Pediatric emergency medicine trisk 1022

return, as well as from shifting mediastinal structures (particularly in younger
children) with compression of the cardiovascular structures.
Clinical Assessment. The symptoms and signs of pneumothorax depend on the
size of the pleural collection and how rapidly it occurs. The most common
presenting symptoms are unilateral chest pain and dyspnea. For example, it is
common for a patient with spontaneous rupture of an emphysematous bleb to
complain of sudden acute pain on the involved side of the chest followed by
tachypnea, pain at the tip of the ipsilateral shoulder, and a sense of shortness of
breath. Such patients usually have a small to moderate pneumothorax (less than
20% of the lung volume), often with no accompanying hypoxia. Decreased breath
sounds may be heard on the ipsilateral side, and a chest radiograph will usually
demonstrate the pneumothorax, particularly if taken at end expiration. Patients
with a more longstanding pneumothorax may not even be in pain.
In general, a patient with a pneumothorax of 50% or more of the lung volume
will exhibit signs and symptoms of ventilatory impairment: dyspnea, tachypnea,
pain, splinting on the involved side, agitation, increased pulse rate, diminished
breath sounds, and increased resonance to percussion on the involved side.
Displacement of the trachea and heart away from the involved side occurs in large
pneumothoraces. Severe dyspnea should alert the physician to the possibility of a
very large or possible tension pneumothorax. A child with existing underlying
lung disease may display more severe symptoms and hypoxemia with a small or
moderate pneumothorax.
In addition to describing symptoms, the patient with pneumothorax should be
asked about potential predisposing conditions or risk factors including asthma,
foreign-body aspiration, underlying infections, inhaled drug use, activities at
onset of symptoms, and history of any prior pneumothoraces.
If the patient’s condition is not severe, an immediate upright PA and a lateral
chest radiograph should be taken. These radiographs are important to determine
not only the site and extent of the pneumothorax but also any complicating
features such as tumor, fluid within the pleural space, or abnormalities of the
lungs, diaphragm, or mediastinum.

Management. There are currently no widely accepted pediatric guidelines
regarding management of spontaneous pneumothoraces. Approaches may vary
depending on the extent of the pneumothorax, the severity of symptoms, ongoing
expansion, presence of tension physiology, and the suspected underlying etiology
or clinical condition. Small spontaneous pneumothoraces (e.g., less than 15% to
20% of lung volume) that are asymptomatic can typically be managed with


prolonged observation alone, either in the ED or through admission to the
hospital. Pediatric patients with a pneumothorax require observation, even if no
chest tube is believed necessary, to monitor for signs of clinical deterioration
(e.g., hypoxia) and to repeat a chest radiograph as clinically indicated to ensure
no progression of the process. Limited evidence suggests supplemental oxygen
may hasten the rate of pleural air absorption; patients with moderate to large
pleural effusions are typically placed on a nonrebreathing facemask.
Patients with larger pneumothoraces, any hypoxemia or respiratory distress, or
those with evidence of ongoing leak from the lung surface usually require
intervention. Options include thoracentesis, placement of a small “pigtail”
catheter, or placement of a standard chest tube (see Chapter 130 Procedures ). In
the ED, the percutaneous “pigtail” catheters are ideal for pneumothoraces without
associated hemothorax or empyema. However, these catheter devices are small
gauge and may develop fibrin plugs. Therefore, in a patient in whom continuous
accumulation of air takes place in the pleural space despite the presence of a
thoracentesis or pigtail catheter, a standard-sized chest tube should be placed. A
surgical consultation is generally warranted for any patient with a pneumothorax,
particularly if there is evidence of a continuing air leak or the mechanism was
traumatic, or due to an underlying anatomic abnormality.
Tension pneumothoraces are a life-threatening emergency and deserve special
consideration. A tension pneumothorax should be clinically obvious from absent
breath sounds on the affected side, respiratory distress, hypoxia, and tracheal

deviation. These patients require immediate decompression with a large-bore (14gauge) angiocatheter into the second intercostal space anteriorly to evacuate the
air and relieve the tension. Treatment should not be delayed to obtain a chest
radiograph. The insertion of the needle and catheter will immediately result in
release of the tension on the mediastinum and diaphragm. This maneuver should
be followed by the controlled placement of an appropriate-sized chest tube.
Depending on the suspected etiology, further studies such as CT may be
indicated.
Definitive surgical therapy, such as VATS with pleurodesis, is typically
reserved for patients who have recurrent spontaneous pneumothoraces, severe
underlying lung disease, or a persistent air leak not responding to conventional
chest tube drainage. Unfortunately, at least half of children who suffer from a
spontaneous pneumothorax will have a recurrence.

