A 47-year-old male non-smoker presents with progressive shortness of breath on exertion and multi-joint arthralgia. He has no known cancer history or occupational hazards, no prior surgeries and no significant pet, farming or travel history. He doesn’t use street drugs. A chest x-ray was performed (Fig 1. above shows the PA film). A subsequent CT scan of the chest further revealed micronodular diffuse interstitial lung disease with marked upper zone fibrosis along with mediastinal and bilateral hilar adenopathy.
What’s the most likely cause of his upper zone lung fibrosis?
a) ankylosing spondylitis
b) pulmonary silicosis
d) eosinophilic granuloma
The chest x-ray on the patient presented revealed marked bilateral symmetric upper lung zone interstitial fibrosis, with secondary volume loss, lower zone hyperinflation and superior retraction of the bilateral hilar regions. With just the recognition of the bilateral upper zone fibrosis pattern on the PA film, a differential diagnosis list should be formed in your head right away to allow you to sort out the correct diagnosis, or at least narrow it down to good possibilities.
The specialty of radiology is known for it’s myriad of various pneumonics to help us remember lists of potential disease conditions in certain scenarios. For the case of bilateral upper lung zone fibrosis, there are a few pneumonics you could use, but I shall provide you with this one: TESTS NEAR.
T – Tuberculosis
E – Eosinophilic granuloma
S – Sarcoidosis
T – Talcosis
S – Silicosis
N – Neurofibromatosis
E – Extrinsic Allergic Alveolitis
A – Ankylosing Spondylitis
R – Radiation
Of that list, a few can be considered significantly less likely in our patient due to the pertinent negatives provided in the patient’s history or from the x-ray appearance. Tuberculosis is usually associated with parenchymal calcifications, not present here and the patient has no awareness of prior infection and no significant travel history to indigenous regions. Eosinophilic granuloma (EG) is a form of Langerhans cell histiocytosis that can involve lung and bone in children and young adults. Isolated lung disease is the most common finding in adults, typically resulting in upper zone fibrocystic change with preservation of lung volumes (unlike most other causes of fibrosis, which led to volume loss). Pulmonary EG is most common in the 3rd and 4th decades, so this patient is a little old and with associated lung volume loss on the x-ray, this would not be the primary consideration. Also, the bone involvement of EG is typically discrete lucent lesions, not multi-joint arthropathy, as this patient had. From our pneumonic list provided above (TESTS NEAR), the disease conditions neurofibromatosis, extrinsic allergic alveolitis and post-radiation changes can be ruled out, typically by history alone.
Sarcoidosis is a systemic inflammatory disease of unkown etiology that can affect any organ, wherein non-necrotizing granulomas form as nodules in multiple organs. 90% of patients with sarcoidosis have an abnormal chest x-ray at some point in their disease course. 50% of patients develop permanent lung changes with 5-15% leading to progressive pulmonary fibrosis. Skin and multiple joint involvement is common as well. In fact, the combination of erythema nodosum (red, inflammatory skin changes often present on both shins), bilateral hilar adenopathy and arthralgia is known as Löfgren syndrome. The disease often responds well to steroids or can improve spontaneously. More than 60% of patients with pulmonary sarcoidosis have no symptoms after 9 years. In our patient, the combination of marked upper zone fibrosis and multijoint arthralgia makes sarcoidosis a good diagnostic possibility and is what this man had.
Talcosis is a pulmonary fibrotic condition resulting from excess inhalation of talc and has also been attributed to heroin users, where the talc is cut into the heroin to increase weight and street value, a fact often unknown to the user. Silicosis is an occupational lung disease (pneumoconiosis) caused by inhalation of silica dust, seen in miners and stonecutters. It results in upper zone pulmonary reticulonodular changes and fibrosis. Lung changes from ankylosing spondylitis (AS) could have been considered, although information is provided that the T-spine was normal (thus no ossification of the anterior spinal longitudinal ligament as seen in AS). The bony changes are not always present in the T-spine but the lack does make the choice less likely than sarcoidosis.
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