#pulmology

The lung’s lobes contain millions of air-filled sacs called alveoli. In congenital lobar emphysema, one of the diagnostic differences is that there are fewer or more than the normal number of sacs. This allows doctors to separate CLE into two types called hypoalveolar and polyalveolar, or "too few" and "too many" alveoli in the affected lobe. Infantile emphysema may also be further distinguished and complicated by the presence of other medical issues. In about 10-15% of cases, children also present with congenital heart defects, and the combination of respiratory problems and heart issues can be very serious.

In many instances, children with congenital lobar emphysema, if not diagnosed in utero, will show signs of respiratory distress in early infancy, and are usually identified quickly. Such distress could occur before newborns leave the hospital, or it might occur in the first few weeks of life. Though CLE is quite rare, affecting only about .005% of the population, the presence of an expanding lung and fluid in the lungs tends to be a good sign of it. It should be noted that the condition can have no symptoms, be unproblematic for years, and might not be caught until people reach adolescence or adulthood. In any case, trouble breathing is always indication to see a physician for diagnosis.

With the most severe cases of congenital lobar emphysema, pulmonary specialists may suggest removing the affected and expanded lung lobe, as this may immediately improve the situation. Such a surgery is not performed lightly since it may compromise breathing to some degree. When possible, moderate types of this condition are treated with medicines instead, and the condition could always be medically instead of surgically managed, or might respond well to medical management for a time before surgery is required.

Air reaches the alveoli via the bronchial tree. The trachea splits into the right and left mainstem bronchi, which branch further into bronchioles and finally ends in the alveolar air sacs.

When we breathe in, air enters the lung and the alveoli expand. Oxygen is transferred onto hemoglobin molecules in the red blood cells to be transported to the rest of the body for use. As oxygen attaches to the red blood cell, carbon dioxide, the waste product of metabolism, detaches and crosses into the alveoli to be exhaled. When we breathe out, the alveoli get squeezed by the elasticity in their walls and air is pushed out of the lungs.

What is emphysema?

Emphysema is a long-term, progressive disease of the lung(s) and occurs when the alveolar walls are destroyed along with the capillary blood vessels that run within them. This lessens the total area within the lung where blood and air can come together, limiting the potential for oxygen and carbon dioxide transfer.

In early emphysema, there is associated inflammation of the small airways or bronchioles that limits the amount of air that can flow to the alveoli. In more severe emphysema, there is also loss of elasticity in the alveolar walls that have not been destroyed. When the person breathes out, the alveoli and small airways collapse. The loss of elasticity of the lung tissue makes it harder for air to get to the periphery or furthest part of the lung during inhalation, and also harder for air to exit the damaged part of the lung during exhalation. As emphysema progresses and more and more alveoli are destroyed, bullae can be formed. Bullae are air filled sacs of lung that do not function. They can become extremely large and often are located in the upper parts of the lung. A bulla (plural=bullae) are at risk for rupturing and causing a pneumothorax, or collapse of the lung.

As more of the lung is destroyed and the lung cannot maintain oxygen concentrations in the bloodstream, the body compensates by gradually increasing the breathing rate. After a while, even hyperventilation (hyper=more + ventilation=breathing) cannot maintain adequate oxygen levels, and the arteries in the lung begin to constrict or narrow. The heart has to work harder to push blood into these narrower blood vessels, causing the blood pressure in the lung arteries to increase (pulmonary hypertension). Over time, the extra work requirement causes the heart muscle to enlarge (hypertrophy) and can cause heart failure.

What are the causes or risk factors for emphysema?

The main risk factor for emphysema is smoking, which activates inflammatory cells in the lung. This inflammation causes; 1) swelling within the bronchioles, and 2) activation of enzymes called proteases which attack and destroy lung tissue (the alveolar wall structures). This leads to centriacinar (centri=central+acinus=sac) emphysema, which begins in the bronchioles and gradually spreads peripherally to the far reaches of the lung. There may be a genetic contribution tot he development of emphysema, since not all people who smoke suffer from emphysema.

