The alveoli are microscopic, balloon-like structures in the lungs that play a crucial role in respiration. If they are damaged, they may be able to self-repair, but medical attention is key to preventing complications.

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Medical Illustration by Bailey Mariner

The outlook for any damage to the alveoli depends on the cause, which may be asthma or emphysema.

This article describes what the alveoli do, how they can be harmed, and the risk factors. It also looks into treatment options.

These microscopic, balloon-shaped parts of the lungs transfer oxygen into the bloodstream and carbon dioxide out of it.

When someone inhales, their alveoli fill up with oxygen. When they exhale, their alveoli decompress, releasing carbon dioxide.

Learn more about lung function.

Any damage to the alveoli can affect how well a person breaths. It can create difficulty getting oxygen into the blood and carbon dioxide out of it.

As a result, harmful chemicals can accumulate, and the body may not have enough oxygen to function optimally.

One cause of damaged alveoli is pulmonary emphysema, a form of chronic obstructive pulmonary disease (COPD). About 14 million people in the United States have it.

COPD is an umbrella term for health conditions that limit airflow in the lungs and damage lung tissue and alveoli.

Other causes of damage

A 2021 review describes various other health conditions that can damage the alveoli:

  • Acute respiratory distress syndrome (ARDS): This noncancerous cause of swelling in the lungs stems from inflammation and the accumulation of fluid in the alveolar space.
  • Asthma: This condition affects around 15–20% of people in developed countries. It leads to inflammation and air being trapped within the alveoli. This constricts the airways.
  • Idiopathic pulmonary fibrosis (IPF): This type of scarring in the lungs, including the alveoli, has no clear cause. Doctors distinguish the features of the scarring under a microscope to rule out any other diagnosis.

There is also evidence that people with COVID-19 can develop alveolar damage.

Various factors can increase the risk of developing a health condition that damages the alveoli.

For example, the primary risk factor for COPD is tobacco smoking, though exposure to other toxins can also increase the risk.

ARDS occurs if the lungs become severely inflamed from an infection such as pneumonia or the flu.

Other potential causes of ARDS include:

  • sepsis
  • a severe chest injury
  • accidentally inhaling vomit, smoke, or toxic chemicals
  • near drowning

Research from 2018 suggests that smoking can also lead to ARDS.

If smoking causes scarring, the diagnosis is not IPF but “combined pulmonary fibrosis and emphysema.”

Potential risk factors for IPF include:

  • exposure to some metals
  • exposure to some woods
  • exposure to dust
  • genetic factors

Scientists remain uncertain about the exact causes of asthma, although genetics and environmental factors may contribute to it.

Alveolar damage can affect lung function. The specific effects depend on the underlying cause.

For example, someone with COPD may experience:

  • shortness of breath
  • a cough
  • chest tightness
  • wheezing

ARDS can cause these symptoms and low blood pressure, also known as hypotension.

IPF can cause similar symptoms, such as shortness of breath and a cough, as well as fatigue.

Asthma causes wheezing and increased mucus production, which may worsen in response to certain triggers. These can be allergens in the home, such as mold or dust, or outside allergens, such as pollen and pollution.

Learn about other triggers of asthma.

The alveoli can self-repair over time. But the extent of the repair can vary from person to person.

Also, the rate of repair needs to exceed the rate of destruction for the area to recover. For this reason, treating the underlying health condition is key.

Scientists have not yet found a cure for COPD, ARDS, asthma, or IPF. Treatments for these conditions aim to slow their progression and relieve the symptoms.

Treating COPD

Medical treatment generally involves a bronchodilator alone or alongside anti-inflammatory drugs. These drugs can be corticosteroids or phosphodiesterase-4 inhibitors.

Other approaches may include:

  • supplemental oxygen
  • noninvasive positive pressure ventilation
  • pulmonary rehabilitation
  • surgical interventions, such as a transplant

Learn more about treatments for COPD.

Treating ARDS

At present, no single drug-based treatment can prevent or manage ARDS.

Doctors ensure that people with ARDS:

  • have mechanical ventilation
  • receive medical attention at the standards of an intensive care unit
  • are monitored and receive diuretics to prevent fluid overload
  • receive nutritional support

Doctors may also prescribe antibiotics if the cause of ARDS is a bacterial infection.

Treating asthma

According to the Global Initiative for Asthma, the initial treatment is a combination of a low-dose inhaled corticosteroid and a bronchodilator.

Doctors may also prescribe anti-inflammatories, such as inhaled steroids. They may prescribe beclomethasone (Beclovent, Qvar).

Learn more about treatments for asthma.

Treating IPF

Medications such as pirfenidone (Esbriet) and nintedanib (Ofev) may slow the progression of the disease and prevent flares.

Over time, the symptoms may affect breathing, and the treatment may include oxygen therapy. In severe cases, a doctor may recommend a lung transplant.

Learn more about treatments for IPF.

Doctors may recommend these strategies for managing the underlying causes of the damage.

Managing COPD

A healthcare professional may recommend:

  • quitting smoking and reducing exposure to secondhand smoke
  • reducing exposure to other toxins
  • using any inhaler properly
  • receiving the annual influenza vaccine

Managing ARDS

On average, people with ARDS require ventilation for 7–14 days.

After this period, a person may require a tracheostomy, which involves receiving ventilation through a surgical incision in the neck. However, most people with ARDS do not require long-term ventilation and regain most of their lung function.

Pulmonary rehabilitation can help address any muscle weakness.

Managing asthma

Using an inhaler is key, as is recognizing triggers, such as:

Doctors also recommend maintaining moderate body weight, to help make asthma easier to manage.

Asthma may predispose a person to obesity, both conditions may simply co-occur, or obesity may affect asthma.

Avoiding any exposure to tobacco smoke and self-monitoring are also important factors in preventing the progression and flares of asthma.

Managing IPF

Similar advice applies to people with IPF. According to a 2021 review, people should:

  • stop smoking, if this applies
  • avoid exposure to harmful gases
  • exercise regularly

The outlook for someone with alveolar damage depends on:

  • the cause of the damage
  • the response to treatment
  • the extent to which a person applies the management strategies

The 4-year survival rate for people with COPD varies from 80–18%, depending on how severe the disease is, its cause, and the effectiveness of the treatment.

The outlook for people with ARDS has improved over the last few years, due to advancements in mechanical ventilation and earlier antibiotic administration. Mortality rates are now around 9–20%, and they were once 30–40%.

Without effective treatment, asthma can lead to persistent poor quality of life. By contrast, IPF has a 24- to 30-month mean survival time. The treatment aims to improve the quality of life and symptoms.

Alveoli are microscopic, balloon-like structures in the lungs that play an essential role in the respiratory system.

Over time, the alveoli may be able to repair any damage. But various health conditions can cause sustained damage, such as COPD, ARDS, asthma, and IPF. Each requires a different treatment.