Patchy Ground Glass Opacities in the Lungs

Patchy ground glass opacities in the lungs are seen in multiple conditions.  Ground glass opacity is when the normally dark lung becomes whiter in appearance.  Patchy implies that those areas are scattered throughout the lungs.  Ground glass refers to glass which has been treated and has a white or frosty appearance.

What causes patchy ground glass opacities in the lungs?

Patchy ground glass opacities are best seen on CT but are sometimes visualized on X-ray.  Ground glass occurs in the lung for many reasons like infections, fluid build up, segments of collapsed lung, scarring and even cancer.

Ground Glass Opacities In Lungs can be in one spot, throughout the lungs or patchy.  The appearance helps us to narrow the possibilities.  The clinical history, symptoms, lab testing, and any prior imaging tests also helps to reach the diagnosis.

Edema

In general, ground glass opacities which are patchy are commonly from fluid in the lungs or edema.  This is most common from heart problems like failure.  There are many less common causes of non heart related edema.

Infections

Infections of the lungs can result in patchy ground glass opacities in the lungs.  COVID pneumonia often results in patchy ground glass opacities.  Often there is subpleural ground glass opacities which means they are along the periphery of the lungs.    Other viral infections can also result in ground glass.

Immunocompromised patients

Patients who have impaired immune systems like those with AIDS or bone marrow transplants can develop opportunistic infections which can lead to patchy ground glass opacities in the lungs.

Adult respiratory distress syndrome

Patients with adult respiratory distress syndrome can develop patchy ground glass opacities as one of the features.  This is associated with lung injury either from a direct cause like pneumonia, smoke inhalation or drowning or a cause that is not in the lungs like pancreatitis, trauma and burns.  Patients often have respiratory failure and high rate of death.

Hypersensitivity pneumonitis

Patchy ground glass opacities can also be seen in lung disease related to an external agent like animal or plant proteins, microbes, chemicals and metals.

Idiopathic interstitial pneumonias

Patchy ground glass opacities can be a finding in the diffuse interstitial pneumonias.  These are inflammatory lung diseases of unknown cause.  They can lead to scarring of the lungs and respiratory failure.

Cancer

Cancer is more commonly one area rather than patchy ground glass opacities in the lungs.  Spread of cancer or metastasis are usually solid or white spots.

How do you reach a diagnosis?

The diagnosis of patchy ground glass opacities in the lungs needs to combine all the clinical and lab testing information.  Old imaging tests are also helpful.  This is especially important because so many conditions can have the appearance of patchy ground glass opacities. In some cases, invasive testing and biopsy may be needed.