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CHAPTER 52  Pneumonitis and Interstitial Disease

• BOX 52.3 Pulmonary Aspiration and Gastroesophageal

Reflux: Associated Disorders
Associated Disorders
•
•
•
•

Bronchopulmonary dysplasia
Asthma
Cystic fibrosis
Infantile apnea

Central Nervous System
•
•
•
•

Convulsive disorders
Anoxic encephalopathy
Neurologic impairment
Myopathies

Congenital Malformations
• Tracheoesophageal fistula
• Hiatal hernia

General
•
•
•
•

Failure to thrive
Achalasia
Cardiopulmonary resuscitation
Emergency surgery

produces direct injury to the mucosal surface of the respiratory
tract, resulting in diffuse alveolar damage, hemorrhage, and necrotizing bronchiolitis. This may be followed by a rapid interstitial
reaction, resulting in an acute inflammatory polymorphonuclear
cell infiltration involving the interalveolar septa. Bronchiolitis
obliterans and fibrosis can occur. In severe instances, the initial
onset of disease closely resembles that of ARDS, with similar
outcomes. Repeated aspiration of small amounts of gastric contents may lead to recurrent pneumonia, airway hyperreactivity,
bronchitis, and bronchiectasis with eventual fibrosis and involvement of the pulmonary interstitium.

Clinical Findings
Clinical symptoms of GERD vary with age.216,217 In older children, heartburn, acid/bitter taste, retrosternal pain, or abdominal
pain may be reported. Infants may be irritable and exhibit stridor,
poor sleeping patterns, or intermittent apnea. Esophagitis can
lead to microcytic anemia because of repeated episodes of gastrointestinal blood loss. Chronic respiratory symptoms may include
coughing, wheezing with choking episodes occasionally resulting
in apnea, or life-threatening events similar to those seen in infants
with sudden infant death syndrome. In the hospitalized pediatric
patient, significant aspirations may occur during or after general
anesthesia. Severe aspiration may be seen in patients receiving

tube feedings as a result of displacement of the feeding catheter.
Findings on a chest radiograph may vary from slight hyperinflation to a pattern of diffuse interstitial and alveolar densities. In
mild cases, a picture of bilateral diffuse infiltrates compatible with
ARDS may be seen. Although a barium esophagogram can help
to evaluate esophageal motility and detect esophagitis, it reflects
only a single point in time. Therefore, a negative study does not
rule out the presence of GERD. Radionuclide scans permit observation of esophageal function following the administration of
a radioactive tracer. Thus, the frequency and severity of reflux
and information on esophageal and gastric dysmotility may be
obtained. If delayed aspiration occurs, the radionuclide may be

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observed in the lung fields on a delayed scan.217 Esophageal motility and intraluminal pressures may be measured by esophageal
manometry. Intraesophageal pH measurement is helpful in that it
allows long-term monitoring of acid reflux by detecting the frequency, duration, and intensity of reflux.218,219 Esophagoscopy is
also useful for assessing the extent of mucosal injury by allowing
direct visualization and obtaining a mucosal biopsy. Use of BAL
for assessment of lipid-laden macrophages has been useful in establishing or corroborating the diagnosis of aspiration in complex
patients.218,219

Treatment
Treatment of patients with GERD frequently includes placing the
patient in an upright prone position and using thickened feedings. Use of antacid preparations—omeprazole, cimetidine, ranitidine, and other inhibitors of H2 gastroreceptors—may be
helpful in decreasing acid production and neutralizing its effects
on the esophageal mucosa. Omeprazole has, on rare occasions,
been associated with electrolyte disturbances. It has also been reported to possibly result in atrophic gastritis with prolonged use,
but its use continues to increase despite these possible adverse effects.220–224 Metoclopramide is used before meals to help improve
lower esophageal function and aid gastric emptying. With the
suspension of cisapride from the marketplace as an effective prokinetic agent because of potentially fatal toxicity, interest in erythromycin as a prokinetic agent has resurfaced. Many trials evaluating its dose and efficacy are underway.225 Bronchodilators are used

frequently to treat bronchospasm associated with GERD. Because
theophylline decreases the lower esophageal sphincter pressure,
aerosolized b2-agonists are preferred. In instances in which medical therapy was attempted and failed or in life-threatening situations, antireflux surgery is indicated. In such instances, a fundoplication, partial plication, or percutaneous gastrojejunostomy is
the appropriate treatment of choice.216 The most favorable outcome and lowest incidence of morbidity in such instances are
achieved when surgery is delayed until the patient is adequately
nourished and optimal pulmonary status has been obtained.

