Pneumomediastinum is uncommon and occurs when air leaks into the mediastinum. The diagnosis can be confirmed via chest X-ray showing a radiolucent outline around the heart and mediastinum or via CT scanning of the thorax.

Bronchopulmonary sequestration (BPS) is a rare congenital malformation of the lower respiratory tract.

It consists of a nonfunctioning mass of normal lung tissue that lacks normal communication with the tracheobronchial tree, and that receives its arterial blood supply from the systemic circulation.

BPS is estimated to comprise 0.15 to 6.4 percent of all congenital pulmonary malformations, making it an extremely rare disorder.

Sequestrations are classified anatomically.

Intralobar sequestration (ILS) in which the lesion is located within a normal lobe and lacks its own visceral pleura.

Extralobar sequestration (ELS) in which the mass is located outside the normal lung and has its own visceral pleura

The blood supply of 75% of pulmonary sequestrations is derived from the thoracic or abdominal aorta.

The remaining 25% of sequestrations receive their blood flow from the subclavian, intercostal, pulmonary, pericardiophrenic, innominate, internal mammary, celiac, splenic, or renal arteries.

Usually the sequestration is removed after birth via surgery. In most cases this surgery is safe and effective; the child will grow up to have normal lung function.

In a few instances, fetuses with sequestrations develop problematic fluid collections in the chest cavity. In these situations a Harrison catheter shunt can be used to drain the chest fluid into the amniotic fluid.

In rare instances where the fetus has a very large lesion, resuscitation after delivery can be dangerous. In these situations a specialized delivery for management of the airway compression can be planned called the EXIT procedure, or a fetal laser ablation procedure can be performed. During this minimally invasive fetal intervention, a small needle is inserted into the sequestration, and a laser fiber is targeted at the abnormal blood vessel going to the sequestration. The goal of the operation is to use laser energy to stop the blood flow to the sequestration, causing it to stop growing. Ideally, after the surgery, the sequestration steals less blood flow from the fetus, and the heart and lungs start growing more normally as the sequestration shrinks in size and the pleural effusion goes away.

The treatment for this is a wedge resection, segmentectomy, or lobectomy via a VATS procedure or thoracotomy.

Pulmonary sequestrations usually get their blood supply from the thoracic aorta.

Respiratory diseases may be investigated by performing one or more of the following tests

- Biopsy of the lung or pleura

- Blood test

- Bronchoscopy

- Chest x-ray

- Computed tomography scan, including high-resolution computed tomography

- Culture of microorganisms from secretions such as sputum

- Ultrasound scanning can be useful to detect fluid such as pleural effusion

- Pulmonary function test

- Ventilation—perfusion scan

The tissues in the mediastinum will slowly resorb the air in the cavity so most pneumomediastinums are treated conservatively. Breathing high flow oxygen will increase the absorption of the air.

If the air is under pressure and compressing the heart, a needle may be inserted into the cavity, releasing the air.

Surgery may be needed to repair the hole in the trachea, esophagus or bowel.

If there is lung collapse, it is imperative the affected individual lies on the side of the collapse, although painful, this allows full inflation of the unaffected lung.

Medical diagnosis of pulmonary hypoplasia in utero may use imaging, usually ultrasound or MRI. The extent of hypoplasia is a very important prognostic factor. One study of 147 fetuses (49 normal, 98 with abnormalities) found that a simple measurement, the ratio of chest length to trunk (torso) length, was a useful predictor of postnatal respiratory distress. In a study of 23 fetuses, subtle differences seen on MRIs of the lungs were informative. In a study of 29 fetuses with suspected pulmonary hypoplasia, the group that responded to maternal oxygenation had a more favorable outcome.

Pulmonary hypoplasia is diagnosed also clinically.

Respiratory disease is a common and significant cause of illness and death around the world. In the US, approximately 1 billion "common colds" occur each year. A study found that in 2010, there were approximately 6.8 million emergency department visits for respiratory disorders in the U.S. for patients under the age of 18. In 2012, respiratory conditions were the most frequent reasons for hospital stays among children.

In the UK, approximately 1 in 7 individuals are affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease, which includes asthma, chronic bronchitis and emphysema.

Respiratory diseases (including lung cancer) are responsible for over 10% of hospitalizations and over 16% of deaths in Canada.

In 2011, respiratory disease with ventilator support accounted for 93.3% of ICU utilization in the United States.

