Clinical Pearls & Morning Reports

Posted by Carla Rothaus

Published May 18, 2022


What conditions are associated with tree-in-bud nodularity on chest CT?

Risk factors for aspiration include a depressed level of consciousness, an abnormal swallowing mechanism, increased gastroesophageal reflux, and an impaired cough reflex. Read the NEJM Case Records of the Massachusetts General Hospital here.

Clinical Pearls

Q: Would polyarteritis nodosa be included in the differential diagnosis for a patient with cough and multiple pulmonary opacities on imaging?

A: Polyarteritis nodosa is a medium-vessel vasculitis that can affect the kidneys, skin, nerves, muscles, and gastrointestinal tract but notably does not cause disease in the lungs.

Q: What are the typical radiographic findings of nocardia infection involving the lungs?

A: Nocardia is a slow-growing modified acid-fast bacterium with tropism for the lungs and brain. Risk factors include immunosuppression, human immunodeficiency virus infection, cancer, and diabetes. Radiographic imaging studies typically show single or multiple pulmonary nodules in the upper lobes that may cavitate.

Morning Report Questions

Q: Describe a characteristic appearance of lung nodules due to aspergillus on computed tomography (CT) of the chest.

A: Although ubiquitous in nature, aspergillus species tend to cause invasive disease in the presence of severe immunosuppression. The lung is the most common site of infection, and chest imaging often shows multiple cavitary nodules. Aspergillus is angioinvasive, and nodules are often surrounded by a “halo” of ground glass, a finding that indicates hemorrhage into surrounding tissue.

Q: What conditions are associated with tree-in-bud nodularity on chest CT?

A: Although mycoplasma pneumonia is typically characterized by patchy reticulonodular and ground-glass opacities, it can also be manifested by centrilobular nodules and tree-in-bud nodularity. Candida pneumonia is rarely diagnosed; because the majority of candida growth in bronchoalveolar-lavage fluid is correctly attributed to colonization, it is difficult to identify cases of pathogenic growth of candida in the lung without histologic confirmation. Lung biopsy could identify invasive disease, but it is rarely performed in such cases. Imaging typically shows bilateral nodules and consolidation, but centrilobular nodules and tree-in-bud nodularity have been reported. Follicular bronchiolitis is a lymphoid proliferation of bronchus-associated lymphoid tissue that is also usually associated with Sjögren’s syndrome or HIV-1 infection; centrilobular nodules and tree-in-bud nodularity are consistent with follicular bronchiolitis. Aspiration can be clinically silent and can occur even in the absence of overt reflux symptoms. Centrilobular nodules and a tree-in-bud pattern of opacities are consistent with aspiration.

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