Inhalation Injury
Acute inhalation injuries are a leading cause of fatalities in pediatric patients. Smoke inhalation accounts for the largest number of
pediatric lives lost to inhalation injury each year. A significant
number of inhalation injuries as a result of irritant gases occur
through industrial or household accidents.226,227 Serious pulmonary inhalation injury may be manifested immediately or delayed
in onset (Table 52.9).228–230

Pathogenesis
Direct injury to the mucosal surface is the most common mode
of pulmonary injury. Inhalation of noxious substances may cause
extensive physical damage to the lungs and seriously impair subsequent gas exchange. The epithelial cells of air passages may become necrotic and desquamate, causing marked airway obstruction. Bronchospasm caused by irritation from the inhaled gases or
particles may lead to further airway obstruction. Severe damage to
the basement membrane may occur and cause subsequent leakage
of intravascular fluid and blood into the alveolar and interstitial
spaces. Injury may occur at all levels of the respiratory tract depending on the physical and chemical properties of the irritant,
the agent concentration, duration of exposure, and breathing pattern of the person exposed.228,231,232 The clinical course usually has


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S E C T I O N V   Pediatric Critical Care: Pulmonary

TABLE

Irritant Gases
52.9

Agent

Exposure/Environment

Direct Mucosal Injury
Acrolein

Plastic, rubber, textiles

Ammonia

Fertilizer, refrigerants, explosives

Chlorine

Bleaching, disinfectant

Formaldehyde

Disinfectant, paper, photography

Hydrogen chloride

Refining, dye making

Hydrogen fluoride

Etching, petroleum

Nitrogen dioxide

Welding, fertilizer, farming

Phosgene

Insecticide, dyes, chemicals

Sulfur dioxide

Bleaching, refrigeration

Asphyxiation Injury
Carbon dioxide

Mining, foundry

Carbon monoxide

Smoke, foundry, mining

Natural gas

Mining, petroleum

three phases: (1) the acute phase, which occurs within minutes or
hours of the insult, resulting in pulmonary edema, hypoxemia,
and respiratory failure; (2) the delayed phase, which occurs within

the first few days and may include continuing effects of the lung
injury, such as pulmonary edema, airway obstruction, and superinfection; and (3) the phase in which long-term sequelae may be
noted because of the hypoxic or ischemic injury to other organ
systems and recurrent pulmonary problems resulting from reactive airways disease or interstitial fibrosis.

Clinical Findings
Clinical manifestations are nonspecific for inhalation of various
irritant gases and may differ depending on the individual child.
Injury of the airways may be manifested as upper airway obstruction resulting in laryngotracheitis, bronchitis, and upper airway
edema. More peripheral airway obstruction may present with
classic findings of asthma and airway edema with hypersecretion.
In cases of massive exposure, the presenting symptoms may be
those associated with ARDS, manifested by profound V/Q mismatch, cyanosis, dyspnea, and respiratory failure. Severe nasopharyngeal and laryngeal edema with hypersecretion may present as
stridor.229,231 Chest radiograph findings are nonspecific, ranging
from scattered areas of atelectasis and infiltrate to dense bilateral
alveolar infiltrates.
Treatment
Prompt physical removal from the offending agent and maintenance of upper airway patency are imperative. Endotracheal intubation is a high-risk procedure; thus, meticulous attention must
be directed toward maintaining proper pulmonary toilet and removal of upper airway secretions and debris from the artificial
airway once it is secured.
Oxygenation should be monitored closely. High oxygen concentrations, mechanical ventilation, and use of positive end-expiratory
pressure may be necessary in the event of acute respiratory failure
because the diminished compliance and formation of pulmonary