Pneumomediastinum
Pneumomediastinum occurs when there is an abnormal collection of air in the
mediastinum from either a spontaneous or traumatic mechanism. As with


pneumothoraces, spontaneous pneumomediastinum tends to be found most often
in tall, thin, adolescent males. Pneumomediastinum is typically caused by
alveolar rupture (though air can also escape from the airways or gastrointestinal
tract), resulting in free air that tracks along the bronchovascular sheath and then
migrates centrally to the hilum and surrounding structures. It often dissects
through soft tissues and fascial planes and can be seen in the neck and chest. Most
of the time, due to this dissection into the soft tissues, there is no significant
buildup of pressure in the mediastinum. It is often found incidentally on chest
radiography. In extreme cases, however, the tension produced in the mediastinum
can be great enough to impair both circulation and ventilation. Although
extremely rare, this phenomenon is most likely to occur in a patient who is
receiving positive-pressure ventilation, which enhances escape of air from the

bronchial tree into the mediastinum (Fig. 124.6 A ).
Clinical Recognition
Pneumomediastinum is most commonly associated with asthma exacerbations,
but can also be identified in cases of Valsalva maneuver, severe cough,
barotrauma, forceful emesis, foreign-body aspiration, and inhalational drug use.
The predominant symptom is pleuritic chest pain, which may radiate and be
accompanied by dyspnea and/or dysphagia. Crepitus over the neck or upper
thorax may be appreciated on physical examination. Auscultation over the heart
may reveal Hamman sign, which is a crunching sound that may obscure the heart
sounds. In the rare cases of tension pneumomediastinum, patients may be in
severe distress with distended neck veins, tachypnea, and cyanosis. In the
majority of cases, however, severe distress should prompt consideration of
additional or alternative diagnoses since it is unusual in isolated spontaneous
pneumomediastinum.
Management
Pneumomediastinum is diagnosed on chest radiography, which demonstrates air
tracking around and outlining mediastinal structures on both frontal and lateral
views. Subcutaneous emphysema is often appreciated as well. These findings
may be quite subtle (Fig. 124.6 B ). Management of pneumomediastinum
depends largely on the suspected etiology. In the vast majority of cases of
spontaneous pneumomediastinum, conservative treatment with rest, observation,
and analgesia is appropriate since most of these self-resolve over several days.
Patients should be instructed to avoid activities like the Valsalva maneuver that
increase pulmonary pressure. If esophageal perforation is suspected due to an


esophageal foreign body or a significant history of forceful emesis, an
esophagram using water-soluble contrast may be helpful. In the extremely rare
case of a tension pneumomediastinum, evacuation of the accumulated air in the
mediastinum is necessary.

FIGURE 124.6 A: Significant pneumomediastinum with accentuation of the cardiac silhouette.
B: A far more subtle pneumomediastinum in an asthmatic patient with chest pain.

Pleural Effusion
Pleural fluid in excess amount is not a disease per se, but it indicates the presence
of pulmonary or systemic illness. The classification of the fluid into transudate ,
which accumulates when the normal pressure relationships between the capillary
pressure in the lung, the pleural pressure, and the lymphatic drainage pressure are
disturbed, or exudate , an inflammatory collection, has less utility today because
of other diagnostic tools presently available. Nevertheless, it is important to
recognize causes of transudative fluid collections, including increased pulmonary
capillary pressure (as in congestive heart failure), decreased colloid osmotic
pressure (as in renal disease), increased intrapleural negative pressure (as in
atelectasis), or impaired lymphatic drainage of the pleural space (e.g., from
surgical trauma to the thoracic duct). In children, the inflammatory cause of
effusion is most commonly a result of pneumonia, with accumulation of infected
fluid in the pleural space, or empyema (see below). Malignant effusions from
associated oncologic diagnoses are much less common than in adults, but also
occur in children. The accumulation of blood in the pleural space because of
trauma is discussed in Chapter 115 Thoracic Trauma . Hemothorax may also