Correct!
5. All of the above
All should be ordered in a patient with multiple cystic lung disease (1-3). As with all diseases, the first step in establishing the correct diagnosis multiple cystic lung disease is a detailed history and physical examination. The development of acute, rapidly progressive cystic change is suggestive of an infectious, inflammatory, or traumatic origin, whereas chronic processes are more likely secondary to congenital, vascular, connective tissue or possibly neoplastic disorders. A history of tobacco exposure or the presence of sicca symptoms can provide insights into smoking and connective tissue disease etiologies, respectively. A detailed family history, especially history of pneumothoraces, skin lesions, and renal tumors in children, siblings, parents, and more distant blood relatives, is useful information for establishing the diagnosis of lymphangioleiomyomatosis (LAM) and folliculin gene-associated syndrome (Birt-Hogg-Dubé, BHD). As part of the detailed pulmonary examination, particular attention must be given to signs of a connective tissue disease or skin findings suggestive of BHD or tuberous sclerosis complex, which may be associated with LAM.
Critical review of a high resolution CT scan by an expert radiologist is essential for accurate diagnosis. The cyst characteristics and associated radiographic findings can suggest the underlying disease. Radiological information can be further supplemented by serum biomarkers such as vascular endothelial growth factor-D, SS-A, SS-B, and α1-antitrypsin. Genetic studies on peripheral blood can be helpful in BHD. Lung biopsy with histopathologic evaluation in conjunction with special studies may be required to establish a definitive diagnosis, given the extensive overlap of clinical and radiographic features in some cases. Raoof et al. (4) have proposed a diagnostic algorithm for the diffuse or multiple cystic lung diseases as shown in Figure 3.
Figure 3. Detailed algorithmic approach to cystic lung disease as proposed by Raoof et al. (4).
The high resolution thoracic CT scan was repeated in December 2020 (Figure 4).
Figure 4. Repeat high resolution thoracic CT scan done in lung windows done in December 2020.
Review of the newer CT suggests slight enlargement in size of one of the cysts (the one in LUL), otherwise, no change compared to January 2019.
The rheumatology panel was unremarkable (Table 1).
Table 1. Rheumatology panel done in December 2020.
- Sedimentation Rate: 25
- C-Reactive Protein (CRP): 3.4
- Antinuclear Ab,: 0.3
- SS-A/Ro Ab, IgG,: <0.2
- SS-B/La Ab, IgG,: <0.2
- Rheumatoid Factor,: <15
The pulmonary function testing (PFTs) are shown in Figure 5.
Figure 5. Pulmonary function testing done in December 2020.
The PFTs were interpreted as showing moderately severe restrictive lung disease and a subsequent fluoroscopic sniff study demonstrated paralysis of the right hemidiaphragm as a contributing cause.
No specific diagnosis had been established and the patient was upset at the lack of progress towards an answer.
What should be done next in her evaluation? (Click on the correct answer to be directed to the fourth of six pages)