In several editions of Physical Diagnosis, concerning mediastinal tumors the author writes:

Many signs and symptoms of a mediastinal tumor do not distinguish between these two principal classes of mediastinal tumor. However, on a radiograph usually the former class will have an irregular shape and the latter class will have a smooth spherical or ovoid shape. A large minority of patients with a mediastinal teratoma (including dermoid cyst) will cough up hair. For a differential diagnosis, the key is to exclude aneurism.

Most common primary anterior mediastinal tumor (20%) in adults but rarely seen in children. It can be classified as lymphocytic, epithelial, or spindle cell histologies, but the clinical significance of these classifications is controversial. Tonofibrils seen under electron microscopy can differentiate thymoma from other tumors such as carcinoid, Hodgkin's, and seminoma. Patients are usually asymptomatic but can present with myasthenia gravis-related symptoms, substernal pain, dyspnea, or cough. Invasive tumors can produce compression effects such as superior vena cava syndrome. (3,4) Thymomas are diagnosed with CT or MRI revealing a mass in anterior mediastinum. Therapy in stage I tumors consists of surgical resection with good prognosis. Stage II-III requires maximal resection possible followed by radiation. Stage IV disease requires addition of cisplatin-based chemotherapy in addition to those in stage II and III. For those with invasive thymoma, treatment is based on induction chemotherapy, surgical resection, and post-surgical radiation. 5-year survival for invasive thymoma is between 12-54% regardless of any myasthenia gravis symptoms (5,6).

Because it is rare and has a wide spectrum of clinical, histological, and imaging features, diagnosing lymphangiomatosis can be challenging. Plain x-rays reveal the presence of lytic lesions in bones, pathological fractures, interstitial infiltrates in the lungs, and chylous effusions that may be present even when there are no outward symptoms.

The most common locations of lymphangiomatosis are the lungs and bones and one important diagnostic clue is the coexistence of lytic bone lesions and chylous effusion. An isolated presentation usually carries a better prognosis than does multi-organ involvement; the combination of pleural and peritoneal involvement with chylous effusions and lytic bone lesions carries the least favorable prognosis.

When lung involvement is suspected, high resolution computed tomography (HRCT) scans may reveal a diffuse liquid-like infiltration in the mediastinal and hilar soft tissue, resulting from diffuse proliferation of lymphatic channels and accumulation of lymphatic fluid; diffuse peribronchovascular and interlobular septal thickening; ground-glass opacities; and pleural effusion. Pulmonary function testing reveals either restrictive pattern or a mixed obstructive/restrictive pattern. While x-rays, HRCT scan, MRI, ultrasound, lymphangiography, bone scan, and bronchoscopy all can have a role in identifying lymphangiomatosis, biopsy remains the definitive diagnostic tool.

Microscopic examination of biopsy specimens reveals an increase in both the size and number of thin walled lymphatic channels along with lymphatic spaces that are interconnecting and dilated, lined by a single attenuated layer of endothelial cells involving the dermis, subcutis, and possibly underlying fascia and skeletal muscle. Additionally, Tazelaar, et al., described a pattern of histological features of lung specimens from nine patients in whom no extrathoracic lesions were identified, which they termed "diffuse pulmonary lymphangiomatosis" (DPL).

Recognition of the disease requires a high index of suspicion and an extensive workup. Because of its serious morbidity, lymphangiomatosis must always be considered in the differential diagnosis of lytic bone lesions accompanied by chylous effusions, in cases of primary chylopericardium, and as part of the differential diagnosis in pediatric patients presenting with signs of interstitial lung disease.

This condition can often be diagnosed before birth and fetal intervention can sometimes help, depending on the severity of the condition.

Infants born with diaphragmatic hernia experience respiratory failure due to both pulmonary hypertension and pulmonary hypoplasia. The first condition is a restriction of blood flow through the lungs thought to be caused by defects in the lung. Pulmonary hypoplasia or decreased lung volume is directly related to the abdominal organs presence in the chest cavity which causes the lungs to be severely undersized, especially on the side of the hernia.

Survival rates for infants with this condition vary, but have generally been increasing through advances in neonatal medicine. Work has been done to correlate survival rates to ultrasound measurements of the lung volume as compared to the baby's head circumference. This figure known as the lung to head ratio (LHR). Still, LHR remains an inconsistent measure of survival. Outcomes of CDH are largely dependent on the severity of the defect and the appropriate timing of treatment.

A small percentage of cases go unrecognized into adulthood.

Diagnosis is by medical imaging with either plain X ray or CT scan.

ACD commonly is diagnosed postmortem, by a pathologist.