There is also an inherited form of emphysema. The relatively rare condition known as alpha 1-antitrypsin deficiency is the genetic deficiency of a chemical that protects the lung from damage by proteases. This results in panacinar (pan=widespread+acinus=sac) emphysema, which destroys the alveoli throughout the lung uniformly.

Emphysema is also a component of aging. As the lungs get older, the elastic properties decrease, and the tensions that develop can result in small areas of emphysema.

Other less common causes of emphysema include:

Intravenous drug use in which some of the non-drug additives like corn starch can be toxic to lung tissue

Immune deficiencies in which infections like Pneumocystis carinii can cause inflammatory changes in the lung

Connective tissue illnesses (Ehlers-Danlos syndrome, Marfan syndrome) in which abnormal elastic tissue in the body can cause alveoli to fail

In underdeveloped countries, a common cause of emphysema is indoor air pollution. In these populations, it is very common to have indoor stoves in the kitchen. The smoke from cooking results in the damage to the lungs.

What are symptoms of emphysema?

Emphysema is a progressive disease with symptoms beginning in patients after 50 years of age. Prolonged exposure to smoke gradually causes enough lung destruction to cause the characteristic cough and shortness of breath. Affected individuals with alpha-1 antitrypsin deficiency tend to develop symptoms of emphysema at earlier ages. Emphysema is a subtype of chronic obstructive pulmonary disease (COPD in the US; COLD in the United Kingdom). Most patients, except in those in whom disease is the result of a genetic deficiency (alpha-1 antitrypsin deficiency), have variable manifestations of the different components of COPD which include:

chronic bronchitis,

asthma,

emphysema, and

bronchiectasis.

Each of the subtypes has characteristic symptoms; those primarily associated with emphysema are shortness of breath and wheezing. Initially the shortness of breath (dyspnea) occurs with activity; as time continues and the disease progresses, the episodes of dyspnea occur more frequently eventually occurring at rest making routine daily activities difficult to perform.

How is emphysema diagnosed?

As is the case with most illnesses, the health care provider will take a careful history to learn about the lung and breathing symptoms.

How long has the shortness of breath been present?

What makes it better?

What makes it worse?

Has there been an infection recently?

Have the symptoms been getting more severe?

Does the patient smoke?

Does the patient have exposure to secondhand smoke or other toxic fumes?

Are there other exposures of diseases that may be contributing to the shortness of breath?

Is there a family history of lung disease?

Physical examination

Physical examination will concentrate on the lung findings, but may also include the heart and the circulatory system.

Is there an increased respiratory rate?

Is the patient short of breath just sitting in the examination room?

In addition to the ribs and the diaphragm, is the patient using the intercostal muscles (those between the ribs) and neck muscles to breathe? When used, accessory muscles cause the appearance of indrawing, where there is observable sucking in of muscles during the breathing cycle. This is normally seen in people who have just exerted themselves as the body recovers from exercise or work. In patients with emphysema it may be observed at rest.

Does the chest appear enlarged or barrel-shaped?

Does the chest cavity sound hollower than it should?

Does exhalation take longer than it should? Since the elasticity of the lung has been lost, it takes longer for air to be forced out in the breathing cycle.

Is the movement of the diaphragm decreased?

Is the patient cyanotic (having a blue tinge to the skin color signifying lack of oxygen in the blood)?

When listening to the lungs, are there wheezes present, especially if the patient is asked to exhale quickly?

Exams and tests

Oximetry

Oximetry is a non-invasive test, in which a sensor is taped or clipped onto a finger or earlobe to measure the percentage of red blood cells that have oxygen. This value is usually greater than 92%. Results less than 90% may signal the need for supplemental oxygen.

Blood Tests

A complete blood cell count (CBC) may be performed to check for an increase in the number of red blood cells. In response to lower blood oxygen concentrations, the body manufactures more red blood cells to try to deliver as much oxygen as possible to cells.

