Pediatric emergency medicine trisk 1026

If a patient is asymptomatic or minimally symptomatic, bronchoscopy may be
helpful in identifying and relieving a reversible cause of bronchial obstruction,
such as a mucous plug or granulation tissue. However, pulmonary lobectomy is
most commonly required and may be needed acutely if symptoms are
progressive. The diseased lobe is evident at thoracotomy because of its
overdistended state, often billowing out of the chest. Lobectomy is curative if the
cause of the obstruction is also relieved.

Congenital Pulmonary Arteriovenous Fistula
Congenital pulmonary AV fistula is a congenitally occurring communication
between a major pulmonary artery and a vein within the lung, usually with an
aneurysmal sac. Fistulae vary in size from a few millimeters to several
centimeters and can be multiple. At times, a systemic artery may also be
involved. Direct right-to-left shunting leads to hypoxemia, and the size of the
fistula correlates with the degree of desaturation.
Clinical Recognition
As the initial presentation of this disorder is frequently that of wheezing and
desaturation, the child may be initially diagnosed with asthma. Clubbing and
cyanosis may demonstrate the hypoxemia. Examination of the chest may reveal a
palpable thrill or murmur. If there are symptoms of hemoptysis and epistaxis, one
may find telangiectasias or hemangiomas of the skin and mucous membranes.
Evaluation of the family may also reveal the presence of hereditary hemorrhagic
telangiectasis (Rendu–Osler–Weber disease), which is present in more than half
the patients with congenital pulmonary AV fistula.
Management
Children who are symptomatic from this condition are best evaluated by CT scan,
contrast echocardiography, perfusion scintigraphy, and arteriogram of the
pulmonary artery and aorta. Chest radiographs may demonstrate the aneurysmal
areas as rounded or lobulated discrete lesions in the parenchyma. Often, tortuous
vessels trace from these rounded areas to the hilum. Symptomatic patients should
be admitted to the hospital while a definitive management course is decided.

Resection of the fistula, often involving lobectomy, is indicated if the lesion is
localized, and may be curative. Multiple small lesions may be amenable to
embolization. Unfortunately, some patients have such diffuse disease that such
intervention is impossible.

Rare Lesions


Unusual lung lesions encountered in the pediatric population include certain rare
tumors and uncommon infections. Rare solid tumors, often identified incidentally
on radiographs, include primary sarcoma, pulmonary blastoma, hamartomas, and
teratomas. Fungal infections, including actinomycosis, histoplasmosis,
mucormycosis, and coccidioidomycosis, may look like tumors on chest
radiograph. Atresia of the bronchus or pulmonary artery is rare and will produce
differences in the density of the two lungs. The reader is referred to texts of
pulmonary medicine or thoracic surgery for further discussion.

MEDIASTINAL TUMORS
CLINICAL PEARLS AND PITFALLS
Symptoms of mediastinal lesions are frequently respiratory in nature.
Orthopnea is a worrisome sign, particularly with anterior mediastinal
masses. Such patients may experience respiratory or circulatory
collapse with sedation or anesthesia.
Chest x-ray is the initial diagnostic study of choice and will demonstrate
most significant mediastinal masses.
Anterior mediastinal tumors are frequently neoplastic and middle
mediastinal tumors are often cystic.
Prompt surgical consultation may be needed in cases of respiratory
distress or circulatory compromise.

Current Evidence
At least one-third of all mediastinal lesions occur in children younger than 15
years of age. The pathology in these cases is varied. Half of these masses are
symptomatic, and half of the symptomatic masses are malignant tumors, with the
likelihood of malignancy increasing with the age of the patient. More than 90% of
asymptomatic masses are benign.
The mediastinum is commonly divided into anterior, superior, middle, and
posterior compartments (Fig. 124.11 ), and the location of a lesion can help to
limit its differential diagnosis. The superior mediastinal compartment contains
germ cell tumors of the thymus, thymomas, and lymphangiomas. The anterior
compartment contains thymic tumors and lymphangiomas as well as lymphomas
and teratomas. Bronchogenic cysts in the area of the hilum are located in the
middle mediastinum, and frequently have a cystic appearance on cross-sectional
imaging. Esophageal cysts and most neurogenic tumors, such as neuroblastomas


and ganglioneuromas, are found in the posterior compartment. Neurogenic
tumors are the most common cause of mediastinal masses, with lymphomas and
germ cell tumors being second and third in frequency. Infection is an uncommon
cause of mediastinal node enlargement, but when present, is frequently caused by
histoplasmosis. Thymic enlargement may mimic an anterior mediastinal mass.