Sometimes ACD is diagnosed clinically. This is common when there is a family history of ACD, but rare otherwise. A clinical differential diagnosis of ACD excludes fetal atelectasis.

ACD is not detectable by prenatal imaging. However, some babies with ACD have associated congenital malformations that are detectable by imaging. The identification of genes involved in ACD offers the potential for prenatal testing and genetic counseling.

Management has three components: interventions before delivery, timing and place of delivery, and therapy after delivery.

In some cases, fetal therapy is available for the underlying condition; this may help to limit the severity of pulmonary hypoplasia. In exceptional cases, fetal therapy may include fetal surgery.

A 1992 case report of a baby with a sacrococcygeal teratoma (SCT) reported that the SCT had obstructed the outlet of the urinary bladder causing the bladder to rupture in utero and fill the baby's abdomen with urine (a form of ascites). The outcome was good. The baby had normal kidneys and lungs, leading the authors to conclude that obstruction occurred late in the pregnancy and to suggest that the rupture may have protected the baby from the usual complications of such an obstruction. Subsequent to this report, use of a vesicoamniotic shunting procedure (VASP) has been attempted, with limited success.

Often, a baby with a high risk of pulmonary hypoplasia will have a planned delivery in a specialty hospital such as (in the United States) a tertiary referral hospital with a level 3 neonatal intensive-care unit. The baby may require immediate advanced resuscitation and therapy.

Early delivery may be required in order to rescue the fetus from an underlying condition that is causing pulmonary hypoplasia. However, pulmonary hypoplasia increases the risks associated with preterm birth, because once delivered the baby requires adequate lung capacity to sustain life. The decision whether to deliver early includes a careful assessment of the extent to which delaying delivery may increase or decrease the pulmonary hypoplasia. It is a choice between expectant management and active management. An example is congenital cystic adenomatoid malformation with hydrops; impending heart failure may require a preterm delivery. Severe oligohydramnios of early onset and long duration, as can occur with early preterm rupture of membranes, can cause increasingly severe PH; if delivery is postponed by many weeks, PH can become so severe that it results in neonatal death.

After delivery, most affected babies will require supplemental oxygen. Some severely affected babies may be saved with extracorporeal membrane oxygenation (ECMO). Not all specialty hospitals have ECMO, and ECMO is considered the therapy of last resort for pulmonary insufficiency. An alternative to ECMO is high-frequency oscillatory ventilation.

Baylor College of Medicine in Houston, Texas has conducted ACD research since 2001.

One way to determine if a baby does in fact have a Bochdalek hernia, would be to have a pediatrician perform a physical on the infant. A chest x-ray can also be done to examine the abnormalities of not only the lungs but also the diaphragm and the intestine. In addition to these, a doctor can also take a blood test, drawing arterial blood to check and determine how well the baby is breathing and his or her ability to breathe. A chromosomal test (done by testing the blood) can also be performed to determine whether or not the problem was genetic. The doctors can also take an ultrasound of the heart (echocardiogram) to evaluate the health of the heart.

Lymphatic malformations may be detected in the human fetus by ultrasound if they are of sufficient size. Detection of a cystic malformation may prompt further investigation, such as amniocentesis, in order to evaluate for genetic abnormalities in the fetus. Lymphatic malformations may be discovered postnatally or in older children/adults, and most commonly present as a mass or as an incidental finding during medical imaging.

Verification of the diagnosis may require more testing, as there are multiple cystic masses that arise in children. Imaging, such as ultrasound or MRI, may provide more information as to the size and extent of the lesion.

Congenital diaphragmatic hernia has a mortality rate of 40–62%, with outcomes being more favorable in the absence of other congenital abnormalities. Individual rates vary greatly dependent upon multiple factors: size of hernia, organs involved, additional birth defects, and/or genetic problems, amount of lung growth, age and size at birth, type of treatments, timing of treatments, complications (such as infections) and lack of lung function.

The mediastinum (from Medieval Latin "mediastinus", "midway") is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, trachea, phrenic and cardiac nerves, the thoracic duct, thymus and lymph nodes of the central chest.

Thoracocentesis, pericardiocentesis, pleurodesis, ligation of thoracic duct, pleuroperitoneal shunt, radiation therapy, pleurectomy, pericardial window, pericardiectomy, thalidomide, interferon alpha 2b, Total Parenteral Nutrition (TPN), medium chain triglyceride (MCT) and high protein diet, chemotherapy, sclerotherapy, transplant;

The diagnosis of Boerhaave's syndrome is suggested on the plain chest radiography and confirmed by chest CT scan. The initial plain chest radiograph is almost always abnormal in patients with Boerhaave's syndrome and usually reveals mediastinal or free peritoneal air as the initial radiologic manifestation. With cervical esophageal perforations, plain films of the neck show air in the soft tissues of the prevertebral space.