Alpha-1 antitrypsin levels may be measured to look for the genetic form of emphysema.

An arterial blood gas test will measure the amount of oxygen and carbon dioxide in the blood and combined with other measurements can help the healthcare provider decide whether the body has been able to adapt to the lower oxygen concentrations in the body. In some laboratories, the arterial blood gas result will include a carbon monoxide percentage, most often found in the body because of smoking. For each hemoglobin molecule that has carbon monoxide attached, there is one less available that can carry oxygen.

The arterial blood gas can also give parameters to establish the diagnosis of chronic respiratory failure. When the measured oxygen level drops below 60 mmHg (millimeters of mercury) and the carbon dioxide level rises above 50 mm Hg, the diagnosis of chronic respiratory failure can be made.

Radiology

A plain chest X-ray may show lungs that have become too inflated and have lost normal lung markings, consistent with destruction of alveoli and lung tissue.

A CT scan can reveal more detail regarding the amount of lung destruction but is not a normal part of the evaluation of patients with emphysema.

Pulmonary Function Tests

Pulmonary function tests or spirometry, can measure the air flow into and out of the lungs and be used to predict the severity of emphysema. By blowing into a machine, the amount of air that is moved and how quickly it moves can be calculated and provides information about lung damage. Results are compared to a "normal" person of the same age, sex, and size.

Some measurements include:

FVC (forced vital capacity): the amount of air that can be forcibly exhaled after the largest breath possible.

FEV1 (forced expiratory volume in 1 second): the amount of air that is forcibly exhaled in 1 second. Even though total air exhalation may be less affected, as the lung loses its elasticity, it takes longer for the air to get out and FEV1 becomes a good marker for disease severity.

FEV (forced expiratory volume): can be measured throughout the exhalation cycle often at 25%, 50%, and 75% to help measure function of different sized bronchi and bronchioles.

PEF (peak expiratory flow): maximal speed of air during exhalation.

DLCO (diffusion capacity): measures how much carbon monoxide can be inhaled and absorbed into the bloodstream within a period of time. A small amount of tracer carbon monoxide is inhaled and then quickly exhaled. The amount of carbon monoxide in the exhaled air is measured and determines how well the lungs work in absorbing the gas. This helps determine and measure lung function.

  What are the stages of emphysema?

Emphysema staging helps determine how much lung damage is present and how severe it is. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) uses FEV1 measurements to help with this determination:

What is the treatment for emphysema?

Emphysema is not a curable disease, once lung damage has occurred it cannot be reversed. The goal of treatment is to stop further lung destruction and preserve lung function. The patient needs to know that the focus is on improving quality of life and limiting the intrusion of emphysema on daily activities. Emphysema tends not to be the primary cause of death, but can be a contributing factor to other organ failure.

Smoking cessation

The number one treatment goal is to have the patient stop smoking. Education, counseling, support groups and medication may be used. Moreover, prevention is most important, and not starting to smoke is much easier than helping a person to quit smoking.

Medications

Bronchodilators

Bronchodilators are used to relax the smooth muscles that surround the bronchioles, allowing the breathing tubes to dilate and air to flow more freely. These medications can be inhaled using an MDI (metered dose inhaler), powder inhaler devices, or a nebulizer machine These medications can either be short or long acting.

The short acting bronchodilators include the albuterol agents (Ventolin HFA, Proventil HFA, and Pro Air) and the anticholinergic agent, ipratropium bromide (Atrovent).

As an aside, in the past patients have been instructed to count the number of puffs used from these devices or "float" the inhaler in water to determine the amount of remaining medicine available. The HFA devices can not be floated, and counting of the number of puffs is the only available method of determining the continued presence of medication. One device, Ventolin HFA, has a built in counter. It is important to understand that the mere presence of propellant coming from the inhaler does not necessarily mean that medication is present.