FIGURE 124.11 Mediastinal tumors in children. Differential diagnosis is based on anatomic
location within the mediastinum.

Goal of Treatment
Since the meadiastinum is a limited and confined space, lesions in this anatomic
area can cause respiratory and circulatory compromise, which may be the
presenting symptoms. Prompt identification of a space-occupying mediastinal
mass and an awareness of the relevant anatomy are critical. These patients require

careful attention and early consultation with appropriate specialists for complete
workup and expeditious treatment.

Clinical Considerations
Clinical Recognition
Mediastinal masses frequently present with chest pain or respiratory symptoms as
a result of airway compression. Patients may present with cough, wheezing,
recurrent respiratory infections, bronchitis, atelectasis, and hemoptysis.
Dysphagia and hematemesis may occur with compression of the esophagus.
Superior vena cava syndrome is a rare complication, usually in association with a
rapidly growing tumor. Orthopnea may occur with vascular compression. If the


recurrent laryngeal nerve is compressed as a result of the mass, hoarseness and
inspiratory stridor may result. Spinal cord compression and vertebral erosion can
be seen with a posterior mediastinal tumor.
A careful history may reveal more subtle symptoms, and families should be
queried specifically about fever, chills, weight loss, and night sweats. Physical
examination should be thorough. It is important to focus on a careful respiratory
and cardiac examination, evaluation of the head and neck for palpable masses or
venous distention, palpation of the abdomen for organomegaly or masses, and
examination of the various nodal basins for adenopathy.

Solid Mediastinal Masses
Children with tumors of the anterior or superior mediastinum should be admitted
to an inpatient ward for urgent evaluation because these tumors may pose an
immediate threat to life. CT scan or MRI of the chest is generally needed to
supplement plain radiographs, in order to further define the location and extent of
the mass, and to potentially provide details that may help establish the diagnosis.
Much of the management depends upon whether the lesion is cystic or solid.

Solid masses raise concern for oncologic pathology, particularly if located in the
anterior mediastinum, and imaging may be very helpful in aiding diagnosis. In the
appropriate clinical setting, tumor markers should be obtained, including serum
alpha fetoprotein (AFP) and beta-human chorionic gonadotropin (bHCG) levels,
and urine catecholamine and metanephrine levels. Lymphomas and teratomas are
the most common mediastinal tumors in children, with other solid masses
occurring more rarely. Thymomas comprise less than 1% of mediastinal tumors in
children, with multimodal therapy the mainstay. Benign thymic hyperplasia
typically does not cause respiratory compromise, but rapid enlargement often
warrants intervention, such as steroid therapy or resection.
When biopsy of a large mediastinal mass is necessary, the logistics of the
procedure require careful, thoughtful evaluation, ideally involving the
pediatrician or emergency clinician, surgeon, oncologist, and anesthesiologist.
Airway and cardiac compression by large mediastinal masses can be significant.
Large mediastinal masses should be evaluated by CT scan of the chest to assess
the presence and extent of tracheal compression. MRI may be a better diagnostic
modality for posterior mediastinal masses because many of them are neurogenic
in origin and may have extension into the spinal canal. An echocardiogram
should also be obtained prior to surgery, to assess the extent of mediastinal shift
and the degree of atrial or ventricular compression by the mass. Delivery of
general anesthesia may lead to occlusion of the thoracic trachea by the tumor.
This situation can be challenging to manage; passage of a rigid bronchoscope