Hours to days later, pleural effusion(s) with or without pneumothorax, widened mediastinum, and subcutaneous emphysema are typically seen. CT scan may show esophageal wall edema and thickening, extraesophageal air, periesophageal fluid with or without gas bubbles, mediastinal widening, and air and fluid in the pleural spaces, retroperitoneum or lesser sac.

The diagnosis of esophageal perforation could also be confirmed by water-soluble contrast esophagram (Gastrografin), which reveals the location and extent of extravasation of contrast material. Although barium is superior in demonstrating small perforations, the spillage of barium sulfate into the mediastinal and pleural cavities can cause an inflammatory response and subsequent fibrosis and is therefore not used as the primary diagnostic study. If, however, the water-soluble study is negative, a barium study should be performed for better definition.

Endoscopy has no role in the diagnosis of spontaneous esophageal perforation. Both the endoscope and insufflation of air can extend the perforation and introduce air into the mediastinum.

Patients may also have a pleural effusion high in amylase (from saliva), low pH, and may contain particles of food.

Pulmonary veno-occlusive disease can only be well diagnosed with a lung biopsy. CT scans may show characteristic findings such as ground-glass opacities in centrilobular distribution, and mediastinal lymphadenopathy, but these findings are non-specific and may be seen in other conditions. However, pulmonary hypertension (revealed via physical examination), in the presence of pleural effusion (done via CT scan) usually indicates a diagnosis of pulmonary veno-occlusive disease. The prognosis indicates usually a 2-year (24 month) life expectancy after diagnosis.

The death rate of people with flail chest depends on the severity of their condition, ranging from 10 to 25%.

There is no one single test for confirming that breathlessness is caused by pulmonary edema; indeed, in many cases, the cause of shortness of breath is probably multifactorial.

Low oxygen saturation and disturbed arterial blood gas readings support the proposed diagnosis by suggesting a pulmonary shunt. Chest X-ray will show fluid in the alveolar walls, Kerley B lines, increased vascular shadowing in a classical batwing peri-hilum pattern, upper lobe diversion (increased blood flow to the superior parts of the lung), and possibly pleural effusions. In contrast, patchy alveolar infiltrates are more typically associated with noncardiogenic edema

Lung ultrasound, employed by a healthcare provider at the point of care, is also a useful tool to diagnose pulmonary edema; not only is it accurate, but it may quantify the degree of lung water, track changes over time, and differentiate between cardiogenic and non-cardiogenic edema.

Especially in the case of cardiogenic pulmonary edema, urgent echocardiography may strengthen the diagnosis by demonstrating impaired left ventricular function, high central venous pressures and high pulmonary artery pressures.

Blood tests are performed for electrolytes (sodium, potassium) and markers of renal function (creatinine, urea). Liver enzymes, inflammatory markers (usually C-reactive protein) and a complete blood count as well as coagulation studies (PT, aPTT) are also typically requested. B-type natriuretic peptide (BNP) is available in many hospitals, sometimes even as a point-of-care test. Low levels of BNP (<100 pg/ml) suggest a cardiac cause is unlikely.

Bochdalek hernia can be a life-threatening condition. Approximately 85.3% of newborns born with a Bochdalek hernia are immediately high risk. Infants born with a Bochdalek hernia have a "high mortality rate due to respiratory insufficiency". Between 25–60% of infants with a Bochdalek hernia die. The lungs, diaphragm, and digestive system are all forming at the same time, so when a Bochdalek hernia permits the abdominal organs to invade the chest cavity rather than remain under the diaphragm in the correct position, it puts the infant in critical condition. These "foreign bodies" in the chest cavity compress the lungs, impairing their proper development and causing pulmonary hypoplasia. Since the lungs of infants suffering from a Bochdalek hernia have fewer alveoli than normal lungs, Bochdalek hernias are life-threatening conditions due to respiratory distress. Also, if the invasion of the intestine or stomach punctures the lung, then the lungs cannot fill completely with air. The baby will not be healthy or stable with this condition because he or she cannot take in enough air and oxygen to keep the body operating properly. Like the lungs, the intestines may also have trouble developing correctly. If the intestines are trapped within the lungs, then the lungs and intestines may not be receiving the amount of blood they need to stay healthy and function properly.