What is Lipoid Pneumonia (cholesterol pneumonia)?

Lipoid pneumonia is a rare lung disease, first identified back in 1925, which is caused by the collection of fat-containing substances in the tiny airways and air sacs in the lungs. These substances can trigger inflammation and make it difficult for oxygen to pass from your lungs into your blood.

This disease can be split into two groups: exogenous and endogenous, which tells us where the fat comes from. Both types can look a lot like other diseases, although patients will often share specific details about their history or there may be unique features in their chest X-rays and tissue samples that help doctors identify this particular kind of pneumonia.

In recent years we’ve started to see more cases due to people using electronic cigarettes or inhaling oils containing a substance known as tetrahydrocannabinol (THC). Unfortunately, lipoid pneumonia is not very well understood by doctors, and many cases are likely going unnoticed, leading to a lack of research on this disease.

What Causes Lipoid Pneumonia (cholesterol pneumonia)?

Exogenous lipoid pneumonia happens when a person breathes in, or inhales, products containing fats or oils. In the past, it was most common from substances like mineral oil laxatives and nasal decongestants. Other causes can be from breathing in petroleum jelly used as a lubricant, like when taking care of a tracheostomy, which is a surgical hole in the neck to help with breathing.

Although it’s considered rare, the number of people with exogenous lipoid pneumonia has risen significantly in all age groups due to the trend of “vaping.” Vaping involves using electronic cigarettes that heat up a liquid to create inhaled vapors. These liquids are made up of oils and different chemicals, which can include nicotine, flavorings, or cannabis. A study in North Carolina by Davidson and colleagues pointed out five cases in July and August 2019 of healthy people without other health conditions who were exposed to these vapors. They all ended up with seriously low oxygen levels that needed hospital care.

On the other hand, endogenous lipoid pneumonia, also known as “cholesterol pneumonia,” is different. This type was first found by Mcdonald and his team in 1949 who named it “obstructive pneumonitis” when found with a lung tumor. It can be divided into smaller groups based on its causes like infection, cancer, or unknown reasons. This condition happens when there’s any event that causes the body to release fats and cholesterol like when tissues are damaged.

Endogenous lipoid pneumonia is also often seen in inherited conditions such as disorders related to fat storage and fat metabolism. It can also be triggered by various immune and rheumatic disorders that cause long-term inflammation.

Risk Factors and Frequency for Lipoid Pneumonia (cholesterol pneumonia)

Lipoid pneumonia, often undiagnosed, has an uncertain incidence rate, but past records from autopsies show it could be between 1% to 2.5%. While it can affect people of all ages, it was usually found among children and the elderly who used mineral oil for constipation. People with neurological disorders that affect swallowing are considered high-risk, as this can lead to higher chances of aspiration. Such conditions can include cleft palate, gastroesophageal reflux disease (GERD), and achalasia. Recently, more healthy individuals are being diagnosed with lipoid pneumonia due to ‘vaping’ and, less commonly, work-related exposures. The occurrence of endogenous lipoid pneumonia is harder to pinpoint, as it largely depends on the incidence of the underlying disease.

Signs and Symptoms of Lipoid Pneumonia (cholesterol pneumonia)

Lipoid pneumonia is a condition that often gets diagnosed after ruling out other potential diseases. Because it doesn’t have any symptoms unique to it, understanding a patient’s medical history is crucial for identifying this disease. The condition can develop suddenly, but in some cases, it may grow gradually or persist for a long time. So, if someone comes in with general symptoms like a cough, shortness of breath, lower than normal levels of oxygen in their blood, and less commonly coughing up blood and fever, lipoid pneumonia could be the cause. They might also show signs of infection on both sides of their chest when getting scanned and have a crackling sound in their lungs during examination.

Testing for Lipoid Pneumonia (cholesterol pneumonia)

Diagnosing lipoid pneumonia, a type of lung inflammation caused by the presence of fat, requires a high degree of suspicion, especially in people with severe lung disease who don’t have other underlying conditions. Various imaging techniques are crucial in confirming the diagnosis. These may include a chest x-ray and a specific type of scan known as a computed tomography (CT) scan of the chest.