The long acting agents include salmeterol (Serevent), formoterol (Foradil) and tiotropium (Spiriva). Often the long acting bronchodilator is used for controlling the symptoms of emphysema as maintenance therapy, and the short acting one is used when symptoms flare up (rescue therapy).

It is important that the patient know which medication is prescribed, since long acting inhalers cannot be used for rescue, because the delayed onset of action. Sometimes, patients will seek medical care in an extremely ill state because they have been using the long-acting controller drug as their rescue inhaler.

Corticosteroids

Since most patients do not have pure emphysema and usually also have other components of COPD, combined therapy is often prescribed which includes a long-acting bronchodilator and an inhaled corticosteroid. The inhaled corticosteroid (ICS) helps suppress the inflammatory components of COPD. While the bronchodilators work to relax the smooth muscle surrounding the breathing tubes, steroids decrease the inflammation within the walls of the tubes themselves.

These agents like Advair, which is a mixture of salmeterol (Serevent) and fluticasone (Flovent), an ICS, simplify treatment by combining both therapies into a single inhaler device. Another combination inhaler is formoterol and budesonide (Symbicort).

Many patients with emphysema need only take steroid inhalers when their symptoms flare, but others require daily therapy. Corticosteroids have direct action on the lung tissue and absorption of inhaled corticosteroids into the blood stream is minimal. Prednisone, an oral corticosteroid, can be taken in addition to the inhaled steroid should further anti-inflammatory effects be required. Moreover, these may be prescribed to be taken only during an acute flare of the emphysema, or may be required to be taken on a daily basis by those patients with more severe disease.

In emergency situations, corticosteroids may be injected intravenously.

Antibiotics

Since patients with emphysema are at risk for infections like pneumonia, antibiotics may be prescribed when the usually clear sputum changes color, or when the patient presents with systemic signs of an infection (fever, chills, weakness).

Oxygen

As the disease progresses, patients may require supplemental oxygen to be able to function. Often it begins with nighttime use, then with exercise, and as the disease worsens, the need to use oxygen during the day for routine activities increases.

The decision to prescribe oxygen depends upon the patient's symptoms as well as results of other tests, including oximetry, pulmonary function tests, and arterial blood gas measurements.

Pulmonary rehabilitation

These programs involve primarily two components, education and exercise.

Patient education includes:

proper breathing techniques,

clearance of secretions,

understanding their medications and devices,

efficient body mechanics, and

networking with other lung patients.

All of the above are essential components of emphysema treatment. Graded physical exercise under supervision allows for better patient mobility. A multidisciplinary program helps improve the patient's quality of life and decreases the number of hospitalizations for exacerbations of their underlying disease.

Surgery

Depending upon what type of damage has occurred to the lung, there is potential to have surgery to decrease the lung volume and help minimize the symptoms of emphysema. Because patients with this disease tend to be older, more ill, and have associated underlying medical problems, this treatment is very patient-specific and is not routinely offered.

Studies have demonstrated that patients with emphysema primarily affecting the upper lobes of both lungs may benefit most from lung volume reduction surgery, often by removing larger bullae.

What is the prognosis and life-expectancy of a person with emphysema?

Emphysema is a disease that affects quality of life and not necessarily the quantity of life. The goal for treatment of emphysema is to prevent further lung damage, and to maximize the function of the remaining healthy lung tissue.

Symptoms of emphysema occur because the body is not being supplied with adequate oxygen, and because it takes significant effort to take deeper breaths. These both contribute to the very miserable sensation of constantly feeling short of breath.

There are no studies that have been able to predict mortality from emphysema, but the U.S. Centers for Disease Control and Prevention report that 127,000 people died from COPD in 2009. In comparison, five times as many people died of heart attack, and four times as many due to cancer.

The BODE score can help measure quality of life and prognosis for future function.

B = Body Mass Index (BMI).

O = Obstruction. Lung function based on pulmonary function tests.

D = Dyspnea (breathlessness)

E = Exercise capacity. How far the emphysema patient can walk in 6 minutes