edema occur rapidly. Use of steroids may be justified in the treatment of patients who have been exposed to oxides of nitrogen;
however, use after exposure to other irritant gases has not been
validated.
Bronchoscopy may be indicated and useful in assessing the
severity of airway injury and as an aid to endotracheal intubation
and treatment of major areas of atelectasis. However, use of BAL

is usually not indicated except in instances in which significant
particulate or carbonaceous material is likely. Humidification of
air and oxygen mixtures to thin secretions is necessary, and chest
percussion/postural drainage may help to mechanically clear the
airways.
Use of prophylactic antibiotics in persons with inhalation injuries is not recommended. If pulmonary infection is suspected,
prompt therapy with broad-spectrum antimicrobial agents should
be started. Use of bronchodilators is advocated because of a high
incidence of bronchospasm. No critical studies have evaluated this
therapy in persons with an inhalation injury; however, the risk
associated with its use is low, and administration to the child with
obvious airflow obstruction is warranted. Use of aerosolized
b2-agonists is preferred. Special attention is required in the presence of smoke inhalation with regard to the treatment of carbon
monoxide poisoning. Hyperbaric oxygen, if available, or sustained
administration of 100% oxygen, is recommended in the initial
treatment of patients with significant carbon monoxide intoxication. Development of upper or lower airway edema may necessitate intubation and mechanical ventilatory support.228,232,233
Administration of artificial surfactant may be beneficial in patients in whom ARDS develops.233 Use of prophylactic steroids
and antibiotics for persons affected by smoke inhalation is not
recommended, especially if burn injuries are present, because
complications are more frequent.

Prognosis
The prognosis of children with acute pulmonary injury produced
by inhalation of toxic gases is generally good. Restrictive and obstructive pulmonary function abnormalities have been observed
following recovery. Residual defects such as bronchiolitis obliterans, bronchiectasis, and reactive airways disease have been observed following smoke inhalation.

Ingestion/Injection of Pharmacologic Agents
Several chemotherapeutic agents and other commonly used drugs
have potentially serious pulmonary toxicity (Box 52.4). Pulmonary toxicity is thought to be a direct effect in most instances, but
immunologic and hypersensitivity mechanisms may also be involved. Toxicity may occur during therapy or after discontinuation of the agent.234 The development of blebs in the capillary

endothelium is followed by an interstitial fibrinous edema and
mononuclear cell response with eventual hyaline membrane formation. Some studies have shown a significant decrease in type 1
pneumocytes with the evolution of type 2 pneumocytes, septal
thickening, and a proliferation of fibrous tissue with a decrease in
the number of alveolar septa. Pleural thickening may accompany
the pneumonitis.

Diagnosis/Clinical Findings
Characteristic clinical features of drug-induced pulmonary disease
include fever, malaise, dyspnea, and a nonproductive cough. Initial radiographic studies may be normal but usually demonstrate
a diffuse alveolar and/or interstitial involvement. Pulmonary


CHAPTER 52  Pneumonitis and Interstitial Disease

• BOX 52.4 Pharmacologic Agents Associated

With Pulmonary Toxicity
Cytotoxic Agents
Antibiotics
• Bleomycin: IP/PF, H, PEFF
• Mitomycin C: IP/PF, PE, PEFF

Alkylating Agents
•
•
•
•

Cyclophosphamide: IP/PF, PE, B

Busulfan: IP/PF, AH
Chlorambucil: IP/PF
Melphalan: IP/PF

Antimetabolites
•
•
•
•

Methotrexate: IP/PF, PE, H, PEFF
Azathioprine: IP/PF
G-mercaptopurine: IP/PF
Cytosine arabinoside: IP/PF, PE

Nitrosoureas
• Carmustine: PF

Noncytotoxic Agents
•
•
•
•
•
•
•

Amiodarone: IP/PF
Carbamazepine: H, B
Gold salts: IP/PF, H

Nitrofurantoin: AH, PEFF, H, B, IP/PF
Diphenylhydantoin: H
Sulfasalazine: H, FA, BO, B
Penicillamine: DA, AH, H, BO

