Postobstructive Pneumonia

The case today involved a 68-year-old man with a history of COPD, untreated lung cancer (metastatic), and schizophrenia who lives in an assisted-living facility.  He was brought to to hospital for a two-day history of fever and dyspnea.  His imaging revealed a densely consolidated right lung with a loculated pleural effusion, as well as findings of obstructive lung disease in the other lung.  Additionally, he had obliteration of his entire right main bronchus by tumour.  His blood culture was positive for S. pneumoniae.  He was treated with oxygen and antibiotics, with a palliative treatment intent.

Learning points:

-It is helpful to begin generating a differential diagnosis immediately upon hearing the “chief complaint.”  This will help frame the questions that you are going to ask, and even frame the way that you obtain the past medical history.  As an example, if this patient had come in with an allergic reaction, his COPD severity is less important in the clinician’s mind than it is when he presents with dyspnea and fever.

-When evaluating patients, always obtain their medical history and the medications that they take.  There is a large prescribing bias towards keeping people on what they were on, even though many clinicians would advocate for stopping medications that we cannot identify a good cause for – examples frequently include proton-pump inhibitors, iron supplementation, cholesterol medications in the frail elderly, dual antiplatelet therapy, etc.  If their medical history does not match up to their medications, our job is to make a reasonable attempt at correcting that.

-Patients with lung cancer who present with dyspnea are usually going to have one of four things: consolidated lung (pneumonia), bronchial obstruction, pleural effusion, and pneumothorax.

-Fever can be present in these patients for a variety of reasons including as a result of the tumour itself.  That said, in the case of a fever with a consolidated lung as a result of obstruction, treatment with antibiotics may be warranted after obtaining cultures.

-Treatment of lung cancer is rarely with a curative intent.  We talked about the types of lung cancer (small cell and non-small cell) and that small-cell generally portends a worse diagnosis.  Treatment options for these patients can include simple interventions like palliative oxygen.  Systemic treatments like chemotherapy and steroids (in the right setting) may alleviate or shrink tumours and re-open airways.  Radiation is another option that may have relatively minor risks.  Finally, thoracic surgery can occasionally “stent” open airways as a result of tumours, but they are relatively selective to whom they offer this.

Resources for further reading:

Hsu-Kim, C., Hoag, J. B., Cheng, G. S., & Lund, M. E. (2013). The Microbiology of Postobstructive Pneumonia in Lung Cancer Patients. Journal of bronchology & interventional pulmonology, 20(3), 266-270.