In a study conducted back in 1996, it was highlighted that CT scans played a significant role in diagnosing lipoid pneumonia. The study included 44 people with lipoid pneumonia. Every one of these individuals had abnormal images that showed different patterns: 57% had what’s known as alveolar consolidation, which is a condition where the small air sacs in the lungs fill with fluid; 39% had ground-glass opacities, which are hazy regions on the lungs that show up on a CT scan; and 23% showed alveolar nodules, which are small, round areas of inflammation or infection in the lungs.

Another comprehensive study included 53 people (35 children and 18 adults) who had definite lipoid pneumonia due to swallowing mineral oil. In this study, most of the individuals (96%), showed changes on both sides of their lungs on their CT scans. Other common findings included airspace consolidations (86%), ground-glass attenuation (47%), airspace nodules (22%), and what is known as a “crazy-paving pattern” (20%). The “crazy-paving pattern” is a combination of a particular cloudy appearance of the lungs on the scan accompanied by a thickening of the walls between tiny air sacs in the lungs.

Doctors may also examine arterial blood gas, a test that measures the levels of certain gases in blood, to check the balance of acid and base, and oxygen levels in your blood.

A procedure called bronchoscopy may be used. During this procedure, a thin tube (bronchoscope) is inserted through the nose or mouth into the lungs allowing doctors to take samples for testing.

Finally, blood and sputum (a mixture of saliva and mucus coughed up from the respiratory tract) cultures can help to exclude the possibility of an underlying infection.

Treatment Options for Lipoid Pneumonia (cholesterol pneumonia)

Presently, there is no specific treatment method for lipoid pneumonia, a rare lung condition where fat particles enter the lungs and cause inflammation. Regardless of how it developed, the first step in managing lipoid pneumonia is cutting off the source of the problem to prevent more harm to the lungs.

In many cases, corticosteroids (medications that reduce inflammation) have been shown to improve the condition, but we still need more studies to understand the best dosage and treatment duration. Other supportive treatments may be recommended based on the root cause of your pneumonia. These can include immunoglobulins, which are proteins that help your body fight infections, and a procedure called whole-lung lavage that washes out the inside of your lungs.

Ultimately, the treatment choice will depend on the specifics of your case, such as how severe your symptoms are, where the fat particles came from, and what your overall health is like. You and your doctor will discuss these factors and decide on the best course of treatment for you.

When a doctor is determining whether a patient has lipoid pneumonia, it’s important to rule out several other conditions that might cause similar symptoms. These might include:

Acute respiratory distress syndrome
Bacterial pneumonia
Viral pneumonia
Fungal pneumonia
Aspiration pneumonia
Lung neoplasm (lung tumors)
Pulmonary fibrosis (scarring of the lungs)
Pulmonary alveolar proteinosis (a lung condition where a protein builds up in the air sacs)

What to expect with Lipoid Pneumonia (cholesterol pneumonia)

The outcome of lipoid pneumonia, a lung disease caused by inhaling or aspirating fats, largely depends on several factors. This includes the root cause of the disease, how quickly it was diagnosed, the age of the patient, and any other existing health conditions they might have.

Possible Complications When Diagnosed with Lipoid Pneumonia (cholesterol pneumonia)

Common Conditions:

Breathing failure
Severe breathing distress syndrome
Widespread bleeding in the air sacs of the lungs
Heart condition related to lung problems
Additional infections occurring on top of existing ones

Preventing Lipoid Pneumonia (cholesterol pneumonia)

It’s crucial for both the general public and health professionals to be educated about early diagnosis and prevention of diseases. Right now, there’s an increase in the number of kids and young adults in the U.S. who are using substances that can lead to a lung infection referred to as exogenous pneumonia. For this reason, it would be beneficial to focus educational efforts on children and their parents.