AH, Alveolar hemorrhage; B, bronchospasm; BO, bronchiolitis obliterans; DA, diffuse alveolitis; FA,
fibrosing alveolitis; H, hypersensitivity lung reaction; IP, interstitial pneumonitis; PE, pulmonary edema;
PEFF, pleural effusion; PF, pulmonary fibrosis.

function studies may be of either an obstructive or restrictive pattern. Hypoxemia enhanced by exercise is an early and clinically
important finding because interstitial pneumonitis and pulmonary fibrosis constitute a major portion of drug-induced pulmonary disease. Histologic examination of lung tissue is frequently
indicated to confirm the clinical diagnosis and to rule out other
potential causes of pneumonitis, such as Pneumocystis, viral, or
fungal infections that often occur in children treated with these
agents.
Other complications—such as hypersensitivity lung disease,
noncardiogenic pulmonary edema, bronchiolitis obliterans, alveolar hemorrhage, and pleural effusion—may occur in these
patients. Persistent and fatal lung dysfunction may follow druginduced pulmonary damage. Therapy should be directed at early
recognition of the problem, discontinuation of the offending
agent, and supportive therapy.

Idiopathic Interstitial Lung Disease
ILD of undetermined etiology is rare in adults but is even more
uncommon in children. Histologic classification of the idiopathic
type of ILD can be somewhat confusing; in the past, pediatric
classification mirrored the adult classification scheme. As research
progressed, some overlap was noted, but it was found that pediatric interstitial lung diseases have features that are unique to
pediatrics. Usual interstitial pneumonitis (UIP) has never been
identified in children, as the diagnostic fibroblastic foci were not

603

found in any of the cases that had initially been labeled UIP.
Other interstitial pneumonias, such as desquamative interstitial
pneumonitis (DIP) and lymphocytic interstitial pneumonia
(LIP), are seen in children but remain quite rare and have some
features that are different from their adult counterparts. DIP in
children is not associated with smoking. Its histologic picture is
one of macrophage being the primary inflammatory cell that fills
the alveolus, although histiocytes, lymphocytes, eosinophils, and
plasma cells are also present. Hyaline membrane formation is not
seen in DIP, and the structural integrity of the alveolar unit is
usually maintained. DIP tends to be responsive to steroids.233 LIP
is seen mostly in patients with immune deficiencies and connective tissue disorders. LIP tends to be insidious in onset and appears as a result of infiltration of the interstitium by plasma cells,
mature lymphocytes, and histiocytes. Nonspecific interstitial
pneumonitis histologically is a mixture of inflammation and fibrosis. This entity has been identified in children. Cryptogenic
organizing pneumonia has been identified in children as an isolated phenomenon or with infection, asthma, drug reactions,
malignancies undergoing chemotherapy, bone marrow transplantation, and autoimmune disorders. Prognosis is usually excellent,
and patients have an excellent response to corticosteroids. Acute
interstitial pneumonia is a rapidly progressive disorder with a
histologic appearance consistent with the organizing form of diffuse alveolar damage. This diagnosis generally has a poor prognosis. Some interstitial lung diseases that are unique to infancy were,
in the past, most likely labeled under the aforementioned interstitial lung diseases but truly belonged in their own classification
scheme. These syndromes are persistent tachypnea of infancy
(neuroendocrine cell hyperplasia of infancy), follicular bronchitis,
cellular interstitial pneumonitis (pulmonary interstitial glycogenosis), chronic pneumonitis of infancy, and genetic abnormalities of surfactant function.235 Detailed discussions of these disorders of infancy or the other interstitial lung diseases and their
management are beyond the scope of this chapter but can be
found in various review articles.236–241 Patients who do not respond to medical therapy should be considered candidates for
lung transplantation.

Pediatric Pulmonary Hemorrhage

Pulmonary hemorrhage (PH) is a potentially life-threatening
event that can occur at any age. The clinical presentation varies
from massive fatal hemoptysis to silent bleeding with respiratory
distress and anemia. Rapid determination of the etiology of the
PH and institution of a specific therapy is often difficult. This
section examines the less common causes of PH. PH resulting
from trauma and infection is not discussed.

