Monday, July 03, 2006

RA-associated lung disease

A 68 y/o woman with a long-standing history of Rheumatoid Arthritis and Sjogren's Syndrome (well controlled on Prednisone 7.5mg QOD, never used a steroid-sparing agent), was referred with mild but progressive dyspnea on exertion for several months.

Full pulmonary function studies show an FEV1 of 2.38, which is 102% of predicted. The FVC was 3.22 or 100% of predicted. The FEV1/FVC ratio is 74%. Total lung capacity is 101% of predicted and residual volume is 104% of predicted. The DLCO is decreased at 51%. This is unchanged from PFT's 18 months ago, with the exception of the decrease DLCO from 57%.

An HRCT (not available to upload), showed:
"Bilateral basilar predominant groundglass opacity with smooth septal
thickening. There are areas of lobular spareing.
A few well-defined scattered thin-walled cysts are present
No intrathoracic lymph node enlargement."

A subsequent bronchoscopy with BAL showed no evidence of infection. The differential had 42% lymphocytes, and 54% histiocytes. Transbronchial biopsies were read as: "Chronic and granulomatous inflammation. Amorphous acellular material. Congo red stain negative for amyloid. GMS stain for fungal organisms negative."

Question: How should one approach this case? Would you take the CT scan, the lack of infection on BAL, and the lymphocytosis on BAL and treat with a presumptive diagnosis of RA-associated NSIP by increasing the steroid dose? Or would you proceed with a surgical lung biopsy. Any other thoughts?

6 comments - CLICK HERE to read & add your own!:

Mendez said...

I would start by ruling out other obvious, possible contributors to a low DLCO (pulmonary vascular disease, anemia) and dyspnea in elderly patient (deconditioning, myopathy). In the absence of these alterantive explanations to progressive dyspnea, I would question how the lung Bx would change my management. In the absence of infection (which was pretty effectively ruled out with bronch- was PC checked?), I think that a course of increased immunosupression with close follow-up for response would be a reasonable approach.

Baleeiro said...

Also, did you do flow (CD4:CD8) on the BAL since there were so many Lymphs?

Jeff H said...

PC is negative. She hasn't had an echo or a PE protocol CT scan, but there is no evidence to suggest heart failure or PE; the only finding on the CT scan is the multifocal/lower lobe predominant ground glass.

Unfortunately, the flow on the BAL was not done as requested.

Jennings said...

I really do not feel that a more extensive workup is necessary with regards to the diagnosis - I am comfortable that this is RA associated ILD, now that the bronch was negative for infection and showed a lymphocytosis. The relative lack of PMNs in the BAL further points to more of a chronic inflammation. Acute alveolitis in RA has mostly macrophages and PMNs, so this patient's BAL seems consitent with acute on chronic. The fact that the patient has worsening dyspnea and an already decreased DLCO is enough to justify treatment in my opinion.
I would want to know the RF titer, as this does indeed correlate with ILD manifestations.
(Perhaps the one caveat is that if he was on methotrexate, could this be mtx-induced ILD, in which case an open lung might be useful)
In any event, I would treat; whether that choice is steroids or something like etanercept would be up to you and the rheumatologist....

Jennings said...

How would flow cytometry help to rule in or out RA-ILD? Would identification of CD4 or CD8 cells change your thinking?

Baleeiro said...

It was more a clinical exercise since the Pt is not on MTx or other DMARDs. But, in general, there will be more CD4 cells in RA BAL (Arthritis Rheum. 2005 Jan;52(1):73-9) vs more CD8s idiopathic IIPs or some lung toxicities associated with anti-rheumatoid drugs.