Chest xray and Chest CT: discrepancy?

Today at #MorningReport we had a case of a common diagnosis with an uncommon presentation.

A patient with recent cancer, s/p kidney transplant on immunosuppression but now with CKDIII came into the hospital for worsening shortness of breath and a dry cough. PA+lateral chest xray showed patchy RLL consolidation with very small bilateral effusions. He was started on antibiotics for community-acquired pneumonia and no JVD, rales and trace bilateral edema.

See the initial PA/lateral CXR:

Over the next 6 hours after lying in his bed, he came significantly more tachynpenic with an ABG of pH 7.42 and pCO2 24 and pO2 56. What do you think?

Repeat portable CXR at that time. Yikes!

Looks like worsening interstitial pattern! Differentials included: 

  • Bacterial: CAP, atypical, legionella, nocardia, actino, aspiration, MRSA
  • Fungal: PCP (“fluffed out”), crypto, histo, NTMB
  • Non-infectious: metastic cancer, pneumotoxicity – COP/BOOP/eos pneumonia 2/2 Tacro or Statin or pneumonitis, PF and DAD 2/2 chemo, DAD, DAH or sarcoid
  • Hypervolemia from CKD
  • Pulmonary embolism
  • ACS, heart failure

CT scan confirmed the diagnosis!

Cause of his SOB and acute worsening? Volume!

Patient recieved some diuretics and tachypnea improved dramatically.

Dr. Meredith Greer sent these notes over from our very own, Dr. Abbara, in the Radiology Department: look at the CT chest because there you can see the bilateral pleural effusions looking much bigger as the patient is laying supine and they are sort of layered out. When the pt is getting the PA/L CXR a lot of the effusion can hide in the gutters. It is possible that while the pt was laying down he developed atelectasis on top of his effusions and when he stood upright for the plain film that his effusions went down but the atelectasis didn’t have time to open back up yet.