Definition
PH is defined as the extravasation of blood into airways and/or
lung parenchyma. Massive PH in adults is defined as blood loss
of 600 mL or more in 24 hours.242–246 In infants, Esterly and
Oppenheimer245 characterized massive PH as the involvement of at
least two pulmonary lobes by confluent foci of extravasated erythrocytes. Loss of 10% of a patient’s circulating blood volume into the
lungs, regardless of age, causes a significant alteration in cardiorespiratory function and should be considered massive. The diagnosis of
PH following an episode of silent bleeding is established by pulmonary hemosiderosis, which is the abnormal accumulation of iron
within lung parenchyma and alveolar macrophages.


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S E C T I O N V   Pediatric Critical Care: Pulmonary

Pathophysiology
Accumulation of blood in the airways following a significant
episode of PH creates multiple problems. These problems include
the production of a diffusion barrier resulting in hypoxemia and
reduction in the diameter of involved airways, which, in turn,
increases airway resistance and may lead to airway obstruction.
Reduction in pulmonary compliance and impairment of ventilation may occur.246–248 These changes in respiratory function

increase both the ventilatory and myocardial work necessary to
maintain a normal arterial oxygen tension. Interstitial fibrosis that
develops following repeated episodes of PH results in reduced
carbon monoxide diffusion and diminished static and dynamic
lung compliance.

Etiology
Classification of the etiologies of PH provides a simple framework
to proceed with diagnostic and therapeutic interventions (Box 52.5).
Diffuse PH is usually associated with less total blood loss and can
occur from either immune or nonimmune mechanisms. Diffuse,
immune PH typically affects adolescents and, less commonly,
school-aged children. Focal PH is commonly responsible for massive PH and carries a mortality rate greater than 50%.247,249–250
Focal PH typically affects preschool-aged children but may occur
in infancy.

Diffuse/Nonimmune Pulmonary Hemorrhage
PH in the neonate occurs in 0.7 to 4 per 1000 live births and is
present in 6% to 26.3% of neonates at postmortem examination.
Risk factors associated with PH in the neonate include asphyxia,
infection/sepsis, CNS injury, weight less than 1500 g and/or smallfor-gestational-age, male sex, congenital heart disease, idiopathic
• BOX 52.5 Causes of Pulmonary Hemorrhage
Diffuse
Nonimmune
• Neonatal
• Congenital heart disease
• Hematologic

respiratory distress syndrome, and coagulation disorders.250,251
Intraalveolar hemorrhage appears to occur more commonly in

neonates of older gestational age. PH in neonates as a primary
occurrence is uncommon.250 Pathogenesis of PH in the neonate is
considered to result from the development of persistent pulmonary hypertension with right-to-left intracardiac shunting of
blood, resulting from hypoxia and acidosis. Left ventricular failure
ensues, causing an increase in pulmonary capillary pressure and
subsequent disruption of pulmonary capillary and alveolar membranes. Severe CNS injury may indirectly affect cardiac function,
causing increased left ventricular end-diastolic pressure.252
Severe hemoptysis and life-threatening PH are rare in the preadolescent child with congenital heart disease. However, a drastic
increase in pulmonary capillary pressure in children with pulmonary atresia, unilateral pulmonary venous atresia, total anomalous
pulmonary venous drainage with obstruction, mitral stenosis, cor
triatriatum, or hypoplastic left heart syndrome may result in massive PH.252,253
Although the lungs are an infrequent site for early manifestations of primary bleeding disorders,243,246 a coagulopathy should
be ruled out during the management of any patient with PH. In
patients with leukemia, PH occurs most frequently when the
platelet count is lower than 10,000/mm.

