saturations | History: risk factors for sepsis, meconium, oligohydramnios, prematurity, abnormal antenatal scans. Examination: tachypnoea, intercostal recession, use of accessory muscles, crackles, wheeze. Cyanosis may improve on crying. CXR: cardiac shadow normal, lung fields will most likely be abnormal. Gas: raised pCO2 and respiratory acidosis. Saturations: no difference in preductal and postductal readings, oxygen saturations will usually normalise in 100% oxygen. Normal ECG and echocardiogram |
| Alveolar ventilation: Neuromuscular hypoventilation: Spinal muscular atrophy, congenital myopathy, congenital myotonic dystrophy Central hypoventilation syndrome | Progressive hypoventilation will ultimately lead to hypoxia | History: may be family history of neurological disorder, respiratory distress since birth, unable to wean from ventilator. Examination: neurological signs: hypotonia, reduced reflexes, poor suck, abdominal breathing |