Keywords cisplatin - etoposide - mediastinum - radiotherapy - subcutaneous emphysema
Introduction
Bleomycin-induced pneumomediastinum in testicular cancer has been reported,[1 ] as has pneumomediastinum, subcutaneous emphysema, and pneumothorax after pulmonary
function testing (the Valsalva maneuver) in a patient with bleomycin-induced interstitial
pneumonitis.[2 ] Herein, we describe and radiologically document pneumomediastinum and subcutaneous
emphysema in the neck, axilla, and chest 2 months after cisplatin/etoposide chemotherapy
and radiotherapy in a patient with olfactory neuroblastoma.
Case Report
A 45-year-old man presented with nasal bleeding for 2 months. Local examination and
computed tomography (CT) scan revealed a mass in the right side of the nasopharynx
extending to the posterior nasal cavity. The mass was diagnosed as an olfactory neuroblastoma
through immunohistochemistry of a biopsy specimen of the primary mass. Complete blood
counts, random blood sugar levels, and liver and renal function tests were within
normal limits. A chest X-ray (posteroanterior view), abdomen/pelvis ultrasound, and
12-lead electrocardiography showed no other abnormalities.
The patient received neoadjuvant chemotherapy with etoposide (100 mg, days 1–3) and
cisplatin (40 mg, days 1–3) every 21 days for 2 cycles followed by external beam radiotherapy
(70 Gy in 35 fractions for 7 weeks). Twenty-eight days after completion of radiotherapy,
the chemotherapy was repeated (every 21 days for 4 cycles). The patient visited the
radiotherapy department 13 days after treatment completion ( first follow-up). He
was asymptomatic, with no evidence of residual local disease.
Two months after treatment completion (second follow-up), the patient presented with
breathlessness. Chest X-ray (posteroanterior view) [Figure 1 ] and CT of the neck and chest showed extensive subcutaneous emphysema in the neck
and axilla extending to the mediastinum [Figure 2 ]. He was referred to the chest unit where an intercostal drain (ICD) was inserted.
The ICD relieved the pneumomediastinum and subcutaneous emphysema, and the patient
was symptomatically better. After withdrawing the ICD, he was discharged from hospital.
One week later, he died suddenly at home after an attack of coughing.
Figure 1: A chest X-ray (posteroanterior view) showing subcutaneous emphysema in the
neck
Figure 2: Computed tomography of the neck and chest showed extensive subcutaneous
emphysema in the neck and axilla extending to the mediastinum
Discussion
The visceral space, which is continuous from the neck and mediastinum to the retroperitoneum
originates during embryological development.[3 ] The visceral pleura overlies both lungs in addition to the organs in the mediastinum
and encloses a space known as the visceral cavity. The fascial planes connect cervical
soft tissue to the mediastinum and retroperitoneum, and the spaces between the fasciae
permit aberrant air arising in any of these areas to spread. In patients with pneumomediastinum,
air can flow from the peribronchial space to the neck, chest wall, pleural cavity,
mediastinum, retroperitoneum, pericardial cavity, pericardial space, and diaphragm.[3 ] Although the body cavity is further divided into thoracic, abdominal, and pericardial
cavities by the pleuroperitoneal and pleuropericardial membranes, the cavities remain
continuous throughout the visceral space.[4 ]
A chest X-ray usually detects pneumomediastinum and subcutaneous emphysema although
better visualization is obtained through CT scan. In our case, CT scan showed extensive
pneumomediastinum and subcutaneous emphysema. The patient underwent respiratory failure,
which resulted in his death 2 months after the completion of treatment. The respiratory
failure may have been chemotherapy drug induced or caused by forced expiration (e.g.,
the Valsalva maneuver with breath holding for a prolonged period).[2 ]
Spontaneous pneumomediastinum is an uncommon event characterized by retrosternal chest
pain, subcutaneous emphysema, dyspnea, and dysphonia. Classic signs of pneumomediastinum
include Hamman’s Crunch, a crepitant sound that varies with the heartbeat on auscultation
of the precordium.[5 ]
[6 ] Known triggers, which can be identified in some cases, include acute asthma exacerbation
and the Valsalva maneuver; such complications are induced by structural changes associated
with interstitial and other lung diseases. Other known triggers include those related
to the Valsalva maneuver, sternuous exercise, weightlifting, inhalation of illicit
drugs, coughing, forced evacuation, and labor as well as vomiting, respiratory infections,
foreign body aspiration, and barotrauma. Pneumomediastinum usually follows a benign,
self-limiting course.[5 ]
[6 ]
Treatment of pneumomediastinum includes mediastinotomy and supportive care consisting
of analgesic use, rest, and the avoidance of maneuvers that increase transpulmonary
pressure (e.g., the Valsalva maneuver and spirometry). Radiotherapy is a treatment
option for patients with prolonged air leaks who are not candidates for surgery.[7 ]
Our patient developed subcutaneous emphysema in the neck, axillary, and chest regions
as well as pneumomediastinum and pneumothorax. He did not experience these complications
during chemotherapy/radiotherapy and had no preexisting lung disease. An earlier study
found that most air leak syndromes resulted from alveolar rupture rather than rupture
of subpleural bullae.[8 ]
Intense respiratory efforts, adjacent atelectasis, and low intravascular pressure
may contribute to the development of air leaks.[8 ] When a person inhales, the diameter of the pulmonary vein increases owing to a decrease
in intrathoracic pressure and an increase in alveolar air volume and the venous return.
Because all compartments increase in length and width in tandem, there is no pressure
gradient in the interstitial space. However, when a person “holds his breath,” venous
stasis occurs, which hinders pulmonary venous filling, reduces vessel lumen size,
and consequently creates the pressure gradient necessary for alveolar rupture. The
Valsalva maneuver is classically related to air leak syndromes because it increases
intrapulmonary pressure.[8 ] Therefore, labor and forced evacuation are associated with pneumomediastinum.[8 ] Unreleased air pressure in the mediastinum can compress the heart and vessels and
prevent lung inflation and deflation, resulting in death.