Diffuse/Immune Pulmonary Hemorrhage
The classic clinical triad of hemoptysis, microcytic hypochromic
anemia, and diffuse alveolar-filling opacities on a chest radiograph
(Fig. 52.1) is found in most episodes of PH in this category. Although the lung may be the only organ affected, more frequently,
multiple organs are involved. In patients with PH, establishing
which extrapulmonary organs are involved by the disease helps to
narrow the differential diagnosis of which of the immune-mediated disorders is most likely present.
Diffuse parenchymal bleeding without evidence of extrapulmonary involvement occurs in patients with idiopathic pulmonary hemosiderosis, Heiner syndrome, and drug-induced PH.
Idiopathic pulmonary hemosiderosis, a disease of childhood, is a
diagnosis of exclusion. Clinically, episodes of PH recur, with 30%
to 50% of patients eventually dying of exsanguination and/or

Immune
•

•
•
•
•
•
•
•
•
•
•

Lower respiratory and renal
Goodpasture syndrome
Idiopathic rapid progressive glomerulonephritis
Upper and lower respiratory and renal
Wegener granulomatosis
Multisystem organ involvement
Systemic lupus erythematosus
Polyarteritis nodosa
Behỗet syndrome
Henoch-Schửnlein syndrome
Rheumatoid arthritis

Focal
•
•
•
•
•
•

Foreign body aspiration and chronic retention
Sequestration
Arteriovenous fistula
Bronchogenic and gastroenteric cysts
Thrombus or embolus
Neoplasms: angiomas, adenomas

•  Fig. 52.1  ​Chest radiograph of a patient with diffuse immune pulmonary
hemorrhage.


CHAPTER 52  Pneumonitis and Interstitial Disease

respiratory failure.254,255 Microscopic examination of the lungs is
compatible with nonspecific injury rather than a specific cause
such as vasculitis or immune deposits.254 Heiner syndrome, which
affects children between the ages of 6 months and 2 years, usually
manifests as other symptoms, such as chronic rhinitis, recurrent
otitis media, and growth retardation.255 Tests for precipitating
antibodies to milk proteins are positive. Symptoms resolve when
milk and milk products are eliminated from the diet.
Although uncommon, exposure to or inhalation of d-penicillamine, lymphangiography dye, trimellitic anhydride, cocaine,
and exogenous surfactant256,257 has been associated with the development of PH. Acute PH of an undetermined etiology occurring
in infants has been reported.258,259
Idiopathic rapidly progressive glomerulonephritis is usually a
disease of older adults (mean age, 55–60 years). In children with
PH and either proteinuria, hematuria, or red cell casts, Goodpasture syndrome is the most likely etiology. The presence of a linear
immunofluorescent staining of Ig and C3 along glomerular capillary walls and antibasement membrane antibody (ABMA) in the
serum confirms the diagnosis of Goodpasture syndrome. Renal

biopsy is the preferred primary method of confirming the diagnosis because an ABMA assay is not readily available at most institutions. ABMA is a cytotoxic plasma Ig that reacts immunologically
with components of alveolar and glomerular basement membrane. Stress failure of pulmonary capillaries because of alteration
of the alveolar and glomerular basement membrane may contribute to the likelihood of PH in these patients.260 Fifty percent of
patients with Goodpasture syndrome die of asphyxia as a result of
massive PH. The presence of sinusitis and/or bilateral, multiple
cavitary pulmonary nodules, and evidence of glomerulonephritis
in patients with PH help distinguish Wegener granulomatosis
from the other vasculitides.261 Serositis, arthritis, facial erythema,
fever, and glomerulonephritis are present before the development
of PH in patients with systemic lupus erythematosus (SLE).262
Ten percent of all cases of immune-mediated PH are associated
with SLE.262 The onset of PH in patients with SLE is abrupt.
Pulmonary histology may or may not reveal a small vessel vasculitis characterized by neutrophilic infiltration of vessel walls and
necrosis of capillaries and alveolar septa. Renal histology shows a
vasculitis represented by focal and segmental glomerulonephritis
with absent or minimal immune deposits. The majority of patients who have SLE and PH die.262 PH has been reported with
most of the vasculitides, but the incidence is much lower than in
the SLE population. Constitutional signs and symptoms, such as
musculoskeletal involvement, blood dyscrasias, and dermatitis,
are the predominant clinical features of polyarteritis nodosa, the
second most likely vasculitis-associated disease to cause PH.263,264
A segmental necrotizing (granular pattern) vasculitis is the characteristic lesion of polyarteritis nodosa, with PH a dominant feature.265 Recurrent uveitis, mucocutaneous ulcerations, and genital
ulcerations in a patient with PH suggest Behỗet syndrome as the
etiology. Other clinical features seen with Behỗet syndrome include arthritis, gastrointestinal disease, cardiovascular involvement, and CNS disease.266,267 A necrotizing vasculitis of small to
medium-sized arteries and veins and thromboses of the terminal
vascular beds or vena cava confirm the diagnosis.
Although PH is an extremely rare complication of HenochSchönlein purpura or syndrome (when abdominal pain and arthritis precede the purpura), it should be treated aggressively because it may be fatal. In a few patients with rheumatoid arthritis,
syndromes resembling idiopathic pulmonary hemosiderosis without evidence of vasculitis or renal disease have developed.

