Cavitary Lung Lesions....

Today we talked about a person who presented with dyspnea and pleuritic chest pain. The diagnosis was greatly narrowed when he was found to have a cavity lung lesion on chest x-ray. Below is a quick summary of the differential discussed for cavitary lung lesions….

C - Cancer – primary lung cancer (especially squamous cell) and metastatic cancer (colon, renal, breast, melanoma etc)

A – Autoimmune - Wegners, Rheumatoid Nodule (rare), Sarcoid

V – Vascular – Pulmonary Embolism with Infarction

I – Infection
Septic Emboli
TB
MAI
Bacterial – staph aureus, strep, anaerobes, nocardia, actinomyces, klebsiella, pseudomonas
Fungal – Aspergillus, Histoplasmosis, Coccidiomycosis, Blastomycosis, Cryptococcus, PJP
Parasite – Echinococcus

T – Trauma – bullous lung disease

Y – Youth –congenital cystic disease, congenital adenomatoid malformation etc

We ultimately settled on the diagnosis of community acquired MRSA. This form of MRSA tends to be more antibiotic sensitive than the hospital acquired relative. The emerging presence of this organism is not to be ignored – For the Canadian experience with MRSA please see the following CMAJ article http://www.cmaj.ca/cgi/reprint/176/1/54