A pneumatocele, or pneumatocyst is a cavity in the lungs filled with air that may result from pulmonary trauma. A pneumatocele results when a lung laceration

Pulmonary laceration

A pulmonary laceration is a chest injury in which lung tissue is torn or cut. An injury that is potentially more serious than pulmonary contusion, pulmonary laceration involves disruption of the architecture of the lung, while pulmonary contusion does not...

, a cut or tear in the lung tissue, fills with air. A rupture of a small airway creates the air-filled cavity. Pulmonary lacerations that fill with blood are called pulmonary hematoma

Pulmonary hematoma

A pulmonary hematoma is a collection of blood within the tissue of the lung. It may result when a pulmonary laceration fills with blood. A lung laceration filled with air is called a pneumatocele. In some cases, both pneumatoceles and hematomas exist in the same injured lung. Pulmonary...

s. In some cases, both pneumatoceles and hematoma

Hematoma

A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...

s exist in the same injured lung. A pneumatocele can become enlarged, for example when the patient is mechanically ventilated or has acute respiratory distress syndrome

Acute respiratory distress syndrome

Acute respiratory distress syndrome , also known as respiratory distress syndrome or adult respiratory distress syndrome is a serious reaction to various forms of injuries to the lung....

, in which case it may not go away for months. Diagnosis can be made using chest X-ray

Chest X-ray

In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...

; the lesion shows up as a small, round area filled with air. Computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

 can give a more detailed understanding of the lesion. Differential diagnoses

Differential diagnosis

A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...

, other conditions that could cause similar symptoms as pneumatocele, include lung cancer

Lung cancer

Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...

, tuburculosis, and a lung abscess

Abscess

An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...

 often created by Staphylococcus aureus

Staphylococcus aureus

Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...

 infection during cystic fibrosis

Cystic fibrosis

Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...

. Treatment includes monitoring and pulmonary toilet

Pulmonary toilet

Pulmonary hygiene, formerly referred to as pulmonary toilet, is a set of methods used to clear mucus and secretions from the airways. The word pulmonary refers to the lungs...

 (the use of methods such as positioning and suction to keep the airways clear of secretions).