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Focal Pulmonary Hemorrhage
Congenital malformations that may be responsible for PH during
infancy include angiomas and bronchogenic and gastroenteric
cysts.249 Angiomas are located in the subglottic area and present
with symptoms of airway obstruction by age 6 months in almost
90% of cases. Bronchogenic cysts arise from abnormal branching
of the tracheobronchial tree, are lined with ciliated columnar epithelium, are filled with mucoid fluid, and, if they are in communication with the airway, they may demonstrate an air-fluid level.
They are prone to infection and may bleed if contiguous vessels
erode. Gastroenteric cysts, which are enteric duplication cysts
lined with gastric mucosa, produce acid peptic secretions that may
erode through adjacent vessels to cause bleeding. Pulmonary sequestration, arteriovenous fistula, and bronchial adenomas are
congenital malformations that may present in childhood or later
life with PH. With its tendency to become recurrently infected, a
sequestered lobe may erode into its systemic arterial supply, causing massive PH.249 Pulmonary arteriovenous fistula with or without telangiectasia (isolated or familial) may produce massive PH
during childhood, but this usually does not occur until adulthood.265,266,268 Adenomas are highly vascular tumors that, with
minor trauma or inflammation, can cause PH. Acquired causes of
focal PH include aspiration of an organic foreign body and development of a pulmonary arterial thrombus or embolus.247 A patient presenting with PH and wheezing should lead the clinician
to suspect a diagnosis of foreign body aspiration. Prolonged retention of an organic foreign body leads to hyperplasia of tortuous
bronchial vessels, varicosities, and bronchiectasis, any of which
may cause PH. Thrombi or emboli may develop in postoperative
immobile children with central venous or pulmonary catheters, in
female adolescents using oral contraceptives, or in patients with
homozygous deficiency of antithrombin III, protein S, and protein C. Focal PH may develop in children with cystic fibrosis as a
result of bronchiectasis.

Treatment
General
The primary objectives in the treatment of PH are twofold: (1) to
rapidly control the bleeding to prevent tissue hypoxia and/or

ischemia resulting from airway obstruction and exsanguination
and (2) to stabilize hemodynamics to prevent further damage to
the kidneys or other extrapulmonary organs by the underlying
disorder.244,267 Initial management of the patient with severe PH
should occur in the setting of a critical care unit because of the
potential lethality of this event (Box 52.6). General care measures
include use of the Trendelenburg position as tolerated, oxygen
supplementation, mechanical ventilation, and hemostasis therapy
when indicated. The Trendelenburg position may help clots
propagate superiorly and exit the airway. This position may not be
well tolerated by patients with respiratory or cardiac embarrassment. Positive end-expiratory pressure during mechanical ventilation may become necessary to reverse hypoxemia and may provide
a measure of tamponade to the site of hemorrhage.244 Coagulation factors should be administered when indicated to lessen the
severity of bleeding. Hemodynamic monitoring with a pulmonary arterial catheter may be beneficial in some instances because
high pulmonary artery occlusion pressure may worsen PH of any
etiology. Short-term control of bleeding may be obtained with
insertion, under direct vision, of a balloon-tipped (Fogarty) catheter into the affected portion of the airway. Right upper lobe