Pediatric Pulmonology

·         Tracheomalacia is quite common after repair of esophageal atresia. Weakness of both the extrathoracic and intrathoracic trachea can produce episodes of cyanosis and respiratory distress often triggered by crying, anxiety, or pain.

·         When the compliance of the chest is greater than the negative intrathoracic pressure generated during inspiration, retractions will develop.The intercostal space is even more compliant than the chest wall.

·         The most common cause of hypoxia in children with acute respiratory disorders is a ventilation/perfusion mismatch.

·         Persistent hypoxia (80% saturation on pulse oximetry) while the patient is on 100% FIO2 is an indication for intubation and mechanical ventilation.

·         Sleeping prone has consistently been shown to increase the risk of SIDS. As rates of prone positioning have decreased in the general population, the odds ratios for SIDS in infants still sleeping prone have increased. The highest risk of SIDS may occur in infants who are usually placed non-prone but placed prone for last sleep (“unaccustomed prone”) or found prone (“secondary prone”). The “unaccustomed prone” position is more likely to occur in daycare or other settings outside the home and highlights the need for all infant caretakers to be educated about appropriate sleep positioning.

·         Enlargement of one tonsil, which occurs acutely, is typical of a peritonsillar abscess and not routine pharyngotonsillitis (for this tonsillectomy is done and not adenoidectomy).

·         Children with trisomy 21 have an increased risk for obstructive sleep apnea.In this case, the pulmonary hypertension is not due to cardiac problems but is most likely to be due to prolonged hypoxia and hypercarbia during sleep.

·         In an unimmunized child, epiglottitis usually manifests with high fever, toxicity, air hunger, and drooling but without a barking cough. Epiglottitis is uncommon in children immunized against H. influenzae type b, and if it occurs, it does so in unimmunized children or those with an unusual bacterial etiology.

Dexamethasone has been quite effective in the management of children with mild to moderate croup. Its efficacy in reducing the need for oxygen in more severely affected children has not been demonstrated.

·         DIOS (Distal intestinal obstruction syndrome), also called meconium ileus equivalent, is an obstruction due to impacted stool, esp in pt with CF. If the patient has been receiving high-dose pancreatic enzymes,a fibrosing colonopathy must also be considered.

·         RDS in a term infant not responding to surfactant replacement therapy is most likely to represent neonatal pulmonary alveolar proteinosis. Neonatal alveolar proteinosis is due to a genetic mutation causing a deficiency of surfactant protein B. ECMO is a temporizing bridge to lung transplantation, which potentially can cure this disorder.

·         Airway hemangiomas may produce stridor and crouplike symptoms with viral upper respiratory tract infections.Facial hemangiomas distributed in a "beard pattern" carry the highest risk for an associated airway hemangioma.Airway lesions may also occur in the absence of any cutaneous lesions.

·         Silo filler's disease results from fermentation and gas production in a closed space due to Nitrogen dioxide toxicity.

·         Pulmonary embolism must be considered with the sudden onset of chest pain, dyspnea, and cyanosis. A normal-appearing chest radiograph with significant hypoxia is classic for pulmonary embolism. A spiral CT study is a useful test to determine the presence of a pulmonary embolism.

·         As a result of concerns about its potential toxicity (e.g., vomiting, tachycardia, seizures), side effects (e.g., behavioral changes, impaired school performance), and questionable efficacy, theophylline is no longer considered part of routine therapy of BA. Its use may be considered in an acute setting if a patient is becoming fatigued and developing respiratory failure. Some practitioners still use it in chronic settings, particularly for nocturnal asthma.

Omalizumab (Xolair) is a recombinant monoclonal antibody that was originally developed by immunizing mice with human IgE. This antibody forms a complex with unbound IgE, interferes with its binding with cell receptors, and thus prevents the subsequent release of inflammatory and chemical mediators, including histamine. It has shown great promise for the treatment of moderate to severe asthma in pediatric patients, and it has an excellent safety profile.

·         sudden infant death syndrome (SIDS) has not been clearly associated with RSV infection.

·         The infant wheezing from bronchiolitis generally has other symptoms (e.g., fever, rhinorrhea), and RSV antigen testing may be positive. If repeated episodes of reversible wheezing occur, especially if they are not during the RSV season, asthma is likely.

·         Pulmonary hemosiderosis. This condition, the presenting symptoms of which can include chronic respiratory problems or acute hemoptysis, is characterized by alveolar hemorrhage and microcytic hypochromic anemia with a low serum iron level. Hemosiderin ingested by alveolar macrophages can often be detected in sputum or gastric aspirates after staining with Prussian blue. Most commonly, the condition is idiopathic and isolated, but it can be associated with cow's milk hypersensitivity (Heiner's syndrome), glomerulonephritis with basement membrane antibodies (Goodpasture's syndrome), and collagen vascular disease.

·         "afebrile infant pneumonia" syndrome: The syndrome is usually the result of Chlamydia trachomatis, cytomegalovirus, Ureaplasma urealyticum, or Mycoplasma hominis. Affected infants develop progressive respiratory distress over several days to a few weeks, along with failure to thrive. A maternal history of a sexually transmitted disease is common. Chest x-rays reveal bilateral diffuse infiltrates with hyperinflation.

·         Kussmaul: Deep, slow, regular respirations with prolonged exhalation; seen in diabetic ketoacidosis and salicylate ingestion

Cheyne-Stokes: Crescendo-decrescendo respirations alternating with periods of apnea (no breathing); causes include heart failure, uremia, central nervous system trauma, increased intracranial pressure, and coma

Biot (also known as ataxic breathing): Characterized by unpredictable irregularity; breaths may be shallow or deep and stop for short periods; causes include respiratory depression, meningitis, encephalitis, and other central nervous system lesions involving the respiratory centers

·         MAS is associated with the majority of cases of PPHN. Other associated disorders include RDS, sepsis or pneumonia, idiopathic PPHN, and lung hypoplasia (including congenital diaphragmatic hernia). In all instances, the pulmonary artery pressure remains near systemic levels and results in right-to-left shunting of blood.

·         Infants with Pena-Shokeir phenotype (also termed arthrogryposis multiplex congenita with pulmonary hypoplasia) have gracile ribs and reduced thoracic volume. Also present are a lack of fetal breathing activity, polyhydramnios resulting from a lack of fetal swallowing, and intrauterine constraint, resulting in muscular hypoplasia involving both intercostal and diaphragmatic musculature. Thoracic wall weakness, hypotonia of the muscles of respiration, and anterior horn cell atrophy or deficiency lead to reduced ventilatory drive, which may improve over time in selected infants.